CN116177832A - System for preparing biochar from sludge - Google Patents

Abstract

The invention provides a system for preparing biochar from sludge, including a sludge low-temperature drying machine for drying sludge, and the first hot water outlet of the heater in the sludge low-temperature drying machine is connected to the heat of the absorption heat pump. The water inlet, the hot water outlet of the absorption heat pump is connected to the first hot water inlet of the heater; the cooling water outlet of the condenser in the sludge low temperature dryer is connected to the cooling water inlet of the absorption heat pump, and the cooling water of the absorption heat pump The outlet is connected to the cooling water inlet of the cooling tower, and the cooling water outlet of the cooling tower is connected to the cooling water inlet of the condenser; the sludge outlet of the sludge low-temperature dryer is connected to the sludge inlet of the sludge carbonization device, and the sludge carbonization device The high-temperature flue gas discharged from the flue gas outlet is used to match the heat source inlet of the absorption heat pump and provide heat source for the absorption heat pump. The invention solves the problems of high energy consumption and high operation cost of the traditional biochar preparation system from sludge.

Description

A system for preparing biochar from sludge

technical field

The invention relates to the technical field of sludge treatment, in particular to a system for preparing biochar from sludge.

Background technique

Sludge is a by-product of sewage treatment, consisting of solid matter in raw sewage and solid matter produced during sewage treatment. Sludge has complex components and contains toxic and harmful substances, such as pathogenic microorganisms, parasite eggs, heavy metals and a large number of refractory substances. If it is not handled properly, it will easily cause direct or potential pollution to the environment. In order to treat the sludge, in the prior art, the sludge is usually stabilized, reduced, and harmless, and the whole process of final digestion and resource utilization of the sludge is carried out, including concentration (conditioning) , dehydration, anaerobic digestion, aerobic digestion, drying and other front-end treatment processes, as well as back-end disposal processes such as composting, incineration, landfill, building material utilization and preparation of carbon-based fertilizers. The specific operation steps are: after the sludge is mechanically dehydrated, it is dried by drying equipment to further reduce the moisture content. The dried sludge releases its internal heat energy and generates high-temperature flue gas through pyrolysis and incineration. The heat of the high-temperature flue gas is recovered for the energy demand of the front-end drying process, but the calorific value of the sludge is low, and the heat released by it is not enough to maintain the drying of the system, and a large amount of fuel is often required to be supplemented, resulting in high operating costs. Therefore, it is necessary to invent a new system for preparing biochar from sludge.

Contents of the invention

The purpose of the present invention is to provide a system for preparing biochar from sludge, which solves the problems of high energy consumption and high operating cost of the traditional system for preparing biochar from sludge.

The technical solution adopted by the present invention to solve its technical problems is:

A system for preparing biochar from sludge, including a sludge low-temperature dryer for drying sludge, the first hot water outlet of the heater in the sludge low-temperature dryer is connected to the hot water inlet of an absorption heat pump , the hot water outlet of the absorption heat pump is connected to the first hot water inlet of the heater;

The cooling water outlet of the condenser in the sludge low-temperature drying machine is connected to the cooling water inlet of the absorption heat pump, and the cooling water outlet of the absorption heat pump is connected to the cooling water inlet of the cooling tower, and the cooling water of the cooling tower is The outlet is connected to the cooling water inlet of the condenser;

The sludge outlet of the sludge low-temperature dryer is connected to the sludge inlet of the sludge carbonization device, and the high-temperature flue gas discharged from the flue gas outlet of the sludge carbonization device is used to cooperate with the heat source inlet of the absorption heat pump and feed An absorption heat pump provides a heat source, and the discharge port of the sludge carbonization device discharges biochar.

Further, the discharge port of the sludge carbonization device is connected to the feed port of the water-cooled screw conveyor, the hot water outlet of the water-cooled screw conveyor is connected to the second hot water inlet of the heater, and the heater's The second hot water outlet is connected to the hot water inlet of the water-cooled screw conveyor.

Further, the sludge carbonization device includes a pyrolysis gasifier and a secondary combustion chamber.

Further, the sludge inlet of the pyrolysis gasifier is connected to the sludge outlet of the low-temperature sludge dryer, and the pyrolysis gas outlet of the pyrolysis gasifier is connected to the pyrolysis gas inlet of the second combustion chamber, The high-temperature flue gas discharged from the flue gas outlet of the second combustion chamber is used to cooperate with the heat source inlet of the absorption heat pump and provide heat source for the absorption heat pump.

Further, the discharge port of the pyrolysis gasifier is connected to the feed port of the water-cooled screw conveyor, and the discharge port of the water-cooled screw conveyor discharges biochar.

Further, the flue gas outlet of the second combustion chamber is connected to the flue gas inlet of the air preheater, and the air outlet of the air preheater is connected to the air inlet of the second combustion chamber; The air outlet is connected to the air inlet of the air preheater; the flue gas outlet of the air preheater is used to cooperate with the heat source inlet of the absorption heat pump and provide heat source for the absorption heat pump.

Further, the absorption heat pump is any one of steam type, hot water type or flue gas type lithium bromide absorption heat pump.

Further, when the absorption heat pump is a steam type lithium bromide absorption heat pump, the flue gas outlet of the air preheater is connected to the flue gas inlet of the steam generator, and the steam outlet of the steam generator is connected to the absorption type The steam inlet of the heat pump, the condensed water outlet of the absorption heat pump is connected to the condensed water inlet of the steam generator;

When the absorption heat pump is a hot water lithium bromide absorption heat pump, the flue gas outlet of the air preheater is connected to the flue gas inlet of the flue gas heat exchanger, and the hot water outlet of the flue gas heat exchanger is connected to To the hot water inlet of the absorption heat pump, the hot water outlet of the absorption heat pump is connected to the hot water inlet of the flue gas heat exchanger;

When the absorption heat pump is a flue gas lithium bromide absorption heat pump, the flue gas outlet of the air preheater is directly connected to the flue gas inlet of the absorption heat pump.

Further, when the absorption heat pump is a steam type lithium bromide absorption heat pump, the flue gas outlet of the steam generator is connected to the flue gas treatment system; when the absorption heat pump is a hot water type lithium bromide absorption When the heat pump is a flue gas heat exchanger, the flue gas outlet of the flue gas heat exchanger is connected to the flue gas treatment system; when the absorption heat pump is a flue gas type lithium bromide absorption heat pump, the flue gas outlet of the absorption heat pump is connected to to the flue gas treatment system.

Further, the flue gas treatment system includes a dust collector, the flue gas inlet of the dust collector is connected to the flue gas outlet of the steam generator, and the flue gas outlet of the dust collector is connected to the flue gas inlet of the activated carbon box, so The flue gas outlet of the activated carbon box is connected to the flue gas inlet of the spray tower.

Beneficial effects of the present invention: the system provided by the present invention, on the one hand, the product biochar after sludge pyrolysis is used for sludge drying by recovering heat, and on the other hand, the pyrolysis gas generated by sludge pyrolysis is burned into a system Provide energy; the energy of pyrolysis gas combustion is used to dry the sludge through the absorption heat pump system and the sludge low-temperature dryer, which reduces the energy consumption required for the sludge drying of the system and reduces the operating cost.

The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

Description of drawings

Figure 1 is a flow chart of a biochar preparation system from sludge using a steam-type absorption heat pump.

Figure 2 is a flow chart of the biochar preparation system from sludge using a hot water absorption heat pump.

Figure 3 is a flow chart of the biochar preparation system from sludge using a flue gas absorption heat pump.

Detailed ways

A kind of sludge preparation biochar system as shown in Figure 1 to Figure 3, comprises the sludge low-temperature drying machine 1 for drying sludge, the heater 1-1 in the said sludge low-temperature drying machine 1 The first hot water outlet is connected to the hot water inlet of the absorption heat pump 2, and the hot water outlet of the absorption heat pump 2 is connected to the first hot water inlet of the heater 1-1;

The cooling water outlet of the condenser 1-2 in the sludge low temperature dryer 1 is connected to the cooling water inlet of the absorption heat pump 2, and the cooling water outlet of the absorption heat pump 2 is connected to the cooling water inlet of the cooling tower 3, The cooling water outlet of the cooling tower 3 is connected to the cooling water inlet of the condenser 1-2;

The sludge outlet of the sludge low-temperature drying machine 1 is connected to the sludge inlet of the sludge carbonization device 4, and the high-temperature flue gas discharged from the flue gas outlet of the sludge carbonization device 4 is used to match the heat source of the absorption heat pump 2 import, and provide heat source to the absorption heat pump 2, and the discharge port of the sludge carbonization device 4 discharges biochar.

Preferably, in combination with the above scheme, in order to cool the biochar discharged from the sludge carbonization device 4, and at the same time make full use of the heat energy generated during the cooling process, and supply it to the heater 1-1 for use, the discharge of the sludge carbonization device 4 The feed port is connected to the feed inlet of the water-cooled screw conveyor 8, and the hot water outlet of the water-cooled screw conveyor 8 is connected to the second hot water inlet of the heater 1-1, and the second hot water inlet of the heater 1-1 The water outlet is connected to the hot water inlet of the water-cooled screw conveyor 8 .

Preferably, in combination with the above solution, in order to fully pyrolyze and gasify the organic matter in the sludge for combustion treatment, the sludge carbonization device 4 includes a pyrolysis gasifier 4-1 and a secondary combustion chamber 4-2.

Preferably, in combination with the above scheme, in order to fully pyrolyze and gasify the organic matter in the sludge, fully burn the pyrolysis gas, and carry out subsequent utilization and treatment of the generated high-temperature flue gas, the pyrolysis gasification The sludge inlet of the furnace 4-1 is connected to the sludge outlet of the low-temperature sludge dryer 1, and the pyrolysis gas outlet of the pyrolysis gasification furnace 4-1 is connected to the pyrolysis gas inlet of the second combustion chamber 4-2 , the high-temperature flue gas discharged from the flue gas outlet of the second combustion chamber 4-2 is used to cooperate with the heat source inlet of the absorption heat pump 2, and provide heat source for the absorption heat pump 2.

Preferably, in combination with the above scheme, in order to cool the biochar discharged from the pyrolysis gasification furnace 4-1, and at the same time make full use of the heat energy generated during the cooling process, and supply it to the heater 1-1 for use, the pyrolysis gasification The discharge port of the furnace 4-1 is connected to the feed port of the water-cooled screw conveyor 8, and the discharge port of the water-cooled screw conveyor 8 discharges biochar.

Preferably, in combination with the above scheme, in order to heat the combustion air and improve the stability of the combustion flame in the secondary combustion chamber 4-2, the flue gas outlet of the secondary combustion chamber 4-2 is connected to the flue gas inlet of the air preheater 5 , the air outlet of the air preheater 5 is connected to the air inlet of the second combustion chamber 4-2; the air outlet of the sludge low temperature dryer 1 is connected to the air inlet of the air preheater 5; the air preheater The flue gas outlet of the heater 5 is used to cooperate with the heat source inlet of the absorption heat pump 2 and provide heat source for the absorption heat pump 2 .

Preferably, in combination with the above scheme, in order to provide heat sources to the absorption heat pump 2 in various ways, to provide the absorption heat pump 2 with any one of the lithium bromide absorption heat pumps of steam type, hot water type or flue gas type kind.

Preferably, in combination with the above scheme, as shown in Figure 1, in order to use high-temperature steam as the heat source of the absorption heat pump 2, when the absorption heat pump 2 is a steam-type lithium bromide absorption heat pump, the air preheater 5 The flue gas outlet is connected to the flue gas inlet of the steam generator 6, the steam outlet of the steam generator 6 is connected to the steam inlet of the absorption heat pump 2, and the condensed water outlet of the absorption heat pump 2 is connected to the steam generator 6 Condensate inlet;

As shown in Figure 2, in order to use hot water as the heat source of the absorption heat pump 2, when the absorption heat pump 2 is a hot water lithium bromide absorption heat pump, the flue gas outlet of the air preheater 5 is connected to the flue gas The flue gas inlet of the gas heat exchanger 9, the hot water outlet of the flue gas heat exchanger 9 is connected to the hot water inlet of the absorption heat pump 2, and the hot water outlet of the absorption heat pump 2 is connected to the flue gas heat exchanger 9 hot water inlets;

As shown in Figure 3, in order to use the high-temperature flue gas as the heat source of the absorption heat pump 2, when the absorption heat pump 2 is a flue gas type lithium bromide absorption heat pump, the flue gas outlet of the air preheater 5 is directly connected to Flue gas inlet to absorption heat pump 2.

Preferably, in combination with the above scheme, in order to carry out subsequent treatment of the exhausted flue gas, when the absorption heat pump 2 is a steam-type lithium bromide absorption heat pump, the flue gas outlet of the steam generator 6 is connected to the flue gas Processing system 7; when the absorption heat pump 2 is a hot water lithium bromide absorption heat pump, the flue gas outlet of the flue gas heat exchanger 9 is connected to the flue gas treatment system 7; when the absorption heat pump When 2 is a flue gas type lithium bromide absorption heat pump, the flue gas outlet of the absorption heat pump 2 is connected to the flue gas treatment system 7 .

Preferably, in combination with the above-mentioned solution, in order to perform better harmless treatment of the discharged flue gas, the flue gas treatment system includes a dust collector 7-1, and the flue gas inlet of the dust collector 7-1 is connected to The flue gas outlet of the steam generator 6, the flue gas outlet of the dust collector 7-1 is connected to the flue gas inlet of the activated carbon box 7-2, and the flue gas outlet of the activated carbon box 7-2 is connected to the spray tower 7- 3 flue gas inlet. The dust collector 7-1 can use a bag dust collector to remove large particles of dust in the flue gas; the activated carbon box 7-2 is used to remove tiny particles and harmful substances in the flue gas; the spray tower 7-3 is used to For flue gas desulfurization and dust removal, the HLPL-5K spray tower provided by Guangdong Ketai Environmental Technology Co., Ltd. can be used.

The sludge low-temperature drying machine 1 in the present invention can adopt the SWG5000 mesh belt dryer provided by Chongqing Shaweigu Environmental Protection and Energy Saving Technology Co., Ltd., which can pass hot water of more than 90 degrees and pass through the heater 1-1 to the body. The air is heated to obtain dry hot air at 70-90 degrees. The hot air is blown by the fan and flows from the bottom to the top of the conveying mesh belt to fully exchange heat on the formed sludge laid on the mesh belt. , when the dry hot air passes through the two layers of sludge mesh belt, it is converted into humid hot air with a humidity above 40% and a temperature between 40 and 60 degrees. The humid hot air circulates through the condenser 1-2 through the fan, and exchanges heat with the cooling water in the condenser 1-2 at about 28 degrees. After the humid hot air reaches the dew point temperature, the water vapor is condensed into condensed waste water and discharged. Harmless treatment is carried out by follow-up equipment; the hot air after drying undergoes repeated cycle heat exchange with hot water of more than 90 degrees.

Absorption heat pump 2 uses the first type of lithium bromide absorption heat pump unit, which is a circulation system that utilizes low-grade heat sources to pump heat from low-temperature heat sources to high-temperature heat sources, and is an effective device for recycling low-temperature heat energy. The dual function of saving energy and protecting the environment. The first type of lithium bromide absorption heat pump unit is a high-temperature heat source (steam, high-temperature hot water, flue gas, etc.) The heat energy is used to prepare the required process or high-temperature heat medium (hot water) for heating, and to realize the equipment for transporting heat energy from low temperature to high temperature. The heat pump consists of main components such as generators, condensers, evaporators, absorbers and heat exchangers, and air extraction devices, as well as auxiliary parts such as shielded pumps (solution pumps and refrigerant pumps). The air extraction device extracts the non-condensable gas in the heat pump, and keeps the heat pump in a high vacuum state. The device uses a small amount of high-temperature heat source as the driving heat source to generate a large amount of useful heat energy at medium temperature. That is, it is driven by high-temperature heat energy, and the heat energy of the low-temperature heat source is raised to a medium temperature, thereby improving the utilization efficiency of heat energy. In this embodiment, the FG-55 vapor-type lithium bromide heat pump unit provided by Panasonic Refrigeration (Dalian) Co., Ltd. can be used.

The cooling tower 3 can use an open cooling tower or a closed cooling tower, and the DBNL3-20T open cooling tower provided by Hebei Shuokang Environmental Protection Equipment Co., Ltd. can be used. Or a device that refrigerates waste heat generated in an air conditioner. The dry (low enthalpy) air enters the cooling tower from the air inlet net after being pumped by the fan; the high-temperature water molecules with high partial pressure of saturated steam flow to the air with low pressure, and the hot and humid (high enthalpy) water self-sows The water system sprinkles into the tower. When water droplets are in contact with air, on the one hand, due to the direct heat transfer between the air and water, and on the other hand, due to the pressure difference between the water vapor surface and the air, evaporation occurs under the action of pressure, that is, through contact with unsaturated dry air The heat transfer takes away the sensible heat of the water, and part of the water evaporates to take away the latent heat in the water, so as to achieve the purpose of cooling the cooling water.

The sludge carbonization device 4 can adopt the XHRJ-1-1.2 sludge pyrolysis gasification combustion furnace provided by Guangdong Xinhuan Electromechanical Equipment Manufacturing Co., Ltd., wherein the pyrolysis gasification furnace 4-1 is a vertical fixed-bed gasification furnace , the upper part is the sludge inlet, the sludge moves from top to bottom in the furnace, and the reacted sludge is discharged from the discharge port at the bottom. After entering the furnace, the sludge is first heated to evaporate water and dried, and the temperature gradually rises during the downward movement. High occurrence of pyrolysis reaction produces pyrolysis gas, and the pyrolysis gas passes through the high-temperature oxidation zone during the downward flow process to release a large amount of heat. At this time, the sludge basically completes the pyrolysis process, the organic matter is fully volatilized, and the reduction reaction occurs when the sludge continues to move downward. . The second combustion chamber 4-2 is used to burn the pyrolysis gas in the second combustion chamber and discharge the generated high-temperature flue gas.

The steam generator 6 can adopt the QC3/700-0.7-0.7 steam generator (waste heat boiler) provided by Henan Yongxing Boiler Co., Ltd. The high-temperature flue gas first enters the furnace of the steam generator, and then the flue gas enters the front smoke box The waste heat recovery device then enters the pyrotechnic pipe, and finally enters the waste heat recovery device in the flue of the rear smoke box to heat the condensed water generated by the absorption heat pump 2 into high-temperature steam, and the high-temperature flue gas becomes low-temperature flue gas and is discharged.

The air preheater 5 can adopt the GB-20 air preheater provided by Nanjing Plant Heat Exchange Equipment Co., Ltd., which is welded by a series of stainless steel tubes and belongs to the tubular heat exchanger. The cold and hot fluids do not touch each other, they flow inside and outside the tube respectively, and exchange heat through the tube wall. The whole heat transfer process belongs to series heat transfer. One of the cold and hot fluids participating in the heat exchange flows inside the tubes, and the other flows outside the tubes. The wall of the tube bundle is the heat transfer surface of the cold and hot fluids, thereby heating the air inside the heat exchanger. By drawing out the internal circulating air of the low-temperature sludge dryer 1, heating it through the air preheater 5 and sending it to the secondary combustion chamber 4-2 for combustion, the air in the low-temperature sludge dryer 1 can be continuously renewed, and the sewage The volatilized organic matter in the mud drying process is fully burned and utilized while achieving the purpose of treating odor.

The water-cooled screw conveyor 8 can adopt the GSL-200×3 water-cooled screw conveyor provided by Guangdong Xinhuan Electromechanical Equipment Manufacturing Co., Ltd., which is used to transport high-temperature materials. The conveyed material is cooled. In the present invention, the water-cooled screw conveyor 8 is used for conveying and cooling biochar. The system recovers the heat of biochar through the water-cooled screw conveyor 8, and provides it to the heater 1-1, which improves the thermal efficiency of the system and reduces energy consumption.

The working principle of the system of the present invention: the wet sludge with a moisture content of 60% is dried by the sludge low-temperature dryer 1 to become dry sludge, which is sent to the pyrolysis gasification furnace 4-1 for reaction, and the reaction generates pyrolysis gas ( The reaction temperature in the core area is 850°C) and biochar (the temperature is about 500°C), wherein the biochar enters the water-cooled screw conveyor 8 to cool down, and the finished biochar is discharged. The pyrolysis gas enters the secondary combustion chamber 4-2 for combustion, releases heat and generates high-temperature flue gas (the flue gas generated by combustion is about 900°C), and the high-temperature flue gas is drawn out from the air preheater 5 together with the sludge low-temperature dryer 1 heat exchange with the air (the flue gas temperature drops to 600°C), the heated air enters the pyrolysis gas secondary combustion chamber 5 and burns together with the pyrolysis gas; the cooled high-temperature flue gas enters the steam generator 6 to generate a saturation of 0.6MPa The steam is further lowered to 150°C, and the steam generated by the steam generator 6 is used to drive the absorption heat pump 2 to provide hot water for the sludge low temperature dryer 1. The temperature of the hot water circulation between the heater 1-1 and the absorption heat pump 2 is 70-90°C, the cooling water discharged from the condenser 1-2 enters the absorption heat pump 2 at a temperature of 45°C, and the absorption heat pump 2 discharges into the cooling water The cooling water of tower 3 is 40°C, and the cooling water discharged into condenser 1-2 by cooling tower 3 is 33°C. Finally, the flue gas discharged from the steam generator 6 is discharged after being treated by the flue gas treatment system.

The present invention has been exemplarily described above in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above methods, as long as various improvements of the method concept and technical solutions of the present invention are adopted, or directly applied to other occasions without improvement All fall within the protection scope of the present invention.

Claims (10)

1. A kind of sludge prepares biochar system, it is characterized in that, comprises the sludge low-temperature drying machine (1) that is used to dry sludge, heater (1-1) in described sludge low-temperature drying machine (1) The first hot water outlet of 1) is connected to the hot water inlet of the absorption heat pump (2), and the hot water outlet of the absorption heat pump (2) is connected to the first hot water inlet of the heater (1-1); The cooling water outlet of the condenser (1-2) in the sludge low temperature dryer (1) is connected to the cooling water inlet of the absorption heat pump (2), and the cooling water outlet of the absorption heat pump (2) is connected to The cooling water inlet of cooling tower (3), the cooling water outlet of described cooling tower (3) is connected to the cooling water inlet of condenser (1-2); The sludge outlet of the sludge low-temperature drying machine (1) is connected to the sludge inlet of the sludge carbonization device (4), and the high-temperature flue gas discharged from the flue gas outlet of the sludge carbonization device (4) is used to cooperate with The heat source of the absorption heat pump (2) is imported and provides the heat source for the absorption heat pump (2), and the discharge port of the sludge carbonization device (4) discharges biochar. 2. the sludge preparation biochar system according to claim 1, is characterized in that, the discharge port of described sludge carbonization device (4) is connected to the feed port of water-cooled screw conveyor (8), and the water-cooled The hot water outlet of the screw conveyor (8) is connected to the second hot water inlet of the heater (1-1), and the second hot water outlet of the heater (1-1) is connected to the water-cooled screw conveyor (8) hot water import. 3. The sludge preparation biochar system according to claim 1 or 2, characterized in that, the sludge carbonization device (4) comprises a pyrolysis gasifier (4-1), a second combustion chamber (4- 2). 4. the sludge preparation biochar system according to claim 3, is characterized in that, the sludge inlet of described pyrolysis gasification furnace (4-1) is connected to the sludge of sludge low-temperature drying machine (1) Outlet, the pyrolysis gas outlet of the pyrolysis gasifier (4-1) is connected to the pyrolysis gas inlet of the second combustion chamber (4-2), and the flue gas outlet of the second combustion chamber (4-2) is discharged The high-temperature flue gas is used to cooperate with the heat source inlet of the absorption heat pump (2), and provide heat source for the absorption heat pump (2). 5. sludge preparation biochar system according to claim 3 is characterized in that, the discharge port of described pyrolysis gasifier (4-1) is connected to the feed port of water-cooled screw conveyor (8), The discharge port of the water-cooled screw conveyor (8) discharges biochar. 6. sludge preparation biochar system according to claim 3 is characterized in that, the flue gas outlet of described second combustion chamber (4-2) is connected to the flue gas inlet of air preheater (5), and described The air outlet of the air preheater (5) is connected to the air inlet of the second combustion chamber (4-2); the air outlet of the sludge low temperature dryer (1) is connected to the air inlet of the air preheater (5) ; The flue gas outlet of the air preheater (5) is used to cooperate with the heat source inlet of the absorption heat pump (2), and provide heat source for the absorption heat pump (2). 7. the sludge preparation biochar system according to claim 6, is characterized in that, described absorption heat pump (2) is any one in the lithium bromide absorption heat pump of steam type, hot water type or flue gas type . 8. according to claim 6 or 7 described sludge preparation biochar systems, it is characterized in that, when described absorption heat pump (2) is the lithium bromide absorption heat pump of vapor type, the air preheater (5) The flue gas outlet is connected to the flue gas inlet of the steam generator (6), the steam outlet of the steam generator (6) is connected to the steam inlet of the absorption heat pump (2), and the condensed water of the absorption heat pump (2) The outlet is connected to the condensed water inlet of the steam generator (6); When the absorption heat pump (2) is a hot water lithium bromide absorption heat pump, the flue gas outlet of the air preheater (5) is connected to the flue gas inlet of the flue gas heat exchanger (9), and the flue gas The hot water outlet of the gas heat exchanger (9) is connected to the hot water inlet of the absorption heat pump (2), and the hot water outlet of the absorption heat pump (2) is connected to the hot water inlet of the flue gas heat exchanger (9) ; When the absorption heat pump (2) is a flue gas type lithium bromide absorption heat pump, the flue gas outlet of the air preheater (5) is directly connected to the flue gas inlet of the absorption heat pump (2). 9. The system for preparing biochar from sludge according to claim 8 is characterized in that, when the absorption heat pump (2) is a steam-type lithium bromide absorption heat pump, the smoke from the steam generator (6) The gas outlet is connected to the flue gas treatment system (7); when the absorption heat pump (2) is a hot water type lithium bromide absorption heat pump, the flue gas outlet of the flue gas heat exchanger (9) is connected to the flue gas Gas treatment system (7); when the absorption heat pump (2) is a flue gas type lithium bromide absorption heat pump, the flue gas outlet of the absorption heat pump (2) is connected to the flue gas treatment system (7). 10. The system for preparing biochar from sludge according to claim 9, characterized in that, the flue gas treatment system comprises a dust remover (7-1), and the flue gas inlet of the dust remover (7-1) is connected to To the flue gas outlet of the steam generator (6), the flue gas outlet of the dust collector (7-1) is connected to the flue gas inlet of the activated carbon box (7-2), and the flue gas of the activated carbon box (7-2) The gas outlet is connected to the flue gas inlet of the spray tower (7-3).

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