Method and system for improving boiler effectivness

专利摘要:
A method for improving effectiveness of a steam generator system includes providing a steam generator system including a steam generator vessel, an air supply system and an air preheater. The air supply system is in communication with the steam generator vessel through the air preheater and the steam generator vessel is in communication with the air preheater. The air supply system provides a first amount of air to the air preheater. At least a portion of the first amount of air is provided to the steam generator vessel. A flue gas mixture is discharged from the steam generator vessel. At least a portion of the flue gas mixture flows into the air preheater. SO3 in the flue gas mixture is mitigated before the flue gas mixture enters the air preheater.
公开号:ES2745035A2
申请号:ES201990006
申请日:2017-07-10
公开日:2020-02-27
发明作者:Kevin O'boyle；Glenn D Mattison；David G Breckinridge；Set Erik Jonas Klingspor
申请人:Arvos Ljungstroem LLC；
IPC主号:

专利说明:

[0001]
[0002] Method and system to improve the effectiveness of a boiler
[0003]
[0004] Field of the Invention
[0005]
[0006] The present invention generally relates to a method and a system for improving the effectiveness of a fossil fuel powered steam generator and the effectiveness of particle removal, and is more specifically directed to a method and system for improving the effectiveness of a preheater. of air reducing the formation of embedded deposits and improving the thermal efficiency of the fossil fuel powered steam generator and the efficiency of an electrostatic precipitator using SO ³ mitigation upstream of the air preheater and further improving the heat regime of the station thermal power comprising the steam generator and facilitating the reheating of the flue gas chimney and / or otherwise.
[0007]
[0008] Background of the invention
[0009]
[0010] Thermal power stations typically include a steam generating system that runs on fossil fuel in which the fuel (for example, coal, natural gas and / or oil) is burned to generate steam to drive turbogenerators that supply electricity to the power grid . The total efficiency of the thermal power station is a measure of the usable electrical power supplied to the network compared to the energy input to create that output. The energy input includes not only the one released by the combustion of the primary fuel in the steam generator vessel, but also the secondary energy sources, such as those required to operate the auxiliary equipment, including fans, pumps and motors, equipment pollution control, inherent thermal conduction losses, and often those required to effect the reheating of the chimney that ensures proper dispersion of draft gas into the atmosphere.
[0011]
[0012] There are many types of steam generating systems that are used for steam generation for use in electricity generation and chemical processing plants. Some of the steam generation systems burn fossil fuel such as coal, natural gas, oil in a steam generator vessel.
[0013] An air supply to the steam generator vessel is required to provide oxygen for fuel combustion. The combustion of the fuel gives rise to products derived in a draft gas stream discharged from the steam generator vessel. To improve the thermal efficiency of the steam generator system, the air supply to the steam generator vessel is heated by recovering heat from the draft gas stream in an Air Preheater (APH), such as a rotating APH.
[0014]
[0015] APH efficiency can be increased using higher efficiency heat transfer elements and heat transfer elements with a larger heat transfer area. However, those skilled in the relevant art have not been able to achieve the full potential of increased APH efficiency, available through the use of higher efficiency heat transfer elements and a larger heat transfer area of the heat transfer elements, due to the operating limitations related to the control of pollutants, as described herein.
[0016]
[0017] Products derived in the outlet gas stream may include particulate matter and contaminants. For example, the combustion of coal gives rise to combustion products such as particulate matter in the form of fly ash and pollutants such as nitrogen oxides (NO ^x ), sulfur dioxide SO ² and sulfur trioxide SO ³ (a often referred to collectively as SO ^x ). SO ² is formed as a result of the combustion of sulfur containing fuels such as coal with high sulfur content. SO ³ is formed by the oxidation of SO ² for example when the oxygen content in the outlet gas is too high or when the temperature of the outlet gas is too high (for example, greater than 800 ° C). SO ³ can form a liquid aerosol known as sulfuric acid mist that is very difficult to remove.
[0018]
[0019] Environmental laws and regulations limit the amount of discharge of particulate matter and pollutants into the environment. Thus, different treatment systems have been used to control the discharge of particulate matter and contaminants. For example, Selective Catalytic Reduction (SCR) is a treatment medium to convert nitrogen oxides, also referred to as NOx, with the help of a catalyst in diatomic nitrogen (N ² ) and water (H ² O). Particle control systems such as bag filters, Electrostatic Precipitators (ESPs) and dry ESPs can be used to remove particulate matter from the stream of draft gas. Dry ESPs are more efficient and easier to maintain than wet ESPs, but dry ESPs require a drier draft gas stream than wet ESPs. The creation of a dry draft gas stream can be difficult because the temperature of the draft gas drops below the dew point of SO ³ at a cold end of the APH, condensation can occur, which causes the SO ³ form H ² SO ⁴ and a relatively wet draft gas. In addition, if the flue gas contains mist of H ² SO ⁴ , then the less efficient wet ESP is typically used to remove H ² SO ⁴ . In addition, ESPs tend to experience dust fouling (for example, an unwanted accumulation of fly ash on ESP collector plates and removal depressions) when the temperature of the draft gas is high (for example, 130 ° C or higher).
[0020]
[0021] Another system used for the control of particulate matter and pollutants is the flue gas desulfurization system (FGD). FGD systems are primarily aimed at eliminating any SO ² , for example through the use of SO ² absorbers. Wet SO ² absorbers typically spray water mixed with an absorbent in a stream of draft gas flowing through the SO ² absorber to absorb 50 ² of the outlet gas. The flue gas leaving the SO ² absorber is saturated with water that contains some SO ² . An operational limitation of the FGD system is that the flue gas exiting the SO ² absorber can be highly corrosive to any downstream equipment such as duct fans and chimneys. Another operational limitation of FGD systems is that SO ² absorbers require a substantial water supply and absorbent regeneration equipment.
[0022]
[0023] An operational limitation related to APHs is that the use of heat transfer elements with increased efficiency and heat transfer area can cause the draft gas temperature to decrease below the dew point of SO ³ at whose temperature, it can be produce condensation of a cold end of APH. 50 ³ reacts with water to form sulfuric acid H ² SO ⁴ that condenses on the heat transfer elements of APH. Particulate matter can adhere to H ² SO ⁴ causing the accumulation of deposits in the APH. Based on this operational limitation, those skilled in the relevant art have dismissed reducing the temperature of the component and / or the temperature of the draft gas leaving the APH below the dew point of SO ³ and also using APHs with elements of increased heat transfer and heat transfer area efficiency. The inability to fully achieve the full potential of increasing efficiency APH therefore limits the ability to increase the thermal efficiency of the steam generator system so that it is increased to its full potential.
[0024]
[0025] A detailed description of the prior art steam generating systems is included in the PCT / US2017 / 13459 Commonly Owned PCT Patent Application, whose subject matter is incorporated herein in its entirety.
[0026]
[0027] Based on the above, there is a need for a steam generator system with improved thermal efficiency and improved treatment systems for particulate matter and improved contaminants.
[0028]
[0029] Compendium
[0030]
[0031] Method for improving the effectiveness of a steam generating system is described herein. The method includes providing a steam generating system that has a steam generating vessel, an air supply system and an air preheater. The air supply system is in communication with the steam generator vessel through the air preheater, and the steam generator vessel is in communication with the air preheater. The air supply system provides a first amount of air to the air preheater and some or all of the first amount of air is provided to the steam generator vessel as combustion air. The method includes discharging a mixture of draft gas from the steam generating vessel and flowing at least a portion of the draft gas mixture into the air preheater. The method includes mitigating SO ³ in the flue gas mixture before the flue gas mixture enters the air preheater.
[0032]
[0033] In one embodiment, the capture means ((for example, heat exchangers, heat transfer elements in the air preheater that have a heat transfer capacity greater than that required to preheat the combustion air and / or cool the flue gas up to a temperature at or near the water dew point (H ² O), duct arrangements, mixers, pipes, tanks and the like) are in communication with the steam generator, the air preheater, the first quantity of air and / or the draft gas mixture In one embodiment, the method includes transferring a first amount of heat out of the steam generator, the air preheater, the first amount of air and / or the shot gas mixture .
[0034] In one embodiment, the method includes providing a particle removal system and a flue gas desulfurization system. The particle removal system is located downstream of the air preheater, and the flue gas desulfurization system is located downstream of the particle removal system. In one embodiment, the method includes discharging a whole part of the draft gas mixture that exits the steam generator vessel directly from the air preheater to the particle removal system thereby removing the particles from the draft gas mixture and creating a first mixture of treated draft gas. In one embodiment, the method includes discharging the first mixture of treated shot gas from the particle removal system in the shot gas desulfurization system thereby creating and discharging a second mixture of the shot gas desulfurization system from the shot. treated draft gas.
[0035]
[0036] In one embodiment, the first amount of heat is of a magnitude of about 10 to 25 percent of that used to preheat combustion air. In one embodiment, the first amount of air is of a magnitude greater than that required as combustion air.
[0037]
[0038] In one embodiment, the flue gas discharge chimney is arranged in the steam generating system. The steam generator system is in communication with the discharge chimney through the air preheater, the particle removal system and / or the flue gas desulfurization system. In one embodiment, the method includes using at least a portion of the first amount of heat to increase the temperature of the draft gas mixture, upstream of a chimney outlet, by a sufficient magnitude to mitigate the column of smoke that leaves the discharge chimney or to mitigate corrosion in the discharge chimney.
[0039]
[0040] In one embodiment, the method includes one or more of the following: (1) use at least part of the first amount of heat during boiler start-up to selectively preheat at least one of the particle removal system, desulfurization system shot gas, and intermediate ducts; (2) use at least a part of the first amount of heat during the operation of the boiler for a coal drying installation, and then be expelled into the atmosphere; (3) release at least a portion of the first amount of heat into the atmosphere; (4) use at least a portion of the first amount of heat to improve the heat regime of the steam generating system; (5) use at least a portion of the first amount to evaporate the water from an ash sludge discharged from a communication ash removal system with at least one of the particle removal system and the steam generator vessel; and (6) use at least a portion of the first amount of heat in a wastewater system to reduce water discharge from it.
[0041]
[0042] In one embodiment, the improvement of the heat regime includes one or more of the following: (1) use at least a portion of the first amount of heat to improve the efficiency of the steam cycle; (2) use at least a portion of the first amount of heat to preheat the water supplied by the condensate supplied to the steam generating system; and (3) use at least a portion of the first amount of heat to reduce parasitic loads (for example, the space and heating of drinking water and steam for turbines to drive rotating equipment such as fans, instead of motors electric drive, and other steam or heat loads other than steam used for electricity generation) in the steam generator system.
[0043]
[0044] In one embodiment, the method includes supplying at least one of a portion of the draft gas mixture and a portion of the first amount of air to the wastewater system to evaporate the wastewater therein, creating a waste of particles in the wastewater system, and transporting the particle waste to the particle removal system.
[0045]
[0046] In one embodiment, the mitigation of SO ³ in the shot gas mixture includes chemical transformation and / or the supply of low sulfur fuel to the steam generating system.
[0047]
[0048] In one embodiment, an air preheater is configured to heat the first amount of air between approximately 288 ° C and 399 ° C (550 ° F to 750 ° C).
[0049]
[0050] In one embodiment, the air supply system provides the first amount of air to the air preheater at a mass flow sufficient to establish a first temperature of a draft gas mixture exiting the air preheater, the first temperature being such that the air preheater has a cold end outlet temperature defined by the improved air preheater that operates with increased heat recovery (RH) of at least 1 percent, calculated according to the equation:
[0051] RH = 100% x ((Tgi-T goAdvX) / (Tgi-T goSTD) -1).
[0052]
[0053] In one embodiment, in an air preheater it has a cold end metal temperature that is not less than (for example, substantially not less than, approximately equal to, or substantially no greater than) a temperature of the water dew point in the air preheater and such that the temperature of cold end metal is less than a dew point temperature of sulfuric acid and the first temperature is between about 105 ° C (220 ° F) and about 125 ° C (257 ° F ). As used herein, the expression "not less than a temperature of the water dew point" connotes a temperature that is approximately equal to the temperature of the water dew point, so that there is no permanent moisture from the Heat transfer elements in the air preheater that produces the corrosion of the inlay.
[0054]
[0055] In one embodiment, in an air preheater it has a cold end metal temperature that is within 0.5 degrees Celsius of the water dew point temperature in the air preheater. In one embodiment, the air preheater has a cold end metal temperature that is within 1 degree Celsius of the water dew point temperature in the air preheater. In one embodiment, the air preheater has a cold end metal temperature that is within 2 degrees Celsius of the water dew point temperature in the air preheater. In one embodiment, the air preheater has a cold end metal temperature that is within 3 degrees Celsius of the water dew point temperature in the air preheater. In one embodiment, the air preheater has a cold end metal temperature that is within 4 degrees Celsius of the water dew point temperature in the air preheater. In one embodiment, the air preheater has a cold end metal temperature that is within 5 degrees Celsius of the water dew point temperature in the air preheater.
[0056]
[0057] A method for updating a steam generator system to be configured to operate according to the methods is also described herein. In the update embodiment, the discharge of the first treated draft gas mixture from the particle removal system directly into the gas desulphurization system of the draft, includes the use of one or more existing heat exchangers in the generator system. steam, between the particle removal system and the system of desulfurization of draft gas, before the update.
[0058]
[0059] A steam generator system configured to operate according to the above methods is further described herein.
[0060]
[0061] A method for improving the effectiveness of a steam generating system is described herein. The method includes providing a steam generating system that has a steam generating vessel, an air supply system, an improved air preheater (for example an AdvX ™ air preheater, formerly with the development name AXRM ™), a particle removal system (for example, a dry electrostatic precipitator and / or a tissue filter), a flue gas desulfurization system, and a flue gas discharge flue. The air supply system is in communication with the steam generator vessel through the air preheater. The steam generator vessel is in communication with the discharge chimney through the air preheater, the particle removal system and the flue gas desulfurization system. The particle removal system is located downstream of the preheater that airs. The flue gas desulfurization system is located downstream of the particle removal system and the flue chimney is located downstream of the flue gas desulfurization system. The method includes having in the air supply system that providing a first amount of air to the air preheater in a mass flow sufficient to establish a first temperature of the draft gas mixture leaving the air preheater. The first temperature is of a magnitude such that the air preheater has a cold end outlet temperature defined by the improved air preheater that operates with the increased heat recovery (RH) of at least 1% as calculated according to The equation
[0062]
[0063] RH = 100% x ((Tgi-TgoAdvX) / (Tgi-TgoSTD) -1), where
[0064]
[0065] Tgi = draft gas inlet temperature, that is, of the mixture of draft gas entering the air preheater;
[0066]
[0067] TgoAdvX = outlet temperature of draft gas, of the gas mixture that shot out of the preheater that improved air;
[0068]
[0069] TgoSTD = outlet temperature of the flue gas, that is, of the flue gas mixture that comes out of the standard air preheater.
[0070]
[0071] The method includes mitigating SO ³ in the shot gas mixture generated in the steam generator vessel. SO ³ mitigation occurs before the draft gas mixture enters the air preheater. The method includes setting the air preheater to heat the first amount of air to a second temperature of approximately 288 ° C to 339 ° C (550 ° F to 750 ° F). The method also includes supplying a first or all of the first amount of air as combustion air to the steam generator vessel for combustion of the fuel. The shot gas mixture is discharged at the first temperature, directly from the air preheater to the particle removal system whereby the particles of the over shot mixture are removed and a first mixture of treated shot gas is created . The method further includes discharging all or a portion of the first mixture of treated draft gas leaving the steam generator vessel from the particle removal system directly into the draft gas desulfurization system, a second mixture of draft gas treated at a third temperature, for example, but not limited to between 52 ° C and about 60 ° C (125 ° F to 140 ° F). The third temperature is of a sufficient magnitude to facilitate the injection of a second part of the air as heating of draft gas reheating air, directly (for example, by mixing) or indirectly (for example, using a heat exchanger), the second mixture of draft gas treated at the third temperature thereby creating the third mixture of draft gas at a fourth temperature (for example, at least about 68 ° C (155 ° F)), before entering the chimney discharge. The third temperature is of sufficient magnitude to allow the draft gas superheat air to rise to the fourth temperature to a sufficient magnitude to mitigate the column of visible smoke leaving the discharge chimney and to mitigate the corrosion of the chimney of download. Finally, the method includes admitting the third mixture of treated draft gas into the discharge chimney at the fourth temperature.
[0072]
[0073] In one embodiment, the first amount of air is of a magnitude greater than that required for combustion of the fuel in the steam generator vessel and the second part of the air is a second part of the first amount of air supplied from the air preheater at the second temperature Although, in another embodiment, the draft gas mixture is upstream of the air preheater divided into two streams in which a first stream is said part of the draft gas mixture fed to and then discharged from the air preheater and in which the second stream It is mixed by conduction upstream of the air preheater. In that other embodiment, the second stream is subsequently fed through a heat exchanger and injected to recombine with the first stream downstream of the air preheater. Typically, the second stream is subsequently supplied through the heat exchanger and the second part of the air is heated by the second draft gas stream in the heat exchanger prior to injection as draft gas superheat air.
[0074]
[0075] In one embodiment, in an air preheater and has a cold end metal temperature that is not less than a dew point temperature of the water in the air preheater and such that the temperature of cold end metal is lower than the dew point temperature of sulfuric acid and the first temperature being between about 105 ° C (220 ° F) and about 125 ° C (257 ° F).
[0076]
[0077] In one embodiment, a third of the first amount of air is provided as preheating air during boiler startup to selectively preheat one or more of the particle removal system, the flue gas desulfurization system, and / or the intermediate duct, or during operation of the boiler for a coal drying installation, and subsequently sent to the atmosphere. In another embodiment, the second draft gas mixing stream is subsequently fed through a heat exchanger to heat a stream of air providing the second part of the air for injection as superheated draft gas. Additionally, in that other embodiment, the air stream provides a third of air as preheating air during boiler start-up to selectively preheat at least one of the particle removal system, the flue gas desulfurization system, the intermediate ducts, or during the operation of the boiler for a coal drying installation, and subsequently it is expelled into the atmosphere.
[0078]
[0079] In one embodiment, the steam generating system further includes a selective catalytic reduction system and the steam generating vessel is in communication with the air preheater through a selective catalytic reduction system.
[0080]
[0081] In one embodiment, the steam generating system further includes one or more of a draft gas reheating air and / or an air particle removal system of Preheating and the air preheater is in communication with the discharge chimney through the draft gas superheat air and / or the preheating air particle removal system. The draft gas superheat air and / or the preheating air particle removal system removes particulate contaminants from the second part of the air that are introduced into the second part of the air from the leak inside the preheater. air (for example, by using inefficient or damaged sector seals) of the draft gas mixture.
[0082]
[0083] In one embodiment, the steam generating system further includes a humidity sensor disposed between the steam generating vessel and the air preheater and the method includes measuring, with the humidity sensor, the humidity of the draft gas mixture to determine a magnitude of the first temperature.
[0084]
[0085] In one embodiment, the steam generator system further includes an infrared sensor and the method includes determining, with the infrared sensor, the temperature of cold end metal in the air preheater; compare the temperature of cold end metal with the temperature of the water dew point; and control the temperature of cold end metal so that it is not less than the temperature of the water dew point. In one embodiment, the mitigation of SO ³ in the shot gas mixture includes supplying a low sulfur fuel to the steam generator vessel, where the low sulfur fuel generates less than 5 parts per million SO ³ .
[0086]
[0087] In one embodiment, the mitigation of SO ³ in the flue gas mixture includes removing the SO ³ in the flue gas mixture before admitting the flue gas mixture than in the air preheater.
[0088]
[0089] In one embodiment, the mitigation of SO ³ in the flue gas mixture includes chemically transforming the SO ³ in the flue gas mixture into an inert salt, before admitting the flue gas mixture into the air preheater. For example, the chemical transformation may include spraying an aqueous suspension of a reagent containing either sodium, magnesium, potassium, ammonium, and / or calcium thiosulfate or containing a soluble salt compound such as one more species of thiosulfate and chloride or containing at least one of sodium carbonate, sodium bicarbonate, sodium hydroxide, ammonium hydroxide, potassium hydroxide, potassium carbonate and potassium bicarbonate to create a mist containing dry particles of at least one soluble salt compound that can react with SO ³ in the flue gas.
[0090]
[0091] In one embodiment, the method further includes providing an injection device (for example a duct manifold) between the flue gas desulfurization system and the discharge chimney and where the injection of the second part of air, into the second temperature, with the second mixture of shot gas treated at third temperature shot is produced in the injection device.
[0092]
[0093] In one embodiment, the injection device includes the duct manifold located between the flue gas desulfurization system and the discharge chimney. The duct manifold has an inlet to receive the second mixture of treated draft gas, a branched connection to receive the second part of the air and an outlet in communication with the discharge chimney. In one embodiment, the injection device includes a mixer, rotating vanes, and a tabulator device.
[0094]
[0095] In one embodiment, the discharge of the draft gas mixture at the first temperature, directly from the air preheater to the particle removal system is performed without heat exchangers arranged between the air preheater and the particle removal system.
[0096]
[0097] In one embodiment, the first mixture of treated draft gas is discharged from the particle removal system directly into the draft gas desulfurization system without heat exchangers arranged between the particle removal system and the system desulfurization of draft gas.
[0098]
[0099] In one embodiment, there are no heat exchangers arranged between the air preheater and the flue gas desulfurization system.
[0100]
[0101] In one embodiment, there are no fans arranged between flue gas desulfurization system and the discharge chimney.
[0102]
[0103] In one embodiment, the injection of the second part of the first amount of air is conducted in a mass ratio of the second part relative to the second mixture of treated draft gas from 1 percent to 16 percent. In one embodiment, the injection of the Second part of the first amount of air is conducted in a mass ratio of the second part with respect to the second mixture of treated draft gas from 9 percent to 16 percent.
[0104]
[0105] A method for providing effectiveness of a steam generating system is described herein. The method includes providing a steam generating system that includes a steam generating vessel, an air supply system, an improved air preheater, a particle removal system and a flue gas discharge chimney. The air supply system is in communication with the steam generator vessel through the air preheater and the steam generator vessel is in communication with the discharge chimney through the air preheater and the particle removal system. The particle removal system is located downstream of the air preheater and the discharge chimney is located downstream of the particle removal system. The air supply system provides a first amount of air to the air preheater in a mass flow sufficient to establish a first temperature of a mixture of draft gas leaving the preheater. The first temperature is such that the air preheater has a cold end outlet temperature defined by the improved air preheater that operates with the increased heat recovery (RH) of at least 1% calculated according to the equation:
[0106]
[0107] RH = 100% x ((Tgi-TgoAdvX) / (Tgi-TgoSTD) - 1), where
[0108]
[0109] Tgi = draft gas outlet temperature, that is to say the mixture of draft gas that enters the air preheater;
[0110]
[0111] TgoAdvX = draft gas outlet temperature, that is, from the draft gas mixture leaving the improved air preheater;
[0112]
[0113] TgoSTD = flue gas outlet temperature, that is, from the flue gas mixture leaving the standard air preheater.
[0114]
[0115] The method includes mitigating the SO ³ in the shot gas mixture generated in the steam generating vessel, where the mitigation of SO ³ occurs before the shot gas mixture enters the air preheater. The air preheater is set to heat the first amount of air to a second temperature of approximately 228 ° C to 399 ° C (550 ° F to 750 ° F). A first part or all of the first amount of air is supplied as combustion air to the steam generator vessel for combustion of the fuel. The, or at least a part of the draft gas mixture is discharged, at the first temperature, directly from the air preheater to the particle removal system whereby the particles of the draft gas mixture are removed and create a first mixture of treated draft gas. The first mixture of treated draft gas is discharged from the system that removes particles directly into the system of desulphurization of draft gas with what is created and discharged from the system of desulphurization of draft gas, a second mixture of gas of shot treated at a third temperature. The third temperature is of sufficient magnitude to facilitate the injection of a second part of the air as preheated air, providing heat to a coal drying installation and / or to preheat the steam generator vessel.
[0116]
[0117] In one embodiment, the air preheater has a cold end metal temperature that is not less than the temperature of the water dew point in the air preheater, and such that the temperature of cold end metal is less than a dew point temperature of sulfuric acid and the first temperature being between about 105 ° C (220 ° F) and about 125 ° C (257 ° F).
[0118]
[0119] A system for improving the efficiency of a steam generating system is described herein. The system includes a steam generator vessel, a preheater in communication with the steam generator vessel, an air supply system configured to provide air to the steam generator vessel through an air preheater, a particle removal system ( for example, a dry electro static precipitator and / or a tissue filter), a flue gas desulfurization system and a discharge chimney. The steam generator vessel is in communication with the discharge chimney through the air preheater, the particle removal system and the flue gas desulfurization system. The particle removal system is located directly downstream of the air preheater. The flue gas desulfurization system is located directly downstream of the particle removal system. The discharge chimney is located directly downstream of the flue gas desulfurization system. The air supply system is configured to provide a first amount of air to the air preheater at a mass flow sufficient to establish a first temperature of a draft gas mixture leaving the air preheater. The first temperature is of such magnitude that the air preheater has a cold end metal temperature that is not less than a dew point temperature of the water in the air preheater and such that the cold end metal temperature is less than a point temperature of dew of sulfuric acid. The first temperature is between about 105 ° C (220 ° F) to about 125 ° C (257 ° F). The system includes the SO ³ mitigation upstream of the air preheater, the SO ³ mitigation is configured to mitigate the SO ³ in the shot gas mixture generated in the steam generator vessel. The air preheater is configured to heat the first amount of air to the second temperature from approximately 288 ° C to 399 ° C (550 ° F to 750 ° F). The particle removal system is configured to transport the draft gas mixture at a third temperature, for example, but not limited to between 52 ° C and approximately 60 ° C (125 ° F to 140 ° F), directly to the system of desulfurization of draft gas. An excess air duct is in communication with the air preheater. A second duct is located between the flue gas desulfurization system and the discharge chimney. The excess air duct is configured to transport a second part of the first amount of air as draft gas superheat air supplied from the air preheater to a second temperature from the air preheater to the second duct. The system includes an injection device (for example, a duct manifold) located between the flue gas desulfurization system and the discharge chimney. The injection device is configured to discharge the draft gas into the discharge chimney at a fourth temperature (for example, at least about 68 ° C (155 ° F)). The third temperature is of a sufficient magnitude to allow the draft gas superheat air to raise the fourth temperature to a sufficient magnitude to mitigate the visible smoke column leaving the discharge chimney and to mitigate corrosion in the chimney of download.
[0120]
[0121] In one embodiment, the steam generating system further includes a selective catalytic reduction system and the steam generating vessel is communicating with the air preheater through the selective catalytic reduction system.
[0122]
[0123] In one embodiment, the steam generator system further includes a draft gas reheat air particle removal system and the air preheater is in communication with the discharge chimney through the preheat air particle removal system. of draft gas to operatively remove particulate contaminants introduced from the leak into the second part of the air air preheater from the draft gas mixture.
[0124]
[0125] In one embodiment, the steam generating system further comprises a humidity sensor arranged in communication between the steam generating vessel and the air preheater to measure the humidity of the draft gas mixture and the humidity sensor being used to determine the magnitude of the first temperature.
[0126]
[0127] In one embodiment, the steam generating system further comprises an infrared sensor for determining the temperature of the air preheater and a control unit configured to control the temperature of the metal that ends cold above the dew point of the water in the preheater. air.
[0128]
[0129] In one embodiment, SO ³ mitigation includes supplying a low sulfur fuel to the steam generator vessel. Low sulfur fuel generates less than 5 parts per million SO ³ .
[0130]
[0131] In one embodiment, SO ³ mitigation includes removing SO ³ in the draft gas mixture before admitting the draft gas mixture in the air preheater.
[0132]
[0133] In one embodiment, the mitigation of SO ³ includes chemically transforming the SO ³ in the flue gas mixture into an inert salt, before admitting the flue gas mixture into the air preheater. For example, the chemical transformation may include spraying an aqueous suspension of a reagent containing either sodium, magnesium, potassium, ammonium and / or calcium thiosulfate and containing one or more soluble salt compounds, such as thiosulfate species or chloride containing at least one of sodium carbonate, sodium bicarbonate, sodium hydroxide, ammonium hydroxide, potassium hydroxide, potassium carbonate and potassium bicarbonate to create a mist containing dry particles of at least one soluble salt compound which can react with SO ³ in the flue gas.
[0134]
[0135] In one embodiment, the system is configured without fans arranged in the flue gas desulfurization system and the discharge chimney.
[0136]
[0137] In one embodiment, the system is configured without heat exchangers arranged between the air preheater and the flue gas desulfurization system.
[0138] In one embodiment, the system is configured without fans arranged between the draft gas reheat particle removal system and the discharge chimney.
[0139]
[0140] A method for updating a steam generating system for improved effectiveness is further described herein. The method includes removing one or more heat exchangers downstream from the air preheater and reconfiguring an air supply source so that the air preheater supplies a first amount of air at a mass flow sufficient to establish a first temperature of a draft gas mixture leaving the air preheater. The first temperature is of a magnitude such that the air preheater has a cold end metal temperature that is not less than a water dew point temperature in the air preheater, and so that the end metal temperature cold is less than a dew point temperature of sulfuric acid. The first temperature is between approximately 105 ° C (220 ° F) and approximately 125 ° C (257 ° F). The method includes providing SO ³ mitigation in communication with the steam generator vessel. The SO ³ mitigation is configured to mitigate the SO ³ in the shot gas mixture generated in the steam generator vessel. SO ³ mitigation occurs before the draft gas mixture enters the air preheater. The method includes configuring the air preheater to heat the first amount of air to a second temperature that is substantially not less than the combustion air temperature of an original system and that is approximately 228 ° C to 339 ° C (550 ° F at 750 ° F) to maintain or improve boiler efficiency. The method includes supplying a first or all of the first amount of air to the steam generator vessel for combustion of the fuel. The method also includes discharging all or a portion of the draft gas mixture leaving the steam generator vessel at the first temperature, directly from the air preheater to the particle collection system, thereby removing the particles from the mixture. of draft gas and creating a first mixture of treated draft gas. The method also includes discharging the first mixture of treated flue gas from the particle removal system directly into the flue gas desulphurization system thereby creating and discharging the flue gas desulphurization system, a second mixture of draft gas treated at a third temperature, for example, but not limited to between 53 ° C and approximately 60 ° C (125 ° F to 140 ° F). The method includes injecting a second part of the air as draft gas reheating air with the second mixture of draft gas treated at a third temperature, thereby creating a third mixture of draft gas treated at a fourth temperature (for example, at least about 68 ° C (155 ° F)), before entering the discharge chimney. The method also includes admitting the third mixture of treated draft gas into the discharge chimney at the fourth temperature. The third temperature is of a sufficient magnitude to allow the draft gas superheat air to raise the fourth temperature to a sufficient magnitude to mitigate the column of visible smoke leaving the discharge chimney and to mitigate corrosion in the chimney of download.
[0141]
[0142] In one embodiment, the update method includes replacing at least a part of an outlet duct that connects the flue gas desulfurization system and the flue chimney with a manifold that connects the flue gas desulphurization system, a conduit of excess air and chimney discharge.
[0143]
[0144] In one embodiment, the steam generating system further includes a draft gas preheating air particle removal system, and the air preheater is in communication with the discharge chimney through the air particle removal system of draft gas overheating. The method of updating includes removing the particulate contaminants from the second part of the air, the particulate contaminants being introduced into the second part of the air from the leak into the air preheater from the draft gas mixture.
[0145]
[0146] In one embodiment, the steam generator system further includes a humidity sensor arranged in communication between the steam generator vessel and the air preheater and the update method includes measuring, with the humidity sensor, the humidity of the gas mixture of shot to determine a magnitude of the first temperature.
[0147]
[0148] In one embodiment, the steam generator system further includes an infrared sensor and the update method includes determining, with the infrared sensor, the temperature of the cold end metal in the air preheater, comparing the temperature of the cold end metal. with the dew point temperature of the water; and control the temperature of cold end metal that is not less than the dew point temperature of the water.
[0149]
[0150] In one embodiment, in the update method, a second thermal efficiency of the Steam generator system, after implementing the update method, is at least as large as a first thermal efficiency of the steam generator system before implementing the update method.
[0151]
[0152] A method for updating a wet chimney steam generator system capable of firing gas outlet velocities of the order of 55 to 60 feet per second is further described herein for enhanced effectiveness. The method includes eliminating the wet chimney, thereby allowing increased draft gas outlet speeds by reconfiguring an air supply source to the air preheater to supply a first amount of air at a mass flow sufficient to establish a first temperature of the draft gas mixture leaving the air preheater, the first temperature being such that the air preheater has a cold end outlet temperature defined by the improved air preheater that operates with increased heat recovery HR of at least 1% As calculated according to the equation:
[0153]
[0154] RH = 100% x ((Tgi-TgoAdvX) / (Tgi-TgoSTD) - 1), where
[0155]
[0156] Tgi = draft gas outlet temperature, that is to say the mixture of draft gas that enters the air preheater;
[0157]
[0158] TgoAdvX = draft gas outlet temperature, that is, from the draft gas mixture leaving the improved air preheater;
[0159]
[0160] TgoSTD = flue gas outlet temperature, that is, the flue gas mixture leaving the standard air preheater.
[0161]
[0162] The method includes providing SO ³ mitigation in communication with the steam generator vessel. The SO ³ mitigation is configured to mitigate the SO ³ in the shot gas mixture generated in the steam generator vessel. SO ³ mitigation occurs before the draft gas mixture enters the air preheater. The method includes configuring the air preheater to heat the first amount of air to a second temperature that is substantially not less than the combustion air temperature of an original system and that is approximately between 228 ° C and 339 ° C (550 ° F to 750 ° F) to maintain or improve boiler efficiency in Comparison with the original system. The method includes supplying a first or all of the first amount of air to the steam generator vessel for combustion of the fuel. The method also includes discharging all or a portion of the draft gas mixture leaving the steam generator vessel at the first temperature, directly from the air preheater to the particle collection system, thereby removing the particles from the mixture of draft gas and creating a first mixture of treated draft gas. The first mixture of treated shot gas is discharged from the particle removal system directly into the shot gas desulphurization system, thereby creating and discharging from the shot gas desulphurization system, a second shot gas mixture. treated at a third temperature. The method includes injecting a second part of the first amount of air as superheat air of shot gas with the second mixture of shot gas treated at a third temperature, thereby creating a third mixture of shot gas treated at a fourth temperature, before entering the discharge chimney. The method includes admitting the third mixture of treated draft gas to the discharge chimney at the fourth temperature. The third temperature is of a sufficient magnitude to allow the draft gas superheat air to raise the fourth temperature to a sufficient magnitude to facilitate that a dry chimney mitigates the column of visible smoke that comes out of the discharge chimney and mitigates corrosion. in the chimney of discharge. The updated steam generator system is capable of increasing loads compared to the original steam generator system (that is, before implementing the update), in which the draft gas outlet speeds exceed those previously allowed with a chimney wet
[0163]
[0164] In one embodiment, in an air preheater it has a cold end metal temperature that is not less than a dew point temperature of the water in the air preheater, and so that the cold end metal temperature is less than a dew point temperature of sulfuric acid and the first temperature being between about 105 ° C (220 ° F) and about 125 ° C (257 ° F).
[0165]
[0166] A method for improving the effectiveness of a steam generating system is further described herein. The method includes providing a steam generating system that includes a steam generating vessel, an air supply system, an air preheater, a first particle removal system, a second particle removal system, a desulphurization system of flue gas, and a flue gas discharge flue. The air supply system is in communication with the Vapor generator vessel through the air preheater, the first particle removal system and the flue gas desulfurization system. The first particle removal system is located downstream of the air preheater and the flue gas desulfurization system is located downstream of the first particle removal system. The discharge chimney is located downstream of the flue gas desulfurization system and the air preheater is in communication with the discharge chimney through the second particle removal system. The method also includes providing a humidity sensor disposed between the steam generator vessel and the air preheater; and provide an infrared sensor in the air preheater. The method includes measuring the humidity of a mixture of draft gas with the humidity sensor to determine a magnitude of a first temperature. The air supply system provides a first amount of air to the air preheater. The first amount of air is in a mass flow sufficient to establish a first temperature of a mixture of draft gas leaving the preheater. The first temperature is of a magnitude such that the air preheater has a cold end metal temperature that is not less than a dew point temperature of the water in the air preheater and so that the temperature of cold end metal It is less than a dew point temperature of sulfuric acid. The first temperature is from about 105 ° C (220 ° F) to about 125 ° C (257 ° F). The method includes determining, with the infrared sensor, the temperature of cold end metal in the air preheater, comparing the temperature of cold end metal with the temperature of the water dew point; and check that the temperature of the cold end metal is not less than the temperature of the water dew point. The method includes mitigating SO ³ in the shot gas mixture generated in the steam generator vessel. SO ³ mitigation occurs before the draft gas mixture enters the air preheater. The method includes setting and air preheater to heat the first amount of air to a second temperature between approximately 288 ° C and 399 ° C (550 ° F to 750 ° F) and supply a first or all of the first amount of air as combustion air to the steam generator vessel for the combustion of fuel. The method includes discharging a whole part of the draft gas mixture leaving the steam generator vessel at a first temperature, directly from the air preheater to the particle removal system, thereby eliminating particles from the gas mixture. shot and creating a first mixture of treated shot gas. The method includes discharging the first mixture of treated flue gas from the particle removal system directly into the flue gas desulfurization system with what is created and discharged from the flue gas system. desulfurization of draft gas, a second mixture of treated draft gas at a third temperature of 50 ° C to 60 ° C (125 ° C to 140 ° C). The method includes removing particulate contaminants from the second part of air. Particulate contaminants are introduced into the second part of the air from the leak inside the air preheater from the draft gas mixture. The method further includes injecting a second part that the first amount of air as superheat air from draft gas at the second temperature with the second mixture of draft gas treated from shot at the third temperature, thereby creating a third gas mixture of treated draft at a fourth temperature of at least 68 ° C (155 ° F), before entering the discharge chimney. The method also includes admitting the third mixture of treated draft gas into the discharge chimney at the fourth temperature.
[0167]
[0168] It is contemplated that any of the preceding embodiments may be combined.
[0169]
[0170] Brief description of the drawings
[0171]
[0172] Fig. 1 is a schematic flow chart of a part of a steam generating system illustrating the present invention;
[0173]
[0174] Fig. 2 is a schematic flow diagram of a steam generating system of the present invention;
[0175]
[0176] Fig. 3 is a schematic flow diagram of a steam generating system of the present invention;
[0177]
[0178] Fig. 4 is a schematic flow chart of another embodiment of the steam generating system of the present invention;
[0179]
[0180] Fig. 5 is a graph of an overheating air ratio to the purified gas for various increases in the temperature of the draft gas;
[0181]
[0182] Fig. 6 is a graph of efficiency improvements of the air preheater;
[0183]
[0184] Fig. 7 is a schematic flow chart of a further embodiment of the steam generating system of the present invention;
[0185] Fig. 8 is a schematic flow chart of yet another embodiment of the steam generator of the present invention, and
[0186]
[0187] Fig. 9 is a schematic flow chart of a hybrid embodiment of the steam generator that combines superheat characteristics of the embodiments illustrated in Fig. 3 and Fig. 8.
[0188]
[0189] Fig. 10 is a schematic flow diagram of yet another embodiment of the steam generator of the present invention that includes a waste water drying loop;
[0190]
[0191] Fig. 11 is a schematic flow diagram of yet another embodiment of the steam generator of the present invention that includes another waste water drying loop;
[0192]
[0193] Fig. 12 is a schematic flow chart of yet another embodiment of the steam generator of the present invention that includes a supply water heating loop;
[0194]
[0195] Fig. 13 is a schematic flow chart of yet another embodiment of the steam generator of the present invention that includes another supply water heating loop;
[0196]
[0197] Fig. 14 is a schematic flow chart of yet another embodiment of the steam generator of the present invention that includes a wet ash system drying loop; Y
[0198]
[0199] Fig. 15 is a schematic flow chart of yet another embodiment of the steam generator of the present invention that includes another drying loop of the wet ash system;
[0200]
[0201] Detailed description
[0202]
[0203] As shown in Fig. 1, a steam generating system that has improved effectiveness is generally designated with reference number 10. The system Steam generator 10 includes a steam generator vessel 11 and an air preheater 13 (for example, a rotary regenerative heat exchanger of the inventor's AdvX ™ design, AdvX ™ is a registered trademark of Arvos Ljunsgstrom LLC). The AdvX ™ 13 air preheater is in communication with the steam generator vessel 11 through the duct 63. The steam generator system 10 includes an air supply system 13D configured to provide air to the steam generator 11 through the preheater of air 13. As used herein, the term "enhanced effectiveness" of the steam generator system includes: 1) maintaining the total thermal efficiency of the steam generator system 10 while eliminating or mitigating another it forms the need for heat exchangers, such as gas-to-gas heat exchangers (GGHs) between the air preheater 13 and a discharge chimney; 2) reduce the formation of scale in the air preheater 13; 3) improve the efficiency of a particle removal system; 4) improve the efficiency of the air preheater 13; and / or 5) improve the total thermal efficiency (ie, the heat regime) of the steam generating system 10 compared to the steam generating systems of the prior art (for example, the steam generating systems 100 and 100 ' of Figs. 1 and 2 of the PTC Patent Application PTC / US2017 / 13459). Through significant analyzes and tests and many years of unsuccessful attempts, the inventors have surprisingly discovered that the steam generating system 10 can operate at least as thermally as efficiently as the prior art steam generating systems 100 shown in the PCT patent application PCT / US2017 / 13459 but without the benefit of increasing the efficiency of GGHs 106X, 106X ', 106Y and 106Y' as shown in PCT Patent Application PCT / US2017 / 13459. The expression "a method for improving the effectiveness of a steam generating system" is also referred to as a method for operating a steam generating system.
[0204]
[0205] As shown in Fig. 1, the steam generating system 10 includes the steam generating vessel 11, an air supply system 13D and the air preheater 13. The air supply system 13D is in communication with the vessel steam generator 11 through the preheater 13 and the steam generator vessel 11 is in communication with the air preheater 13. The air supply system 13D provides a first amount of air to the preheater 13. At least a part of the first amount of air is provided to the steam generator vessel 11 as combustion air. A mixture of draft gas FG is discharged from the steam generating vessel 11 through the duct 63. All or a portion of the draft gas mixture FG flows to the air preheater 13. The SO ³ in the draft gas mixture is mitigated before the draft gas mixture FG enters the air preheater 13, as described in more detail herein.
[0206]
[0207] The steam generating system 10 includes heat capture means (for example, heat exchangers, heat transfer elements in the air preheater that have a heat transfer capacity greater than that required for preheating combustion air and / or to cool the draft gas, so that the cold end metal temperature is a temperature at or near the dew point of the water (H ² O), conduit arrangements, mixers, tubes, tanks and the like) in communication with the steam generator, is the air preheater, the first amount of air and / or the draft gas mixture, as described in more detail herein. The first amount of heat is transferred outside the steam generator, the air preheater, and / or the flue gas mixture to various locations as described herein. For example, all or a portion of the first amount of heat can be: (1) used during boiler start-up to selectively preheat the particle removal system, the flue gas desulfurization system and / or the intermediate ducts as shown and described with reference to Fig. 7; (2) during operation of the boiler for a coal drying installation 69, and is subsequently expelled into the atmosphere, as shown and described with reference to Fig. 7; (3) released into the atmosphere, as illustrated by the lines of expulsion into the atmosphere AV1 and AV2 in Figs. 3 and 8, respectively; (4) to improve the heat regime of the steam generating system 10, as shown, for example, in Figs. 12 and 13; (5) to evaporate the water from an ash sludge discharged from a wet ash removal system communicating with a particle removal system as shown in Figs. 10 and 11, and / or the steam generator vessel 11; and (6) in a wastewater system to reduce water discharge thereof, as shown, for example, in Figs. 10 and 11. The use of all or a portion of the first amount of heat to improve the heat regime of the steam generating system 10 includes: (1) using at least a portion of the first amount of heat to improve the efficiency of the steam cycle; (2) use at least a portion of the first amount of heat to preheat the supply water by the condensate supplied to the steam generating system; and (3) use at least a portion of the first amount of heat to reduce parasitic loads (for example, the space and heating of drinking water and steam for turbines to drive rotating equipment, such as fans instead of electrically driven motors , and other steam or heat loads other than used for electricity generation) in the steam generator system.
[0208]
[0209] As Fig. 2 is shown, the steam generating system 10 also includes a particle removal system 14, a flue gas desulfurization system 17 and a discharge chimney 19. The steam generator vessel 11 is in communication with the discharge chimney 19 through the air preheater 13, the particle removal system 14 and the flue gas desulfurization system 17. The particle removal system 14 is located directly downstream of the air preheater 13, of so that there are no other substantive components such as fans or heat exchangers located between the air preheater 13 and the particle removal system 14 that are in fluid communication with each other through the conduit 60. In particular, there is no GGH 106X 'similar to that shown in Fig. 2 of PCT Patent Application PCT / US2017 / 13459, located between the air preheater 13 and the particle removal system 14. The d system shot gas sulfurization 17 is located directly downstream of the particle removal system 14, so that there are no other substantive components, such as heat exchangers, located between the particle removal system 14 and the gas desulfurization system of draft 17 that are in fluid communication with each other through a conduit 61. In particular, there is no GGH 106X similar to that shown in Fig. 1 of PCT Patent Application PCT / US2017 / 13459, located between the system of removal of particles 14 and the draft gas desulphurization system 17. The discharge chimney 19 is located directly downstream of the draft gas desulphurization system 17, so that there are no other substantive components located between the desulphurization system of draft gas 17 and the discharge chimney 19 which are in fluid communication with each other through the duct 62. In particular, there is no GGH 106Y or 106Y 'similar to that shown in l to Figs. 1 and 2 of PCT Patent Application PCT / US2017 / 13459, located between the draft gas desulphurization system 17 and the discharge chimney 19. There are no heat exchangers located between the air preheater 13 and the discharge chimney 19. In one embodiment, as shown in Fig. 3, the duct 62 includes an overheating air injection device 21, such as a mixer, one or more rotating vanes, a gasket and / or a tabulator device, arranged therein to mix a second part P2 of the first quantity A1 of air with a second mixture of treated draft gas FG2, as described herein.
[0210]
[0211] As illustrated in Fig. 3, the air supply system 13D is configured to provide a first quantity A1 of air to the air preheater 13. The first quantity of air A1 is of a magnitude greater than that required for combustion of the fuel in the steam generator vessel 11 (for example, the first amount of heat is of a magnitude greater than that used to preheat the part of the first amount of air provided to the steam generator vessel 11). In one embodiment, the first amount of heat is approximately 10 to 25 percent of that used to preheat combustion air. In one embodiment, the first amount of heat is of a given magnitude based on the excess capacity or the design range of the existing air supply system 13D (for example, the mass flow outlet margin of the fan), For example, the first amount of heat is approximately 10 to 15 percent of that used to preheat combustion air. In an update application, the use of the existing 13D air supply system eliminates the need to replace expensive fans and related systems. In one embodiment, the first amount of air is of a magnitude greater than that required as combustion air. The air preheater 13 is configured to provide the first quantity A1 of air at a mass flow sufficient to establish a first temperature T1 of a mixture of draft gas FG leaving the air preheater 13. The first quantity of air A1 is regulated by conventional means such as, but not limited to, variable speed fans and / or compressors, control valves and / or dampers. The first temperature T1 of the draft gas mixture FG leaving the air preheater is cooler than the draft gas leaving the steam generator vessel 11 due to gas air leakage (for example, the leakage due to inefficient, inefficient or damaged sector seals or other seals in the air preheater 13) that occurs at the cold end of the air preheater 13. The temperature of the draft gas leaving the steam generator vessel 11 is often referred to as the "uncorrected" gas outlet temperature, and the first temperature T1 of a mixture of draft gas FG leaving the air preheater 13 after mixing with the cold air leak is often referred to as the gas temperature " corrected. " The first temperature T1 is such that the air preheater 13 has a cold end metal temperature that is not less than (for example, substantially not less than, approximately equal to, or substantially not more than) a dew point temperature of the water in the air preheater 13 and such that the temperature of cold end metal is less than a dew point temperature of sulfuric acid. The term "cold end metal" as used herein is the part of the air preheater 13 that is at the lowest temperature therein. The first temperature T1 is between approximately 105 ° C (220 ° F) and approximately 125 ° C (257 ° F). As used herein, the expression "not greater than a dew point temperature" connotes a temperature that is approximately equal to the dew point temperature, so that there is no permanent moisture in the transfer elements of heat in the air preheater that produce the corrosion of the scale.
[0212]
[0213] In another embodiment, the first temperature T1 is defined by the improved air preheater (for example, the AdvXTM air preheater, a trademark of ARVOS Ljungstrom LLC.) Which operates with increased heat recovery HR compared to an air preheater. standard of at least 1% (one percent). This increased heat recovery HR expresses a percentage number calculated according to the equation HR = 100% x ((Tgi-TgoAdvX) / (Tgi-TgoSTD) -1). It will be appreciated that a negative number would represent the decreased heat recovery. Here, the standard air preheater is defined as an air preheater where the first amount of air is of a magnitude equal to that required for combustion, that is, it is combustion air and air is not preheated in excess, and having a rotor of equivalent diameter and improved air preheater depth.
[0214]
[0215] In the equation HR = 100% x ((Tgi-TgoAdvX) / (Tgi-TgoSTD) -1):
[0216]
[0217] Tgi = draft gas inlet temperature, that is to say the mixture of draft gas entering the air preheater;
[0218]
[0219] TgoAdvX = draft gas outlet temperature, that is, from the draft gas mixture leaving the improved air preheater;
[0220]
[0221] TgoSTD = draft gas outlet temperature, that is, the mixture of draft gas leaving the standard air preheater;
[0222]
[0223] For example, if Tgi = 700 degrees Fahrenheit; TgoSTD = 300 degrees Fahrenheit; and TgoAdvX = 295 degrees Fahrenheit, then, HR = 100% x ((700-295) / (700-300) -1) = 1.25%.
[0224]
[0225] In one embodiment, the air supply system 13D provides a first amount of air A1 to the air preheater 13 and the first amount of air A1 is regulated by conventional means (eg, variable speed fans, blowers, compressors, dampers, valves, duct arrangements, and combinations thereof). Thus, the first amount of air A1 is regulated at a mass flow sufficient to establish a first temperature T1 of a mixture of draft gas leaving the air preheater 13. In one embodiment, the magnitude of the mass flow of the first amount of air A1 is determined based on the performance of the improved air preheater 13 and in particular the amount of heat recovery HR, which depend on the extent of the improved seals and / or improved heat transfer sheets employed. The first temperature T1 is such that in an air preheater it has a cold end outlet temperature defined by the improved air preheater that operates with increased heat recovery (RH) of at least 1% as calculated according to the equation. :
[0226]
[0227] RH = 100% x ((Tgi-T goAdvX) / (Tgi-T goSTD) -1).
[0228]
[0229] In one embodiment, the air preheater has a cold end metal temperature that is not less than (for example, a temperature that is approximately equal to the dew point temperature of the water, so that there is no permanent moisture from the heat transfer elements that cause corrosion of the inlay) at a temperature of the dew point of the water in the air preheater, so that the temperature of the cold end metal is less than a dew point temperature of the sulfuric acid and the first temperature being between about 105 ° C (220 ° F) and about 125 ° C (257 ° F).
[0230]
[0231] In one embodiment, the increased heat recovery HR of the improved air preheater is achieved by using heat transfer element with improved heat transfer coefficients and an increased heat transfer area, compared to the heat transfer elements of the prior art For example, the improved heat transfer elements described and / or embodied in the Arvos Ljungstrom Applicant's LLC: US Patent Application Serial No. 14 / 089,139, "Heat Transfer Elements for a Closed Channel Rotary Regenerative Air Preheater, ”Filed on November 25, 2013; (2) International Application No. PCT / US2016 / 069186," A Heat Transfer Sheet Assembly with an Intermediate Spacing Feature, "filed on December 29, 2016; (3) International Application No. PCT / US2017 / 026840, "A Heat Transfer Sheet Assembly with an Intermediate Spacing Feature ”, presented on April 10, 2017; (4) United States Patent Application Serial No. 14 / 877,451, "Alternating Notch Configuration for Spacing Heat Transfer Sheets," filed October 7, 2015; (5) International Application No. PCT / US2016 / 056209 "Alternating Notch Configuration for Spacing Heat Transfer Sheets, ”October 10, 2016; (6) Applicant DN8 ™ brand heat transfer sheet; and / or (7) heat transfer foil of the applicant's TF4 ™ brand, are used individually or in combinations thereof in improved air preheaters to achieve increased HR heat recovery.
[0232]
[0233] In one embodiment, the increased heat recovery HR of the improved air preheater is achieved using improved seals compared to prior art seals. For example, the improved seals described and / or embodied in the Arvos Ljungstrom Applicant's LLC: (1) US Patent Application Serial No. 14 / 829,210, "Flexible Seal for Rotary Regenerative Preheater," filed August 18 2015; (2) International Application No. PCT / US2016 / 056209, "Flexible Seal for Rotary Regenerative Preheater," filed on October 10, 2016; (3) International Application No. PCT / US2017 / 017414, "Flexible Seal for Rotary Regenerative Preheater," February 10, 2017; (4) flexible seal of the Applicant's Optiflex ™ brand; and / or (5) seal of the The applicant's Taperflex II ™ brand, are used individually or in combinations thereof in improved air preheaters to achieve increased HR heat recovery.
[0234]
[0235] In one embodiment, both improved heat transfer sheets and improved seals are employed in improved air preheaters to achieve increased HR heat recovery.
[0236]
[0237] The above equation (i.e., HR = 100% x ((Tgi-TgoAdvX) / (Tgi-TgoSTD) - 1)) is used to quantify the percentage of improvement in HR heat recovery achieved using heat transfer sheets improved prior and improved seals in the improved air preheater 13, compared to prior art air preheats.
[0238]
[0239] The Applicant discovered that the mitigation of SO ³ in the draft gas mixture before the shot gas mixture FG enters the air preheater 13, allows them to be Improved air preheater employees with increased HR heat recovery, while with prior art steam generating systems, those skilled in the relevant art have not been able to realize the full potential of increased APH efficiency available through the use of higher efficiency heat transfer elements and greater heat transfer area of heat transfer elements, due to operating limitations related to contaminant control. However, those skilled in the art will understand how to install such improved heat transfer elements in an improved air preheater to achieve increased HR heat recovery.
[0240]
[0241] The air preheater 13 is also configured to heat the first amount of air A1 to a second temperature T2 of approximately 288 ° C to 399 ° C (550 ° F to 750 ° F) for use in combustion of the fuel and to reheat air as described herein.
[0242]
[0243] The steam generator system 10 includes one or more systems or devices for mitigating the SO ³ upstream of the air preheater 13 which are configured to mitigate the SO ³ in the shot gas mixture FG generated in the steam generator vessel 11 In one embodiment, one or more systems or devices for the mitigation of SO ³ upstream of the air preheater 13 include supplying a low sulfur fuel to the steam generator vessel 11. The low sulfur fuel has a composition suitable for generating less than 5 parts per million SO ³ . In one embodiment, the one or more systems or devices for the mitigation of SO ³ upstream of the air preheater 13 include removing in the SO ³ of the shot gas mixture FG before admitting the shot gas mixture FG in the preheater that air 13, for example in the duct 63. In one embodiment, the one or more systems or devices for the mitigation of SO ³ upstream of the air preheater 13 includes chemically transforming the SO ³ in the draft gas mixture into an inert salt, before admitting the FG draft gas mixture into the air preheater 13. In one embodiment, the chemical transformation includes either spraying an aqueous suspension of a reagent containing sodium, magnesium, potassium, ammonium and / or calcium thiosulfate and containing one or more soluble salt compounds such as thiosulfate and chloride species or containing at least one of sodium carbonate, sodium bicarbonate, sodium hydroxide, ammonium hydroxide, hydroxide of potassium, potassium carbonate and potassium bicarbonate to create a particulate mist containing dry particles of at least one soluble salt compound that can react with SO ³ in the flue gas.
[0244] As shown in Fig. 3, the particle removal system 14 is configured to transport the flue gas mixture FG1 at the first temperature T1 directly to the flue gas desulfurization system, through the conduit 61. As Fig. 3 shows, the particle removal system 14 is configured to transport the gas mixture from shot FG1 at the first temperature T1 directly to the shot gas desulphurization system 17, through conduit 61, so that T1 is in an appropriate range for efficient operation of system 17. As shown in Fig. 3, the particle removal system 14 is configured to transport the flue gas mixture FG1 at the first temperature T1 to the desulphurization system of flue gas 17, through the duct 61, so that T1 is in an appropriate range for the operation of the system. In one embodiment, the particle removal system 14 is a dry Electrostatic Precipitator (ESP). Such dry ESP includes rows of thin vertical cables (not shown) followed by a chimney of large flat metal plates (not shown), oriented vertically. FG draft gas flows horizontally through the spaces between the cables, and then crosses the plate chimney. A negative voltage of several thousand volts is applied between the cables and the plates. If the applied voltage is high enough, an electric corona discharge ionizes the draft gas around the electrodes, which then ionize the particles in the draft gas stream. Ionized particles, due to electrostatic force, are diverted to the plates connected to ground. The particles are accumulated in the collection plates and are removed from them. The operation of ESPs at lower temperatures with the shot gas compositions described herein provides significant efficiency benefits and could be capable of a reduction in ESP size necessary for use in various steam generating systems. Although a dry ESP is shown and described, the present invention is not limited in this regard since a wet ESP can be employed.
[0245]
[0246] As Fig. 4 is shown, in one embodiment, the steam generator system 10 'further comprises a system for removing air particles from draft gas 33 superheat located in and between the ducts 64 and 65. The air preheater 13 is in communication with the discharge chimney 13 through the system for removing air particles from the draft gas 33 to operatively remove, from the second part P2 of the air, the particulate contaminants introduced from the leak inside of the air preheater 13 from the FG draft gas mixture. In one embodiment, the air particle removal system of the draft gas reheat 33 is configured similarly to the particle removal system 14 as has been described herein. As illustrated in Fig. 4, there are no fans arranged between the draft gas reheat air particle removal system 33 and the discharge chimney 19.
[0247]
[0248] As shown in Fig. 3, an excess air duct 65 is in communication with the air preheater 13 and the duct 62 located between the flue gas desulfurization system 17 and the discharge chimney 19. The duct Excess air 65 is configured to transport the second part P2 of the first quantity A1 of air as the draft gas superheat air P2 supplied from the air preheater 13 to the second temperature T2 from the air preheater 13 to the second duct 62 For example, the excess air duct 65 is covered with a thermal insulator (not shown) in order to minimize heat loss from the excess air duct 65. In addition, the excess air duct 65 is configured with a suitable cross-sectional flow area, internal surfaces ready and with a minimum number of elbows to minimize pressure loss through the excess air duct 65.
[0249]
[0250] As Fig. 3 is shown, an overheating air injection device 21 is located between the flue gas desulfurization system 17 and the discharge chimney 19. The overheating air injection device 21 is configured to discharge the flue gas in discharge chimney 19 at a fourth temperature T4 of at least 68 ° C (155 ° F), typically raising the temperature of flue gas by at least about 5 ° F. In one embodiment, the reheating air injection device 21 includes a mixer, one or more rotating vanes, a gasket and / or a tabulator device disposed therein for mixing the second part P2 (i.e. the reheating air of draft gas P2) of the first quantity A1 of air with the second mixture of treated draft gas FG2. In one embodiment, the reheating air injection device 21 is configured to inhibit corrosion during startup or to otherwise maintain the dynamic stability of the operational fluid in the intake of draft gas to the chimney 19. In one embodiment, The reheating air injection device is part of a manifold 39 that connects the flue gas desulfurization system 17, the excess air duct 65 and the discharge chimney 19. The manifold includes a branched connection to which it is connected the excess air duct 65. In another embodiment, the reheating air indirectly reheats the mixture FG2 suitably by means of tubes with heat exchange ducts through which the draft gas is flowed adjacent to the chimney of download 19.
[0251] As shown in Fig. 4, in one embodiment, the steam generator system 10 'includes a selective catalytic reduction (SCR) system 31 to convert nitrogen oxides, also referred to as NOx with the aid of a catalyst in diatomic nitrogen ( N ² ) and water (H ² O). The steam generator vessel 11 is in communication with the air preheater 13 through the SCR 31.
[0252]
[0253] As Fig. 4 is shown, in one embodiment, the steam generator system 10 'includes a humidity sensor 34 disposed at an outlet of the steam generator vessel 11 and upstream of the air preheater 13 for measuring the humidity of the mixture FG draft gas. The humidity sensor is configured to determine the magnitude of the first temperature T1.
[0254]
[0255] As Fig. 4 is shown, in one embodiment, the steam generator system 10 'includes an infrared sensor 32 to determine the temperature of the air preheater. The infrared sensor 32 is configured to determine the temperature of the air preheater for example, the temperature of the cold end metal, by measuring the temperature of a part of the air preheater 13 that is in thermal communication with or near the cold end. The steam generator system 10 'includes a control unit 71, such as a computer processor, memory and electronic signal processing components configured to control the temperature of cold end metal above the water dew point in the preheater of air 13.
[0256]
[0257] As shown in Fig. 7, in another embodiment, in the steam generating system 10 '' the excess air duct 65 is provided with an excess air purge 66 for transporting a third part P3 of the first quantity A1 of the air as preheating air P3 usable, for example, during the start-up of a preheating and driving equipment downstream of the air preheater 13. Shock absorbers (not shown) are selectively arranged to feed the preheating injection sites 67, 68 respectively waters above ESP 14 and FGD 17 to introduce preheated air P3 into the flue gas mixtures FG and FG1. Additionally, the preheating air P3 can be supplied to a remote carbon dryer 69 (CD) which is particularly useful when wet coals are used as lignite, for example. The preheating required for the drying of coal would typically be required for the ignition of coal and would not be necessary during the start-up ignition with oil or natural gas for example. The lower outlet temperatures provided by the air preheater 13 are advantageous when coal is dried as a attempt to remove moisture and not raise the temperature of coal in excessively (since such elevation could increase the probability of preignition within mills, for example). It will be understood that the purging of air ^{6 6} can be selectively used during operation to preheat the equipment / ducts and / or dry coal and is particularly useful during startup to inhibit condensation within the equipment and ducts. It will be appreciated in other embodiments that preheating air may be required only upstream of ESP 14 or FGD 17 and not upstream of both as illustrated in Fig. 7.
[0258]
[0259] The present invention includes a method for improving the effectiveness of a steam generating system 10. The method includes providing a steam generating system.
[0260] ^{1 0} as described in detail herein and which includes the steam generator vessel 11, the air supply system 13D, the air preheater 13, the particle removal system 14, the gas desulfurization system of draft 17, and the flue gas discharge chimney 19. The air supply system 13D is in communication with the steam generator vessel 11 through the air preheater 13, and with the steam generator vessel ¹¹ which is in communication with the discharge chimney 19 through the air preheater 13, the particle removal system 14 and the flue gas desulfurization system 17. The particle removal system 14 is located downstream of the air preheater 13 The flue gas desulfurization system 17 is located downstream of the particle removal system 14. The flue chimney 19 is located downstream of the flue gas desulphurization system 17.
[0261]
[0262] The method includes that the air supply system 13D supplies the first quantity A1 of air to the air preheater 13. The first quantity A1 of air is of a magnitude greater than that required for the combustion of the fuel in the steam generator vessel 11 The air preheater 13 provides the first quantity A1 of air at a mass flow sufficient to establish a first temperature T ¹ of a mixture of draft gas FG leaving the air preheater 13. The first temperature T ¹ is such that The air preheater has a cold end metal temperature that is not less than the temperature of the water dew point in the air preheater 13 and such that the cold end metal temperature is less than a dew point temperature. of sulfuric acid. The first temperature T1 being between approximately 105 ° C (220 ° F) and approximately 125 ° C (257 ° F).
[0263]
[0264] The method includes mitigating SO ³ in the FG shot gas mixture generated in the vessel steam generator 11, before the shot gas mixture FG enters the air preheater 13. The method includes configuring the air preheater 13 to heat the first amount of air A1 to a second temperature T2 of approximately 288 ° C at 399 ° C (550 ° F to 750 ° F) and supply a first part P1 of the first quantity A1 of air as combustion air to the steam generator vessel 11 for combustion of the fuel. The method includes discharging the shot gas mixture FG at the first temperature T1, directly from the air preheater 13 to the particle removal system 14 thereby removing the particles from the shot gas mixture FG and creating a first mixture FG1 treated draft gas. The method further includes discharging the first flue gas mixture FG1 from the particle removal system 14 directly into the flue gas desulfurization system 17 thereby creating and discharging the flue gas desulphurization system 17, a second mixture of FG2 treated draft gas at a third temperature T3 from 52 ° C to 60 ° C (125 ° F to 140 ° F). The method also includes injecting a second part P2 of the first quantity A1 of air as a draft gas superheat air from the preheater 13 to the second temperature T2 with the second mixture of treated draft gas FG2 at the third temperature T3 thereby creating a third mixture of treated draft gas FG3 at a fourth temperature T4 of at least 68 ° C (155 ° F), before entering the discharge chimney 19. The third mixture of treated draft gas FG3 is admitted in the discharge chimney 19 at the fourth temperature T4.
[0265]
[0266] In one embodiment, the steam generating system 10 further includes an SCR 13 as shown in Fig. 4 for transforming nitrogen oxides, also referred to as NOx with the aid of a catalyst in diatomic nitrogen (N ² ) and water (H ² O). The steam generator vessel 11 is in communication with the air preheater 13 through the SCR 31.
[0267]
[0268] As shown in Fig. 4, in one embodiment, the steam generator system 10 'includes a draft gas reheat air particle removal system 33. The air preheater 13 is in communication with the discharge chimney 19 through the draft gas reheat air particle removal system 33. In one embodiment, the method includes removing particulate contaminants from the second part P2 of the air. The particulate contaminants are introduced into the second part P2 of the air from the leak into the air preheater 13 from the flue gas mixture FG1.
[0269] As shown in Fig. 4, in one embodiment, the steam generator system 10 'includes a humidity sensor 34 disposed between the steam generator vessel 11 and the air preheater 13. In one embodiment, the method includes measuring, with the humidity sensor 34, the humidity of the shot gas mixture FG to determine a magnitude of the first temperature T1.
[0270]
[0271] As Fig. 4 is shown, in one embodiment, the steam generator system 10 'includes an infrared sensor 32. In one embodiment, the method includes determining, with the infrared sensor, the temperature of cold end metal in the air preheater 13. The infrared sensor 32 determines the temperature of the air preheater for example, the temperature of cold end metal, by measuring the temperature of a part of the air preheater 13 that is in thermal communication with or near the cold end . The steam generator system 10 'includes a control unit 71, such as a computer processor, memory and electronic signal processing components and the method includes comparing the temperature of cold end metal with the temperature of the water dew point and control, with the control unit, the temperature of the cold end metal above the dew point of the water in the air preheater 13.
[0272]
[0273] In one embodiment, the method includes mitigating SO ³ in the FG draft gas mixture by supplying a low sulfur fuel to the steam generator vessel 11. The low sulfur fuel being of a composition that generates less than 5 parts per million SO ³ .
[0274]
[0275] In one embodiment, the method includes mitigating the SO ³ in the shot gas mixture FG by removing the SO ³ in the shot gas mixture FG before admitting the shot gas mixture FG in the preheater 13.
[0276]
[0277] In one embodiment, the method includes mitigating the SO ³ in the shot gas mixture FG by chemically transforming the SO ³ in the shot gas mixture into an inert salt, before admitting the mixture of shot gas FG in the preheater of air 13. In one embodiment, the chemical transformation step includes spraying an aqueous suspension of a reagent containing at least one of sodium, magnesium, potassium, ammonium and calcium thiosulfate and containing at least one salt compound soluble chosen from the group consisting of thiosulfate and chloride species or containing at least one of sodium carbonate, sodium bicarbonate, sodium hydroxide, ammonium hydroxide, potassium hydroxide, potassium carbonate and potassium bicarbonate to create a particulate mist containing dry particles of at least one soluble salt compound that can react with the SO ³ in the draft gas.
[0278]
[0279] In one embodiment, the method includes providing some injection device 21 between the draft gas desulfurization system 17 and the discharge chimney 19 and wherein the injection of the second part P2 of the first quantity A1 of air, into the second temperature T2, with the second mixture of shot gas treated with shot FG2 at the third temperature T3 is produced in the injection device 21.
[0280]
[0281] In one embodiment, the method includes discharging the flue gas mixture FG at the first temperature T1, directly from the air preheater 13 to the particle removal system 14 without heat exchangers arranged between the air preheater 13 and the system of particle removal 14.
[0282]
[0283] In one embodiment, the method includes discharging the first mixture of treated shot gas FG1 from the particle removal system 14 directly into the shot gas desulfurization system 17, without heat exchangers arranged between the particle removal system 14 and the draft gas desulphurization system 17.
[0284]
[0285] In one embodiment, the method includes the injection of the second part P2 of the first quantity A1 of air in a mass ratio of the second part P2 relative to the second mixture of treated draft gas FG2 from 1 percent to 16 percent. In one embodiment, the method includes the injection of the second part P2 of the first quantity A1 of air at a mass ratio of the second part P2 relative to the second mixture of treated draft gas FG2 from 9 percent to 16 percent .
[0286]
[0287] The present invention includes a method for updating a steam generator system 100, 100 'to improve effectiveness. The method for the update includes removing one or more heat exchangers downstream from the air preheater 13. The method for the update includes reconfiguring an air supply source 13D in the air preheater 13 to supply a first quantity A1 of air greater than that required for the combustion of the fuel in the steam generator vessel 11 and reconfigure at least one of the air supply source 13D and the preheater of air 13, so that the first quantity A1 of air is provided at a mass flow sufficient to establish a first temperature T1 of a mixture of draft gas FG leaving the air preheater 13, the first temperature T1 being such that the air preheater has a cold end metal temperature that is not less than the temperature of the water dew point in the air preheater 13 and such that the cold end metal temperature is less than the dew point temperature of the sulfuric acid and the first temperature T1 being comprised between about 105 ° C (220 ° F) and about 125 ° C (257 ° F).
[0288]
[0289] In another embodiment, the first temperature T1 is defined by the improved air preheater (for example, the AdvX ^TM air preheater) that operates with improved efficiency compared to a standard air preheater of at least 1% (one percent) as defined herein. The reconfiguration of the air supply 13D includes but is not limited to employing a fan of higher flow and / or pressure capacity or a blower and / or reducing the pressure drop in the air supply system, as compared to that used in the prior art air supply 103D, 103D 'as shown in Figs. 1 and 2 of PCT Patent Application PCT / US2017 / 13459, respectively.
[0290]
[0291] The method for the update includes providing one or more SO ³ mitigation systems in communication with the steam generator vessel 11. The SO ³ mitigation systems are configured to mitigate the SO ³ in the shot gas mixture generated in the steam generator vessel 11. In one embodiment, the mitigation of SO ³ occurs before the shot gas mixture FG enters the preheater 13. The method for the upgrade includes setting in an air preheater 13 to heat the first amount of air A1 at a second temperature T2. The second temperature is substantially not less than the combustion air temperature of an original system (for example, a prior art steam generator system 100, 100 'of Figs. 1 and 2, of the PCT Patent Application PCT / US2017 / 13459, respectively). In one embodiment, the second temperature is about 288 ° C to 399 ° C (550 ° F to 750 ° F) to maintain or improve the thermal efficiency of the boiler. The method for updating includes supplying a first part P1 of the first quantity A1 of air to the steam generator vessel 11 for combustion of the fuel. The update method includes discharging the shot gas mixture FG at the first temperature T1, directly from the air preheater 13 to the particle collection system 14, thereby removing the particles from the shot gas mixture FG and creating a first FG1 treated draft gas mixture. The first mixture of treated shot gas FG1 is discharged from the particle removal system 14 directly into the shot gas desulfurization system 17 (i.e., without flowing through the heat exchanger such as GGH 106Y, 106Y ' of the prior art heat exchange systems of Figs. 1 and 2 of PCT Patent Application PCT / US2017 / 13459, respectively). However, in an update embodiment, the first mixture of treated shot gas FG1 is discharged from the particle removal system 14 directly into the shot gas desulfurization system 17 flowing through one or more existing heat exchangers such as GGH 106Y, 106Y 'of the prior art heat exchange systems of Figs. 1 and 2 of PCT Patent Application PCT / US2017 / 13459, respectively. In such an update embodiment, the existing heat exchangers may be in full operation or be of reduced performance or be made non-functionally for heat exchange. The method for the update includes creating and downloading from the desulphurisation system of draft gas 17, a second mixture of treated draft gas FG2 at a third temperature T3 from 52 ° C to 60 ° C (125 ° F to 140 ° F ).
[0292]
[0293] The method for updating includes injecting a second part P2 of the first quantity A1 of air as the draft gas superheat air fed from the air preheater 13 at a second temperature T2 with the second mixture of treated draft gas FG2 at the third temperature T3 thereby creating a third mixture of treated draft gas FG3 at a fourth temperature T4 of 68 ° C (155 ° F), before entering the discharge chimney 19; and admit the third mixture of treated draft gas FG3 into the discharge chimney 19 at the fourth temperature T4.
[0294]
[0295] In one embodiment, the method for the upgrade includes replacing at least a part of an outlet duct that connects the flue gas desulphurization system 17 and the flue chimney 19 with a manifold 39 that connects the gas desulphurization system of shot 17, and the excess air duct 65 and the discharge chimney 19.
[0296]
[0297] In one embodiment, the method for the update includes providing a draft gas reheat air particle removal system 33, so that the preheater 13 is in communication with the discharge chimney 19 through the particle removal system of draft gas reheating air 33. Particulate pollutants are removed from the second part P2 of the air, the particulate contaminants being introduced into the second part P2 of the air from a leak inside the air preheater 13 from the flue gas mixture FG.
[0298]
[0299] In one embodiment, the update method includes a humidity sensor 34 arranged in communication between the steam generator vessel 11 and the air preheater 13. The humidity sensor 34 measures the humidity of the shot gas mixture FG to determine a magnitude of the first temperature T1.
[0300]
[0301] In one embodiment, the update method includes providing an infrared sensor 32, and determining, with the infrared sensor, the cold end metal temperature of the air preheater 13, comparing the cold end metal temperature with the temperature of water dew point; and controlling the temperature of cold end metal so that it is not less than the temperature of the water dew point, with the control unit 71 as described herein.
[0302]
[0303] After implementing the update method, the steam generator system 10, 10 ', 10 "has a second thermal efficiency that is at least as large as the first thermal efficiency of the prior art steam generator system (for example, the steam generator system 100, 100 'of Figs. 1 and 2 of PCT Patent Application PCT / US2017 / 13459, respectively) before implementing the update method In such an embodiment, the original steam generator system operates with a humid chimney limited to draft gas outlet speeds of the order of 55 to 60 and feet per second thereby preventing the contaminating mist from leaving the discharge chimney 19. Such a wet chimney is equipped with condensate collection means that drain into the water treatment facility that removes contaminants before draining from the installation.Using this invention, the updated installation works with a dry chimney that Technically it can work with firing gas output speeds of up to approximately 100 feet per second. The draft gas velocity that is a function of the load, that is under low load conditions is low and the maximum operational load can be limited by the maximum sustainable draft gas velocity. It will therefore be appreciated that once updated, the steam generator system 10, 10, 10 'can operate at higher loads than was previously possible resulting in the generation of steam and increased power output from the steam generator vessel 11. Even when operating at a load no greater than the previous one, the absence of a humid chimney results in decreased water use together with associated cost savings because it does not need to operate any condensate water treatment so far collected from the discharge chimney 19. The present invention also includes another method for improving the effectiveness of a steam generating system 10. The method includes providing a steam generating system 10 that includes a steam generating vessel 11, the supply system of air 13D, the air preheater 13, the first particle removal system 14, the second particle removal system 33, the flue gas desulfurization system 17, and the flue gas discharge chimney 19. The system steam generator 10 has the air supply system 13D in communication with the steam generator vessel 11 through the air preheater 13. The steam generator vessel 11 is in communication with the discharge chimney 19 through the air preheater 13, the first particle removal system 14 and the flue gas desulfurization system 17, with the first particle removal system 14 being located downstream of the precalen tador of air 13, with the system of desulfurization of gas of shot 17 being located downstream of the first system of withdrawal of particles 14; with the discharge chimney 19 being located downstream of the flue gas desulfurization system and with the air preheater 13 being in communication with the discharge chimney 19 through the second particle removal system 33. The method includes providing a humidity sensor 34 disposed between the steam generator vessel 11 and the air preheater 13, and providing an infrared sensor 32 close to, or in the air preheater 13. The method includes measuring the humidity of the draft gas mixture. FG with the humidity sensor to determine a magnitude of a first temperature T1.
[0304]
[0305] The method includes providing, through the air supply system 13D, a first quantity A1 of air to the air preheater 13, the first quantity A1 of air being of a magnitude greater than that required for the combustion of the fuel in the generator vessel of steam 11, and the air preheater 13 providing the first quantity A1 of air at a mass flow sufficient to establish a first temperature T1 of a mixture of draft gas FG leaving the air preheater 13, the first temperature being T1 such that the air preheater has a cold end metal temperature that is not less than the temperature of the water dew point in the air preheater 13, and such that the temperature of cold end metal is less than a temperature from the dew point of sulfuric acid and the first temperature T1 being from about 105 ° C (220 ° F) to about 125 ° C (257 ° F).
[0306]
[0307] The method includes determining, with the infrared sensor 32, the metal temperature of cold end in the air preheater 13, compare the temperature of the cold end metal with the temperature of the water dew point; and controlling the temperature of cold end metal to be lower than the temperature of the water dew point, using control unit 71, as described herein.
[0308]
[0309] The method includes mitigating SO ³ in the shot gas mixture generated in the steam generator vessel 11. Mitigation of SO ³ occurs before the shot gas mixture FG enters the air preheater 13. The preheater Air 13 is configured to heat the first amount of air A1 to a second temperature T2 of about 228 ° C to 399 ° C (550 ° F to 750 ° F). A first part P1 of the first quantity A1 of air is supplied as combustion air to the steam generator vessel 11 for combustion of the fuel.
[0310]
[0311] The method includes discharging the shot gas mixture FG at the first temperature T1, directly from the air preheater 13 to the particle removal system 14, thereby removing the particles from the shot gas mixture FG and creating a first mixture FG1 treated draft gas. The first mixture of treated shot gas FG1 is discharged from the particle removal system 14 directly into the shot gas desulfurization system 17 thereby creating and discharging from the shot gas desulfurization system 17, a second mixture of FG2 treated draft gas at a third temperature T3 from 52 ° C to 60 ° C (125 ° F to 140 ° F).
[0312]
[0313] The method includes removing particulate contaminants from the second part P2 of the air. The particulate contaminants being introduced into the second part P2 of the air from a leak inside the air preheater 13 from the shot gas mixture FG. A second part P2 that the first quantity A1 of air is injected as draft gas superheat air fed from the air preheater 13 at the second temperature T2 with the second mixture of treated draft gas FG2 at the third temperature T3 thereby creating a third mixture of treated draft gas FG3 at a fourth temperature T4 of at least 68 ° C (155 ° F), before entering the discharge chimney 19. The third mixture of treated draft gas FG3 is admitted in the discharge chimney 19 at the fourth temperature T4.
[0314]
[0315] As Fig. 5 is shown, a graph generally designated with the number 70 has the temperature of the superheat air of draft gas P2 in degrees Fahrenheit designated on an X-axis 72 and the ratio of superheat air RR in percentage equal to the mass flow rate Wr of the air of the draft gas superheat P2 (i.e., the second part P2 of the first quantity A1 of air) divided by 100 times the mass flow rate W ^g of the purified gas FG2 leaving the FGD 17 system (Figs. 3 and 4) at 125 ° F, on a Y-axis 71. Graph 70 and includes graphs for six different temperature increases DTr of the FG2 draft gas leaving FGD 17 (Figs. 3 and 4). Specifically, the chart includes a chart 80 for DTr of 5 ° F, a chart 81 for DTr of 10 ° F, a chart 82 for DTr of 20 ° F, a chart 83 for DTr of 30 ° F; a graph 84 for DTr of 40 ° F and a graph 85 for DTr of 50 ° F, illustrating the ratio of RR superheat air as a function of the temperature of the superheat air P2. For example, the RR superheat ratio is between approximately 1 percent at point 86 (i.e. 800 ° F, 0.9% for the 5 ° F DTr of Figure 80) approximately 16 percent at point 87 (that is, 500 ° F, 15.9% at 500 ° F for the 50 ° F DTr of Figure 85). For figure 85 for the 50 ° F DTr, the RR is between approximately 9 percent at point 88 (i.e. 800 ° F, 9.1% for the 50 ° F DTr of figure 85) to approximately 16 by the way at point 87 (i.e. 500 ° F, 15.9% at 500 ° F for the 50 ° F DTr of figure 85). Although the ranges of the RR overheating ratio of 1 percent to 16 percent are shown and described, other ranges of the overheating ratio may be employed, depending on the DTr and the temperature of the overheating air P2. The inventors arrived at data points and graphs 80-85 of Fig. 5 as a result of significant test analyzes, thereby discovering the surprising results graphically illustrated in graph 70 of Fig. 5.
[0316]
[0317] As Fig. 6 is shown, a graph 90 has an air preheater effectiveness 13 in the percentage shown on the X axis 92 and temperature in degrees Celsius shown on the Y axis 91 for a 1000 MW steam generator system 10, 10 'with a temperature rise of 28 ° C (50 ° F) of the flue gas FG2 leaving the FGD 17 as a result of the injection of the flue air of the flue gas P2 in the duct 62 between the FGD 17 and the discharge chimney 19. Figure 90 includes a graph 93 of the effectiveness of the air preheater 13 in terms of temperature T2 of secondary air P1, P2 (Figs. 3 and 4). Graph 90 includes a graph 94 of the effectiveness of the air preheater 13 in terms of temperature T1 of fG draft gas outlet (Figs.
[0318] 3 and 4). The inventors have discovered that maintaining the thermal efficiency of the steam generator system 10.10 'at a differential temperature DT of 35 ° C between the outlet temperature of FG of flue gas of 150 ° C of the steam generator system of prior art 100, 100 'shown in PCT Patent Application PCT / US2017 / 13459 (illustrated by dashed line 98''in figure 90) and the outlet temperature T1 of the FG draft gas (Figs. 3 and 4 ) of approximately 105 C (illustrated by dashed line 98 'in figure 90) is required. As the differential temperature DT of the flue gas outlet temperature increases, the thermal efficiency improvements of the steam generator system 10, 10 'are made. For example, as shown in graph 90, an increase in thermal efficiency is performed at point 94A of line 94 where the outlet temperature of draft gas T1 is 90 ° C and the effectiveness of the air preheater It's 97 percent. The increased thermal efficiency and effectiveness of the air preheater is the result of the first amount of air A1 that is greater than that supplied through the air preheaters and / or increased efficiency or increased area of the heat transfer elements in the air preheater 13 in comparison to the heat transfer elements used in prior art air preheaters. As shown in graph 90, the effectiveness of the air preheater 13 and the increased thermal efficiency of the steam generating system 10, 10 ', compared to the steam generating systems of the prior art 100, 100' of the Application for PCT patent PCT / US2017 / 13459, is also realized through an increase in the temperature of the first part P1 of the first quantity A1 of air supplied to the steam generator vessel 11 for combustion of the fuel. Graph 90 includes a graph 93 illustrating an increase in the effectiveness of the air preheater 13 as a function of the temperature of the first part P1 of the first quantity A1. For example, at point 93A where the temperature of the first part P1 of the first quantity A1 is 368 ° C and the effectiveness of the air preheater 13 is 97 percent, an increase in thermal efficiency is made of the steam generator system 10, 10 ', as compared to the steam generator systems of the prior art 100, 100' of the PCT Patent Application PCT / US2017 / 13459.
[0319]
[0320] In the embodiment illustrated in Fig. 8, in order to achieve low temperature operation of the air preheater 13 the amount of draft gas fed to the air preheater 13 has been reduced instead of using excess air as in the previous embodiments. This is facilitated upstream of the air preheater 13 by providing a purge duct 200 so that the draft gas FG leaving the steam generator vessel 11 is divided into two streams FG4 and FG5. The first stream FG4 is fed to, and discharged from, the air preheater 13 and the second stream FG5 purged into the duct 200. The volume of the second stream FG5 it can be controlled by means of valves (not shown) to achieve the first desired temperature T1 of the flue gas mixture FG4 leaving the air preheater 13. This second current FG5 is adequately cooled in an HX heat exchanger at a temperature T5 and then fed through the conduit 201 to the manifold 202, so that it is recombined with the first current FG4 to recreate the current of the draft gas FG which then enters the ESP 14 at a temperature T1 '. In one embodiment, the temperature T1 referred to in the embodiments of Figs. 3, 4 and 7 and the temperature T1 'referred to in the embodiment of Fig. 8, are identical or almost identical. In the embodiment shown in Fig. 8, the amount of air A2 passing through the air preheater 13 is that volume P1 that is required for combustion, that is, unlike the first quantity A1 required for the illustrated embodiments. in Figs. 3, 4 and 7 and there is no part of excess air P2 produced.
[0321]
[0322] In the embodiment illustrated in Fig. 8 instead of using excess air P2 for the superheating of draft gas, a stream of air A3 enters and is heated in the heat exchanger HX by the second stream of draft gas FG5. The air stream A3 exits the heat exchanger HX and is fed through the duct 203 at a temperature T6 to the manifold 204 through which it is injected as draft gas reheating air to effect the chimney reheating as described the embodiments illustrated in Figs. 3, 4 and 7. In one embodiment, the temperature T6 illustrated in Fig. 8 and the temperature T2 referred to in the embodiments of Figs. 3, 4 and 7, are identical or almost identical. In one embodiment, the heat exchanger HX is configured so that the second draft gas stream FG5 passes over the tubes directly through which the air stream A3 flows (for example, a direct heat exchanger). In one embodiment, the heat exchanger HX is configured so that the air stream A3 passes over the tubes directly through which the draft gas stream FG5 flows (for example, a direct heat exchanger). In one embodiment, the heat exchanger HX is configured in a known manner with a fluid heat exchange means that conducts heat from the draft gas stream FG5 to the air stream A2 (ie, an indirect heat exchanger) .
[0323]
[0324] As shown in Fig. 8, an optional air purge 205 can be used so that some or all of the air stream A3 can be used, similar to the third part P3 of the excess preheating air as has been described with reference to the embodiments illustrated in Figs. 3, 4 and 7, for example. Purging of Air 205 can avoid using the A3 air stream for reheating the chimney and instead use air purging 205 selectively to dry coal and / or start preheating applications as described herein.
[0325]
[0326] The applicant has discovered unexpected characteristics of the configuration illustrated in Fig. 8, compared to the use of conventional air preheater arrangements, are the reduction of the air outlet temperature of the air preheater in combination with the heat extraction FG flue gas to use for chimney reheating, preheating and / or coal drying purposes, for example. In the embodiment of Fig. 8, this is done by supplying less heat of draft gas in the air preheater 13 by diverting the second draft gas stream FG5 upstream of the air preheater 13 and extracting heat from it to be used for chimney reheating, preheating and / or coal drying purposes selectively if desired. On the contrary, in the embodiments illustrated in Figs. 3, 4 and 7 this is done by supplying excess air in the air preheater 13, so that the first quantity A1 produces both air for both combustion and air P2 for chimney overheating, preheating and / or drying purposes of coal selectively if desired. In the hybrid embodiment illustrated in Fig. 9, a combination of both solutions is used, that is, both the bypass gas bypass (i.e., FG5) and excess air (i.e., A1) in the air preheater 13.
[0327]
[0328] In the prior art, the heat extracted from the draft gas by the air preheaters is reintroduced into the steam generating vessels by the combustion air flowing through them. With the exception of thermal conduction losses, all heat extracted from the draft gas by the air preheater is reintroduced by the combustion air into the steam generating vessel. A feature of the preferred embodiments of the invention is that none of the heat extracted from the draft gas stream FG, nor in the excess air "produced" by the air preheater or by the heat exchanger associated with the draft gas removed / diverted upstream of the air preheater, is wasted during normal operation. Although it is not used to preheat combustion air, all the heat extracted is reintroduced in what could be called the complete steam water cycle, such as chimney reheating and / or for drying coal, for example.
[0329]
[0330] Although in the hybrid embodiment illustrated both the second part that excess air P2 Since the diverted draft gas FG5 heated the A3 air stream, it is used in whole or in part for the reinjection when the chimney overheats, it will be understood that the combination of the measurement of the second draft gas stream FG5 and the volume of the first quantity A1 of the preheater air that facilitates the downstream outlet temperature required for the air preheater 13. This measure can be adequately selective to achieve the desired results when appropriate during start-up or with different operating loads, i.e. , as referred to the outlet temperatures of draft gas FG of the steam generating vessel 11.
[0331]
[0332] In alternatives to the embodiments of Fig. 8 and Fig. 9, some or all of the excess air part P2 and / or some or all of the heated air stream A3 could, instead of being used to reheat the chimney , be used for preheating, starting preheating and / or carbon drying applications. It may, for example, be particularly advantageous to use the heated air stream A3 for coal drying applications. Similarly, it can be advantageous to avoid or minimize the flow in the draft gas stream FG5 during start-up or in low load conditions. Similarly, it may be advantageous to minimize the excess air part P2 during start-up or in low load conditions.
[0333]
[0334] Although in the embodiments illustrated in Fig. 8 and in Fig. 9 the second draft gas stream FG5 is recombined with the first draft gas stream FG4 immediately downstream of the air preheater 13, it will be understood that in other embodiments such recombination can be carried out further downstream. Alternatively, this second draft gas stream FG5 can be expelled into the atmosphere and / or treated separately from the first draft gas stream FG4.
[0335]
[0336] When the removal of particles and / or other pollution control equipment is necessary, it can be used to properly condition the second draft gas stream FG5 independently of those used to condition the portion of draft gas FG that passes through the preheater. air 13. Advantageously, the heat exchanger HX does not allow gas leakage from the draft gas stream FG5 to the air stream A3. Consequently, similar conditioning of the A3 air stream is not required before use for chimney reheating, equipment overheating and / or drying of coal.
[0337] As described above, the present invention includes a method for updating a steam generator system 100, 100 'of the PCT Patent Application PCT / US2017 / 13459 for its enhanced effectiveness. That method for updating includes reconfiguring an air supply source 13D so that the air preheater 13 supplies a first quantity A1 of air greater than that required for combustion of the fuel in the steam generator vessel 11 and reconfiguring at least one of the air supply source 13D and the air preheater 13 the air preheater 13 so that the first quantity A1 of air is provided at a mass flow sufficient to establish a first temperature T1 of a mixture of draft gas FG which leaves the air preheater 13, having the character of requirement that the invention requires. It will be appreciated that the present invention also includes a method for updating a steam generating system such as 100, 100 'of PCT Patent Application PCT / US2017 / 13459 with the apparatus of the embodiments illustrated in Fig. 8 and in Fig. 9 associated with the second draft gas stream FG5.
[0338]
[0339] The inventors have surprisingly discovered through years of experimentation, analysis and testing a combination of optimum temperature ranges and system configurations for the operation of the steam generator system 10 of the present invention that improves the thermal efficiency of the generator system. steam compared to prior art steam generating systems such as 100 and 100 'while reducing the potential for fouling deposits and visible chimney smoke column.
[0340]
[0341] For example, those skilled in the art have tried and failed to be able to increase the air flow through the preheater 13 to achieve a magnitude that exceeds that required for the combustion of the fuel in the steam generator vessel 11 and at the same time that is sufficient to establish the first temperature T1 of the shot gas mixture FG leaving the air preheater 13 having a temperature of 105 ° C (220 ° F) or lower, while in the same system employing all the characteristics of following specific design: 1) SO ³ mitigation in the draft gas mixture generated in the steam generator vessel 11, the SO ³ mitigation occurring before the shot gas mixture FG enters the air preheater 13; 2) set the air preheater 13 to heat the first amount of air A1 to a second temperature T2 from 288 ° C to 399 ° C (550 ° F to 750 ° F); 3) supplying a first part P1 of the first quantity A1 of air to the steam generator vessel 11 for combustion of the fuel; 4) download the FG shot gas mixture to the first temperature T1, directly from the air preheater 13 to the particle collection system 14 thereby eliminating the particles from the shot gas mixture FG and creating a first treated shot gas mixture FG1; 5) discharge the first mixture of treated shot gas FG1 from the particle removal system 14 directly into the shot gas desulfurization system 17 thereby creating and discharging the shot gas desulfurization system 17, a second FG2 treated draft gas mixture at a third temperature T3 from 52 ° C to 60 ° C (125 ° F to 140 ° F); 6) injecting a second part P2 of the first quantity A1 of air at the second temperature T2 with the second mixture of treated draft gas FG2 at the third temperature T3 thereby creating or a third mixture of treated draft gas FG3 a a fourth temperature T4 from 79 ° C to 88 ° C (175 ° F to 190 ° F), before entering the discharge chimney 19; and 7) admit the third mixture of treated draft gas FG3 into the discharge chimney 19 at the fourth temperature T4. A person skilled in the relevant art would understand that there is an almost infinite number of configurations that could be attempted by varying the temperature of the draft gas leaving the preheater 13 together with the seven design features defined above. Only as a result of the analysis, experimentation and testing have the inventors overcome the problems by completing the design features and discovering the optimal combinations as described and claimed herein.
[0342]
[0343] In general, testing, experimentation and analysis included the consideration of: 1) mixing the injection efficiency of the second part P2 of the first quantity A1 of air at the second temperature T2 with the second mixture of treated draft gas FG 2 shot; 2) concentrations of fly ash in different locations in the steam generating system including the amount in the second part P2 of the air; 3) determination of the amount of the second part P2 of the air that would provide sufficient heat to justify the removal of the GGH heat exchangers; 4) pressure drops through the steam generator system 10; 5) heat losses in the excess air duct 65; 6) the effect on the combustion of fuel in the steam generator vessel; 7) the effect on the thermal efficiency of the steam generator system; and 8) efficiency and water supply requirements for FGD 17.
[0344]
[0345] Those skilled in the art have been discouraged in reducing the temperature of the flue gas leaving the preheater to 105 ° C (220 ° F) or less due to various problems encountered. A first problem is that the level of draft gas temperature reduction (that is, reducing the temperature of the draft gas leaving the preheater to 105 ° C (220 ° F) or lower) cannot normally be achieved economically without increasing air flow. There is a practical limit to the amount of heat that can be recovered from the draft gas that passes through a normal air preheater. This limit is set based on the maximum possible heat transfer qmax = (m * c) min * (Tgi-Tai), where Tgi is the temperature of the draft gas entering the air preheater and Tai is the temperature of the air entering the air preheater. The quantity (m * c) min is the product of the mass flow rate and the specific heat of the minimum fluid, and for a normal air preheater the minimum fluid is the combustion air. As the mass air flow increases, there is a direct increase in the maximum possible heat transfer. The present invention makes use of the incremental air flow as part of the means for incrementally reducing the temperature of draft gas. In maintaining and improving the efficiency of the steam generator however, it is also necessary to maintain or improve the amount of heat returned to the steam generator. This is done by maintaining or improving the effectiveness of the air preheater, Effectiveness = Actual Heat Transfer / Maximum Possible Heat Transfer. It is the transfer of real heat to the combustion air that must be maintained or improved, and this is done a) by eliminating the use of the cold air vapor air preheater; or b) the use or more, and / or more highly effective heat transfer surface.
[0346]
[0347] A second problem is that there has been no significant demand for incremental, preheated air flow in the plants. The present invention provides a preheated air source that can be used for chimney gas reheating.
[0348]
[0349] A third problem is that for many fuels, a reduction in the temperature of the flue gas leads to a significant formation of scale deposits and / or corrosion of the air preheater. As needed based on the SO ³ content of the flue gas, the present invention makes use of SO ³ mitigation to reduce the SO ³ content at less than or equal to 5 ppmv entering the air preheater. This has been shown to prevent fouling and corrosion at reduced draft gas temperatures below the dew point of the original draft gas.
[0350]
[0351] A fourth problem is that plants without the means for adequate control of the minimum temperature of the cold end element have experienced severe corrosion due to the condensation of halogen acids at temperatures close to the dew point. of the water. In one embodiment, the present invention employs a draft gas moisture sensor to establish the water content of the draft gas, which can be used to calculate the water dew point. The dew points of the critical halogen acids (HCl, HF, HBr) can then be calculated using dew point correlations available in the literature. The use of an infrared sensor or other sensor can be used to determine the minimum cold end element temperature, which can be compared to critical dew points. Avoiding dew point condensation is achieved by a) the use of steam coils to preheat cold incoming air or 2) the reduction of the amount of preheated air used for chimney gas reheating.
[0352]
[0353] In another embodiment of the invention (it did not show) the second part P2 of the first quantity A1 of air is not used, or is only used in part, as a draft gas superheat air instead of being used exclusively, or predominantly, as preheating air supplied to a coal dryer during operation and selectively to the associated steam generator vessel 11 and / or upstream of the particle removal system 14 during commissioning. The use of excess air for the drying of coal effectively reduces the humidity in the coal supplied to the steam generator vessel 13 which reduces the thermal losses that can be expected as a result of the excess steam into which it becomes the draft gas. It is to be understood that this reduction in humidity can reduce the incidence of condensation in the equipment downstream at startup. In modern coal boilers, during startup it is necessary to light the steam generator vessel 11 with oil or natural gas as the starting fuel fed through combustion lances until the moment when the steam generator vessel 11 is sufficiently heated to keep the vortex flames formed by burning the coal fed from the coal burners. It is believed that starting too quickly can lead to unnecessary thermal impacts on pipe welds and consequent damage within the steam generator vessel, for example. Too slow starts will result in unnecessary use of oil and gas and an unwanted delay in bringing the steam generation system to a full operational load. Any way in which the start-up time can be reduced without increasing thermal impacts leads to operational and cost benefits beneficial to the plant operator. The use of the preheated air of this embodiment in addition to the normal preheated combustion air effectively puts more preheating on the vessel again during the start-up. 11 steam generation at moderately low temperatures and comparison with oil or gas flame. This allows a faster start without the additional thermal impacts of the burning start fuel more voluminously to provide the equivalent additional preheating. It will be appreciated that in this other embodiment the operation of the steam generating system does not depend on the presence of an FGD or on the rise of the draft gas temperatures and / or the operation of a dry chimney as is required variously in other described embodiments.
[0354]
[0355] As Fig. 10 is shown, the first amount of heat is used in the waste water drying system 77 which is in communication with the steam generating system 10. The waste water drying system 77 includes a waste tank. waste water storage 77T that is in fluid communication with the flue gas desulphurization system 17 through conduit 77W1 or through conduit 77K that supplies wastewater from other wastewater systems in the steam generating system . The waste water drying system 77 includes a spray drying vessel 77D that is downstream of the waste water storage tank 77T and in fluid communication with it through the ducts 77W2 and 77W3. A pump 77P is disposed between ducts 77W2 and 77W3 to transport waste water to the spray drying vessel 77D. The 77D waste water drying vessel has a water inlet that is configured with a 77N spray nozzle. The spray drying vessel 77D is in fluid communication with the air preheater 13 via a duct 77A that conveys heated air to the waste water drying vessel 77D. The heated air is mixed with, and evaporates, the wastewater sprayed into the waste water drying vessel 77D and thereby creating a particle waste that is transported out of the wastewater drying vessel 77D through a 77R discharge duct. The discharge conduit 77R transports the dry particle waste to the conduit 60 upstream of the particle removal system 14 for collection therein. The waste water drying vessel 77D also has a 77Q particle discharge port located in a lower conical part thereof, for optimum discharge of the particle waste for cleaning the internal parts of the waste water drying vessel. 77D. The waste water drying system 77 has utility in reducing or eliminating the amount of liquid effluents from the flue gas desulfurization system 17, although it does not adversely affect the heat regime of the steam generating system 10.
[0356] As Fig. 11 is shown, the first amount of heat is used in the waste water drying system 77 'which is in communication with the steam generating system 10. The waste water drying system 77' includes a waste water storage tank 77T 'that is in fluid communication with the flue gas desulfurization system 17' through the 77W1 'line or through the 77K' pipeline that supplies wastewater from other wastewater systems in the steam generator system. The waste water drying system 77 'includes a spray drying vessel 77D' which is downstream of the waste water storage tank 77T 'and in fluid communication with it through the ducts 77W2' and 77W3 '. A pump 77P 'is disposed between the ducts 77W2' and 77W3 'to transport the waste water to the spray drying vessel 77D'. The waste water drying vessel 77D 'has a water inlet that is configured with a spray nozzle 77D'. The spray drying vessel 77D 'is in fluid communication with the air preheater 13 through a duct 77F' that conveys the flue gas FG5 to the waste water drying vessel 77D '. The flue gas FG5 is mixed with, and evaporates, the waste water sprayed in the waste water drying vessel 77D 'and thereby creating a dry particle waste that is transported out of the wastewater drying vessel 77D 'through a discharge duct 77R'. The discharge duct 77R 'transports the dry particle waste in the duct 60 upstream of the particle removal system 14 for collection therein. The waste water drying vessel 77D 'also has a 77Q' particle discharge port located in a conical bottom thereof, for optimum discharge of the dry particle waste or for cleaning the internal parts of the drying vessel of waste water 77D '. In one embodiment, the flue gas FG5 flows through the heat exchanger HX through the conduit 200 and again into the conduit 60 through the conduit 201. The air stream A3 flows through the heat exchanger HX and the air The heated air is discharged therein into the duct 203. The heated air is optionally supplied to the waste water drying vessel 77D 'through the purge duct 205. The wastewater drying system 77' has utility to reduce or eliminate the amount of liquid effluents from the flue gas desulphurization system 17, although not adversely affecting the heat regime of the steam generating system 10.
[0357]
[0358] As shown in Fig. 12, the first amount of heat is used to improve the heat regime of the steam generating system 10, for example, by preheating the supply water supplied to the steam generating vessel 11. A heat exchanger 51 (for example, a low temperature economizer or a low pressure economizer) is located between, and in fluid communication with the air preheater 13 and the particle removal system 14. The heat exchanger 51 has a tube bundle 51T arranged therein. FG draft gas flows around the outside of the tube bundle 51T. The tube bundle 51T has an inlet 51A to receive the water or supply condensate to be heated; and an outlet 51B to discharge its supply water. The heated supply water is transported to other supply water heaters before being discharged into the water wall tubes (not shown) of the steam generator vessel 11.
[0359]
[0360] As Fig. 13 is shown, the first amount of heat is used to improve the heat regime of the steam generating system 10, for example, by preheating the supply water that is supplied to the steam generating vessel 11. A heat exchanger 51 'is in fluid communication with the conduit 63 that carries the flue gas FG5 to the heat exchanger 51'. Heat exchanger 51 'is in fluid communication with conduit 60 through conduit 201. Heat exchanger 51' has a bundle of tubes 51T 'disposed therein. FG5 draft gas flows around the outside of the tube bundle 51T '. The tube bundle 51T 'has an inlet 51A' to receive the supply water or condensate to be heated; and an outlet 51B 'to discharge the supply water thereof. The heated supply water is transported to another of the supply water heaters before being discharged into the wall tubes that water (not shown) from the steam generator vessel 11.
[0361]
[0362] Although Figs. 12 and 13 illustrate that the first amount of heat is used to improve the heat regime of the steam generating system 10, for example, by preheating the supply water that is supplied to the steam generating vessel 11, the present invention is not limited in this sense, since the first amount of heat can be used by other means that include but are not limited to condensation heating, mitigation of parasitic strokes (for example, space and heating of drinking water and steam for turbines to drive rotating equipment such as fans instead of electrically driven motors, and other steam or heat loads other than steam used to generate electricity) and efficiency improvements of the steam cycle.
[0363]
[0364] As shown in Fig. 14, the first amount of heat is used to evaporate water from an ash sludge discharged from a wet ash removal system 29. The wet ash removal system 29 includes a collection tank 29T what It is in fluid communication with the fly ash hoppers 14H of the particle removal system 14 through the conduits 29C and 29D. A water supply 29W is in fluid communication with the collection tank 29T through the conduits 29X and 29B and a pump 29Y located between them. An evaporator vessel 29V (for example, a direct or shell and tube heat exchanger) is located downstream of the collection tank 29D and is in fluid communication with it through the conduit 29E. The evaporator vessel 29V is in fluid communication with a raft 29P through a conduit 29F. All or a portion of the first amount of heat is supplied to the evaporator vessel 29V through the conduit 29A. The conduit 29A exits from one side downstream of the air side of the air preheater 13. The heated air from the air preheater 13 evaporates a whole part of the water contained in the ash sludge residing in the evaporator vessel 29V to reduce the amount of water transported to the 29P ash pool.
[0365]
[0366] As Fig. 15 is shown, the first amount of heat is used to evaporate water from an ash mud discharged from a wet ash removal system 29 '. The wet ash removal system 29 'includes a collection tank 29T' which is in fluid communication with the fly ash hoppers 14H 'of the particle removal system 14' through the conduits 29C 'and 29D'. A water supply 29W 'is in fluid communication with the collection tank 29T' through the conduits 29X 'and 29B' and a pump 29Y 'located between them. An HX evaporator vessel (for example, a direct or shell and tube heat exchanger) is located downstream of the collection tank 29D 'and is in fluid communication with it through a conduit 29E'. The evaporator vessel HX is in fluid communication with a basin of ashes 29P 'through a conduit 29F'. All or a portion of the first amount of heat is supplied to the evaporator vessel HX through the draft gas FG5 which is transported to the evaporator vessel 29D 'through the conduit 200. The conduit 200 exits the conduit 63 upstream of the gas side draft of the air preheater 13. The draft gas FG5 from the air preheater 13 evaporates all or part of the water contained in the ash sludge that resides in the evaporator vessel HX to reduce the amount of water transported to the raft of 29P 'ashes. The draft gas FG5 is returned to the downstream side of the draft gas side of the air preheater 13 in the duct 60 through the duct 201. It will be appreciated that the ash mud derived directly from the steam generator 11 can be treated as similarly as mentioned above for the derivative of the wet ash removal system 29.
[0367] Although the present invention has been set forth and described with reference to certain embodiments thereof, it should be noted that other variations and modifications may be made, and it is intended that the following claims cover variations and modifications within the true scope of the invention.

权利要求:
Claims (16)
[1]
1. A method to improve the effectiveness of a steam generating system, the method comprising:
providing a steam generating system comprising a steam generating vessel, an air supply system and an air preheater, the air supply system being in communication with a steam generating vessel through the air preheater, and being the steam generator vessel in communication with the air preheater;
the air supply system providing a first amount of air to the air preheater;
provide at least a portion of the first amount of air to the steam generator vessel as combustion air;
discharge a mixture of draft gas from the steam generator vessel;
flow at least part of the draft gas mixture into the air preheater; Y
mitigate the SO3 in the draft gas mixture before the draft gas mixture enters the air preheater.
[2]
2. The method of claim 1, further comprising:
provide heat capture means in communication with at least one of the steam generator, the air preheater, and the draft gas mixture; Y
transfer a first amount of heat away from at least one of the steam generator, the air preheater, and the draft gas mixture.
[3]
3. The method in any one of the preceding claims, further comprising:
provide a particle removal system and a flue gas desulfurization system, the particle removal system being downstream of the air preheater, and the flue gas desulfurization system being downstream of the particle removal system;
Discharge all or a portion of the draft gas mixture leaving the steam generator vessel directly from the air preheater to the particle removal system thereby removing the particles from the draft gas mixture and creating a first gas mixture of the treated shot; Y
Discharge the first gas mixture from the treated draft from the particle removal system directly into the gas desulphurization system of the shot thereby creating and discharging a second gas mixture from the treated draft from the shot gas desulfurization system.
[4]
4. The method of any one of the preceding claims, wherein the first amount of heat is approximately 10 to 25 percent of that used to preheat combustion air.
[5]
5. The method of any one of the preceding claims, wherein the first amount of air is of a magnitude greater than that required as combustion air.
[6]
6. The method of any one preceding fabric claims, further comprising:
provide a flue gas discharge chimney, with the steam generator vessel being in communication with the flue gas chimney through at least one of the air preheater, the particle removal system and the flue gas desulfurization system ; Y
use at least a portion of the first amount of heat to increase the temperature of the draft gas mixture, upstream of a chimney outlet, to a sufficient extent to mitigate the visible smoke column that comes out of the discharge chimney or to mitigate corrosion in the discharge chimney.
[7]
7. The method of any one of the preceding claims, further comprising at least one of:
use at least a portion of the first amount of heat during boiler start-up to selectively preheat at least one of the particle removal system, the flue gas desulfurization system, and intermediate ducts;
use at least a portion of the first amount of heat during operation of the boiler for a coal drying installation, and then expel it into the atmosphere;
release at least a portion of the first amount of heat into the atmosphere;
use at least part of the first amount of heat to improve the steam generator system regime:
use at least a portion of the first amount of heat to evaporate water from an ash sludge discharged from a wet ash removal system in communication with at least one of the particle removal system and the steam generating vessel; Y
use at least a portion of the first amount of heat in a wastewater system to reduce the discharge of water from it.
[8]
8. The method of claim 7, wherein the improvement of the heat regime comprises at least one of:
use at least part of the first amount of heat to improve the efficiency of the steam cycle;
use at least a portion of the first amount of heat to preheat the feed water or condensate supplied to the steam generating system; Y
use at least part of the first amount of heat to reduce parasitic loads in the steam generator system.
[9]
9. The method according to one of claims 3 and 7, further comprising:
supplying at least one of a part of the draft gas mixture and a part of the first amount of air to the wastewater system to evaporate the wastewater therein;
create a particle waste in the wastewater system; Y
transport the particle waste to the particle removal system.
[10]
10. The method of any one of the preceding claims, wherein the mitigation of SO ³ in the flue gas mixture comprises at least one of:
chemical transformation; Y
supply low sulfur fuel to the steam generator system.
[11]
11. The method of any one of the preceding claims, further comprising configuring the air preheater to heat the first amount of air approximately 288 ° C to 399 ° C (550 ° F to 750 ° F).
[12]
12. The method of any one of the preceding claims, wherein the air supply system provides the first amount of air to the air preheater at a mass flow sufficient to establish a first temperature of the draft gas mixture that leaves the air preheater, the first temperature being such that the air preheater has a cold end outlet temperature defined by the air preheater that operates with increased heat recovery (RH) of at least 1% as calculated from according to the equation:
RH = 100% x ((Tgi-TgoAdvX) / (Tgi-TgoSTD) - 1).
[13]
13. The method of claim 12, wherein the air preheater has a cold end metal temperature that is not less than a water dew point temperature in the air preheater, and such that the metal temperature cold end is less than a dew point temperature of acid sulfuric and the temperature is between about 105 ° C (220 ° F) and about 125 ° C (257 ° F).
[14]
14. A method for updating a steam generating system to be configured to operate according to any one of the preceding claims.
[15]
15. The method for updating a steam generator of claim 14, wherein the discharge of the first mixture of treated draft gas from the particle removal system directly into the desulfurization system of the draft of at least one heat exchanger existing in the steam generating system, between the particle removal system and the flue gas desulfurization system, before the update.
[16]
16. A steam generator system configured to operate according to any one of claims 1-15.

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同族专利:

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公开号 | 公开日

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ZA201900427B|2019-09-25|

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JP2019525114A|2019-09-05|

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ES2738919B1|2021-02-25|

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CN107923610A|2018-04-17|

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EP3482124A1|2019-05-15|

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KR20190026783A|2019-03-13|

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GB2567104A|2019-04-03|

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ES2745035R1|2020-03-03|

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CN107923610B|2020-05-19|

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WO2018009247A1|2018-01-11|

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PL429398A1|2019-11-18|

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US20180010792A1|2018-01-11|

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EP3482124B1|2020-09-02|

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US10955136B2|2021-03-23|

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SI3482124T1|2021-01-29|

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PL3482124T3|2021-03-08|

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JP2022024062A|2022-02-08|

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US20190301735A1|2019-10-03|

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KR20190024970A|2019-03-08|

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AU2017291660A1|2019-02-07|

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EP3482125A1|2019-05-15|

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CN110036238B|2021-08-10|

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ES2738919A2|2020-01-27|

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US20210285637A1|2021-09-16|

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US10267517B2|2019-04-23|

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PL429572A1|2019-11-18|

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CN110036238A|2019-07-19|

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WO2018009781A1|2018-01-11|

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JP2019520543A|2019-07-18|

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GB2567104B|2021-09-22|

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WO2018009926A1|2018-01-11|

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GB201901694D0|2019-03-27|

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ES2830731T3|2021-06-04|

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ES2738919A8|2020-02-19|

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WO2018009233A1|2018-01-11|

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AU2017292939A1|2019-02-07|

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ES2738919R1|2020-02-20|

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ZA201900378B|2019-10-30|

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优先权:

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申请号 | 申请日 | 专利标题

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US15/205,243|US10267517B2|2016-07-08|2016-07-08|Method and system for improving boiler effectiveness|

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PCT/US2016/055958|WO2018009233A1|2016-07-08|2016-10-07|Method and system for improving boiler effectiveness|

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PCT/US2017/013459|WO2018009247A1|2016-07-08|2017-01-13|Method and system for improving boiler effectiveness|

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PCT/US2017/041078|WO2018009781A1|2016-07-08|2017-07-07|Method and system for improving boiler effectiveness|

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PCT/US2017/041332|WO2018009926A1|2016-07-08|2017-07-10|Method and system for improving boiler effectivness|

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