Small-sized household garbage pyrolysis and gasification treatment system

Abstract

The application provides a small household garbage pyrolysis gasification treatment system and relates to the technical field of household garbage treatment, and comprises a garbage pyrolysis combustion and flue gas purification system, a flue air heat exchange system, a gas-water heat exchange system and a NOx removal system; hot air is generated by arranging the flue air heat exchanger, the hot air is mainly used for drying the garbage, the calorific value of the fuel into the furnace is improved, the garbage accumulation density in the pyrolysis chamber is reduced, the water evaporation heat absorption in the pyrolysis chamber is reduced, the purpose of increasing the pyrolysis gas flow at the outlet of the pyrolysis chamber and improving the pyrolysis gas outlet temperature is achieved, and the condensation problem of the tar in the pyrolysis gas conveying pipeline is eliminated. The system is provided with the NOx removal equipment to ensure that the flue gas NOx emission concentration is reduced under full load. The system does not adopt the flue gas water spraying quenching mode, the water consumption of the system can be reduced, and the energy saving and emission reduction level of the system is improved.

Description

Technical Field

[0001] This invention belongs to the field of municipal solid waste treatment technology, and in particular relates to a small-scale municipal solid waste pyrolysis gasification treatment system. Background Technology

[0002] Municipal solid waste pyrolysis gasification is a process in which the organic components of solid waste are decomposed under anaerobic or oxygen-deficient conditions using high temperatures, releasing volatile substances (pyrolysis gas). The ungasified residue cokes and burns completely. As a waste treatment technology, municipal solid waste pyrolysis gasification is characterized by its simple system, small footprint, low investment, large waste reduction volume, and low secondary pollution. It is suitable for small to medium-sized on-site treatment of municipal solid waste in counties, towns, and villages, achieving the reduction, harmlessness, and resource recovery of municipal solid waste.

[0003] Existing municipal solid waste gasification systems are not yet mature and suffer from the following problems: The moisture content of raw waste is as high as 50-60%, and the pretreatment dehydration methods used in current systems (such as underfloor heating and composting fermentation dehydration) are ineffective. This results in excessive heat consumption for evaporating moisture from the waste in the pyrolysis chamber, leading to a low overall temperature within the chamber, low pyrolysis gas production, and excessively high waste moisture content entering the chamber, causing excessively high packing density and making it difficult for pyrolysis gas to penetrate and escape. The low temperature of the pyrolysis gas causes tar components to condense on the walls of the conveying pipelines, causing blockages that are difficult to clean and reduce the continuous operating time of the equipment. Low pyrolysis gas production results in low heat production in the secondary combustion chamber, high consumption of combustion fuel, and high operating costs. To avoid dioxin generation, traditional processes often use rapid water cooling, which consumes a large amount of water and does not effectively utilize the heat from the flue gas. The composition of municipal solid waste fluctuates greatly, and NOx emissions are prone to exceed standards during certain periods (when the calorific value of the waste is high). Existing systems often only consider desulfurization, deacidification, and dust removal equipment, neglecting NOx removal equipment. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a small-scale municipal solid waste pyrolysis gasification treatment system that can effectively increase the temperature of the pyrolysis chamber, accelerate the system start-up speed, increase the temperature of the pyrolysis gas, eliminate the problem of tar condensation and pipe blockage, extend the continuous operation time of the system, and produce hot water to increase the utilization rate of combustion heat, thereby solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides a small-scale municipal solid waste pyrolysis gasification treatment system, including a waste pyrolysis combustion and flue gas purification system, a flue gas heat exchange system, a gas-water heat exchange system, and a NOx removal system;

[0006] The waste pyrolysis combustion and flue gas purification system includes a waste crusher, a waste dryer, a pyrolysis chamber, a secondary combustion chamber, a deacidification tower, a dust collector, and a chimney connected in sequence. The deacidification tower is connected to the deacidification solution tank.

[0007] The flue gas heat exchange system includes a blower, a flue gas heat exchanger, and a duct system. The flue gas heat exchanger is located between the secondary combustion chamber and the deacidification tower and is used to cool the flue gas. The duct system is used to supply the hot air generated by the flue gas heat exchanger to the waste pyrolysis combustion and flue gas purification system and the gas-water heat exchange system.

[0008] The gas-water heat exchange system includes a gas-water heat exchanger and a water pipeline system. The gas-water heat exchanger uses the hot air generated by the flue gas heat exchanger to heat the water. The water pipeline system is used to prepare urea solution for the NOx removal system and to transport the hot water generated by the gas-water heat exchanger to the deacidification solution tank.

[0009] The NOx removal system is used to prepare a urea solution to remove NOx from flue gas, ensuring a full-load reduction in NOx emission concentration.

[0010] Flue gas heat exchangers can rapidly cool high-temperature flue gas, replacing the traditional method of using water spray for rapid cooling to eliminate dioxins. This can effectively reduce operating water consumption and improve the system's energy-saving and emission-reduction levels.

[0011] Furthermore, the waste shredder and the waste dryer are located inside the waste raw material room. The waste shredder is connected to the waste shredder via a waste conveying device one, and the waste dryer is connected to the pyrolysis chamber via a waste conveying device two. A pyrolysis chamber feeder is installed above the pyrolysis chamber. Waste from the waste conveying device two is sent to the pyrolysis chamber feeder, which then feeds the waste into the pyrolysis chamber. The pyrolysis chamber is connected to the secondary combustion chamber via a pyrolysis gas conveying pipeline. A pyrolysis gas jacket is installed on the outside of the conveying pipeline. A burner is installed on the top of the secondary combustion chamber, and supplementary combustion fuel is provided through auxiliary fuel supply equipment. The area above the secondary combustion chamber is designed as a thin cylindrical shape to achieve a concentrated ignition and combustion effect, increase the local temperature, and ensure stable combustion. The secondary combustion chamber is connected to the deacidification tower through a secondary combustion chamber outlet flue and an intermediate flue connected in sequence. The deacidification tower is connected to the dust collector through a deacidification tower outlet flue. The dust collector is connected to the chimney through a flue pipe, and an induced draft fan is installed on the flue pipe.

[0012] Furthermore, the air duct system includes a cold air duct, a hot air duct, a secondary combustion chamber air supply branch pipe, a pyrolysis chamber hot air branch pipe, a dryer air inlet pipe, a dryer air outlet pipe, a pyrolysis gas jacket air inlet pipe, and a pyrolysis gas jacket air outlet pipe.

[0013] The cold air duct is used to send the cold air in the waste raw material room into the flue gas heat exchanger through the blower, which can reduce the odor leakage from the waste raw material room and improve the air quality of the surrounding environment of the waste treatment unit. The hot air ducts are connected to the secondary combustion chamber air supply branch pipe, the pyrolysis chamber hot air branch pipe, and the dryer air inlet pipe, respectively. The secondary combustion chamber air supply branch pipe is connected to the combustion air inlet of the secondary combustion chamber. The secondary combustion chamber air supply branch pipe is connected to the pyrolysis gas jacket through the pyrolysis gas jacket inlet pipe. The pyrolysis gas jacket is connected to the secondary combustion chamber through the pyrolysis gas jacket outlet pipe. The pyrolysis chamber hot air branch pipe is connected to the pyrolysis chamber. The dryer air inlet pipe is connected to the waste dryer. The waste dryer uses hot air provided by a flue gas heat exchanger as a heat source, which can remove nearly half of the moisture in the raw waste and effectively improve the unit calorific value of the waste. A dryer outlet and flue gas mixer are installed in the intermediate flue. The dryer outlet pipe is used to send the exhaust gas of the waste dryer into the intermediate flue.

[0014] By setting up a flue gas heat exchanger to generate hot air, the hot air is mainly used to dry the waste, increase the calorific value of the fuel entering the furnace, reduce the waste accumulation density in the pyrolysis chamber, reduce the heat absorption of moisture evaporation in the pyrolysis chamber, and increase the pyrolysis gas flow rate and temperature at the pyrolysis gas outlet, thereby eliminating the problem of tar condensation in the pyrolysis gas delivery pipeline.

[0015] The pyrolysis gas is drawn from the pyrolysis gas delivery pipeline above the side wall of the pyrolysis chamber and sent to the secondary combustion chamber. The pyrolysis gas delivery pipeline is equipped with a pyrolysis gas sleeve. During normal operation, hot air is introduced into the pyrolysis gas sleeve through the pyrolysis gas sleeve inlet pipe to increase the wall temperature of the pyrolysis gas delivery pipeline, keeping it above the condensation point temperature of most tar components. This minimizes the risk of tar in the pyrolysis gas condensing on the wall of the pyrolysis gas delivery pipeline and causing pipe blockage. The hot air in the pyrolysis gas sleeve is sent into the secondary combustion chamber through the pyrolysis gas sleeve outlet pipe.

[0016] The combustion-supporting air for the secondary combustion chamber is introduced from the air supply branch pipe of the secondary combustion chamber and the gas outlet pipe of the pyrolysis gas casing. Compared with the method of drawing in cold air for combustion support, the consumption of combustion-supporting fuel can be significantly reduced.

[0017] Furthermore, the air duct system also includes an air inlet duct and an air outlet duct for the air-water heat exchanger;

[0018] The hot air duct is connected to the gas-water heat exchanger through the air inlet duct of the gas-water heat exchanger, and the air outlet duct of the gas-water heat exchanger is used to send the exhaust gas of the gas-water heat exchanger into the outlet flue of the deacidification tower.

[0019] Furthermore, the air duct system also includes an air bypass pipe for the gas-water heat exchanger. One end of the air bypass pipe is connected to the hot air duct, and the other end is connected to the air outlet duct of the gas-water heat exchanger. The air bypass pipe is used to discharge part or all of the hot air directly to the outlet flue of the deacidification tower when necessary.

[0020] Furthermore, the NOx removal system includes a urea solution preparation tank, a urea solution dilution tank, a urea solution delivery pump, a flow distribution and metering module, and a spray grid connected in sequence. The spray grid is located in the flue gas outlet of the secondary combustion chamber, where urea solution is sprayed. The NH3 produced by urea pyrolysis can react with the NOx produced by combustion in the subsequent flue gas, thereby removing more than half of the NOx components in the flue gas and controlling the NOx emission concentration below the environmental protection limit.

[0021] Furthermore, the water pipeline system includes a cold water inlet pipe, a hot water main pipe, a bypass water pipe for the gas-water heat exchanger, a water supply branch pipe for the urea solution preparation tank, a water supply branch pipe for the urea solution dilution tank, a water supply branch pipe for the deacidification solution tank, and an external hot water supply pipe;

[0022] The cold water inlet pipe is used to supply cold water to the gas-water heat exchanger. The hot water generated by heat exchange in the gas-water heat exchanger enters the hot water main pipe. One end of the bypass water pipe of the gas-water heat exchanger is connected to the cold water inlet pipe, and the other end is connected to the hot water main pipe for regulating the hot water temperature. The hot water main pipe is connected to the water supply branch pipes of the urea solution preparation tank, the urea solution dilution tank, and the deacidification solution tank, and to the external hot water supply pipe. The water supply branch pipe of the urea solution preparation tank is connected to the urea solution preparation tank, the water supply branch pipe of the urea solution dilution tank is connected to the urea solution dilution tank, and the water supply branch pipe of the deacidification solution tank is connected to the deacidification solution tank. The external hot water supply pipe is used to transport excess hot water.

[0023] Furthermore, a deacidification solution pump and a deacidification solution flow regulating valve are installed on the pipeline connecting the deacidification tower and the deacidification solution tank, and the deacidification solution is sprayed out through the deacidification solution spray grid, which is located inside the deacidification tower.

[0024] Furthermore, an ash discharge hopper is provided at the bottom of the pyrolysis chamber, which is connected to the slag discharge device. A pyrolysis chamber grate is provided above the ash discharge hopper, and the pyrolysis chamber grate is supported by a row of air inlet pipes. One end of the air inlet pipe is connected to the pyrolysis chamber suction pipe, and a damper is provided on the pyrolysis chamber suction pipe. The intake air volume is adjusted by adjusting the opening of the damper. The air inlet pipe is a flute-shaped pipe, and multiple ventilation holes are opened on the pipe wall of the inner part of the pyrolysis chamber. The damper can be closed when necessary, and hot air is drawn in through the pyrolysis chamber hot air branch pipe to increase the working temperature of the pyrolysis chamber.

[0025] Above the grate of the pyrolysis chamber are, in sequence, an ash layer, a coke combustion layer, a waste pyrolysis layer, and a waste drying layer. After the waste undergoes drying pretreatment, its heat absorption in the pyrolysis chamber decreases, increasing the outlet temperature and thus the pyrolysis gas production. Because the waste has been dried and is loosely packed, it facilitates the discharge of pyrolysis gas through the waste drying layer.

[0026] Furthermore, gas pipeline flow regulating valves are installed on the cold air duct, the secondary combustion chamber air supply branch pipe, the pyrolysis chamber hot air branch pipe, the dryer air inlet pipe, the dryer air outlet pipe, the pyrolysis gas jacket air inlet pipe, the gas-water heat exchanger air inlet pipe, the gas-water heat exchanger air outlet pipe, and the gas-water heat exchanger air bypass pipe. Liquid pipeline flow regulating valves are installed on the cold water inlet pipe, the gas-water heat exchanger bypass water pipe, the urea solution preparation tank water supply branch pipe, the urea solution dilution tank water supply branch pipe, the deacidification solution tank water supply branch pipe, and the external hot water supply pipe.

[0027] Beneficial effects:

[0028] This invention provides a small-scale municipal solid waste pyrolysis gasification treatment system, which can be used to treat municipal solid waste with complex composition and high humidity. It includes a waste pyrolysis combustion and flue gas purification system, a flue gas heat exchange system, a gas-water heat exchange system, and a NOx removal system. The system utilizes the heat generated by combustion to produce hot air through a flue gas heat exchanger, which is then supplied to the waste dryer, pyrolysis chamber, secondary combustion chamber, and gas-water heat exchanger. This achieves pre-dehydration of the high-humidity waste, increases the temperature of the pyrolysis chamber and the output of pyrolysis gas, and effectively accelerates the system start-up speed. The increased temperature of the pyrolysis gas leads to a greater amount of tar condensation. To further reduce the impact of pyrolysis gas, it is recommended to install a pyrolysis gas jacket to increase the wall temperature of the pyrolysis gas delivery pipeline, effectively solving the pipe blockage problem caused by tar condensation and significantly extending the continuous operation time of the system. The gas-water heat exchanger can produce hot water, which can meet the system's own needs and also provide hot water to external systems, increasing the utilization value of the heat generated by waste incineration and reducing operating water consumption. The installation of a NOx removal system can ensure a reduction in NOx emission concentration in flue gas at full load. Replacing the water spray quenching method with a flue gas-air heat exchanger to reduce flue gas temperature can reduce the system's operating water consumption and improve the system's energy saving and emission reduction level.

[0029] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a preferred embodiment of the present invention;

[0031] Figure label:

[0032] 1. Waste raw material storage room; 2. Waste crusher; 3. Waste conveying equipment one; 4. Waste dryer; 5. Waste conveying equipment two; 6. Pyrolysis chamber feeder; 7. Pyrolysis chamber; 7.1 Pyrolysis chamber suction pipe; 7.2 Ash hopper; 7.3 Air damper; 8. Slag discharge device; 9. Pyrolysis chamber grate; 10. Pyrolysis gas conveying pipeline; 10.1 Pyrolysis gas sleeve; 10.2 Pyrolysis gas sleeve inlet pipe; 10.3 Pyrolysis gas sleeve outlet pipe; 11. Secondary combustion chamber; 11.1 Burner; 11.2 11.3 Auxiliary fuel supply equipment; 11.4 Secondary combustion chamber accumulator; 12. Deacidification tower; 12.1 Deacidification solution tank; 12.2 Deacidification solution pump; 12.3 Deacidification solution flow regulating valve; 12.4 Deacidification solution spray grille; 13. Dust collector; 14. Flue gas duct; 14.1 Deacidification tower outlet flue gas duct; 14.2 Secondary combustion chamber outlet flue gas duct; 14.3 Intermediate flue gas duct; 15. Exhaust fan; 16. Chimney; 17. Blower; 18. Flue gas heat exchanger ; 19. Ductwork System; 19.1. Cold Air Ductwork; 19.2. Hot Air Ductwork; 19.3. Secondary Combustion Chamber Air Supply Branch Pipe; 19.4. Pyrolysis Chamber Hot Air Branch Pipe; 19.5. Dryer Inlet Pipe; 19.6. Gas-Water Heat Exchanger Inlet Pipe; 19.7. Gas-Water Heat Exchanger Outlet Pipe; 19.8. Gas-Water Heat Exchanger Air Bypass Pipe; 19.9. Dryer Outlet Pipe; 20. Gas Pipeline Flow Control Valve; 21. Dryer Outlet Gas and Flue Gas Mixer; 22. Gas-Water Heat Exchanger; 23. Water Pipeline System; 23 23.1 Cold water inlet pipe; 23.2 Hot water main pipe; 23.3 Bypass water pipe for gas-water heat exchanger; 23.4 Water supply branch pipe for urea solution preparation tank; 23.5 Water supply branch pipe for urea solution dilution tank; 23.6 Water supply branch pipe for deacidification solution tank; 23.7 External hot water supply pipe; 24 Liquid pipeline flow regulating valve; 25.1 Urea solution preparation tank; 25.2 Urea solution dilution tank; 25.3 Urea solution transfer pump; 25.4 Flow distribution and metering module; 25.5 Spray grid. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0034] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0035] Example:

[0036] like Figure 1 As shown, in a preferred embodiment, a small-scale municipal solid waste pyrolysis gasification treatment system is provided, including a waste pyrolysis combustion and flue gas purification system, a flue gas heat exchange system, a gas-water heat exchange system and a NOx removal system;

[0037] The waste pyrolysis combustion and flue gas purification system includes a waste crusher 2, a waste dryer 4, a pyrolysis chamber 7, a secondary combustion chamber 11, a deacidification tower 12, a dust collector 13, and a chimney 16 connected in sequence. The deacidification tower 12 is connected to a deacidification solution tank 12.1. A deacidification solution pump 12.2 and a deacidification solution flow regulating valve 12.3 are installed on the pipeline connecting the deacidification tower 12 and the deacidification solution tank 12.1. The deacidification solution is sprayed out through a deacidification solution spray grid 12.4, which is located inside the deacidification tower 12.

[0038] The flue gas heat exchange system includes a blower 17, a flue gas heat exchanger 18, and a duct system 19. The flue gas heat exchanger 18 is located between the secondary combustion chamber 11 and the deacidification tower 12 and is used to cool the flue gas. The duct system 19 is used to transport the hot air generated by the flue gas heat exchanger 18 to the waste pyrolysis combustion and flue gas purification system and the gas-water heat exchange system.

[0039] The gas-water heat exchange system includes a gas-water heat exchanger 22 and a water pipeline system 23. The gas-water heat exchanger 22 uses the hot air generated by the flue gas heat exchanger 18 to heat the water. The water pipeline system 23 is used to prepare urea solution for the NOx removal system and to transport the hot water generated by the gas-water heat exchanger 22 to the deacidification solution tank 12.1.

[0040] The NOx removal system is used to prepare a urea solution to remove NOx from flue gas, ensuring a reduction in NOx emission concentration at full load.

[0041] The flue gas heat exchanger 18 can rapidly cool high-temperature flue gas, replacing the traditional solution of using water spray for rapid cooling to eliminate dioxins, and can effectively reduce operating water consumption.

[0042] Waste shredder 2 and waste dryer 4 are installed inside waste raw material room 1. Waste shredder 2 is connected to waste conveying equipment 3. Waste dryer 4 is connected to pyrolysis chamber 7 via waste conveying equipment 5. A pyrolysis chamber feeder 6 is installed above pyrolysis chamber 7. Waste from waste conveying equipment 5 is sent to the pyrolysis chamber feeder 6, which then feeds the waste into pyrolysis chamber 7. Pyrolysis chamber 7 is connected to secondary combustion chamber 11 via pyrolysis gas conveying pipeline 10. A pyrolysis gas sleeve 10.1 is installed outside the pyrolysis gas conveying pipeline 10. A burner 11.1 is installed on the top of secondary combustion chamber 11, and auxiliary fuel supply equipment is used to supply fuel. 11.2 Provides supplementary combustion fuel. The area 11.4 above the secondary combustion chamber is designed as a thin cylindrical shape to achieve a concentrated ignition and combustion effect, increase the local temperature, and ensure stable combustion. A secondary combustion chamber accumulator 11.3 is installed inside the secondary combustion chamber 11 to increase the overall temperature of the secondary combustion chamber 11 and reduce the temperature fluctuation of the outlet of the secondary combustion chamber 11. The secondary combustion chamber 11 is connected to the deacidification tower 12 through the secondary combustion chamber outlet flue 14.2 and the intermediate flue 14.3 connected in sequence. The deacidification tower 12 is connected to the dust collector 13 through the deacidification tower outlet flue 14.1. The dust collector 13 is connected to the chimney 16 through the flue pipe 14, and an induced draft fan 15 is installed on the flue pipe 14.

[0043] The air duct system 19 includes a cold air duct 19.1, a hot air duct 19.2, a secondary combustion chamber air supply branch duct 19.3, a pyrolysis chamber hot air branch duct 19.4, a dryer air inlet duct 19.5, a dryer air outlet duct 19.9, a pyrolysis gas jacket air inlet duct 10.2, a pyrolysis gas jacket air outlet duct 10.3, a gas-water heat exchanger air inlet duct 19.6, a gas-water heat exchanger air outlet duct 19.7, and a gas-water heat exchanger air bypass duct 19.8.

[0044] Cold air duct 19.1 is used to send cold air from the waste raw material room 1 into the flue gas heat exchanger 18 via blower 17, which can reduce odor leakage from the waste raw material room 1 and improve the air quality of the surrounding environment of the waste treatment unit. Hot air duct 19.2 is connected to the secondary combustion chamber supply air branch duct 19.3, the pyrolysis chamber hot air branch duct 19.4, and the dryer inlet air duct 19.5 respectively. The secondary combustion chamber supply air branch duct 19.3 is connected to the combustion air inlet of the secondary combustion chamber 11. The secondary combustion chamber supply air branch duct 19.3 is connected to the pyrolysis gas jacket 10.1 via the pyrolysis gas jacket inlet pipe 10.2. The pyrolysis gas jacket 10.1 is connected to the secondary combustion chamber 11 via the pyrolysis gas jacket outlet pipe 10.3. The hot air branch pipe 19.4 is connected to the pyrolysis chamber 7, and the dryer inlet pipe 19.5 is connected to the garbage dryer 4. The garbage dryer 4 uses hot air provided by the flue gas heat exchanger 18 as a heat source, which can remove nearly half of the moisture in the raw garbage and effectively improve the unit calorific value of the garbage. The dryer outlet and flue gas mixer 21 is installed in the intermediate flue 14.3. The dryer outlet pipe 19.9 is used to send the exhaust gas of the garbage dryer 4 into the intermediate flue 14.3.

[0045] A discharge hopper 7.2 is installed at the bottom of the pyrolysis chamber 7, and the discharge hopper 7.2 is connected to the slag discharge device 8. A pyrolysis chamber grate 9 is installed above the discharge hopper 7.2. The pyrolysis chamber grate 9 is supported by a row of air inlet pipes spaced 100-400mm apart. One end of the air inlet pipe is connected to the pyrolysis chamber suction pipe 7.1. A damper 7.3 is installed on the pyrolysis chamber suction pipe 7.1. The intake air volume is adjusted by adjusting the opening of the damper 7.3. The air inlet pipe is a flute-shaped pipe, and multiple ventilation holes are opened on the pipe wall inside the pyrolysis chamber 7. The damper 7.3 can be closed when necessary, and hot air is drawn in through the pyrolysis chamber hot air branch pipe 19.4 to increase the working temperature of the pyrolysis chamber 7.

[0046] Above the pyrolysis chamber grate 9 are, in sequence, an ash layer, a coke combustion layer, a waste pyrolysis layer, and a waste drying layer. After the waste undergoes drying pretreatment, its heat absorption in the pyrolysis chamber 7 decreases, resulting in an increase in the outlet temperature of the pyrolysis chamber 7 and a corresponding increase in pyrolysis gas production. Because the waste has already undergone drying treatment and is loosely piled, it is easier for pyrolysis gas to pass through the waste drying layer and be discharged.

[0047] The pyrolysis gas is led out from the pyrolysis gas delivery pipeline 10, which is drawn from the upper side wall of the pyrolysis chamber 7, and sent to the secondary combustion chamber 11. The pyrolysis gas delivery pipeline 10 is equipped with a pyrolysis gas sleeve 10.1. During normal operation, hot air is introduced into the pyrolysis gas sleeve 10.1 through the pyrolysis gas sleeve inlet pipe 10.2 to increase the wall temperature of the pyrolysis gas delivery pipeline 10, keeping it above the condensation point temperature of most tar components. This minimizes the risk of tar in the pyrolysis gas condensing on the wall of the pyrolysis gas delivery pipeline 10 and causing blockage. The hot air in the pyrolysis gas sleeve 10.1 is sent into the secondary combustion chamber 11 through the pyrolysis gas sleeve outlet pipe 10.3.

[0048] Combustion-supporting air is introduced into the secondary combustion chamber 11 from the secondary combustion chamber air supply branch pipe 19.3 and the pyrolysis gas casing outlet pipe 10.3. Compared with the method of drawing in cold air for combustion support, the consumption of combustion-supporting fuel can be significantly reduced.

[0049] Hot air duct 19.2 is connected to gas-water heat exchanger 22 via gas-water heat exchanger inlet duct 19.6, and gas-water heat exchanger outlet duct 19.7 is used to send the exhaust gas from gas-water heat exchanger 22 into deacidification tower outlet flue 14.1.

[0050] One end of the air bypass pipe 19.8 of the gas-water heat exchanger is connected to the hot air pipe 19.2, and the other end is connected to the air outlet pipe 19.7 of the gas-water heat exchanger. The air bypass pipe 19.8 of the gas-water heat exchanger is used to discharge part or all of the hot air directly to the deacidification tower outlet flue 14.1 when necessary.

[0051] The NOx removal system includes a urea solution preparation tank 25.1, a urea solution dilution tank 25.2, a urea solution delivery pump 25.3, a flow distribution and metering module 25.4, and a spray grille 25.5 connected in sequence. The spray grille 25.5 is located in the flue gas duct 14.2 at the outlet of the secondary combustion chamber, where urea solution is sprayed. The NH3 produced by the pyrolysis of urea can react with the NOx produced by combustion in the subsequent flue gas, thereby removing more than half of the NOx components in the flue gas and controlling the NOx emission concentration below the environmental protection limit.

[0052] The water piping system 23 includes a cold water inlet pipe 23.1, a hot water main pipe 23.2, a bypass water pipe for the gas-water heat exchanger 23.3, a water supply branch pipe for the urea solution preparation tank 23.4, a water supply branch pipe for the urea solution dilution tank 23.5, a water supply branch pipe for the deacidification solution tank 23.6, and an external hot water supply pipe 23.7;

[0053] The cold water inlet pipe 23.1 is used to supply cold water to the air-water heat exchanger 22. The hot water generated by heat exchange in the air-water heat exchanger 22 enters the hot water main pipe 23.2. One end of the air-water heat exchanger bypass water pipe 23.3 is connected to the cold water inlet pipe 23.1, and the other end is connected to the hot water main pipe 23.2. It is used to regulate the hot water temperature. The hot water main pipe 23.2 is connected to the urea solution preparation tank water supply branch pipe 23.4, the urea solution dilution tank water supply branch pipe 23.5, the deacidification solution tank water supply branch pipe 23.6, and the external hot water supply pipe 23.7. The urea solution preparation tank water supply branch pipe 23.4 is connected to the urea solution preparation tank 25.1, the urea solution dilution tank water supply branch pipe 23.5 is connected to the urea solution dilution tank 25.2, the deacidification solution tank water supply branch pipe 23.6 is connected to the deacidification solution tank 12.1, and the external hot water supply pipe 23.7 is used to transport excess hot water.

[0054] Gas pipeline flow regulating valve 20 is installed on the following pipes: cold air duct 19.1, secondary combustion chamber air supply branch pipe 19.3, pyrolysis chamber hot air branch pipe 19.4, dryer air inlet pipe 19.5, dryer air outlet pipe 19.9, pyrolysis gas jacket air inlet pipe 10.2, gas-water heat exchanger air inlet pipe 19.6, gas-water heat exchanger air outlet pipe 19.7, and gas-water heat exchanger air bypass pipe 19.8. Liquid pipeline flow regulating valve 24 is installed on the following pipes: cold water inlet pipe 23.1, gas-water heat exchanger bypass water pipe 23.3, urea solution preparation tank water supply branch pipe 23.4, urea solution dilution tank water supply branch pipe 23.5, deacidification solution tank water supply branch pipe 23.6, and external hot water supply pipe 23.7.

[0055] The process of waste treatment using the small-scale municipal solid waste pyrolysis gasification treatment system provided by this invention is as follows:

[0056] After being sent to the waste raw material room 1, the domestic waste is processed into smaller pieces by the waste crusher 2. Then, it is sent to the waste dryer 4 by the waste conveying equipment 3. The waste dryer 4 uses hot air (inlet temperature above 400℃) from the flue gas heat exchanger 18 as a heat source, which can remove nearly half of the moisture in the raw waste, reducing the moisture content from more than 50% to less than 30%, effectively improving the unit calorific value of the waste. Subsequently, it is sent to the pyrolysis chamber feeder 6 at the top of the pyrolysis chamber 7 by the waste conveying equipment 2 5, and enters the pyrolysis chamber 7.

[0057] The pyrolysis chamber 7 adopts a simple and easy-to-maintain fixed bed design. During operation, it operates under negative pressure, with an ash discharge hopper 7.2 at the bottom. Ash is discharged periodically by a slag removal device 8. Above the ash discharge hopper 7.2 is the pyrolysis chamber grate 9, typically supported by a row of air inlet pipes spaced 100-400mm apart. One end of each inlet pipe connects to the pyrolysis chamber suction pipe 7.1, and the air intake volume is adjusted by changing the opening of the damper 7.3. The inlet pipes are flute-shaped, with multiple ventilation holes on the inner wall of the pyrolysis chamber 7. The damper 7.3 can be closed if necessary, allowing hot air to be drawn in through the pyrolysis chamber hot air branch pipe 19.4, thus increasing the operating temperature of the pyrolysis chamber 7. Above the pyrolysis chamber grate 9 are, in sequence, an ash layer, a coke combustion layer, a waste pyrolysis layer, and a waste drying layer. After drying pretreatment, the waste absorbs less heat within the pyrolysis chamber 7, allowing the outlet temperature of the pyrolysis chamber 7 to reach over 300℃, thereby increasing the pyrolysis gas production. Since the waste has been dried and is loosely piled, it facilitates the discharge of pyrolysis gas through the waste drying layer. The pyrolysis gas is led out from the pyrolysis gas delivery pipeline 10, which is located on the upper side wall of the pyrolysis chamber 7, and sent to the secondary combustion chamber 11. The pyrolysis gas delivery pipeline 10 is equipped with a pyrolysis gas sleeve 10.1. During normal operation, hot air is introduced into the pyrolysis gas sleeve 10.1 through the pyrolysis gas sleeve inlet pipe 10.2 to increase the wall temperature of the pyrolysis gas delivery pipeline 10, keeping it above the condensation point temperature of most tar components. This minimizes the risk of tar in the pyrolysis gas condensing on the wall of the pyrolysis gas delivery pipeline 10 and causing blockage. The hot air in the pyrolysis gas sleeve 10.1 is sent into the secondary combustion chamber 11 through the pyrolysis gas sleeve outlet pipe 10.3.

[0058] The secondary combustion chamber 11 is designed with sufficient length to ensure complete gas combustion and the required residence time, and adopts a U-shaped arrangement. A burner 11.1 is located at the top, and an auxiliary fuel supply device 11.2 provides supplementary combustion fuel (such as liquefied petroleum gas, natural gas, oil, etc.). A secondary combustion chamber accumulator 11.3 is installed inside the secondary combustion chamber 11 to increase the overall temperature of the secondary combustion chamber 11 and reduce the temperature fluctuation range at the outlet of the secondary combustion chamber 11. To improve ignition stability, the upper region 11.4 of the secondary combustion chamber is designed as a narrow cylindrical shape to achieve concentrated ignition and combustion, increase local temperature, and ensure stable combustion. Combustion-supporting air is introduced into the secondary combustion chamber from the secondary combustion chamber air supply branch pipe 19.3 and the pyrolysis gas jacket outlet pipe 10.3. Compared with the method of drawing in cold air for combustion support, this can significantly reduce the consumption of combustion-supporting fuel.

[0059] The exhaust gas from the waste dryer 4 is injected into the intermediate flue 14.3 between the urea solution spray grille 25.5 and the flue gas heat exchanger 18 through the dryer outlet pipe 19.9. To ensure uniform mixing, a dryer outlet gas and flue gas mixer 21 is installed. After mixing, the flue gas temperature drops to about 700℃ before entering the flue gas heat exchanger 18, ensuring that low-melting-point ash in the flue gas does not condense and cause blockage in the flue gas heat exchanger 18. The exhaust gas from the waste dryer 4 contains a small amount of combustible components, which are basically burned off when the high-temperature flue gas is sent through the dryer outlet gas and flue gas mixer 21.

[0060] The flue gas heat exchanger 18 is used to rapidly cool the flue gas from approximately 700℃ to approximately 200℃ (cooling time controlled within 2 seconds), replacing the traditional method of using water spray for rapid cooling to eliminate dioxins, which can effectively reduce operating water consumption. The blower 17 draws cold air from the cold air duct 19.1 at the top of the waste material room 1 and sends it into the flue gas heat exchanger 18. This reduces odor leakage from the waste room and improves the air quality around the waste treatment unit. The flue gas heat exchanger 18 is made of corrosion-resistant stainless steel, and the outlet hot air temperature can be increased to over 400℃. Hot air is delivered from hot air duct 19.2 to the combustion air inlet of the secondary combustion chamber 11 via the secondary combustion chamber air supply branch pipe 19.3, to the air intake of the pyrolysis chamber 7 via the pyrolysis chamber hot air branch pipe 19.4, to the inlet of the pyrolysis gas jacket 10.1 via the pyrolysis gas jacket air inlet pipe 10.2, to the inlet of the waste dryer 4 via the dryer air inlet pipe 19.5, and to the inlet of the gas-water heat exchanger 22 via the gas-water heat exchanger air inlet pipe 19.6. The exhaust from the gas-water heat exchanger 22 is delivered to the deacidification tower 12 deacidification tower outlet flue 14.1 via the gas-water heat exchanger outlet pipe 19.7. The air bypass pipe 19.8 of the gas-water heat exchanger is used to directly discharge some or all of the hot air to the deacidification tower outlet flue 14.1 when necessary.

[0061] The air-water heat exchanger 22 is used to generate hot water for the system's own use and for external supply. The desalinated cold water enters the air-water heat exchanger 22 through the cold water inlet pipe 23.1, is heated to hot water, and then enters the hot water main pipe 23.2. A bypass water pipe 23.3 is provided in the air-water heat exchanger 22 to regulate the hot water temperature. The hot water enters the urea solution preparation tank 25.1 through the urea solution preparation tank supply branch pipe 23.4, the urea solution dilution tank 25.2 through the urea solution dilution tank supply branch pipe 23.5, and the deacidification solution tank 12.1 through the deacidification solution tank supply branch pipe 23.6. Excess hot water is sent externally through the external hot water supply pipe 23.7.

[0062] The NOx removal system employs an SNCR system. Urea solution is injected at the outlet flue 14.2 of the secondary combustion chamber, where the flue gas temperature is 900-1200℃. Injecting urea solution here ensures complete pyrolysis of the urea. The urea solution preparation process is as follows: hot water from the gas-water heat exchanger 22 and the input urea are mixed in a urea solution preparation tank 25.1 to prepare the urea solution. The solution is then diluted to a specified concentration in a urea solution dilution tank 25.2 and pumped by a urea solution delivery pump 25.3 through a flow distribution and metering module 25.4 into a spray grille 25.5 before being injected into the outlet flue 14.2 of the secondary combustion chamber. The NH3 produced by urea pyrolysis reacts with the NOx produced during combustion in the outlet flue 14.2, thereby removing more than half of the NOx components from the flue gas and controlling the NOx emission concentration below the environmental protection limit. Gas flow regulating valves 20 and liquid flow regulating valves 24 can be installed on each air and exhaust pipeline as needed.

Claims

1. A small-scale municipal solid waste pyrolysis and gasification treatment system, characterized in that, This includes a waste pyrolysis combustion and flue gas purification system, a flue gas heat exchange system, a gas-water heat exchange system, and a NOx removal system; The waste pyrolysis combustion and flue gas purification system includes a waste crusher (2), a waste dryer (4), a pyrolysis chamber (7), a secondary combustion chamber (11), a deacidification tower (12), a dust collector (13), and a chimney (16) connected in sequence. The deacidification tower (12) is connected to a deacidification solution tank (12.1). The flue gas heat exchange system includes a blower (17), a flue gas heat exchanger (18), and a duct system (19). The flue gas heat exchanger (18) is located between the secondary combustion chamber (11) and the deacidification tower (12) and is used to cool the flue gas. The duct system (19) is used to transport the hot air generated by the flue gas heat exchanger (18) to the waste pyrolysis combustion and flue gas purification system and the gas-water heat exchange system. The gas-water heat exchange system includes a gas-water heat exchanger (22) and a water pipeline system (23). The gas-water heat exchanger (22) uses the hot air generated by the flue gas heat exchanger (18) to heat the water. The water pipeline system (23) is used to prepare urea solution for the NOx removal system and to transport the hot water generated by the gas-water heat exchanger (22) to the deacidification solution tank (12.1) for preparing deacidification solution. The NOx removal system is used to prepare a urea solution for removing NOx from flue gas; The waste shredder (2) and the waste dryer (4) are located inside the waste raw material room (1). The waste shredder (2) and the waste dryer (4) are connected by a waste conveying device (3). The waste dryer (4) and the pyrolysis chamber (7) are connected by a waste conveying device (5). The pyrolysis chamber (7) and the secondary combustion chamber (11) are connected by a pyrolysis gas conveying pipeline (10). A pyrolysis gas sleeve (10.1) is installed on the outside of the pyrolysis gas conveying pipeline (10). The secondary combustion chamber (11) is... A burner (11.1) is installed at the top, and supplementary fuel is provided through an auxiliary fuel supply device (11.2). The secondary combustion chamber (11) and the deacidification tower (12) are connected by a secondary combustion chamber outlet flue (14.2) and an intermediate flue (14.3) connected in sequence. The deacidification tower (12) and the dust collector (13) are connected by a deacidification tower outlet flue (14.1). The dust collector (13) and the chimney (16) are connected by a flue pipe (14). An induced draft fan (15) is installed on the flue pipe (14). The air duct system (19) includes a cold air duct (19.1), a hot air duct (19.2), a secondary combustion chamber air supply branch pipe (19.3), a pyrolysis chamber hot air branch pipe (19.4), a dryer air inlet pipe (19.5), a dryer air outlet pipe (19.9), a pyrolysis gas jacket air inlet pipe (10.2), and a pyrolysis gas jacket air outlet pipe (10.3); The cold air duct (19.1) is used to send the cold air in the waste raw material room (1) into the flue gas heat exchanger (18) through the blower (17). The hot air duct (19.2) is connected to the secondary combustion chamber air supply branch pipe (19.3), the pyrolysis chamber hot air branch pipe (19.4), and the dryer air inlet pipe (19.5) respectively. The secondary combustion chamber air supply branch pipe (19.3) is connected to the secondary combustion chamber (11). The secondary combustion chamber air supply branch pipe (19.3) is connected to the pyrolysis gas jacket (…). 10.1) are connected by a pyrolysis gas jacket inlet pipe (10.2), the pyrolysis gas jacket (10.1) is connected to the secondary combustion chamber (11) through the pyrolysis gas jacket outlet pipe (10.3), the pyrolysis chamber hot air branch pipe (19.4) is connected to the pyrolysis chamber (7), the dryer inlet pipe (19.5) is connected to the garbage dryer (4), and the dryer outlet pipe (19.9) is used to send the exhaust gas of the garbage dryer (4) into the intermediate flue (14.3); The air duct system (19) also includes an air inlet pipe (19.6) and an air outlet pipe (19.7) for the air-water heat exchanger; The hot air duct (19.2) is connected to the gas-water heat exchanger (22) through the gas-water heat exchanger inlet duct (19.6), and the gas-water heat exchanger outlet duct (19.7) is used to send the exhaust gas of the gas-water heat exchanger (22) into the deacidification tower outlet flue (14.1). The air duct system (19) also includes an air bypass pipe (19.8) for the air-water heat exchanger. One end of the air bypass pipe (19.8) is connected to the hot air duct (19.2), and the other end is connected to the air outlet pipe (19.7) of the air-water heat exchanger.

2. The small-scale municipal solid waste pyrolysis gasification treatment system as described in claim 1, characterized in that, The NOx removal system includes a urea solution preparation tank (25.1), a urea solution dilution tank (25.2), a urea solution delivery pump (25.3), a flow distribution and metering module (25.4), and a spray grid (25.5) connected in sequence. The spray grid (25.5) is located inside the secondary combustion chamber outlet flue (14.2).

3. The small-scale municipal solid waste pyrolysis gasification treatment system as described in claim 2, characterized in that, The water pipeline system (23) includes a cold water inlet pipe (23.1), a hot water main pipe (23.2), a bypass water pipe for the gas-water heat exchanger (23.3), a water supply branch pipe for the urea solution preparation tank (23.4), a water supply branch pipe for the urea solution dilution tank (23.5), a water supply branch pipe for the deacidification solution tank (23.6), and an external hot water supply pipe (23.7). The cold water inlet pipe (23.1) is used to supply cold water to the gas-water heat exchanger (22). The hot water generated by heat exchange in the gas-water heat exchanger (22) enters the hot water main pipe (23.2). One end of the gas-water heat exchanger bypass water pipe (23.3) is connected to the cold water inlet pipe (23.1), and the other end is connected to the hot water main pipe (23.2) to regulate the hot water temperature. The hot water main pipe (23.2) is connected to the water supply branch pipe (23.4) of the urea solution preparation tank and the water supply branch pipe (23.4) of the urea solution dilution tank. The branch pipe (23.5), the deacidification solution tank water supply branch pipe (23.6), and the external hot water supply pipe (23.7) are connected. The urea solution preparation tank water supply branch pipe (23.4) is connected to the urea solution preparation tank (25.1). The urea solution dilution tank water supply branch pipe (23.5) is connected to the urea solution dilution tank (25.2). The deacidification solution tank water supply branch pipe (23.6) is connected to the deacidification solution tank (12.1). The external hot water supply pipe (23.7) is used to transport excess hot water.

4. The small-scale municipal solid waste pyrolysis gasification treatment system as described in claim 1, characterized in that, A deacidification solution pump (12.2) and a deacidification solution flow regulating valve (12.3) are installed on the pipeline connecting the deacidification tower (12) and the deacidification solution tank (12.1). The deacidification solution is sprayed out through the deacidification solution spray grid (12.4), which is located inside the deacidification tower (12).

5. The small-scale municipal solid waste pyrolysis gasification treatment system as described in claim 1, characterized in that, A discharge hopper (7.2) is provided at the bottom of the pyrolysis chamber (7). The discharge hopper (7.2) is connected to the slag discharge device (8). A pyrolysis chamber grate (9) is provided above the discharge hopper (7.2). The pyrolysis chamber grate (9) is supported by a row of air inlet pipes. One end of the air inlet pipes is connected to the pyrolysis chamber suction pipe (7.1). A damper (7.3) is provided on the pyrolysis chamber suction pipe (7.1).

6. The small-scale municipal solid waste pyrolysis gasification treatment system as described in claim 3, characterized in that, Gas pipeline flow regulating valves (20) are installed on the cold air duct (19.1), the secondary combustion chamber air supply branch pipe (19.3), the pyrolysis chamber hot air branch pipe (19.4), the dryer air inlet pipe (19.5), the dryer air outlet pipe (19.9), the pyrolysis gas jacket air inlet pipe (10.2), the gas-water heat exchanger air inlet pipe (19.6), the gas-water heat exchanger air outlet pipe (19.7), and the gas-water heat exchanger air bypass pipe (19.8). Liquid pipeline flow regulating valves (24) are installed on the cold water inlet pipe (23.1), the gas-water heat exchanger bypass water pipe (23.3), the urea solution preparation tank water supply branch pipe (23.4), the urea solution dilution tank water supply branch pipe (23.5), the deacidification solution tank water supply branch pipe (23.6), and the external hot water supply pipe (23.7).

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