Household garbage incineration cascade heat recovery system

Abstract

The utility model discloses a household garbage incineration cascade heat recovery system, which belongs to the technical field of household garbage incineration treatment and comprises an incinerator, a boiler and a steam turbine. The system further comprises a flue gas pollution treatment system used for carrying out pollution treatment on high-temperature flue gas generated by incineration, a flue gas waste heat recovery system used for recycling waste heat of flue gas, a steam waste heat recovery system used for utilizing steam waste heat generated by the boiler, and a dead steam waste heat recovery system used for utilizing waste heat of dead steam. Through the mode, flue gas waste heat, biogas, boiler drainage waste heat, dead steam waste heat and the like are recycled in links by adopting a plurality of forms and a cascade heat exchange mode, and the generated electric quantity is greatly increased compared with the electric quantity generated by adopting a steam turbine unit exhaust heating mode; meanwhile, biogas generated by landfill leachate treatment is effectively utilized, and economic benefits are improved.

Description

Technical Field

[0001] This utility model relates to the field of municipal solid waste incineration technology, specifically to a municipal solid waste incineration cascade heat recovery system. Background Technology

[0002] In the current technology, incineration is one of the main methods of municipal solid waste disposal, which can generate electricity while treating waste, so as to realize the resource utilization of waste.

[0003] However, as the waste incineration industry matures and becomes saturated, the reduction of subsidies is becoming increasingly apparent. Therefore, reducing production costs and increasing incineration power generation are becoming increasingly crucial for waste incineration plants to maintain operation. Currently, waste incineration systems generally use steam turbine generator sets to extract steam to heat the medium within the system, which significantly increases internal steam consumption and reduces the power generation from incineration.

[0004] Based on this, this utility model designs a cascade heat recovery system for municipal solid waste incineration to solve the above problems. Utility Model Content

[0005] In view of the above-mentioned shortcomings of the existing technology, the present invention provides a cascade heat recovery system for municipal solid waste incineration.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A municipal solid waste incineration cascade heat recovery system includes an incinerator, a boiler, and a steam turbine, and also includes a flue gas pollution treatment system for treating the high-temperature flue gas generated during incineration, a flue gas waste heat recovery system for reusing the waste heat of the flue gas, a steam waste heat recovery system for utilizing the waste heat of the steam generated by the boiler, and a waste steam waste heat recovery system for utilizing the waste heat of the exhaust steam.

[0008] The incinerator's exhaust pipe is connected to the boiler's flue gas inlet pipe, the boiler's high-temperature steam exhaust pipe is connected to the turbine's inlet pipe, the incinerator is connected to the flue gas waste heat recovery system, the boiler is connected to the flue gas pollution treatment system, the flue gas waste heat recovery system, and the steam waste heat recovery system, the flue gas pollution treatment system is connected to the flue gas waste heat recovery system, and the steam waste heat recovery system is connected to the exhaust steam waste heat recovery system.

[0009] Furthermore, the flue gas pollution treatment system includes an economizer, a circulating fluidized bed reactor, a bag filter, a heat exchanger assembly, and a selective catalytic reduction device; the inlet pipe of the economizer is connected to the flue gas outlet pipe of the boiler, the outlet pipe of the economizer is connected to the inlet pipe of the boiler, the outlet pipe of the economizer is connected to the inlet pipe of the circulating fluidized bed reactor, the outlet pipe of the circulating fluidized bed reactor is connected to the inlet pipe of the bag filter, the outlet pipe of the bag filter is connected to the inlet pipe of the heat exchanger assembly, the outlet pipe of the heat exchanger assembly is connected to the inlet pipe of the selective catalytic reduction device, and the selective catalytic reduction device is connected to the flue gas waste heat recovery system.

[0010] Furthermore, the flue gas waste heat recovery system includes a primary air preheater, a biogas combustion mixer, and a secondary air preheater; the inlet pipe of the primary air preheater is connected to the outlet pipe of the selective catalytic reduction device, the outlet pipe of the primary air preheater is connected to the inlet pipe of the biogas combustion mixer, the outlet pipe of the biogas combustion mixer is connected to the inlet pipe of the secondary air preheater, the feed pipe of the secondary air preheater is connected to the main steam outlet pipe of the boiler, and the discharge pipe of the secondary air preheater is connected to the inlet pipe of the incinerator.

[0011] Furthermore, the biogas source of the biogas combustion mixer is the gas produced by the fermentation of leachate from domestic waste.

[0012] Furthermore, the steam waste heat recovery system includes a heat exchange expansion vessel, a low-pressure heater, and a deaerator; the feed pipe of the heat exchange expansion vessel is connected to the secondary steam outlet pipe of the boiler, the discharge pipe of the heat exchange expansion vessel is connected to the feed pipe of the low-pressure heater, the discharge pipe of the low-pressure heater is connected to the feed pipe of the deaerator, the water outlet pipe of the deaerator is connected to the water inlet pipe of the boiler, and the deaerator is connected to the waste steam waste heat recovery system.

[0013] Furthermore, the waste heat recovery system includes a heat exchanger in the unloading hall and a cooling device; the inlet pipe of the heat exchanger in the unloading hall is connected to the outlet pipe of the deaerator, and the outlet pipe of the heat exchanger in the unloading hall is connected to the inlet pipe of the cooling device.

[0014] Furthermore, the waste heat recovery system also includes a second deaerator; the outlet pipe of the cooling device is connected to the inlet pipe of the second deaerator.

[0015] Furthermore, the outlet pipe of the deaerator 2 is connected to the inlet pipe of the boiler.

[0016] Compared with the prior art, the advantages of this utility model are as follows: 1. When this utility model is used, the incinerator burns domestic waste into high-temperature flue gas, which enters the boiler. Outside air is introduced into the incinerator to assist combustion. The heat of the flue gas causes the boiler to heat up and generate steam. The superheated steam enters the steam turbine and is converted into electrical energy. The waste heat of the steam is further recovered and utilized through the waste heat recovery system. The waste heat of the exhaust steam generated by the waste heat recovery system is further utilized through the exhaust steam waste heat recovery system. The flue gas from the incinerator enters the flue gas pollution treatment system through the boiler's flue gas pipe for pre-emission toxic gas treatment. At the same time, the waste heat of the flue gas is further utilized through the waste heat recovery system to fully utilize the heat to supplement the energy of the incinerator and boiler, realizing multi-stage resource utilization and reducing energy consumption.

[0017] 2. In use, the high-temperature flue gas in the boiler enters the economizer through pipelines and exchanges heat with the cold water entering the economizer. Hot water is supplied from the economizer to the boiler. The flue gas enters the circulating fluidized bed reactor for deacidification reaction to remove sulfide gases. The flue gas and the reaction precipitate in the circulating fluidized bed reactor continue to enter the bag filter for solid dust removal and filtration. At this time, the flue gas enters the heat exchange tube group for heating, and then enters the selective catalytic reduction device for denitrification to remove related gases, thus achieving the pollution treatment of incineration flue gas and increasing the heat reserve for subsequent treatment.

[0018] 3. When this utility model is used, the exhaust gas from the selective catalytic reduction device enters the primary air preheater. Air is introduced into the primary air preheater to exchange heat with the exhaust gas. The air is heated to form primary air. The primary air further utilizes the energy from biogas combustion in the biogas combustion mixer to generate heat and raise its temperature. The main steam in the boiler exchanges heat with the heated primary air from the biogas combustion mixer. The primary air is further heated to form secondary air. The secondary air is introduced into the incinerator as oxygen and heat supplementation to improve combustion efficiency and heat.

[0019] 4. When this utility model is used, the waste heat of steam in the boiler exchanges heat with the low-temperature water introduced into the heat exchange expansion vessel to heat the water source. The heated water and low-pressure steam in the heat exchange expansion vessel enter the low-pressure heater for further heat exchange and heating of the water source. The water heated in the low-pressure heater enters the deaerator to remove oxygen and improve the purity of the water. For boiler feedwater, while providing heat, the steam heat generated by the pure water is more sufficient.

[0020] 5. When this utility model is used, the waste heat steam from deaerator one is used as exhaust steam. It passes through the heat exchanger in the unloading hall to reduce the temperature of the exhaust steam and increase the ambient temperature of the unloading hall. The waste heat exhaust steam enters the cooling device and exchanges heat with the cold water introduced into the cooling device to raise the temperature of the cold water. It then enters deaerator two for deoxygenation. The deoxygenated hot water is then introduced into the boiler to improve the heating efficiency of the boiler and further utilize the waste heat temperature of the exhaust steam. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart of a municipal solid waste incineration cascade heat recovery system according to the present invention.

[0023] The labels in the diagram represent:

[0024] 1. Incinerator; 2. Boiler; 3. Steam turbine; 4. Economizer; 5. Circulating fluidized bed reactor; 6. Bag filter; 7. Heat exchanger assembly; 8. Selective catalytic reduction unit; 9. Primary air preheater; 10. Biogas combustion mixer; 11. Secondary air preheater; 12. Heat exchange expansion tank; 13. Low-pressure heater; 14. Deaerator I; 15. Heat exchanger in the unloading hall; 16. Cooling device; 17. Deaerator II. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0026] Example 1: In some embodiments, please refer to the accompanying drawings. Figure 1 A municipal solid waste incineration cascade heat recovery system includes an incinerator 1, a boiler 2 and a steam turbine 3, and also includes a flue gas pollution treatment system for treating the high-temperature flue gas generated during incineration, a flue gas waste heat recovery system for reusing the waste heat of the flue gas, a steam waste heat recovery system for utilizing the waste heat of the steam generated by the boiler 2, and a waste steam waste heat recovery system for utilizing the waste heat of the exhaust steam.

[0027] The exhaust pipe of the incinerator 1 is connected to the flue gas inlet pipe of the boiler 2, the high-temperature steam exhaust pipe of the boiler 2 is connected to the inlet pipe of the steam turbine 3, the incinerator 1 is connected to the flue gas waste heat recovery system, the boiler 2 is connected to the flue gas pollution treatment system, the flue gas waste heat recovery system and the steam waste heat recovery system, the flue gas pollution treatment system is connected to the flue gas waste heat recovery system, and the steam waste heat recovery system is connected to the exhaust steam waste heat recovery system; the inlet pipe of the incinerator 1 is connected to an external air pump, the product of the incinerator 1 in treating domestic waste is used as the energy source for the boiler 2, and the water inlet pipe of the boiler 2 is connected to an external water pump.

[0028] In use, this invention involves incinerator 1 burning municipal solid waste into high-temperature flue gas, which then enters boiler 2. Outside air is introduced into incinerator 1 to aid combustion. The heat from the flue gas heats boiler 2 to generate steam. The superheated steam enters turbine 3 and is converted into electrical energy. Waste heat from the steam is further recovered and utilized through a waste heat recovery system. The waste heat from the exhaust steam generated by the waste heat recovery system is further utilized through an exhaust steam waste heat recovery system. The flue gas from incinerator 1 enters the flue gas pollution treatment system through the flue gas pipe of boiler 2 for pre-emission toxic gas treatment. Simultaneously, the waste heat from the flue gas is further utilized through the waste heat recovery system to fully supplement the energy of incinerator 1 and boiler 2, achieving multi-stage resource utilization and reducing energy consumption.

[0029] The flue gas pollution treatment system includes an economizer 4, a circulating fluidized bed reactor 5, a bag filter 6, a heat exchanger assembly 7, and a selective catalytic reduction device 8. The inlet pipe of the economizer 4 is connected to the flue gas outlet pipe of the boiler 2, the outlet pipe of the economizer 4 is connected to the inlet pipe of the boiler 2, the outlet pipe of the economizer 4 is connected to the inlet pipe of the circulating fluidized bed reactor 5, the outlet pipe of the circulating fluidized bed reactor 5 is connected to the inlet pipe of the bag filter 6, the outlet pipe of the bag filter 6 is connected to the inlet pipe of the heat exchanger assembly 7, the outlet pipe of the heat exchanger assembly 7 is connected to the inlet pipe of the selective catalytic reduction device 8, and the selective catalytic reduction device 8 is connected to the flue gas waste heat recovery system.

[0030] In use, the high-temperature flue gas in boiler 2 enters economizer 4 through pipelines, where it exchanges heat with the cold water entering economizer 4. Hot water is supplied from economizer 4 to boiler 2. The flue gas then enters circulating fluidized bed reactor 5 for deacidification reaction to remove sulfide gases. The flue gas and the reaction precipitates in circulating fluidized bed reactor 5 continue to enter bag filter 6 for solid dust removal and filtration. At this point, the flue gas enters heat exchanger tube group 7 for heating, and then enters selective catalytic reduction device 8 for denitrification to remove related gases, thus achieving pollution treatment of incineration flue gas and increasing heat reserves for subsequent processing.

[0031] The flue gas waste heat recovery system includes a primary air preheater 9, a biogas combustion mixer 10, and a secondary air preheater 11. The inlet pipe of the primary air preheater 9 is connected to the outlet pipe of the selective catalytic reduction device 8, the outlet pipe of the primary air preheater 9 is connected to the inlet pipe of the biogas combustion mixer 10, the outlet pipe of the biogas combustion mixer 10 is connected to the inlet pipe of the secondary air preheater 11, the feed pipe of the secondary air preheater 11 is connected to the main steam outlet pipe of the boiler 2, and the discharge pipe of the secondary air preheater 11 is connected to the inlet pipe of the incinerator 1. The biogas in the biogas combustion mixer 10 is derived from the gas produced by the fermentation of leachate from municipal solid waste.

[0032] When this utility model is in use, the exhaust gas from the selective catalytic reduction device 8 enters the primary air preheater 9. Air is introduced into the primary air preheater 9 to exchange heat with the exhaust gas. The air is heated to form primary air. The primary air further utilizes the energy from biogas combustion in the biogas combustion mixer 10 to generate heat and raise its temperature. The main steam in the boiler 2 exchanges heat with the heated primary air from the biogas combustion mixer 10. The primary air is further heated to form secondary air. The secondary air is introduced into the incinerator 1 as oxygen and heat supplementation to improve combustion efficiency and heat output.

[0033] The steam waste heat recovery system includes a heat exchange expansion vessel 12, a low-pressure heater 13, and a deaerator 14. The feed pipe of the heat exchange expansion vessel 12 is connected to the secondary steam outlet pipe of the boiler 2, the discharge pipe of the heat exchange expansion vessel 12 is connected to the feed pipe of the low-pressure heater 13, the discharge pipe of the low-pressure heater 13 is connected to the feed pipe of the deaerator 14, the water outlet pipe of the deaerator 14 is connected to the water inlet pipe of the boiler 2, and the deaerator 14 is connected to the exhaust steam waste heat recovery system.

[0034] When this utility model is in use, the waste heat of steam in boiler 2 exchanges heat with the low-temperature water introduced into heat exchange expansion vessel 12 to heat the water source. The heated water and low-pressure steam in heat exchange expansion vessel 12 enter low-pressure heater 13 for further heat exchange and heating of the water source. The water heated in low-pressure heater 13 enters deaerator 14 to remove oxygen and improve the purity of the water. When feeding water to boiler 2, the pure water provides heat while the steam heat generated by the pure water is more sufficient.

[0035] The waste heat recovery system includes a heat exchanger 15 in the unloading hall and a cooling device 16; the inlet pipe of the heat exchanger 15 in the unloading hall is connected to the outlet pipe of the deaerator 14, and the outlet pipe of the heat exchanger 15 in the unloading hall is connected to the inlet pipe of the cooling device 16; the waste heat recovery system also includes a deaerator 2 17; the outlet pipe of the cooling device 16 is connected to the inlet pipe of the deaerator 2 17; the outlet pipe of the deaerator 2 17 is connected to the inlet pipe of the boiler 2.

[0036] When this utility model is in use, the waste heat steam from deaerator 14 is used as exhaust steam. It passes through heat exchanger 15 in the unloading hall to reduce the exhaust steam temperature and increase the ambient temperature of the unloading hall. The waste heat exhaust steam enters cooling device 16 and exchanges heat with cold water introduced into cooling device 16 to raise the temperature of the cold water. It then enters deaerator 17 for deoxygenation and the deoxygenated hot water is introduced into boiler 2 to improve the heating efficiency of boiler 2. At the same time, the waste heat temperature of the exhaust steam is further utilized.

[0037] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A cascade heat recovery system for municipal solid waste incineration, comprising an incinerator (1), a boiler (2), and a steam turbine (3), characterized in that: It also includes a flue gas pollution treatment system for treating the high-temperature flue gas generated by incineration, a flue gas waste heat recovery system for reusing the waste heat of flue gas, a steam waste heat recovery system for utilizing the steam waste heat generated by the boiler (2), and a waste steam waste heat recovery system for utilizing the waste heat of the exhaust steam. The gas outlet pipe of the incinerator (1) is connected to the flue gas inlet pipe of the boiler (2), the high-temperature steam outlet pipe of the boiler (2) is connected to the inlet pipe of the steam turbine (3), the incinerator (1) is connected to the flue gas waste heat recovery system, the boiler (2) is connected to the flue gas pollution treatment system, the flue gas waste heat recovery system and the steam waste heat recovery system, the flue gas pollution treatment system is connected to the flue gas waste heat recovery system, and the steam waste heat recovery system is connected to the exhaust steam waste heat recovery system.

2. The municipal solid waste incineration cascade heat recovery system according to claim 1, characterized in that, The flue gas pollution treatment system includes an economizer (4), a circulating fluidized bed reactor (5), a bag filter (6), a heat exchanger assembly (7), and a selective catalytic reduction device (8); The inlet pipe of the economizer (4) is connected to the flue gas outlet pipe of the boiler (2), the outlet pipe of the economizer (4) is connected to the inlet pipe of the boiler (2), the outlet pipe of the economizer (4) is connected to the inlet pipe of the circulating fluidized bed reactor (5), the outlet pipe of the circulating fluidized bed reactor (5) is connected to the inlet pipe of the bag filter (6), the outlet pipe of the bag filter (6) is connected to the inlet pipe of the heat exchanger assembly (7), the outlet pipe of the heat exchanger assembly (7) is connected to the inlet pipe of the selective catalytic reduction device (8), and the selective catalytic reduction device (8) is connected to the flue gas waste heat recovery system.

3. The municipal solid waste incineration cascade heat recovery system according to claim 2, characterized in that, The flue gas waste heat recovery system includes a primary air preheater (9), a biogas combustion mixer (10), and a secondary air preheater (11); The air inlet pipe of the primary air preheater (9) is connected to the air outlet pipe of the selective catalytic reduction device (8), the air outlet pipe of the primary air preheater (9) is connected to the air inlet pipe of the biogas combustion mixer (10), the air outlet pipe of the biogas combustion mixer (10) is connected to the air inlet pipe of the secondary air preheater (11), the feed pipe of the secondary air preheater (11) is connected to the main steam outlet pipe of the boiler (2), and the discharge pipe of the secondary air preheater (11) is connected to the air inlet pipe of the incinerator (1).

4. The municipal solid waste incineration cascade heat recovery system according to claim 3, characterized in that, The biogas source of the biogas combustion mixer (10) is the gas produced by the fermentation of leachate from domestic waste.

5. The municipal solid waste incineration cascade heat recovery system according to claim 1, characterized in that, The steam waste heat recovery system includes a heat exchange expansion vessel (12), a low-pressure heater (13), and a deaerator (14); The feed pipe of the heat exchange expansion vessel (12) is connected to the secondary steam outlet pipe of the boiler (2), the discharge pipe of the heat exchange expansion vessel (12) is connected to the feed pipe of the low-pressure heater (13), the discharge pipe of the low-pressure heater (13) is connected to the feed pipe of the deaerator (14), the water outlet pipe of the deaerator (14) is connected to the water inlet pipe of the boiler (2), and the deaerator (14) is connected to the waste heat recovery system.

6. The municipal solid waste incineration cascade heat recovery system according to claim 5, characterized in that, The waste heat recovery system includes a heat exchanger (15) in the unloading hall and a cooling device (16); The inlet pipe of the unloading hall heat exchanger (15) is connected to the outlet pipe of the deaerator (14), and the outlet pipe of the unloading hall heat exchanger (15) is connected to the inlet pipe of the cooling device (16).

7. The municipal solid waste incineration cascade heat recovery system according to claim 6, characterized in that, The waste heat recovery system also includes a second deaerator (17); The outlet pipe of the cooling device (16) is connected to the inlet pipe of the deaerator (17).

8. The municipal solid waste incineration cascade heat recovery system according to claim 7, characterized in that, The outlet pipe of the deaerator 2 (17) is connected to the inlet pipe of the boiler (2).

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