Waste incineration fly ash in-situ pyrolysis system and pyrolysis method thereof

Abstract

The invention discloses a waste incineration fly ash in-situ pyrolysis system and a pyrolysis method thereof. The pyrolysis system comprises an incinerator hearth, an incinerator ash hopper and a heating module, the incinerator ash hopper communicates with a fly ash bin through a first conveying module, the fly ash bin communicates with a fly ash pyrolysis channel of a pyrolysis furnace through a second conveying module, and the fly ash pyrolysis channel of the pyrolysis furnace communicates with a high-temperature area of the incinerator hearth; and the heating module is communicated with a heating medium channel of the pyrolyzing furnace. The pyrolysis system is adopted in the pyrolysis method. Hot air is fed into a heating medium channel of the pyrolyzing furnace, fly ash is fed into a fly ash pyrolyzing channel of the pyrolyzing furnace, detoxified fly ash and pyrolyzing gas are generated after the fly ash is pyrolyzed, the pyrolyzing gas enters a high-temperature area of a hearth of the incinerator, and organic pollutants are decomposed at high temperature. The fly ash pyrolysis gas treatment system has the beneficial effects that the fly ash pyrolysis gas is introduced into the incinerator of the waste incineration plant for combustion and decomposition, the existing flue gas purification system is utilized for in-situ treatment, and secondary pollution generated by pyrolysis gas treatment is avoided.

Description

Technical Field

[0001] This application belongs to the field of waste incineration fly ash disposal technology, specifically relating to an in-situ pyrolysis system for waste incineration fly ash and its pyrolysis method. Background Technology

[0002] Waste incineration fly ash is a residue collected by the flue gas purification system of incineration plants, containing high concentrations of dioxins and other persistent organic pollutants. Waste incineration fly ash is classified as hazardous waste. Traditional solidification and landfill disposal methods pose problems such as large land occupation and long-term environmental risks. New fly ash pyrolysis technology involves continuously heating and maintaining the temperature of waste incineration fly ash, which can effectively decompose and remove dioxins, stabilize heavy metals, and reduce leaching toxicity, resulting in better economic and environmental benefits.

[0003] At present, the application of fly ash pyrolysis technology in waste incineration is gradually being adopted at home and abroad. However, the high operating costs of conventional electric heating pyrolysis and centralized disposal modes, the easy occurrence of secondary pollution during fly ash transportation, and the need for further treatment of pollutants remaining in fly ash pyrolysis gas have hindered the large-scale promotion of this technology. Summary of the Invention

[0004] The purpose of this application is to provide an in-situ pyrolysis system and method for waste incineration fly ash. The system collects and seals the fly ash on-site before transporting it to the pyrolysis furnace. By setting up heated air pipelines or heated air circulation pipelines, the heat from the flue gas in the incinerator is used for fly ash pyrolysis. Simultaneously, a heated air bypass, heater, and cooler are included to more accurately and safely control the temperature of the heated air. The fly ash pyrolysis gas is connected to the high-temperature zone of the incinerator flue, utilizing the high temperature of incineration to thoroughly treat the organic pollutants in the fly ash and avoid secondary pollution problems. This application can achieve low-cost, efficient, and safe pyrolysis treatment of waste incineration fly ash, and has better prospects for large-scale application.

[0005] The objective of this application is achieved through the following technical solution: An in-situ pyrolysis system for waste incineration fly ash includes an incinerator furnace and an incinerator ash hopper, and also includes a heating module. The incinerator ash hopper is connected to a fly ash silo via a first conveying module, and the fly ash silo is connected to a fly ash pyrolysis channel of a pyrolysis furnace via a second conveying module. The fly ash pyrolysis channel of the pyrolysis furnace is connected to the high-temperature zone of the incinerator furnace, and the heating module is connected to the heating medium channel of the pyrolysis furnace.

[0006] Furthermore, the incinerator furnace is connected to the second flue, the second flue is connected to the third flue, the third flue is connected to the horizontal flue, the horizontal flue is equipped with a waste heat boiler heating surface, and the rear end of the horizontal flue is equipped with a spray reaction tower and a bag filter. The ash hopper of the spray reaction tower and the bag filter is the incinerator ash hopper.

[0007] Furthermore, the first conveying module includes a screw conveyor, which is connected to the ash hopper of the incinerator and to the first conveying pipeline. The first conveying pipeline is equipped with a fly ash shut-off valve and is connected to the fly ash silo. The second conveying module is a screw conveyor or a belt conveyor.

[0008] Furthermore, the heating module includes a heat exchanger pipeline, on which a heat exchanger inlet valve and a heat exchanger are provided. The heat exchanger is located in the three flues of the incinerator furnace. The heat exchanger pipeline is connected to the air inlet pipeline, and a heater is provided on the air inlet pipeline. The heating module also includes a bypass pipeline connected in parallel with the heat exchanger pipeline, on which a bypass valve and a one-way valve are provided.

[0009] Furthermore, it also includes a makeup air module, which includes a blower connected to a makeup air pipeline. The makeup air pipeline is equipped with a makeup air valve. The exhaust pipeline of the heating medium channel of the pyrolysis furnace is connected to the circulation pipeline. The circulation pipeline is equipped with a cooler and a circulation fan. The circulation pipeline is connected to the makeup air pipeline, and the makeup air pipeline is connected to the heating module.

[0010] Furthermore, the exhaust pipe of the heating medium channel of the pyrolysis furnace is connected to the combustion air pipe, and the combustion air pipe is connected to the combustion zone in the lower part of the incinerator furnace.

[0011] A pyrolysis method for an in-situ pyrolysis system of waste incineration fly ash, comprising the aforementioned in-situ pyrolysis system of waste incineration fly ash; fly ash collected in the ash hopper of the incinerator is transported to an on-site fly ash silo via a first conveying module; a heating module sends hot air at 450-550°C into the heating medium channel of the pyrolysis furnace; fly ash in the fly ash silo is transported to the fly ash pyrolysis channel of the pyrolysis furnace via a second conveying module; hot air heats the fly ash and raises its temperature to 350-400°C for pyrolysis; after the fly ash remains for more than 1.5 hours for pyrolysis, detoxified fly ash and pyrolysis gas are generated; detoxified fly ash is deposited in a detoxified ash hopper for processing; and pyrolysis gas enters the high-temperature zone of the incinerator furnace, where organic pollutants decompose at temperatures above 900°C.

[0012] Furthermore, using the aforementioned in-situ pyrolysis system for waste incineration fly ash, air passes through heat exchanger pipes, is directly heated to 450-550℃ through the heat exchanger, and then sent to the pyrolysis furnace through the heater; or, air passes through heat exchanger pipes, is heated to 200-250℃ through the first stage of the heat exchanger, and then heated to 450-550℃ through the second stage of the heater, and then sent to the pyrolysis furnace; or, air passes through bypass pipes, is directly heated to 450-550℃ through the heater, and then sent to the pyrolysis furnace.

[0013] Furthermore, in the above-mentioned in-situ pyrolysis system for waste incineration fly ash, air is pressurized by a blower and sent to the heating module through a makeup air pipeline; and / or, the temperature of the hot air in the pyrolysis furnace is reduced to 350-400℃, and then sent to the circulation pipeline through the exhaust pipeline of the heating medium channel of the pyrolysis furnace, and then cooled to below 400℃ by a cooler, and then pressurized by a circulating fan and sent to the makeup air pipeline and the heating module.

[0014] Furthermore, the temperature of the hot air inside the pyrolysis furnace drops to 350-400℃, and it is sent to the combustion air pipeline through the exhaust pipe of the heating medium channel of the pyrolysis furnace, and enters the combustion zone located in the lower part of the incinerator furnace as part of the replacement of the hot secondary air.

[0015] The beneficial effects of this application are as follows: The in-situ pyrolysis system and method for waste incineration fly ash provided by this application achieve in-situ storage of waste incineration fly ash by setting up fly ash silos; by setting up circulating fans to achieve the circulation of hot air between the pyrolysis furnace and the heat exchanger, or by using a two-stage heating method of heat exchanger-heater, the in-situ self-sustaining pyrolysis of fly ash is fully utilized, achieving efficient utilization of medium and low grade heat; by introducing fly ash pyrolysis gas into the incinerator of the waste incineration plant for combustion and decomposition and using the existing flue gas purification system for in-situ treatment, equipment investment is significantly reduced, while avoiding secondary pollution generated by the treatment of pyrolysis gas.

[0016] The aforementioned main solution and its various further alternatives can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed in this application; furthermore, the (non-conflicting alternatives) can also be freely combined with each other and with other alternatives. Those skilled in the art, after understanding the solution of this application, will realize from the prior art and common general knowledge that there are many combinations, all of which are technical solutions to be protected by this application, and will not be exhaustively listed here. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this application.

[0018] In the diagram: 1-Incinerator furnace, 2-Second flue, 3-Third flue, 4-Heat exchanger, 5-Horizontal flue, 6-Spray reaction tower, 7-Bag filter, 8-Screw conveyor, 9-Fly ash shut-off valve, 10-Fly ash silo, 11-Pyrolysis furnace, 12-Cooler, 13-Circulating fan, 14-Blower, 15-Make-up air valve, 16-Heat exchanger inlet valve, 17-Bypass valve, 18-Check valve, 19-Heater, 20-Combustion air valve. Detailed Implementation

[0019] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, and not all, of the embodiments of this application. Based on the description of this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0020] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every value between these two endpoints. Unless otherwise specified, when the numerical interval refers only to the integers within that interval, including the two endpoint integers and every integer between them is equivalent to directly listing every integer. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges contained therein.

[0021] In the description of this invention, "multiple" means two or more, "greater than", "less than", "exceeding" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself.

[0022] Example 1 refer to Figure 1 As shown, an in-situ pyrolysis system for fly ash from waste incineration includes an incinerator furnace 1, a second flue 2, a third flue 3, a horizontal flue 5, a spray reaction tower 6, a bag filter 7, an incinerator ash hopper, a heating module, a first conveying module, a fly ash silo 10, a second conveying module, a pyrolysis furnace 11, and a makeup air module.

[0023] The incinerator furnace 1 is the incineration equipment for waste raw materials, and the incinerator ash hopper is used to collect fly ash after waste incineration. The incinerator ash hopper is connected to the fly ash silo 10 through the first conveying module. The first conveying module conveys and collects the fly ash into the silo, and the fly ash silo 10 stores the fly ash for natural cooling and awaits pyrolysis.

[0024] The fly ash silo 10 is connected to the fly ash pyrolysis channel of the pyrolysis furnace 11 via a second conveying module. The second conveying module transports the fly ash to the fly ash pyrolysis channel of the pyrolysis furnace 11 for pyrolysis. After pyrolysis, the fly ash generates detoxified fly ash and pyrolysis gas. The fly ash pyrolysis channel of the pyrolysis furnace 11 is connected to the high-temperature zone of the incinerator furnace 1 to deliver the pyrolysis gas to the high-temperature zone of the incinerator furnace 1, allowing the organic pollutants in the pyrolysis gas to decompose at high temperatures. The pyrolysis gas delivered to the incinerator furnace 1 should be at least 4 meters below the 850°C flue gas temperature measuring point in the incinerator furnace.

[0025] The heating module is connected to the heating medium channel of the pyrolysis furnace 11. The heating medium is hot air. The heating module is used to provide hot air. The hot air enters the heating medium channel of the pyrolysis furnace 11 for heating. The hot air in the heating medium channel exchanges heat with the fly ash in the fly ash pyrolysis channel in a partitioned manner, so that the fly ash pyrolysis channel of the pyrolysis furnace 11 has the temperature required for pyrolysis and ensures the stability of fly ash pyrolysis.

[0026] The incinerator furnace 1 is connected to the second flue 2, the second flue 2 is connected to the third flue 3, and the third flue 3 is connected to the horizontal flue 5. The horizontal flue 5 is equipped with the heat exchange surface of the waste heat boiler. The high-temperature flue gas after combustion in the incinerator furnace 1 enters the horizontal flue 5 after passing through the second flue 2 and the third flue 3. There are usually no heat exchange surfaces in the second flue 2 and the third flue 3, so the flue gas exchanges heat with the heat exchange surfaces of the waste heat boiler at each stage.

[0027] The rear end of the horizontal flue 5 is equipped with a spray reaction tower 6 and a bag filter 7 for flue gas treatment system. The ash hoppers of the spray reaction tower 6 and the bag filter 7 are the incinerator ash hoppers. That is, after the cooled flue gas passes through the spray reaction tower 6 and the bag filter 7 for dust suppression, toxic fly ash is deposited in the ash hopper.

[0028] The first conveying module includes a screw conveyor 8 and a first conveying pipeline. The screw conveyor 8 is connected to the incinerator ash hopper to push and convey the fly ash in the hopper. The screw conveyor 8 is connected to the first conveying pipeline, which is connected to the fly ash silo 10 to seal and convey the fly ash to the fly ash silo 10. A fly ash shut-off valve 9 is installed on the first conveying pipeline to control the on / off of fly ash conveying. A level gauge is installed inside the fly ash silo 10 to reflect the internal fly ash storage status. When the fly ash in the silo is full, the fly ash shut-off valve 9 is shut off in time to prevent fly ash from overflowing.

[0029] Similarly, the first conveying module can also use a belt conveyor, but a screw conveyor combined with piping provides better sealing. The second conveying module can be either a screw conveyor or a belt conveyor.

[0030] The heating module includes heat exchanger piping, heat exchanger inlet valve 16, heat exchanger 4, air inlet piping, bypass piping, bypass valve 17, and check valve 18. The heat exchanger piping is equipped with heat exchanger inlet valve 16 and heat exchanger 4. Heat exchanger inlet valve 16 controls the on / off state of the heat exchanger piping. Heat exchanger 4 is located in the three flue ducts 3 of the incinerator furnace 1. The air entering the heat exchanger piping can absorb heat from the high-temperature flue gas in the flue duct at heat exchanger 4 for subsequent fly ash pyrolysis.

[0031] The heat exchanger piping is connected to the air inlet piping, which is equipped with a heater 19. The air can be heated to the required temperature for subsequent pyrolysis through a single heat exchanger 4. Alternatively, the air can be heated in one stage through the heat exchanger 4, followed by a second stage of heating in the heater 19. It is even possible to directly heat the air to the required temperature through the heater 19 without passing through the heat exchanger 4. A thermometer is installed at the outlet of the heater 19 to ensure that the hot air supplied to the pyrolysis furnace 11 meets the requirements and to control the heating power of the heater 19.

[0032] The bypass line is connected in parallel with the heat exchanger line, meaning that air can directly enter the air inlet line through the bypass line without passing through the heat exchanger line, or part of the air can pass through the bypass line and the other part through the heat exchanger line. The bypass line is equipped with a bypass valve 17 and a check valve 18. The bypass valve 17 controls the opening and closing of the bypass line, while the check valve 18 ensures one-way flow in the line.

[0033] The make-up air module provides the air source required by the heating module. The make-up air module includes a blower 14, a make-up air pipeline, a make-up air valve 15, a circulation pipeline, a cooler 12, and a circulating fan 13. The blower 14 is connected to the make-up air pipeline, which is equipped with a make-up air valve 15. The make-up air valve 15 controls the opening and closing of the make-up air pipeline. The make-up air pipeline is connected to the bypass pipeline of the heating module and / or the heat exchanger pipeline. The blower 14 provides fresh air, which is delivered to the bypass pipeline and / or the heat exchanger pipeline through the make-up air pipeline.

[0034] The exhaust pipe of the heating medium channel of the pyrolysis furnace 11 is connected to the circulation pipe, which in turn is connected to the make-up air pipe. The circulation pipe is used to circulate the hot air after pyrolysis to achieve heat recovery and improve heat utilization. A cooler 12 and a circulating fan 13 are installed on the circulation pipe. The cooler 12 cools the circulating air to prevent high-temperature air from damaging the fan on the subsequent pipe. The hot side of the cooler 12 contains hot air, and a thermometer is installed at the hot side outlet of the cooler 12 to ensure that the air outlet temperature meets the standard and to control the cooling power of the cooler 12.

[0035] The circulating fan 13 delivers the cooled air to the make-up air duct. A flow meter and pressure gauge are installed at the outlet of the circulating fan 13 to monitor air pressure and volume. The flow meter controls the supply fan 14 and the make-up air valve 15 to ensure normal flow in the heated air circulation loop. The pressure gauge controls the frequency of the circulating fan 13 to ensure normal temperature and pressure in the heated air circulation loop.

[0036] The exhaust pipe of the heating medium channel of the pyrolysis furnace 11 is connected to the combustion air pipe, and the combustion air pipe is connected to the combustion zone in the lower part of the incinerator furnace 1. The combustion air pipe utilizes the hot air after pyrolysis and sends the hot air as part of the hot secondary air to the combustion zone in the lower part of the incinerator furnace 1 for combustion.

[0037] Example 2 refer to Figure 1 As shown, a pyrolysis method for an in-situ pyrolysis system of waste incineration fly ash is described, using the waste incineration fly ash in-situ pyrolysis system of Example 1.

[0038] The fly ash collected in the incinerator ash hopper is transported to the local fly ash silo 10 via the first conveying module. The heating module sends hot air at 450-550℃ into the heating medium channel of the pyrolysis furnace 11. The fly ash in the fly ash silo 10 is transported to the fly ash pyrolysis channel of the pyrolysis furnace 11 via the second conveying module. The hot air heats the fly ash and raises its temperature to 350-400℃ for pyrolysis. After the fly ash remains for more than 1.5 hours, it generates detoxified fly ash and pyrolysis gas. The detoxified fly ash is deposited in the detoxified ash hopper for processing. The pyrolysis gas enters the high-temperature zone of the incinerator furnace 1, where organic pollutants are decomposed at temperatures above 900℃.

[0039] Air passes through heat exchanger pipes, is directly heated to 450-550℃ through heat exchanger 4, and then sent to pyrolysis furnace 11 through heater 19; or, air passes through heat exchanger pipes, is heated to 200-250℃ through the first stage of heat exchanger 4, and then heated to 450-550℃ through the second stage of heater 19, and then sent to pyrolysis furnace 11; or, air passes through bypass pipes, is directly heated to 450-550℃ through heater, and then sent to pyrolysis furnace 11.

[0040] Air is pressurized by the blower 14 and sent to the heating module through the make-up air pipeline; and / or, the temperature of the hot air in the pyrolysis furnace 11 drops to 350-400℃, is sent to the circulation pipeline through the exhaust pipeline of the heating medium channel of the pyrolysis furnace 11, is then cooled to below 400℃ by the cooler 12, and is then pressurized by the circulating fan 13 and sent to the heating module through the make-up air pipeline.

[0041] When the temperature of the hot air inside the pyrolysis furnace 11 drops to 350-400℃, it can also be sent to the combustion air pipeline through the exhaust pipe of the heating medium channel of the pyrolysis furnace 11, and enter the combustion zone located in the lower part of the incinerator furnace 1 as a partial replacement for the hot secondary air.

[0042] Case 1 refer to Figure 1 As shown, an in-situ pyrolysis system for waste incineration fly ash is implemented based on Example 1.

[0043] After the waste raw materials are burned in the waste incinerator grate and the incinerator furnace 1, high-temperature flue gas is generated and enters the second flue 2 and the third flue 3. Due to the characteristics of waste fuel, there is usually no heat exchange surface in the second flue 2 and the third flue 3. The high-temperature flue gas flows from the third flue 3 to the horizontal flue 5, where it exchanges heat with the heat exchange surfaces of each stage of the waste heat boiler, and then is discharged to the spray reaction tower 6 and bag filter 7 of the flue gas treatment system.

[0044] Heat exchanger 4 is installed in the cavity of the three flues 3. The air on the cold side of heat exchanger 4 exchanges heat with the high-temperature flue gas in the three flues 3 in a wall-type heat exchange to raise the temperature.

[0045] At the rear end of the horizontal flue 5, the fly ash collected at the bottom of the spray reaction tower 6 and bag filter 7 is conveyed to the fly ash silo 10 by a screw conveyor 8. The fly ash silo 10 is equipped with a level gauge. During the operation of the fly ash pyrolysis system, when the fly ash silo level is too high, the fly ash shut-off valve 9 can be closed until the fly ash level returns to normal.

[0046] The fly ash from the fly ash silo 10 is fed evenly into the inner cylinder of the pyrolysis furnace 11 via a spiral or belt conveyor. The pyrolysis furnace 11 is a long cylindrical structure, divided into an inner cylinder and an outer cylinder. The inner cylinder is the fly ash pyrolysis channel, and the outer cylinder is the heating medium channel, which is hot air.

[0047] The blower 14 continuously supplies heating medium air into the system through the make-up air valve 15. Under normal operating conditions, cold air enters the cold side of heat exchanger 4 through the heat exchanger inlet valve 16, and the air is heated to 500-550℃ in heat exchanger 4. Heat exchanger 4 will cause a slight decrease in the inlet flue gas temperature of the waste heat boiler. To ensure the normal operation of the waste heat boiler, the desuperheating spray volume of the superheater in the horizontal flue duct 5 of the waste heat boiler is appropriately reduced.

[0048] The heater 19 is heated by electric heating or steam heating. The heater 19 and the outlet thermometer have the following functions: to ensure that the air outlet temperature of the heat exchanger 4 rises to 500-550℃.

[0049] Hot air enters the outer cylinder of the pyrolysis furnace 11 and heats the fly ash entering the inner cylinder. After the temperature drops to 350-400℃, it enters the hot side of the cooler 12. At the same time, the fly ash in the inner cylinder of the pyrolysis furnace 11 heats up. The waste incineration fly ash is heated and pyrolyzed in the pyrolysis furnace 11, generating two products: pyrolysis gas and detoxified fly ash. The pyrolysis gas is carried into the high-temperature zone of the incinerator furnace 1 by its own pressure, the negative pressure of the incinerator furnace, and the pressure of the inert protective gas. The organic pollutants in the pyrolysis gas decompose at a high temperature above 900℃.

[0050] Cooler 12 is either water-cooled or air-cooled. Hot air is cooled at cooler 12 to ensure the temperature drops below 400℃. Cooler 12 and the outlet thermometer serve the following functions: preventing hot air temperature from accumulating and preventing abnormal operation of the downstream circulating fan 13 due to excessive temperature. After cooling, the hot air is pressurized by circulating fan 13 to form a hot air circulation loop. The outlet of circulating fan 13 is equipped with a pressure gauge and a flow meter. When the air flow reaches the rated value, the supply fan 14 and the make-up air valve 15 are shut off.

[0051] Case 2 refer to Figure 1 As shown, an in-situ pyrolysis system for waste incineration fly ash is implemented based on Example 1.

[0052] The blower 14 continuously supplies air at a rated flow rate through the make-up air valve 15. The air flow rate is controlled by the flow meter controlling the frequency of the blower 14 and the opening degree of the make-up air valve 15.

[0053] Cold air enters heat exchanger 4 through heat exchanger inlet valve 16. Based on the polluting components in the waste, flue gas temperature, performance and arrangement of heat exchanger 4, and secondary air properties of the waste incinerator, in order to slow down material corrosion and improve thermal efficiency, the air can be heated in the following two-stage heating method: the air is heated to 200-250℃ in heat exchanger 4, and then heated to 450-500℃ at heater 19.

[0054] After the hot air enters the pyrolysis furnace 11 for heat exchange, it opens the combustion air valve 20 and enters the incinerator furnace 1, serving as a partial replacement for the hot secondary air and burning in the combustion zone located at the bottom of the incinerator furnace 1.

[0055] Case 3 refer to Figure 1 As shown, an in-situ pyrolysis system for waste incineration fly ash is implemented based on Example 1.

[0056] When heat exchanger 4 is offline, close heat exchanger inlet valve 16, open bypass valve 17, close combustion air valve 20, and blower 14 introduces cold air through make-up air valve 15 into cold air bypass pipeline, which then enters heater 19 through check valve 18. In heater 19, the air is directly heated to 500-550℃ and then enters pyrolysis furnace 11 to heat fly ash.

[0057] The hot air is cooled at the cooler 12 to ensure that the temperature drops below 400°C. After cooling, the hot air is pressurized by the circulating fan 13 to form a hot air circulation loop. When the air flow reaches the rated value, the supply fan 14 and the make-up air valve 15 are shut off.

[0058] Case 4 refer to Figure 1 As shown, a pyrolysis method for an in-situ pyrolysis system of waste incineration fly ash is implemented based on Example 2.

[0059] Specifically, the steps are as follows: S1: Fly ash is collected by the bottom ash hopper of the spray reaction tower 6 and the bag filter 7, and the fly ash is conveyed to the fly ash silo 10 by the screw conveyor 8 in a sealed manner, and then continuously and stably conveyed into the local pyrolysis furnace 11 by the screw or belt.

[0060] S2: A heat exchanger 4 is arranged in the three flue ducts 3. Cold air is sent into the heat exchanger 4 by the blower 14 and heated to 450-500℃, or heated to 450-500℃ in two stages by the heat exchanger 4 and the heater 19, and then sent to the pyrolysis furnace 11 as a heat source for pyrolysis. Alternatively, a bypass line is set for the heat exchanger 4, and the bypass valve 17 is opened when the heat exchanger 4 is offline, so that the heater 19 can be used to supply heat to the pyrolysis furnace 11.

[0061] S3: Hot air in the middle wall of the pyrolysis furnace 11 heats the waste incineration fly ash input from the fly ash silo 10, raising the fly ash temperature to 350-400℃, generating detoxified fly ash and pyrolysis gas, and the hot air temperature drops to 350-400℃.

[0062] S4: The pyrolysis gas enters the high-temperature zone of the incinerator furnace 1, where the organic pollutants it contains decompose at a high temperature of over 900°C.

[0063] S5: After the hot air supplies heat to the pyrolysis furnace 11, its temperature drops to 350-400℃. The blower 14 continues to run, and the hot air, as a supplement to the hot secondary air, enters the incinerator for combustion through the combustion air valve 20. Alternatively, after being cooled by the cooler 12, it is pressurized by the circulating fan 13 and then enters the heat exchanger 4 for heating. After establishing the hot air circulation, the blower 14 and the make-up air valve 15 are shut off.

[0064] The foregoing basic examples and their further alternative examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed in this application. In the scheme of this application, each alternative example can be arbitrarily combined with any other basic example and alternative example.

[0065] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A system for in-situ pyrolysis of waste incineration fly ash, comprising an incinerator hearth (1) and an incinerator hopper, characterized in that: The heating module is communicated with the heating medium channel of the pyrolysis furnace (11).

2. The MSW incinerator fly ash in-situ pyrolysis system of claim 1, wherein: The incinerator hearth (1) is communicated with the second flue (2), the third flue (3) is communicated with the horizontal flue (5), and the horizontal flue (5) is provided with a waste heat boiler heating surface.

3. The MSW incinerator fly ash in-situ pyrolysis system of claim 1 or 2, wherein: The first conveying module comprises a screw conveyor (8) which is communicated with the incinerator ash hopper and communicated with the first conveying pipeline provided with a fly ash cut-off valve (9), and the first conveying pipeline is communicated with the fly ash bin (10).

4. The MSW incinerator fly ash in-situ pyrolysis system of claim 1, wherein: The heating module comprises a heat exchanger pipeline provided with a heat exchanger inlet valve (16) and a heat exchanger (4) located in the third flue (3) of the incinerator hearth (1), and the heat exchanger pipeline is communicated with an air inlet pipeline provided with a heater (19).

5. The MSW incinerator fly ash in-situ pyrolysis system of claim 4, wherein: The air supply module comprises an air supply fan (14) communicated with an air supply pipeline provided with an air supply valve (15), and the exhaust pipeline of the heating medium channel of the pyrolysis furnace (11) is communicated with a circulating pipeline provided with a cooler (12) and a circulating fan (13), and the circulating pipeline is communicated with the air supply pipeline.

6. The MSW incinerator fly ash in-situ pyrolysis system of claim 1, wherein: The exhaust pipeline of the heating medium channel of the pyrolysis furnace (11) is communicated with a combustion air pipeline which is communicated with the combustion area of the lower part of the incinerator hearth (1).

7. A pyrolysis method of a waste incineration fly ash in-situ pyrolysis system, characterized by: The garbage incineration fly ash in-situ pyrolysis system of any one of claims 1-6 is adopted. The fly ash collected by the incinerator ash hopper is conveyed to the fly ash bin (10) by the first conveying module, the heating module sends hot air at 450-550 DEG C into the heating medium channel of the pyrolysis furnace (11), the fly ash of the fly ash bin (10) is conveyed to the fly ash pyrolysis channel of the pyrolysis furnace (11) by the second conveying module, the hot air heats the fly ash and raises the temperature of the fly ash to 350-400 DEG C for pyrolysis, the fly ash is pyrolyzed for more than 1.5 hours to generate detoxified fly ash and pyrolysis gas, the detoxified fly ash is deposited into a detoxified ash hopper for treatment, the pyrolysis gas enters the high-temperature area of the incinerator hearth (1), and the organic pollutants in the pyrolysis gas are decomposed at a high temperature of 900 DEG C or above.

8. The method of pyrolysis of a waste incineration fly ash in-situ pyrolysis system of claim 7, wherein: The air passes through the heat exchanger pipeline, is directly heated to 450-550 DEG C through the heat exchanger (4), is sent to the pyrolysis furnace (11) through the heater (19), or the air passes through the heat exchanger pipeline, is heated to 200-250 DEG C in a section through the heat exchanger (4), is heated to 450-550 DEG C in a second section through the heater (19), and is then sent to the pyrolysis furnace (11), or the air passes through the bypass pipeline, is directly heated to 450-550 DEG C through the heater, and is then sent to the pyrolysis furnace (11).

9. The method of pyrolysis of a waste incineration fly ash in-situ pyrolysis system of claim 8, wherein: The air passes through the air blower (14) to increase the pressure, is sent to the heating module through the air supplement pipeline, and / or the hot air temperature in the pyrolysis furnace (11) is reduced to 350-400 DEG C, is sent to the circulating pipeline through the exhaust pipeline of the heating medium channel of the pyrolysis furnace (11), is cooled to below 400 DEG C through the cooler (12), is pressurized into the air supplement pipeline through the circulating blower (13) and is sent to the heating module.

10. The pyrolysis method of the waste incineration fly ash in-situ pyrolysis system according to claim 7, characterized in that: The hot air temperature in the pyrolysis furnace (11) is reduced to 350-400 DEG C, is sent to the combustion air pipeline through the exhaust pipeline of the heating medium channel of the pyrolysis furnace (11), is partially replaced as the hot secondary air into the combustion area located in the lower part of the incinerator hearth (1) and is combusted.

Images