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    • 专利摘要:
    A process for producing oxygen-free water, in which carbon dioxide-containing gas is pressurized, feeds the pressurized gas into an absorption tank, feeds pure water into an absorption tank or shortly before it, absorbs carbon dioxide containing pressurized gas into water in an absorption tank, the water circulates in which carbon dioxide has been absorbed from an absorption tank to a desorption tank, absorbs carbon dioxide absorbed in water from water in a desorption tank, recovers desorbed carbon dioxide from the water, recycles oxygen-free water from the water leaving the desorption tank, and optionally recirculates part of the water from the desorption tank.
    公开号:FI20185573A1
    申请号:FI20185573
    申请日:2018-06-27
    公开日:2019-12-28
    发明作者:Lauri Soronen；Timo Juutilainen
    申请人:Carbonreuse Finland Oy；
    IPC主号:
    专利说明:

    A method for producing deoxygenated water
    Object of the invention
    The invention relates to a process for producing anoxic water. The process involves removing oxygen from the water and recovering carbon dioxide from the gas containing it. The method involves pressurizing the gas, absorbing the carbon dioxide contained in the pressurized gas in water, desorbing the carbon dioxide absorbed in the water, recovering deoxygenated water, and recovering the carbon dioxide desorbed from the water.
    State of the art
    Non-oxygenated water is needed, for example, in the soft drinks industry, since it is important for food preservation that they do not come in contact with oxygen. 15 Traditionally, deoxygenated water is produced by dedicated equipment that removes oxygen from the incoming water. The general principle is that oxygen desorption is achieved using added stripping gas (usually carbon dioxide or nitrogen) at normal atmospheric pressure. Water is passed from the top of the column and downstream of the stripping gas in the opposite direction. The column is often a filler column which improves the contact surface between water and gas. The oxygen-depleted water is recovered at the bottom end of the column. The process also often uses pasteurization and CIP (Clean-In-Place) technology to improve water quality for food applications. The process always requires a separate stripping gas to make it work. The loss of gas in the process can be up to 5%.
    The capture of carbon dioxide (CO 2 ) is described, for example, in Patent Fl 127351. The publication describes a system and method for recovering carbon dioxide from a gas containing it. The method comprises pressurizing the gas, absorbing the carbon dioxide contained in the pressurized gas in water in an absorption tank, desorbing the carbon dioxide absorbed in water from the water in the desorption tank, recirculating water from the absorption tank to the desorption tank, and recovering from the The patent does not describe a process for producing anoxic water.
    20185573 prh 27-06- 2018
    Another method and system for carbon capture is described in FI 124060. The method of this publication comprises the steps of: pressurizing the gas, feeding the pressurized gas and water used as solvent to the absorption column, supplying the carbon dioxide from , the carbon dioxide leaving the desorption column is recovered. The method also feeds gas into an auxiliary adsorption column prior to pressurizing the gas and feeds water exiting the desorption column back into the auxiliary adsorption column. The patent does not describe a process for producing anoxic water.
    Prior art solutions always require a separate process and equipment to produce deoxygenated water.
    Description of the Invention
    The present invention solves the problems of the prior art by providing a cost-effective combined process that can produce deoxygenated water while recovering carbon dioxide from the gas it contains. It is an object of the invention to provide a more economical, efficient and environmentally friendly process for producing deoxygenated water compared to the prior art. The process is characterized by what is disclosed in the independent claim. Preferred embodiments are disclosed in the dependent claims.
    The invention is based on the finding that good synergistic effects are achieved by combining the production of deoxygenated water (i.e. deaerated water) and the capture of carbon dioxide from gas. In order to maximize the absorption of carbon dioxide, it is advisable to displace oxygen from the water. Thus, the inventors have developed a process for removing oxygen competing with carbon dioxide from a water absorption point of view.
    Non-oxygenated water and carbon capture are needed, for example, in breweries. There are no other known processes that can simultaneously capture carbon dioxide and produce oxygen-free water. The advantages to be achieved include, among other things, that the purification result is improved and even more pure oxygen-free water is obtained than by known methods. Combining processes also brings savings in investment, maintenance and operating costs.
    The invention thus relates to a process for producing anoxic water.
    The process for producing anoxic water according to the invention is characterized in that the process comprises the steps of:
    - pressurized gas containing carbon dioxide,
    - supplying pressurized gas to an absorption tank,
    - feeding clean water to or from the absorption tank,
    - the carbon dioxide contained in the pressurized gas is absorbed into the water in an absorption tank,
    - recycling the water in which the carbon dioxide has been absorbed from the absorption vessel to the desorption vessel,
    - desorbing the carbon dioxide absorbed in water from the water in a desorption tank,
    - recovering carbon dioxide desorbed from water,
    recovering deoxygenated water from the water stream leaving the desorption tank, and
    optionally recirculating some of the water from the desorption tank back to the absorption tank.
    Brief description of the figures
    The invention will now be described in detail by way of example with reference to the accompanying drawings, in which Figure 1 shows a Kohl Nielsen curve.
    20185573 prh 27-06-2018 Figure 2 is a flow chart of a system suitable for an embodiment of the method of the invention.
    Figure 3 is a flow diagram of a system suitable for an embodiment of another method according to the invention.
    Definitions
    In the context of the present invention, deoxygenated water or similar expressions refers to water with up to 0.02 ppm dissolved oxygen.
    20185573 prh 27-06- 2018
    In the context of the present invention, pure water or similar expressions refer to food grade water that does not contain hazardous chemicals. For example, pure water can be tap water.
    In the context of the present invention, carbon dioxide-containing gas or crude gas or the like is meant to mean a gas mixture having, in addition to carbon dioxide gas, at least one other substance in gaseous form. The carbon dioxide-containing gas may be gas recovered from the fermentation vessel, flue gas, natural gas, etc.
    In the context of the present invention, an absorption vessel means any absorption vessel or absorption column suitable for the process of the invention, e.g., a bubble column or a filler column.
    In the context of this invention, a desorption tank means any desorption tank or desorption column suitable for the process of the invention.
    Detailed Description of the Invention
    The present invention is based on utilizing a carbon dioxide capture process using pure water to produce anoxic water. The action is based on physical absorption, in which carbon dioxide is dissolved in a liquid (water) under high pressure and released by lowering the pressure and / or raising the temperature. If carbon dioxide is absorbed (i.e. absorbed) into the pure water by means of elevated pressure and / or low temperature and subsequently removed from the process by reducing the pressure and / or heating the liquid, oxygen-free water may be formed after the desorption step.
    The synergistic effect of the process of the invention is that the more the oxygen is removed from the water, the more efficient the carbon dioxide capture process is, since the carbon dioxide displaces the oxygen in the water. For this reason, the inventors realized that certain methods of carbon capture could work effectively in the simultaneous production of deoxygenated water. An advantage of the invention is that the process works to produce food-grade deoxygenated water, if carbon
    20185573 prh 27-06-2018 In the oxide recovery process no chemicals are added to the water. Also, in the process of the invention, after desorption of carbon dioxide, the freshly decarbonised water no longer contains oxygen.
    According to Henry's law, the absorption (or absorption) of a gas depends not only on the gas-specific constant but also on the partial pressure. If the pressure is, for example, 10 bar and the carbon dioxide content is, for example, 25%, its partial pressure is 25/100 * 10 = 2.5 bar, so that only one-fourth of the gas can be contained in the water. In the process according to the invention, the process has been developed such that the water is completely emptied of all gas, thereby absorbing as much carbon dioxide as possible. When the carbon dioxide is removed from the water during the desorption step, only a little absorbed carbon dioxide, but no oxygen, is left in it, producing oxygen-free water.
    The inventors realized that if water, i.e. deoxygenated water, is recovered from the desorption tank and replacement water is added to or just before the absorption tank, then the process will work just as well or better and in addition, deoxygenated water may be produced. The method according to the invention is thus based on the finding that the dissolution efficiencies of carbon dioxide and oxygen can be utilized to produce anoxic water. Carbon dioxide is highly soluble in water. Oxygen also dissolves in water, but not as well. According to Hen20 ry's law, dissolution is effected by:
    C H = K H * Po
    The amount of gas dissolved is Henry's constant. for gas times the partial pressure of that gas. The partial pressure is calculated at that gas concentration times the pressure of the liquid. For example, CO 2: Ha 10 bar and a temperature of 10 ° and a solubility in water of 21 to 25 g / l maximum (FIG. 1). According to Henry's law, each gas reserves its own share of the dissolution rate at its partial pressure. Thus, according to the invention, it is advantageous to increase the concentration of carbon dioxide gas at the expense of other gases, whereby more carbon dioxide is contained in the water and the recovery is improved.
    In the case of the same pressure (10 bar) but only 10% CO 2 , the partial pressure of carbon dioxide is only 1 bar, whereby it dissolves at about 3 g / l, ie the curve (Figure 1) is considered to be the dissolution at 1 bar. Each gas has its own coefficient K H and, for example, with oxygen it is about 1:30 compared to CO 2 .
    20185573 prh 27-06- 2018
    Synergy works for different carbon capture processes. In the absorption step, for example, a surface mixer or a bubble column may be used. However, not all carbon capture processes produce oxygen-free water. For example, the so-called. the amine in a method of mixing a MEA chemical to enhance absorption does not work because pure water is not used. The second is the distillation technique, in which the carbon dioxide is cooled, for example, to -20 degrees Celsius at 10 bar, whereupon the carbon dioxide is liquefied. Again, pure water is not used in this process, so oxygen-free water cannot be produced.
    The process for producing deoxygenated water according to the invention comprises the steps of:
    - pressurized gas containing carbon dioxide,
    - supplying pressurized gas to an absorption tank,
    - feeding clean water to or from the absorption tank,
    - the carbon dioxide contained in the pressurized gas is absorbed into the water in an absorption tank,
    - recycling the water in which the carbon dioxide has been absorbed from the absorption vessel to the desorption vessel,
    - desorbing the carbon dioxide absorbed in water from the water in a desorption tank,
    - recovering carbon dioxide desorbed from water,
    recovering deoxygenated water from the water stream leaving the desorption tank, and
    optionally recirculating some of the water from the desorption tank back to the absorption tank.
    The process of the invention is also a process for recovering carbon dioxide from a gas containing it. The method of the invention is also a method for removing air from water.
    According to a preferred embodiment, the carbon dioxide-containing gas contains at least 10 vol.% Carbon dioxide.
    According to a preferred embodiment, the desorbed carbon dioxide from the desorption vessel is recycled to the absorption vessel.
    According to a preferred embodiment, the gas is heated or water is cooled to increase absorption.
    20185573 prh 27-06- 2018
    According to a preferred embodiment, water in the absorption tank is mixed with a mixer which causes the water to circulate in the absorption tank by throwing it into the air space of the absorption tank and spreading it over the widest possible area of the air space of the absorption tank.
    According to a preferred embodiment, water in the desorption tank is mixed with a mixer which causes the water to circulate in the desorption tank by throwing it into the air space of the desorption tank and spreading it over as wide an area as possible in the air space of the desorption tank.
    According to a preferred embodiment, the water is mixed with a mixer comprising a motor, a drive shaft and at least one propeller located near the water surface at a depth where the hydrostatic pressure of the water is non-existent or nearly zero.
    According to a preferred embodiment, the method comprises introducing gas into the auxiliary adsorption tank or column prior to gas pressurization, and / or feeding a portion of the water leaving the desorption tank to the auxiliary adsorption tank or column.
    According to a preferred embodiment, at least part of the carbon dioxide exiting the desorption tank is liquefied and optionally distilled for recovery.
    A common process for producing deoxygenated water and carbon capture is advantageous, for example, in the beer and soft drinks industry. Carbon dioxide must be recovered, for example, from fermentation gas. In this case, carbon dioxide is usually dissolved in water. In a preferred embodiment of the invention, the process for producing deoxygenated water is combined with carbon dioxide recovery in a beer and / or soft drink facility, e.g., from a fermentation vessel.
    In a preferred embodiment of the invention, the carbon dioxide desorbed from the desorption vessel is recycled to the absorption vessel.
    20185573 prh 27-06- 2018
    In a preferred embodiment of the invention, the process comprises a pre-sorption step. According to a preferred embodiment, the pressure is dropped in at least two steps during the pre-sorption step. The partial pressure of carbon dioxide can then be increased gradually.
    In a preferred embodiment of the invention, the method comprises the step of introducing the carbon dioxide-containing gas into an auxiliary absorption vessel or column prior to feeding into an absorption vessel, and / or a step of after the absorption tank. The effect of this is to gradually increase the partial pressure of carbon dioxide, thereby strengthening the synergy between oxygen removal and carbon capture.
    As the proportion (partial pressure) of carbon dioxide is gradually increased in the absorption tank, it will displace the oxygen in the water and also enhance the capture (i.e. absorption) in the water. This can be achieved by dropping the pressure, e.g., in two steps; in the pre-sorption tank (e.g. the so-called Flash tank), the pressure is slightly reduced, whereby less absorbed gases such as oxygen and a small amount of CO 2 are returned to auxiliary adsorption and the rest to actual desorption. This positively influences the amount of CO 2 in the auxiliary adsorption and subsequently the absorption. In desorption, carbon dioxide is removed from the water by vacuum, but there is always a small amount of carbon dioxide left in the water. When water is recycled back to assist in sorption, the carbon dioxide will also utilize the total carbon dioxide partial pressure.
    In one embodiment, water from which the carbon dioxide has been absorbed from the absorption vessel is fed to a pre-adsorption vessel, from which the exhaust gas is fed back to the auxiliary adsorption vessel or column.
    In some preferred embodiments, the gas is heated or water is cooled to increase absorption. Similarly, water is heated in a pre-sorption tank (e.g.
    the so-called. Flash tank) and / or desorption in the separation of CO 2 gases. By thus enhancing the absorption and release of carbon dioxide, the proportion of carbon dioxide is thus increased, which thus contributes to the displacement of oxygen.
    20185573 prh 27-06- 2018
    In the final step, desorption, the carbon dioxide is separated from the water and the water is deoxygenated. After this step, deoxygenated water is recovered. According to one embodiment, the water is further disinfected by either heat treatment or UV light, making it more suitable for food use.
    In one embodiment of the method, water in the absorption tank is mixed with a stirrer that causes the water to circulate in the absorption tank by throwing it into the air space of the absorption tank and spreading it over the air space of the absorption tank. This provides the most efficient absorption of the carbon dioxide contained in the gas, such as flue gas, into the water mass contained in the absorption tank.
    In one embodiment of the method according to the invention, water in the desorption tank is mixed with a stirrer that causes the water to circulate in the desorption tank by throwing it into the air space of the desorption tank and spreading it over as wide an area as possible. This provides the most efficient desorption of the carbon dioxide of the carbon dioxide-absorbed water from the absorption vessel to the desorption vessel in the desorption vessel.
    According to one embodiment of the invention, water in the absorption tank is mixed with a mixer comprising a motor, a drive shaft and at least one propeller located near the water surface at a depth where the hydrostatic pressure of the water is virtually non-existent. The motor is preferably an electric motor.
    Combining the production and capture of deoxygenated water with a carbon capture process offers the following benefits:
    - producing cleaner oxygen-free water compared to the state of the art,
    - there is no need for separate stripping gas, as the carbon dioxide to be recovered can be used and this saves on gas supply costs,
    - the integration of processes results in savings in investment, maintenance and operating costs, since there is no need for separate equipment to produce deoxygenated water,
    20185573 prh 27-06- 2018
    the controllability of the method of the invention is improved by adjusting the amount of deoxygenated water recovered and the amount of replacement water added.
    If the carbon content of the raw gas (carbon dioxide gas) is high, even all the water can be recovered as oxygen-free water. However, if the carbon dioxide content of the crude gas is low, only about 30% to 50% of the circulating water should be used as anoxic water, so as not to jeopardize the oxygen displacement process described above, which is utilized in the process of the invention.
    The carbon dioxide capture system for the production of deoxygenated water can control parameters, heat pumps, water flow, etc. in each situation in an economically optimized manner. According to one embodiment, the pressure used in the absorption vessel is from 1 to 15 bar, preferably from 3 to 12 bar. According to one embodiment, the water to be added to the absorption vessel has a usable temperature of less than 10 ° C, preferably less than 5 ° C, more preferably less than 1 ° C. According to one embodiment, the pressure used in the desorption vessel is a vacuum, preferably less than 0.8 bar, more preferably less than 0.5 bar, more preferably 0.3 bar. Suitable pressures, temperatures, etc., will depend upon the entity as a whole and may be other than the above.
    The method according to the invention can be implemented in a system in which the absorption tank has a mixer whose function is to make water circulate in the absorption tank by throwing it into the air space of the absorption tank and spreading it in the air space of the absorption tank. In this way, carbon dioxide contained in a gas such as a flue gas can be absorbed as efficiently as possible into the water mass contained in the absorption tank.
    In one embodiment, the desorption tank also has a stirrer which serves to circulate water in the desorption tank by throwing it into the air space of the desorption tank and spreading it over as wide an area as possible in the air space of the desorption tank. This law provides for the most efficient desorption of carbon dioxide from water from the absorption tank to the desorption tank in the desorption tank.
    20185573 prh 27-06- 2018
    In one embodiment of the system, the agitator comprises a motor, a drive shaft and at least one propeller located near the water surface at a depth at which the hydrostatic pressure of the water is virtually non-existent. This provides 5 energy efficient blends. In the system, it is also advantageous that the drive shaft of said at least one propeller has a disadvantage above the water surface for spreading the water thrown by said at least one propeller over a wide area in the air when the water strikes against the harm. This further enhances the absorption of carbon dioxide in water in the absorption tank or the desorption from water in the desorption tank.
    Preferably, the agitator motor is provided with a protective housing having an upside down U-tube, one end of which opens inside the protective housing and the other end outside the housing into the air space of the absorption and / or desorption tank. This creates the same pressure inside and outside the engine, preventing gas from leaking through the bearing of the drive shaft of the engine, which would cause the lubrication of the bearing to wash off - and dissolve partly due to the gas flow but also due to carbon dioxide solubility. In addition, for example, the flue gas may contain ash, etc., which in turn dirt. bearing. If the pressure is the same on both sides of the bearing, no fouling problem will occur.
    In the system, the shaft of the mixer and at least one propeller is preferably surrounded by a guide tube which leads the water upwards above the water level. This ensures that the propeller does not have to reverse the direction of moving water, which would consume more energy.
    In a preferred embodiment of the system, there is a pre-reactor between the pressurizing means and the absorption vessel, into which the pressurized gas and water returning from the desorption vessel to the absorption vessel are fed and wherein the pressurized gas and water returning from the desorption vessel are mixed. The advantage of this is that pre-mixing does not have to bring in external energy and that the system's own energy is utilized.
    In another embodiment of the system, a desorption tank after the water desorbed carbon dioxide recovery means is provided with a feedback circuit for recirculating up to 35 parts of the desorbed carbon dioxide back into the absorption tank.
    20185573 prh 27-06- 2018 through the pre-reactor. This yields pure carbon dioxide among the crude gas, increasing the partial pressure of the carbon dioxide and improving the absorption proportionally according to Henry's law.
    It is also preferred that the system has a first heat pump after the gas pressurizing means, the gas pressurized by the condenser being heated before being mixed with water. In addition, it is preferred that the evaporator of the first heat pump cools the water leaving the desorption tank before returning it to the absorption tank. The hotter the gas and / or the colder the water, the more effective the carbon dioxide absorption in the water.
    In another preferred embodiment of the system, after the absorption tank there is a second heat pump, by means of which the water leaving the absorption tank can be heated by a condenser before being introduced into the desorption tank. In this connection, it is particularly advantageous for the evaporator of the second heat pump to cool the water leaving the desorption tank before being returned to the absorption tank via a pre-reactor. The warmer the water in the desorption tank, the more effective the desorption of carbon dioxide from the water.
    In yet another preferred embodiment of the system, the system comprises a third heat pump having a vaporizer located between the second heat pump vaporizer and the first heat pump vaporizer, whereby the condenser removes friction or excess heat introduced into the system by friction or other process equipment.
    It is further preferred that the system has a fourth heat pump having a condenser in the water rotation direction between the condenser of the second heat pump and a desorption tank and through which a gas from which carbon dioxide is absorbed in the absorption tank passes out of the system. In this way, heat can be recovered from the gas in question to heat the water that has absorbed the carbon dioxide entering the desorption tank.
    examples:
    1. Description of an Embodiment of the Method of the Invention (Figure 2)
    20185573 prh 27-06- 2018
    Fig. 2 illustrates a system suitable for carrying out an embodiment of the process of the invention in which deoxygenated water is produced and carbon dioxide is recovered from gas 14 containing it. and recovering deoxygenated water in a desorption tank. Other gases contained in gas 14 are removed from the system.
    For example, the steps of the method may be implemented by the apparatus 10 of FIG
    - pressurizing (1) the carbon dioxide-containing gas (14),
    - supplying pressurized gas to an absorption tank,
    - feeding clean water to or just before the absorption tank,
    - absorbing the carbon dioxide contained in the pressurized gas (141) in water (35) in an absorption tank (3),
    - recycling the water into which the carbon dioxide has been absorbed (15) from the absorption vessel (3) to the desorption vessel (5),
    - desorbing the carbon dioxide absorbed from the water (35 ') in the desorption tank (5),
    - recovering (6) the desorbed carbon dioxide (16) from the water (35 '),
    recovering deoxygenated water from the water stream leaving the desorption tank, and
    - optionally recirculating some of the water from the desorption tank (5) back to the absorption tank (3).
    The carbon dioxide-containing gas 14 is first pressurized by the pressurizing means 1 shown in Figure 2, which in this example consists of a compressor, a pressurized gas 141, which is introduced into the pre-reactor 2 for premixing with water 15 supplied to the pre-reactor. After the gas pressurizing means 1, there is a first heat pump 12 which, by means of a condenser 12a, heats the pressurized gas 141 before mixing with water 15, 35. The evaporator 30 12b of the first heat pump 12 cools the water then to the absorption tank 3. The premix will streamline the process and utilize the difference in gas and water flow without using any other energy. The premix may also be of the injector type.
    20185573 prh 27-06- 2018
    In the example, the absorption tank 3 has a mixer 32 which serves to cause water to circulate in the absorption tank 3 by throwing it into the air space 36 of the absorption tank and spreading it over the air space of the absorption tank 3. Also, the desorption tank 5 has a similar mixer 32 'which serves to circulate water in the desorption tank 5 by throwing it into the air space 36' of the desorption tank and spreading it over the air space of the desorption tank 5.
    The absorption tank mixer 30 comprises an electric motor 31, a drive shaft 34 and a propeller 32 located near the water surface at a depth where the hydrostatic pressure 10 of the water is non-existent or non-existent. The desorption tank 5 comprises a similar electric motor 31 ', a drive shaft 34' and a propeller 32 'located near the water surface at a depth where the hydrostatic pressure of the water is virtually non-existent. The drive shaft 34, 34 'of each of the mixers 30 and 30' propeller 32, 32 'has a disadvantage 39, 39' above the water surface for spreading the water thrown up by said propeller over a wide area of air 36, 36 'when the water strikes the harm 39, 39'. Each drawback 39 and 39 'in this example is a downwardly tapered conical plate. The handicap can also be shaped in other shapes.
    The motor 31, 31 'of each mixer 30 and 30' may be provided with a shield casing 37, 20 37 'having an upside-down U-tube 38, 38' with one end opening of the shield casing
    37, 37 'inside and one end outside the housing into the air space of the absorption tank 3 and the air space 36' of the desorption tank 5. The U-tube 38, 38 'provides a pressure equalization on both sides of the motor 31, 31' bearing (not shown) of each mixer 30 and 30 '.
    Without the agitator enclosure, it would be difficult to keep the motor dry, especially in an absorption tank under pressure. The pressure is leaking through the shaft seal. If the engine is equipped with a separate housing with the same pressure as the tank, the engine will remain dry and no liquid or gas will move through the shaft. In this case, the lubricant on the laa30 kerl does not wash off, which is important as carbon dioxide is a solvent. This engine compartment pressure can be taken from the entire tank or brought through the cover connection.
    20185573 prh 27-06- 2018
    Each mixer 30, 30 'axis 34, 34' and propeller 32, 32 'is surrounded by a guide tube 33, 33' which leads and raises the absorption vessel 3 to the air space 36 of the water 35 absorption vessel and the desorption vessel 5 to the air space 36 '. The water 35 absorbed by the carbon dioxide from the absorption tank 3 is led to the desorption tank 5 by means of a pump 7 positioned after the desorption tank 5 of the system 15 first through the condenser 22 of the second heat pump 10 and then through the condenser 13b of the fourth heat pump 13. Condenser 22 and 13b are used to heat the water absorbed by the carbon dioxide in the desorption tank of carbon dioxide, depending on the efficiency.
    In desorption tank 5, carbon dioxide 16 (in the form of gas) desorbed from water 35 'is recovered by recovery means 6 consisting of a compressor. After the recovery means 6, feedback 6 is provided for recycling at least a portion of the desorbed carbon dioxide 16 back into the absorption tank 3 via the pre-reactor 2. Recirculation of the separated CO 2 to the absorption, due to the increase in partial pressure, improves the absorption more than the energy required.
    After desorption of carbon dioxide, some of the water in the desorption tank 5 is first passed through the evaporator 23 of the second heat pump 10, then through the evaporator 11a of the third heat pump 11 and then back through the evaporator 23, 11a and 12b the temperature of the incoming water 15 to provide a suitable cold for effective absorption of carbon dioxide in the absorption vessel 3.
    After desorption of carbon dioxide, a second portion of the water in the desorption tank 5 is discharged from the plant through outlet 41 and recovered as pure anoxic water.
    Immediately before this, clean water is added to the absorption tank 3 or to the line through the inlet 40 and / or 40 '(alternatives marked with dotted lines). The amount of new water will depend on how much deoxygenated water is removed from the system via outlet 41.
    20185573 prh 27-06- 2018
    By means of the condenser 11b of the third heat pump 11, the excess heat introduced into the system by the friction or other process device can be removed from the system and transferred to its environment or other utility.
    The pre-reactor 2 produces a significant mixing effect on the difference between the flow rates of the pressurized gas 141 and the water 15 to it, since the flow of the gas 141 (crude gas) is about 10 times that of the water. It can optionally be equipped with different mixers.
    In the absence of heat control devices in the process, the water in the absorption vessel 3 would thus be heated and the cooling in the desorption vessel 5 would be equally cooled. In addition, the friction of the devices would tend to heat the water.
    In the system of Fig. 1, all heat pumps 10, 11, 12 and 13 are compressor-based, i.e., they have a compressor and a throttle valve in addition to the condenser and evaporator. The second heat pump 10 has a condenser 22, a vaporizer 23, a compressor 21 and a throttle valve 20.
    The absorption tank 3 delivers slightly heated water 15 to the condenser 22 of the second heat pump 10 and the desorption tank 5 back to the evaporator 23 of the second heat pump 10 where it cools back to a low temperature favorable for absorption.
    Here, the condenser 22 warms the water, thereby improving desorption. In the design of the second heat pump 10, the power ratio of the condenser 22 to the evaporator 23 is adapted to the natural need of the process, also taking into account seasonal differences. For example, the saturation point of water for carbon dioxide changes so that at 10 bar it is about 30 g / l and at 20 ° C it is only about 12 g / l. Thus, for absorption where it is desired to absorb as much CO 2 as possible in water, it is sought to be close to 0 ° C and for desorption where CO 2 is desired to be removed from the water, e.g. 20 ° C or more would be good.
    In addition, it is good to consider the relationship between operational efficiency and operating costs. The most important aspect of control is the adjustment of the absorption temperature to just above 0 ° C. The desorption water temperature then adjusts to the above dimension, but can be controlled by the bypass valve 24 35 of the condenser 22 of the second heat pump 10.
    20185573 prh 27-06- 2018
    If this bypass is on the side of the condenser 22 as in Figure 2, opening it will reduce heating of the desorption water 15 because a portion of the water 15 bypasses the heat exchanger or condenser 22. The bypass could never completely bypass and thus get the entire heat pump 10 out of its operating range.
    The efficiency of the absorption is influenced not only by the fact that the water is as cold as possible in the pre-reactor 2 and in the absorption tank 3 but also by the fact that the gas 141 supplied to it is as hot as possible. For this reason, a first heat pump 12 is required.
    This heat is transferred to the desorption by the second heat pump 13. a fourth heat pump 11 removes excess heat brought into the system by friction or other process equipment and transfers it to the environment or other utilization. The fourth heat pump 11 can be used to adjust the process conditions in winter and allow the process to be used outdoors even in frost. Heat pumps 10, 11,12 and 13 may be heat exchangers when they are economically more economical. Heat pumps enhance the heat transfer by raising the temperature differences to a significant advantage in terms of operation.
    Heat pumps increase the heat gradient and thus improve performance compared to conventional heat exchangers. The associated control system drops the heat transfer efficiency if the water cools below the set value, typically to 3 ° C.
    2. Description of an embodiment of the method according to the invention (Figure 3)
    Fig. 3 illustrates a system suitable for carrying out an embodiment of the method according to the invention, wherein oxygen-free water is produced and carbon dioxide is recovered from the gas containing it. The main components of the system are 1 30 absorption bubble columns, 2 pre-adsorption tanks, 3 desorption columns and 4 auxiliary adsorption columns. In addition, the system comprises 5 carbon dioxide suction and pressurization units, 6 carbon dioxide rich gas depression and pressurization units; gray flow line water flow us; black flow line gas flow.
    20185573 prh 27-06-2018 = CO2 inlet = Addition water (can also be supplied to or just before the absorption tank) = Turbocharging of the feed gas = Extracting the pressurized energy of the exhaust gas with a gas turbine
    15 = Exhaust Gas = Circulating Water Cooler = Back Pressure Regulator = Condensation Water from Carbon Dioxide Distillation = Compressor Turbo Compressor for Low Pressure and Carbon Rich Gas Desorption.
    = anoxic water recovery
    The starting point for the design and operation of the absorption tank or column is that at both the top and bottom of the column the gas and liquid phase are as close as possible to the theoretical equilibrium of theo15. Differences in gas and liquid concentration, bubble size, and bubble rise rate largely determine how close the bubble gas is to equilibrium with the surrounding water in accordance with Henry's law. In a preferred embodiment, the gas is in equilibrium with the circulated feed water as it exits the top of the reactor. The smaller bubbles the feed gas can split, the slower the bubble rises and the faster the carbon dioxide is absorbed.
    The carbon saturated liquid leaving the bottom of the absorption column 1 is led to a pre-sorption vessel 2 where the pressure is lowered. The gas released during pre-sorption is returned to the feed gas of the pressurizing unit 5 and further pressurized to an absorption size of 25 l. The purpose of pre-adsorption gas recovery is to increase the carbon content of the product gas released from the actual desorption and to improve the efficiency of absorption. At a slightly lower pressure of pre-adsorption, nitrogen gas is released in relative proportions more than carbon dioxide. This desorption step can increase the carbon dioxide content of the product gas.
    At the bottom of the pre-adsorption vessel, the carbon dioxide water is led to the actual desorption step, to the top of the packing column 3. The column aims to release as much as possible all the supersaturated carbon dioxide. At the bottom of the column, the carbon dioxide content of the water should be as close as possible to the equilibrium state of the desorption pressure with the gas in the bulk. From desorption, gas flows into the inlet of the product gas pressurizing unit, compressor 6.
    From the desorption column, the circulating water and the residual CO 2 remaining therein are returned with circulating water to the auxiliary adsorption, to the top of the packing column 4. Optionally, after cooling and washing the crude gas, the crude gas is conducted to the bottom of column 4 and further from the top of the packing column to the pressurizing unit 5. The purpose of auxiliary adsorption is to transfer (strip)
    From the auxiliary adsorption, the gas, together with the pre-adsorption return gas, is further passed through the pressurizing unit to the absorption column.
    The exhaust gas released from the absorption step is led to a gas turbine of the compression unit 5 where the pressurized energy of the gas to be removed from the process can be utilized.
    Before feeding to the turbine, the exhaust gas temperature is raised in the heat exchanger by the gas heated in the turbocharger and by the heat exchanger from the hot gas stream entering the process. Heat increases the expansion of gas in the turbine, which increases the power available from the turbine.
    权利要求:
    Claims (14)
    [1]
    A process for producing deoxygenated water, characterized in that the process comprises the steps of
    5 - pressurized gas containing carbon dioxide,
    - supplying pressurized gas to an absorption tank,
    - feeding clean water to or from the absorption tank,
    - the carbon dioxide contained in the pressurized gas is absorbed into the water in an absorption tank,
    10 - recycle the water in which the carbon dioxide has been absorbed from the absorption vessel to the desorption vessel,
    - desorbing the carbon dioxide absorbed in water from the water in a desorption tank,
    - recovering carbon dioxide desorbed from water,
    recovering deoxygenated water from the water stream leaving the desorption tank, and
    15 - optionally recycle some of the water from the desorption tank back to the absorption tank.
    [2]
    Process according to Claim 1, characterized in that the carbon dioxide-containing gas contains at least 10% by volume of carbon dioxide.
    [3]
    Method according to one of the preceding claims, characterized in that the carbon dioxide desorbed from the desorption vessel is recycled to the absorption vessel.
    [4]
    Method according to one of the preceding claims, characterized in that the gas is heated or water is cooled to increase absorption.
    [5]
    Method according to one of the preceding claims, characterized in that water in the absorption tank is mixed with a mixer which causes the water to circulate in the absorption tank by throwing it into the air space of the absorption tank and applying it to the air.
    30 sorption tanks in the air as wide as possible.
    [6]
    Method according to one of the preceding claims, characterized in that the desorption vessel is mixed with water by means of a mixer which causes the water to circulate in the desorption vessel by throwing it into the air space of the desorption vessel and applying it to the
    35 sorption tanks in the air as wide as possible.
    20185573 prh 27-06- 2018
    [7]
    Method according to one of the preceding claims, characterized in that the water is mixed with a mixer comprising a motor, a drive shaft and at least one propeller located near the water surface at a depth where the water is hydro-
    5 the static pressure is non-existent or almost non-existent.
    [8]
    A method according to any one of the preceding claims, characterized in that the carbon dioxide-containing gas is introduced into the auxiliary absorption vessel or column before the gas is pressurized, and / or a portion of the effluent leaving the desorption vessel is fed.
    10 from water to an auxiliary adsorption tank or column.
    [9]
    Process according to any one of the preceding claims, characterized in that the process comprises a pre-sorption step in a pre-sorption vessel.
    15
    [10]
    Process according to Claim 9, characterized in that the partial pressure of the carbon dioxide is gradually increased by dropping the pressure in at least two steps in the pre-sorption step.
    [11]
    Method according to one of Claims 9 to 10, characterized in that
    From the 20 absorption tanks, the water into which the carbon dioxide has been absorbed is fed to a pre-sorption tank, from which the exhaust gas is fed back to the auxiliary adsorption tank or column.
    [12]
    Method according to one of Claims 9 to 11, characterized in that
    The gas containing carbon dioxide is introduced into the auxiliary absorption vessel or column prior to feeding into the absorption vessel, and / or the water leaving the absorption vessel is first fed to the pre-adsorption vessel and then to the desorption vessel and / or the gas is recirculated
    30 then into the absorption tank.
    [13]
    Process according to any one of the preceding claims, characterized in that at least part of the carbon dioxide exiting the desorption tank is liquefied and optionally distilled for recovery.
    [14]
    Process according to one of the preceding claims, characterized in that the process for producing deoxygenated water is combined with the capture of carbon dioxide in a beer and / or soft drink plant, e.g. from a fermentation vessel.
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    FI128505B|2020-06-30|
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