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    • 专利摘要:
    Process and plant for utilizing heat from a drying plant for drying dry goods in the form of particulate matter e.g. wood chips, wood shavings, sawdust, straw, wood pellets or litter, including litter used in a barn. The method and the plant comprise a drying step for drying the particulate matter heated by a hot oil. A boiler for heating the oil is connected to means for supplying at least a partial flow of the drying material to the boiler for burning the drying material in the boiler. In addition, the boiler has means for transferring the combustion heat from the flue gas to the oil before returning the oil to the drying chamber. The plant further comprises a heat exchanger which, with a partial flow of the hot oil from the boiler, is heated by a circulating heating medium, such as water, from a heating strand in the heating side of a central heating system for heating and / or hot water production to one or more buildings. Prior to the heat exchanger, a condenser is provided which condenses steam in the drying air and transfers the heat to the heating medium for preheating and utilizing the heat from the drying air.
    公开号:DK201570447A1
    申请号:DKP201570447
    申请日:2015-07-06
    公开日:2016-12-05
    发明作者:Kristian Trolle Bennedsgaard Rosenkilde；Peer Ejlersgaard；Jan Bilstrup
    申请人:Ktb Invest Ivs；
    IPC主号:
    专利说明:

    1
    Process and dryer for drying dry goods and utilizing heat from the dryer in one or more buildings
    FIELD OF THE INVENTION
    The present invention relates to a drying plant for drying dry matter in the form of particulate matter, preferably of biological origin, such as wood chips, wood shavings, sawdust, straw, wood pellets or litter, including litter that has been used in a stable for which the drying plant is adapted. utilization of heat from the dryer in one or more buildings.
    The present invention also relates to a method for drying dry matter in the form of particulate matter, preferably of biological origin, such as wood chips, wood shavings, sawdust, straw, wood pellets or litter, including litter used in a barn and for the utilization of heat from the dryer in one or more buildings.
    BACKGROUND OF THE INVENTION
    For homes and / or commercial properties that do not have access to district heating or gas, heating of the property with other energy sources will be necessary. It is e.g. often the case in areas with agricultural properties that are scattered and sometimes isolated, and therefore energy providers have chosen not to deploy district heating or gas supply networks in such areas.
    Therefore, these properties must be heated with alternative energy sources, e.g. large straw-fired plants that can heat both residential and commercial buildings on the property.
    Alternatively, a stoker furnace is fired with particulate solid (bio) fuel in the form of wood pellets, wood chips, sawdust, shavings, grains, etc., which are fed into the boiler using the stoker which is automated. The stoker uses one or more auger conveyors to transport and dispense the fuel to the boiler for burning and generating heat and / or hot water for the building (s) of the property. 2
    This type of plant is usually cheap as the price of fuel is low compared to fossil fuel. However, regular supplies of fuel are required to ensure adequate heating of the building (s) of the property.
    Alternatively, the property itself must be capable of supplying fuel, e.g. grain or wood chips to ensure adequate energy supply for heating and hot water supply on the property.
    This can often be associated with problems as any suitable biofuel from the property's own production can have a relatively high water content and therefore not suitable for being fed to the stoker and into the boiler without prior drying, partly because a wet fuel can cause clogging in the stoker's conveyor systems, partly because the wet fuel causes problems in the boiler with incomplete / poor combustion and problems with soot and / or downtime.
    An example of material that is not currently used as fuel due to high water content is used bedding from stables. Bedding is e.g. wood shavings, wood chips, sawdust, wood pellets or other pelleted material of other organic materials, e.g. straw, paper and the like. This type of bedding is often used today as an alternative to straw in stables, e.g. in poultry or horse herds since litter based on e.g. shavings of wood or wood pellets usually dust less than straw and therefore provide a better indoor climate in the barn.
    After use in the barn, litter is collected. Due. the contents of the animal's excrement and / or urine, the used litter can normally not be used without further processing and must today be transported away by disposal. For example, the material can be delivered to a biogas plant which converts the litter and manure into biogas. However, this is associated with significant costs, as there can be large amounts of used litter to be carried away, typically by trucks.
    Therefore, it is necessary to be able to utilize this waste stream locally on the property, so that you can avoid having to transport large quantities of used litter away for disposal. 3
    Today, there are plants on the market that can dry organic matter, making it suitable for biofuels. CN203298580U discloses a drying auger for drying organic fertilizers where the heat is recovered and utilized in the circulating medium by means of a heat tank. Suction is used on the dryer and evaporation of liquid from the dryer takes place at low temperature and low pressure. There are no instructions for recycling residual or waste heat. US2013 / 0014678A1 discloses a drying auger which dries wastewater sludge in a first drying step and a second drying step. After the first drying step, where the sewage sludge is dried to a paste similar in consistency, the sludge is subsequently extruded into pellets and then dried in a second drying step. Pellets are burnt in a kettle. The drying screw in the first drying stage uses oil or water vapor as a heat transfer medium. Oil / steam can be heated by heat exchange with hot air from the second drying stage and by heat exchange with the gas from the burning of the pelleted and dried sludge. Steam from the drying screw is condensed and the heat is transferred to drying air to the second stage. The excess heat from the process is used internally in the plant. DE 3911716 A describes a plant with a drying auger which dries sludge, litter and the like with, for example, oil as circulating heat transfer medium. The oil is circulated in the casing around the auger and heated to up to approx. 250 ° C in the boiler. The motor is connected directly to the auger via various couplings and transmissions. Steam from the drying stage is used as a heat source when preheating the sludge in the heat exchanger, preheating the sludge before passing it to the drying auger. There is no recovery or utilization of excess heat or waste heat.
    Therefore, there is a need to better utilize waste and / or residual heat in drying systems. 4
    The object of the invention
    It is therefore an object of the invention to provide a method and a plant for drying particulate dry goods which effectively utilize the waste and / or excess heat.
    It is therefore also an object of the invention to make it possible to improve the utilization of waste and / or residual heat in drying plants and use it locally for heating in a property's buildings.
    It is therefore also an object of the invention to make it possible to utilize waste streams of spent litter locally on the property, so as to avoid having to transport large quantities of used litter away for disposal.
    Description of the Invention
    These objects are achieved by a plant for utilizing heat from a drying plant for drying dry matter in the form of particulate matter, preferably of biological origin, such as wood chips, planer shavings, litter, including litter used in a barn. The plant comprises a drying step for drying the particulate material heated by a heating medium in the form of an oil. In addition, the plant comprises a boiler for heating the oil, which is connected to means for supplying at least a partial flow of the drying material to the boiler for burning the drying material in the boiler. The boiler comprises means for transferring the combustion heat from the flue gas to the oil before returning it to the drying chamber. In addition, the plant comprises a heat exchanger which, with a partial flow of the heated oil from the boiler, is used for heating a circulating heating medium, such as water, from a heating string in the heating side of a central heating system for heating and / or hot water production to one or more buildings.
    The object of the invention is further achieved with a method of utilizing heat from a drying plant for drying dry matter in the form of particulate matter, preferably of biological origin, such as wood chips, planer shavings, litter, including litter used in a barn. The process comprises drying the particulate material in a drying step using circulating oil. Then at least λμ / 4 I nf * · ϊλλ n -t- 4-tl / - »« n -t- 4 · Λ «·« · αι> / Ν / Ίη * Ιτ-λλΙλμ λ / v 5 sel of combustion heat from the flue gas to the oil before returning the oil to the drying step. A partial stream of the oil from the boiler is taken out for heating in a heat exchanger of a circulating heating medium, such as water, from a heating string in the heating side of a central heating system for heating and / or hot water production to one or more buildings.
    Hereby, the heat generated by burning the drying material is utilized to generate heat, partly for use in the drying process and partly for heating the circulating heating medium in a heating string in a central heating system. The drying material is fed directly into the drying chamber or preferably into an initial mixer with cutters for partitioning and simultaneous mixing of the drying material. The mixer is described in more detail below.
    Between the mixer and the drying chamber, a first cell lock is preferably arranged which transfers the drying material from the mixer outlet to the inlet of the drying chamber. This first cell lock prevents drying air from escaping unhindered from the drying chamber through the inlet. The drying chamber preferably comprises a horizontal or sloping auger conveyor with a surrounding heat jacket through which the heated oil circulates, as described in more detail below.
    The auger conveyor carries the drying material from the inlet of the drying chamber to the outlet from the drying chamber while simultaneously stirring and heating from the heating jacket.
    In order to ensure sufficient air circulation and good transfer of heat to the drying air in the drying chamber, air is drawn through the drying chamber in the direction from the outlet end to the inlet end, preferably with an air pump or a fan in the air outlet duct from the drying chamber.
    It is preferred that the air pressure in the drying chamber is maintained around atmospheric pressure in part to reduce the leakage of drying air to the surroundings, which may cause odor nuisance. This also ensures sufficient air circulation in the drying chamber and thus increased heating of the drying air in the drying chamber and consequently improved efficiency 6 for the drying stage, since the air thus does not reach saturation with water vapor before leaving the drying chamber. The drying air with increased content of water vapor is sucked away under a light vacuum which is preferably up to 0.1-0.2 bar, e.g. with a fan or pump. The drying air can then be discharged to the atmosphere or passed to a condenser, which is described in more detail below. During the evaporation of the water content of the drying material, a slight increase in pressure will occur in the drying chamber due to the increased water vapor pressure. By sucking the drying air out of the drying chamber, the total pressure is lowered to about atmospheric pressure and the water vapor pressure in the drying chamber is reduced, which increases the drying speed of the drying material in the drying chamber. The drying material is also preferably carried out of the drying chamber via another cell lock which also prevents the drying air from escaping unobstructed to the surroundings through the outlet.
    The second cell lock transfers dried dry goods to a buffer tank for storage until the dry goods are burned in the boiler. When the stoker furnace's control calls for fuel, one or more conveyors will feed the drying material into the boiler for firing with the accompanying heating of the circulating oil. ) The auger conveyor is preferably horizontal or slightly angled relative to the horizontal, so that the outlet from the auger is above the level of the inlet. The angle of the auger relative to the horizontal of an inclined auger is preferably 5-25 °.
    The size of the plant is dimensioned according to the amount of drying material to be treated. Experiments have shown that the drying material should have a residence time in the drying chamber of 1-3 hours, preferably about two hours, to be sufficiently dry to be stored and subsequently burnt in the boiler without causing operational problems in the form of clogging) and / or soot formation. in the kettle.
    In order to make the control as simple as possible, it is preferred that the auger conveyor in the drying chamber runs at a constant speed, which gives a constant residence time for the drying goods in the drying chamber. This is e.g. an advantage when the plant and method are applied to a farm where dry, used livestock litter is dried by the method and plant of the invention. The production of moist, used bedding in an animal herd is relatively constant year-round, and the plant can therefore be sized to constantly treat the same amount per hour. In the summer, when the need for heat in buildings is low and the need to generate heat when burning the dry goods is low, any excess production of dry goods is taken out of the system, e.g. for storage and / or subsequent production of fuel pellets.
    The auger conveyor in the drying chamber is driven by a motor, preferably an electric motor. The motor pulls the shaft of the auger, either via a transmission system, e.g. a chain or belt drive or the motor is mounted directly on the shaft. When the motor is mounted directly on the shaft, there is a risk that the heat from the sheath flows through the auger conveyor shaft, screw connections, etc. and into the engine, which can destroy heat-sensitive parts of the engine, e.g. gears, bearings, gaskets and the like. To prevent this, washers, bushings, etc. between the motor and the auger conveyor in the drying chamber made of a heat insulating material. The heat insulating material is e.g. a composite material, for example, cotton fibers and phenolic resin or polyester fibers and epoxy, marketed under the name Etronax ®.
    The oil can circulate through the heating sheath countercurrent or co-flow with the drying material, but it is preferred that the oil circulates in co-flow with the drying material, since the drying material fed into the drying stage has the greatest water content and thus also the greatest need for heat transfer to evaporate the water in the drying material. .
    The oil is circulated, e.g. with a circulation pump, applying a small excess pressure of up to 1 bar to the oil, such as 0.3-0.7 bar, or preferably approx. 0.5 bar to allow the oil to circulate. Keeping a low pressure in the oil reduces the risk that dangerous situations can arise in the event of any leaks where hot oil can spray out of the system and cause personal injury. In addition, the plant design is avoided under European pressure regulations that require special approvals of the plant.
    Within the heating jacket itself, a number of flow-routing elements are preferably located. The flow routing elements include e.g. round steel bars, radially protruding plates, walls or the like. The flow-routing elements are preferably twisted around the auger conveyor so that the oil in the casing circulates in the casing in channels between the flow-routing elements, and at the same time the oil circulates around the auger conveyor between the inlet and the outlet of the oil in the casing. These flow routing elements ensure optimal transfer of heat to the drying material inside the casing, which is transported by the snail conveyor between the inlet and outlet of the drying chamber.
    The heating sheath preferably also comprises an outer insulating layer which insulates against heat loss to the surroundings.
    The oil introduced into the tubes in the heat jacket around the auger conveyor in the drying chamber is heated in a boiler to 180-200 ° C, preferably about 185-195 ° C.
    At the output of the heat jacket around the auger conveyor in the drying chamber, the temperature of the oil has dropped to approx. 160-180 ° C, preferably approx. 165-175 ° C.
    From the outlet of the heating jacket, the oil is returned to the boiler for reheating to the operating temperature as described above.
    The boiler is a combustion plant for combustion of solid fuel in a combustion chamber. In this case, the drying material is also used as fuel. However, it is possible to supplement with other fuel sources, e.g. purchased wood chips or pellets if fuel production in the form of dry goods is not sufficient.
    The boiler transfers heat from the combustion chamber to the oil and heats it to approx. 180-200 ° C, as described above.
    Since it is preferred that the boiler has automatic feeding and dosing of solid fuel, a stoker furnace is preferably used. The stoker furnace comprises conveyors for supplying the solid fuel from a storage tank and into the combustion chamber. The storage container is preferably a buffer, which is discussed below. The conveyors are preferably one or more auger conveyors which feed the dry goods into the combustion chamber. 9
    The oil used as a heating medium is a heat-resistant oil that can withstand high temperatures without being degraded. It is preferred that the oil can withstand temperatures of up to 300 ° C.
    A partial stream of the oil leaving the boiler after heating is led to a heat exchanger for heat exchange with and heating of a heat strand from a central heating system used for heating and / or hot water production for buildings, including residential and / or commercial buildings as described below. The oil outlet from this heat exchanger is returned to the boiler where it is reheated as described above.
    At the inlet to the heat exchanger, the hot oil partial flow from the boiler is approx. 180-200 ° C, preferably approx. 185-195 ° C. At the outlet of the heat exchanger, where the hot oil has delivered heat to the heating medium from the heat string in the central heating system, the temperature of the oil has dropped to approx. 160-180 ° C, preferably approx. 165-175 ° C.
    Alternatively, oil from the outlet of the drying chamber heating sheath is fed into the heat exchanger for heat exchange with and heating of the heat string from a central heating system. From the heat exchanger, the cooled oil is returned to the boiler for reheating.
    The heat exchanger is preferably a pipe, coil or plate heat exchanger, preferring to use a conventional co-or countercurrent heat exchanger which is approved for heating oil and the aforementioned operating temperatures. In a central heating system, a heating medium, typically water, is circulated in a heat string where heat is delivered to a utility heat string that is passed to radiators for heating one or more buildings and / or the water in the heat string is passed to a heat exchanger for heating hot water to the property. (e) s taps.
    The inlet temperature at the inlet to the central heating system after heating the heating medium in the heat exchanger is 60-80 ° C, preferably approx. 65-75 ° C. The reflux temperature from the central heating system, ie. in the heating medium in the heating string, which is discharged from the central heating system, is approx. 30-50 ° C, preferably approx. 35-45 ° C depending on the heat and / or hot water consumption in the building or buildings. Heating in the heat exchanger and possibly a preconnected condenser reduces the discharge of waste heat to the environment without being utilized and transfers heat to the central heating system's heat string from a cheap fuel form. The condenser is described in more detail below.
    The circulating heating medium is returned after preheating and subsequent main heating to the central heating system for supplying heat to the heating string for radiators and / or for heating of domestic water. The drying material is preferably biological material, preferably plant-based material, which is suitable for burning after prior drying. Suitable biological material is e.g. wood chips, wood shavings, sawdust, straw or wood pellets. These can all be used as bedding in an animal shed with animal husbandry, e.g. in stables for horses, poultry, cattle, sheep, goats and / or pigs, etc. as mentioned below. The faeces and / or urine of the animals are mixed with the litter and significantly increases the water content of the litter. The bedding is removed after a few days as needed. Greater or lesser amount of used litter is generated with a varying water content depending on the animal species and the number of animals in the barn.
    The water content of spent litter containing animal decomposition and / or urine is typically up to 60-70% by weight before drying. After drying, the water content of the drying material is reduced to approx. 1-15% by weight, preferably 1-8% by weight, since a higher water content can lead to possible clogging downstream of the drying chamber when the material has been used as bedding. If the drying material is pure wood, such as wood chips, sawdust or planer chips that have not been used as bedding prior to drying, the residual water content can be somewhat higher, typically up to 15% by weight, without causing any clogging in the plant.
    These types of fuels are inexpensive compared to fossil fuels (calculated per kW of heat), and when dried, used litter from stables is used, a waste stream is used as a heat source rather than having to deduct the costs of disposal of the used litter. This further reduces the cost of heating and saves the costs of disposal. 11
    Thus, the plant and method can be used as a substitute for gas or oil-fired central heating systems or as a substitute for district heating in areas where gas or district heating is not available.
    It is preferred that the plant comprise a condenser for condensing condensable vapors and / or gases from an air stream taken from the drying chamber, the heating medium from the heating strand on the heating side of the central heating system being used as the cooling medium in the condenser and thus being preheated before the subsequent heating in the heat exchanger.
    It is also preferred that the process comprises condensable vapors and / or gases from an air stream taken from the drying stage being cooled and condensed in a condenser, the heating medium in the heating string from the heating side of the central heating system being used as a refrigerant in the condenser for preheating the heating string heating medium. heat exchanger. The temperature of the drying air out of the drying stage is on the order of 100-180 ° C, though typically at the lower end thereof, if the drying material contains large amounts of water which must be evaporated in the drying step as described above.
    The temperature of the heating medium in the condenser inlet is usually on the order of approx. 30-50 ° C, preferably approx. 35-45 ° C depending on the heat and / or hot water consumption in the building or buildings. The temperature of the heating medium in the outlet of the condenser is usually approx. 10 ° C higher than the inlet, ie. Typically 40-60 ° C. 40-55 ° C,
    Hereby, the latent heat is utilized in the exhaust air from the drying stage, including in steam from evaporated water from the drying material and other gases, e.g. ammonia, in the air stream, the heat being used to preheat the heating medium in the heating string from the central heating system. Thus, the heat that would otherwise be wasted is exploited if the drying air is simply discharged to the atmosphere from the drying stage.
    The condenser is preferably a heat exchanger, in which the cooled heating medium from the heating string in the central heating system is directed countercurrent to the exhaust air from the drying stage. 12
    Suitable heat exchangers are e.g. plate heat exchangers or heat exchangers of the radiator type, including in particular a pipe heat exchanger with fins on the outside of the pipes.
    The cooled heating medium from the central heating system's heating string is passed inside the pipes and heated by the drying air on the casing side. The drying air thereby gives heat to the heating medium inside the pipes and the steam in the drying air is condensed on the fins.
    At the entrance to the condenser, the cooled heating medium from the heating string in the central heating system is approx. 30-50 ° C, preferably approx. 35-45 ° C, as mentioned above. At the exit from the condenser, the preheated heating medium from the heating string in the central heating system is heated by approx. 10 ° C relative to the inlet, and the temperature at the outlet of the condenser is therefore approx. 40-60 ° C, preferably 45-55 ° C, as the temperature rise has occurred by transfer of heat and condensation of water vapor from the drying air to water. Thereby, the waste heat in the drying air is used to preheat the heat medium prior to heating to the flow temperature in a heat exchanger by heat exchange with a partial flow of the hot oil from the boiler.
    The heating medium is then passed on to the heat exchanger, where it is further heated by heat exchange with a partial flow of the hot oil from the boiler as described above.
    In addition, if the drying material is litter that has been used in a livestock barn and therefore includes excrement and / or animal urine, such as for example horses, poultry, sheep, goats, cattle and / or pigs, etc., the drying air will include gases, eg. ammonia, sulfur hydrogen and other gases that can cause odor nuisance in the environment. When the water vapor is condensed out of the drying air in the condenser, it can be diverted to sewage, or collected, otherwise utilized, e.g. such as irrigation water for plant crops, water for flushing house furniture with and other things. In addition, a large portion of any ammonia present as well as any other gases, including any sulfur hydrogen present, in the drying air will be washed out of the drying air by means of the condensate in the condenser. Thereby ammonia and possibly sulfur hydrogen can be collected and their fertilizer value can be utilized, e.g. by using the condensate as irrigation water for crops in, for example, fields or greenhouses. 13
    It is preferred that prior to the drying chamber, a mixer, such as a double-screw conveyor, is provided for mixing and simultaneously dividing the particle size of the drying material. In the process, it is also preferred that prior to the drying chamber, a mixer, such as a double-screw conveyor, be arranged for mixing and simultaneously dividing the particle size of the drying material. The drying material is therefore preferably fed into an initial mixer with cutters for subdivision and simultaneous mixing of the drying material. For example, the initial mixer is a container, e.g. with one or two sloping bottom sides where a double auger is arranged at the bottom of the container and the auger conveyors have cutters so that they can cut and simultaneously divide the drying material while mixing and transporting the drying material to the outlet from the container. The auger conveyors in the mixer are preferably driven by their own motor.
    In the process, a partial flow of the drying material can be withdrawn for subsequent pelleting. In this way, excess dry goods can be further processed during periods when the amount of dry goods exceeds the fuel consumption in the boiler.
    The second cell lock transfers dried dry goods to a buffer tank for storage until the dry goods are burned in the boiler. The buffer tank is preferably a container with an inclined wall that acts as a slide, so that the drying material automatically slides against the bottom of the buffer tank. When the stoker boiler calls for fuel, an inclined auger conveyor will carry the drying material up from the bottom of the buffer tank and into the boiler, possibly. via one or more additional conveyors for burning and accompanying heating of the circulating oil as described above.
    In excess production of dried dry goods, e.g. In summer, when the need for heat in buildings is low, the drying material will fall into the buffer tank via the second cell lock. When the buffer tank is full, any surplus production of dried dry goods will be carried away with a transverse auger conveyor. 14
    The transverse auger conveyor is preferably located below the cell lock and above the buffer tank.
    The transverse auger conveyor preferably runs at a constant speed and is activated simultaneously with the second cell lock. When the buffer tank is full and drying material rises in the envelope around the transverse conveyor, this will be able to carry dried drying material out of the system. When the buffer tank is being filled, the drying material will simply fall past the rotating transverse auger conveyor and into the buffer tank. This construction means that only dried dry goods are discharged from the plant when the buffer tank is full. In addition, the design is simple and reliable, does not require pre-programmed control and means for controlling the operation of the transverse auger conveyor.
    Alternatively, the transverse auger conveyor may be activated when it is detected that the buffer tank is full, e.g. in that the drying material rises in the envelope around the transverse conveyor. It is possible to use one or more level sensors to detect the level of dry goods and activate the transverse auger conveyor when the buffer tank is full. The transverse auger conveyor carries dried dry goods out of the plant for further processing, e.g. for pressing for fuel pellets, storage and / or transport away from the plant.
    Alternatively, the transverse conveyor is mounted with one end inside the upper portion of the buffer tank. When the transverse auger conveyor is activated and the buffer tank level is so high as to cover it in whole or in part, it is activated as described above
    drawing Description
    The invention will be described in the following with reference to the drawings, in which:
    FIG. 1 shows a diagram of drying systems with heat recovery FIG. Figure 2 shows perspective of the dryer elements that treat, transport and burn dry goods in perspective.
    FIG. 3-4 show the mixer, partly from one end and partly in cross-section along the line D-D in FIG. 3 FIG. 5-6 shows the drying chamber with auger conveyor and heating jacket as well as a partial detail of the connection between auger conveyor and motor, both shown in cross-section 15
    FIG. 7-8 show discharge from drying stage to buffer tank partly seen from one end and partly in cross-section along line E-E in fig. 7th
    Detailed description of the invention
    FIG. 1 shows a diagram of the dryer 1 with heat recovery from the drying air and the transfer of heat to a central heating system (not shown) for heating and / or hot water production in one or more buildings 15. In the following, plants and processes are described with drying of used litter in the form of wood shavings. Used litter in the form of wood shavings containing animal scrubs and / or urine has a water content typically up to 60-70% by weight before drying. After drying, the water content of the drying material is reduced to approx. 1-5% by weight. However, as mentioned above, other drying goods can also be dried in the plant and the invention is therefore not limited to drying of used litter. The drying material is fed into the system of a mixer 2. In the mixer 2, the drying material is mixed and divided as described below. From the mixer 2, the drying goods are led via a first cell lock 3 into the drying chamber 4 itself, which is described in more detail below.
    From the drying chamber 4, the dried litter is fed via a second cell lock 5 into a buffer tank 6.
    The buffer tank 6 constitutes fuel storage for a boiler 7 for a stove furnace having means for automatically feeding fuel to the boiler 7. The stoker furnace has automatic control of the supply of fuel. During periods of surplus production of dry goods relative to fuel consumption in the boiler, part of the dry goods is carried for storage and / or subsequent pelleting 8. From warehouse 8 the dry goods can be carried away 8 ', e.g. after making pellets. It is also possible that stored and / or pelleted dried litter is returned (shown with a dotted arrow in Figure 1) to the buffer tank 6 during periods when the drying chamber is not running, e.g. by service, repair or the like. 16 In the stoker boiler 7, the dried litter is burned and the heat is transferred to oil circulating through the heating furnace. The now heated oil then returns to the drying chamber 4 via an oil feed 10 to the heating sheath 32 of the drying chamber 4 (not shown in Fig. 1, see Fig. 5) and returns to the boiler boiler via an oil return flow 11 from the drying cap 32 of the drying chamber 4 (shown in Figs. 5) to the boiler boiler 7.
    The hot oil at outlet from the boiler is approx. 180-200 ° C, preferably approx. 185-195 ° C or especially about 190 ° C. At the outlet of the heating jacket 32 of the drying chamber 4, where the hot oil has delivered heat to the drying material, the temperature of the oil has dropped to approx. 160-180 ° C, preferably approx. 165-175 ° C, or more preferably ca. 170 ° C.
    The oil is circulated with a circulation pump 24. The circulation pump applies a small excess pressure of up to 1 bar to the oil, such as 0.3-0.7 bar, or preferably approx. 0.5 bar sufficient to allow the oil to circulate in the system.
    A partial stream 12 of the hot oil stream 9 from the boiler is fed to a heat exchanger 13, preferably a plate heat exchanger, preferably a co-current or countercurrent heat exchanger. The partial flow is preferably taken out by a three-way swivel 23 with an actuator (not shown) which is activated when a temperature sensor in the heat exchanger 13 calls for heat. When the oil exits the heat exchanger 13, it has delivered heat to the water in the heat string from the central heating system and the temperature of the oil has dropped to approx. 160-180 ° C, preferably approx. 165-175 ° C, or more preferably ca. 170 ° C. The oil is passed through return line 14 return to the stoker boiler for re-heating together with return 11 of the oil from the drying chamber 4. In a not shown variant, a partial flow of hot oil is not taken out to the heat exchanger 13. Instead, the return line 11, or a partial flow thereof , of oil from the drying chamber into the heat exchanger 13, before returning the return to the boiler of the stoker 7 for reheating in the boiler.
    An example of a suitable oil is e.g. Termway® from Statoil, which can withstand temperatures up to 300 ° C. 17 In the heat exchanger 13, a heating medium, preferably water, is circulated in a heating string to a central heating system (not shown) in a building 15. The central heating system produces heat and / or hot water for use in one or more buildings 15 which may be residential (s) and / or commercial buildings, e.g. farm buildings on a farm. The reflux 17 of the heating string to the central heating system is thus fed into the heat exchanger 13 from the central heating system with a temperature of approx. 30-50 ° C, preferably approx. 35-45 ° C, depending on the heat and / or hot water consumption in the building or buildings. After heating the heating medium in the heat exchanger 13, to a temperature of approx. 60-80 ° C, preferably approx. 65-75 ° C, the heating medium is returned via reflux 16 to the central heating system for delivery of heat in the central heating system. The drying air is discharged from the drying chamber 4 via air outlet duct 19.1 The air outlet duct has a fan or air pump 20 which sucks the drying air out of the drying chamber 4, so that no excess pressure is generated as a result of evaporated water and the delivery of other gaseous components to the drying air in the drying chamber 4. if desired (not shown in Figure 1). The drying air has a high content of water vapor and the temperature of the drying air is on the order of 100-180 ° C. It is therefore possible to extract the heat from the drying air and the energy of the steam into the drying air by condensing the water vapor and extracting energy from the condensation heat from the drying air.
    Therefore, it is preferred that the outlet duct 19 of the drying air is directed to a condenser 18. The condenser 18 is a heat exchanger, preferring to use a pipe heat exchanger with fins on the outside of the pipes.
    The cooled heating medium in the reflux 17 from the central heating system's heating string is conducted inside the pipe side and heated by the drying air on the casing side of the condenser 18. The drying air thereby gives heat to the heating medium inside the pipes and the steam in the drying air is condensed on the fins.
    Cooled dry air 21a and condensed water 21b leave condenser 18 in two separate streams 21a and 21b. The condensate 21b can be led to sewage (not shown) or used on the property, e.g. as irrigation water for crops. The cooled dry air 21a is directed directly to the surroundings. When the drying material is used litter, the condensate will comprise components, e.g. nitrogen (ammonium nitrogen) which has a fertilizer value, so it is possible to collect or use the condensate as irrigation water with fertilizer value.
    At the entrance to the condenser 18, the cooled heating medium in the return flow 17 from the heating string in the central heating system is approx. 30-50 ° C, preferably approx. 35-45 ° C, as mentioned above. At the exit from the condenser, the preheated heating medium for feed 16 in the heating string in the central heating system is now heated by approx. 10 ° C relative to the inlet 17, and the temperature at the outlet of the condenser 18 is therefore approx. 40-60 ° C, preferably 45-55 ° C, as the temperature rise has occurred by transfer of heat and condensation of water vapor from the drying air to water.
    The heating medium in the return pipe 17 is passed, via pipe 22, thereafter to the heat exchanger 13, where it is further heated by heat exchange with a partial flow 12 of the hot oil from the boiler 7 as described above.
    FIG. 2 shows the components which process and / or transport the drying material in the order from left to right, ie. mixer 2, first cell lock 3 (not visible in Fig. 2), drying chamber 4, second cell lock 5, buffer tank 6 and boiler 7 including one or more conveyors 25 which carry dried dry goods into boiler boiler 7.
    The mixer 2, see in particular figs. 3-4, is an inclined container with inclined side walls 28 which acts as a hopper for the drying goods when thrown into mixer 2. At the bottom of mixer container 2, two first auger conveyors 26 are mounted in an upwardly open auger passage (not shown). The auger conveyors 26 preferably have cuts along the periphery of the helical carrier so that the drying goods are cut while being transported towards the outlet (not shown) of the mixer 2. The auger conveyors are driven by their respective motor 27. The outlet is located at the upper end of the inclined mixer. 2. The drying material thus falls out of the outlet from the mixer 2 and down into the first cell lock 3, from which it is transferred to the inlet 29 of the drying chamber 4 at the first end of the drying chamber 4 ', see fig. 2 and 5. 19 The drying chamber 4 is shown in FIG. 5-6. Another auger conveyor 31 is mounted in a casing which includes a heat jacket 32 through which the hot oil circulates. The inlet 29 directs dry goods into the drying chamber 4 and the auger conveyor 31.
    The hot oil from the boiler 7 (shown in Fig. 1) is passed through the heating sheath 32 for heating and consequently drying the drying material in the drying chamber 4. Hot oil is fed into the heating sheath 32 at the drying end 4 'of the drying chamber and is passed out of the heating sheath at the outlet end. 4 '' for the drying material as described above. Preferably, in the heating jacket 32, a plurality of flow routing elements 33 are placed. The flow routing elements 33 comprise e.g. round steel bars, radially protruding plates, walls or the like.
    The flow routing elements 33 are preferably twisted around the inner wall of the heating sheath 32 which lies against the auger conveyor 31. The flow routing elements 33 thus cause the oil in the heating sheath 32 to pass in the channels which arise between the flow routing elements 33 and at the same time circulate around the auger conveyor 31 between the inlet and outlet (not shown in Figs. 5-6) for the oil in the heat jacket.
    A drive motor 36 for rotation of the auger conveyor 31 is mounted on the auger shaft 34. The helical carrier 35 carries the drying goods from the inlet 29 to the outlet 30 by rotation of the auger conveyor 31. Since the motor 36 is mounted directly on the auger conveyor shaft 34, there is a risk that the heat from the heat jacket 32 travels via the auger conveyor shaft, screw connections, etc. and out the engine. To prevent this, washers, bushings 37 ', 37', 37 '', etc. between the motor 36 and the auger conveyor 31 in the drying chamber 4 made of a heat insulating material. The heat insulating material is preferably a composite material of, for example, cotton fibers and phenolic resin or polyester fibers and epoxy marketed under the name Etronax ®.
    FIG. 7-8 show the drying goods outlet 30 from the drying chamber 4. Another cell lock 5 directs dried drying goods from the drying chamber outlet 30 down into the buffer tank 6.
    The buffer tank 6 is preferably a container with an inclined side wall 38 which acts as the bottom of the buffer tank 6. A third auger 25 is mounted along the bottom 38 of the buffer tank 6. This third auger 25 transfers dry drying material to the boiler 7 of the stove for firing. of the dry goods, possibly. via one or more additional conveyors 25 ', 25' (see Fig. 2). When the buffer tank 6 is full, any excess production of dried dry goods will be carried away with a transverse fourth auger conveyor 39. The transverse auger conveyor 39 is preferably located below the second cell lock 5 and above the buffer tank 6.
    The transverse snail conveyor 39 preferably runs constantly at the same time as the second cell lock 5. When the buffer tank is full 6 and the drying material rises in the envelope around the transverse conveyor 39, the transverse snail conveyor 39 will be able to carry dried drying material out of the system 1. When the buffer tank 6 When filling is complete, the drying material will simply fall past the rotating transverse auger conveyor 39 and down into the buffer tank 6. This construction causes only dried drying material to be discharged from the plant when the buffer tank is full. In addition, the design is simple and reliable, does not require pre-programmed control and means for controlling the operation of the transverse auger conveyor 39.
    Alternatively, the transverse auger conveyor 39 can be activated when it is detected that the buffer tank is full 6, e.g. by providing dry goods in the shell around transverse conveyor 39. One or more level sensors are used to detect the level of dry goods and activate transverse auger conveyor 39 when the buffer tank 6 is full.
    The transverse auger conveyor 39 carries dried dry goods out of plant 1 for further processing 8, e.g. for pressing for fuel pellets, storage and / or transport 8 'away from plant 1 (shown in Fig. 1).
    Example In a plant with a drying chamber with a length of 6 m and a diameter of 800 mm, approx. 30 kW of heat per hour. In the drying chamber, used, wet litter from a horse stable is dried down to a water content of 1-5% by weight. 21
    The plant has the capacity to produce approx. 1500 kg of dried used litter per Day. Approximately half of this is burnt in the boiler, and approx. 750 kg of dry matter per day, which is post-processed by pelleting. ) The auger conveyor in the drying chamber rotates relatively slowly and the rotational speed is adjusted so that the drying time of the drying goods in the drying chamber is approx. 2 hours.
    The boiler has a capacity of 140 kW.
    The plate heat exchanger is a conventional plate heat exchanger with a capacity of 125) kW. In the condenser, approx. 15 kW pr. hour from cooling of dry air and condensation of the water vapor in the drying air in the condenser. 5 The plant's energy production, which is transferred to the central heating system's heating circuit, ensures heating and hot water production for 1200 m buildings.
    权利要求:
    Claims (8)
    [1]
    22
    1. Drying plant (1) for drying dry goods in the form of particulate matter, preferably of biological origin, such as wood chips, wood shavings, sawdust, straw, wood pellets or litter, including litter used in a stable where the drying plant (1) is adapted for utilizing heat from the drying plant (1) in one or more buildings, the plant (1) comprising: - a drying chamber (4) for drying dry goods in the form of particulate matter heated by a circulating stream (9,11 ) of oil, - a boiler (7) for heating the oil connected to means (6) for supplying at least a partial flow of the drying material to the boiler (7) for burning the drying material in the boiler (7), and with means for transferring the combustion heat from the flue gas to the oil before returning the oil to the drying chamber (4), characterized in that the drying system further comprises -a heat exchanger (13), which is used with a partial flow (14) of the oil from the boiler (7) heating of a circulating heating medium, such as water, from a heating strand (16,17) in the heating side of a central heating system for heating and / or hot water production to one or more buildings (15).
    [2]
    Drying system according to claim 1, characterized in that the system comprises a condenser (18) for condensing condensable water vapor and / or condensable gases from an air stream (19) taken from the drying chamber (4), the heating medium from the heating string (17) on the heating side. in the central heating system is used as refrigerant in the condenser (18) for preheating thereof prior to heating in the heat exchanger (13).
    [3]
    Drying system according to claim 1 or 2, characterized in that the drying chamber (4) comprises a horizontal or inclined snail conveyor (31) with an surrounding heat jacket (32) through which the heated oil circulates, preferably in co-flow with the drying material.
    [4]
    Drying system according to any of claims 1-3, characterized in that a mixer (2) comprising cutting means for mixing and dividing the particle size of the drying material is arranged prior to the drying chamber (4). 23
    [5]
    5. A process for drying dry matter in the form of particulate matter, preferably of biological origin, such as wood chips, planter shavings, sawdust, straw, wood pellets or litter including litter used in a barn and for utilizing heat from the drying plant in a or more buildings, the method comprising: 5 - drying the particulate material in a drying chamber (4) using a circulator the flow of oil (9,11), - supplying at least a partial stream of the drying material to a boiler ( 7) for burning drying goods in the boiler (7), - transferring combustion heat from flue gas to the oil before returning the oil to the drying chamber (4), and - removing a partial stream (14) of the oil from the boiler (7) and is passed to a heat exchanger (13) for heating a circulating heating medium, such as water, from a heating string (16, 17, 22) in the heating side of a central heating system for heating and / or hot water production to one or more buildings. ger (15). 15
    [6]
    Process according to claim 5, characterized in that condensable vapors and / or gases from an air stream (19) taken from the drying chamber (4) are cooled and condensed in a condenser (18), the heating medium in the heating string (17) from the heating side in the central heating system. is used as a refrigerant in the condenser (18) for preheating the heating medium of the heating string prior to heating in the heat exchanger (13).
    [7]
    Process according to claim 5 or 6, characterized in that a mixer (2), such as a conveyor with a double screw comprising cutting means, is arranged in front of the drying chamber (4) for mixing and simultaneously dividing the particle size of the drying material. .
    [8]
    Method according to any of claims 5-7, characterized in that a partial flow of the drying material is taken out for subsequent pelletizing (8). 30
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    同族专利:
    公开号 | 公开日
    EP3115722B1|2018-12-26|
    DK178722B1|2016-12-05|
    ES2717511T3|2019-06-21|
    EP3115722A1|2017-01-11|
    PL3115722T3|2019-07-31|
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    CN201523652U|2009-10-23|2010-07-14|云南省烟草公司楚雄州公司|Heating oil furnace central heat supply tobacco flue-curing device|CN105841452A|2016-02-01|2016-08-10|宜兴市凯世达科技有限公司|Adjustable ultrahigh moisture wet material dryer|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DKPA201570447A|DK178722B1|2015-07-06|2015-07-06|Process and dryer for drying dry goods and utilizing heat from the dryer|DKPA201570447A| DK178722B1|2015-07-06|2015-07-06|Process and dryer for drying dry goods and utilizing heat from the dryer|
    PL16178225T| PL3115722T3|2015-07-06|2016-07-06|Method and drying plant for drying material and utilising heat from the drying plant|
    ES16178225T| ES2717511T3|2015-07-06|2016-07-06|Method and drying plant for drying materials and heat utilization of the drying plant|
    EP16178225.5A| EP3115722B1|2015-07-06|2016-07-06|Method and drying plant for drying material and utilising heat from the drying plant|
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