A waste power plant leachate zero discharge and compressed air making system and method

Abstract

The application discloses a garbage power plant leachate zero emission and compressed air making system and method, which comprises a garbage incineration boiler, a flue gas heat exchanger, a steam turbine, an air compressor, a waste heat heat exchanger, a steam air preheater, a wastewater evaporation pretreatment pool and a waste heat evaporation crystallizer, the garbage incineration boiler is communicated with the flue gas heat exchanger, the air compressor, the waste heat heat exchanger and the steam air preheater, the waste heat evaporation crystallizer is communicated with the steam turbine, the air compressor, the waste heat heat exchanger, the steam air preheater and the wastewater evaporation pretreatment pool, and the steam turbine is communicated with the flue gas heat exchanger and the air compressor. The garbage power plant waste heat utilization, leachate zero emission and compressed air system are organically coupled, the waste heat of tail flue gas is reasonably utilized, the steam generated by the waste heat evaporation crystallizer is used to preheat the combustion-supporting air of the garbage incineration boiler, the garbage incineration power station waste heat utilization is realized, the whole plant energy efficiency is improved, and the efficient and economic operation of the whole garbage power generation system is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of landfill leachate zero emission and compressed air production, and particularly relates to a landfill power plant leachate zero emission and compressed air production system and method. BACKGROUND

[0002] At present, the boiler outlet flue gas temperature of the waste incineration waste heat boiler is designed to be 190-210 DEG C. With the continuous improvement of living standards, the calorific value of domestic waste is gradually increasing. At the same time, due to the existence of coking or ash deposition in the boiler, the outlet flue gas temperature of the waste incineration waste heat boiler of some waste incineration power plants is higher than the design value. This part of energy is directly discharged into the environment through the chimney with the flue gas, which reduces the overall plant thermal efficiency and wastes energy.

[0003] The steam air preheater of the waste power plant generally uses the first-stage extraction steam of the turbine body or the main steam of the steam turbine as the heating steam source. The temperature of the steam drain after heating is generally high, usually in a wet steam state, and is directly recovered to the deaerator. This makes the deaerator unable to completely recover the drain amount in the circulating system, and may even cause the deaerator to boil, affecting the deaeration effect and causing energy waste.

[0004] The landfill leachate of the waste power plant is difficult to treat. At present, it is usually sent to a membrane concentration device for concentration after pretreatment. The water production rate is usually only 40-60%. The concentrated water is usually sprayed into the waste incinerator for vaporization, which often leads to deterioration of combustion, especially a significant reduction in the steam production of the incinerator, which seriously affects the power generation of the steam turbine, and the operating cost is very high. In addition, the amount of other main process wastewater generated in the plant, such as desalted water concentrated water, cooling tower blowdown water, and flushing water, is large. If not utilized, it will cause a large waste of water resources. SUMMARY

[0005] To solve the technical problems in the prior art, the purpose of the present application is to provide a landfill power plant leachate zero emission and compressed air production system and method.

[0006] To achieve the above-mentioned purposes and achieve the above-mentioned technical effects, the technical solution adopted by the present application is as follows:

[0007] A landfill power plant leachate zero emission and compressed air production system, comprising a waste incineration boiler, a flue gas heat exchanger, a steam turbine, an air compressor, a waste heat heat exchanger, a steam air preheater, a wastewater evaporation pretreatment tank, and a waste heat evaporation crystallizer, the waste incineration boiler is in communication with the flue gas heat exchanger, the air compressor, the waste heat heat exchanger, and the steam air preheater, respectively, the waste heat evaporation crystallizer is in communication with the steam turbine, the air compressor, the waste heat heat exchanger, the steam air preheater, and the wastewater evaporation pretreatment tank, respectively, and the steam turbine is in communication with the flue gas heat exchanger and the air compressor, respectively.

[0008] Further, the system further comprises a bag filter and a chimney, and the garbage incineration boiler, the bag filter, the flue gas heat exchanger and the chimney are sequentially communicated.

[0009] Further, the system further comprises an air tank and a deaerator, and the water outlet of the air compressor is communicated with the water inlet of the deaerator, and then communicated with the garbage incineration boiler, and the air compressor is communicated with the air tank.

[0010] Further, the system further comprises a blower, and the blower is communicated with the waste heat heat exchanger.

[0011] Further, the system further comprises a solidification device, and the outlet of the high-concentration water or the crystallized salt of the waste heat evaporation crystallizer and the outlet of the fly ash S generated by the garbage incineration boiler are communicated with the feeding port of the solidification device respectively, the waste heat evaporation crystallizer adopts a graphene vertical anti-fouling evaporation heat exchange and salt crystallization structure, and the solidification device adopts a fly ash chelation solidification facility or a ceramsite granulation device.

[0012] Further, the high-temperature outlet of the flue gas heat exchanger is communicated with the steam inlet of the steam turbine, and the exhaust steam outlet of the steam turbine is communicated with the low-temperature inlet of the flue gas heat exchanger.

[0013] Further, the leachate outlet of the wastewater evaporation pretreatment tank is communicated with the feed liquid inlet of the waste heat evaporation crystallizer, the condensate water outlet of the waste heat evaporation crystallizer is communicated with the cooling water inlet of the air compressor, the heat source inlet of the waste heat evaporation crystallizer is communicated with the outlet of the steam air preheater, and the secondary steam outlet of the waste heat evaporation crystallizer is communicated with the steam inlet of the steam turbine, the high-temperature side inlet of the waste heat heat exchanger and the steam recirculation inlet of the waste heat evaporation crystallizer respectively.

[0014] Further, the recirculation heating condensate water N outlet of the waste heat evaporation crystallizer and the condensate water N outlet of the waste heat heat exchanger are respectively communicated with a plant process raw water pipe.

[0015] The application further discloses a garbage power plant leachate zero discharge and compressed air production method, which comprises the following steps:

[0016] The garbage power plant leachate Q0 is sent into the wastewater evaporation pretreatment tank for pretreatment, and the concentrated water Q1 after the pretreatment is sent into the waste heat evaporation crystallizer;

[0017] The concentrated water Q1 is heated and evaporated, concentrated or crystallized by the steam produced by the steam air preheater steam heating side in the waste heat evaporation crystallizer, the condensate water produced after the steam heat release enters the air compressor to cool the compressed air, and the heated water is sent into the garbage incineration boiler through the deaerator;

[0018] The high-concentration water or crystallized salt of the waste heat evaporation crystallizer and fly ash S are sent into a solidification device together to be converted into building material raw materials or landfill solid waste E;

[0019] The second steam of the waste heat evaporation crystallizer is divided into three parts: the first part enters the waste heat exchanger to preheat combustion-supporting air of the garbage incinerator to increase the temperature of the combustion-supporting air; the second part is recycled and returned to the waste heat evaporation crystallizer to assist in heating, evaporating, concentrating or crystallizing the pretreated leachate concentrated water; and the third part enters the steam turbine to do work to drive the air compressor to produce compressed air required in the plant and send it into the air storage tank.

[0020] The exhaust steam of the steam turbine enters the flue gas heat exchanger, and the steam generated by the exhaust heat of the tail flue gas of the garbage incinerator is mixed with the third part of the steam generated by the leachate concentrated water to enter the steam turbine to continue to do work to drive the air compressor to produce compressed air and send it into the air storage tank.

[0021] Compared with the prior art, the garbage power plant leachate zero emission and compressed air production system and method have the following beneficial effects:

[0022] The garbage power plant leachate zero emission and compressed air production system and method provided by the application utilize the waste heat of the tail flue gas of the garbage incinerator and utilize the steam generated by the waste heat evaporation crystallizer to preheat the combustion-supporting air of the garbage incinerator to increase the temperature of the combustion-supporting air, realize the waste heat utilization of the garbage incineration power plant, improve the energy efficiency of the whole plant, do not need to spray a large amount of garbage leachate into the garbage incinerator, can significantly improve the steam production of the garbage incinerator and the stability of the combustion process, and can improve the thermal efficiency and power generation capacity of the garbage incinerator by 10% to 20%; the solid in the garbage leachate is finally solidified to be harmless and even recycled, which is green and environmentally friendly; the garbage power plant waste heat utilization, leachate zero emission and compressed air system are organically coupled to realize the efficient and economic operation of the whole garbage power generation system. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The figure is a structural schematic diagram of the application;

[0024] Wherein, 1-waste incineration boiler, 2-bag dust collector, 3-flue gas heat exchanger, 4-chimney, 5-steam turbine, 6-air compressor, 7-gas storage tank, 8-oxygen remover, 9-blower, 10-heat recovery heat exchanger, 11-steam air preheater, 12-waste water evaporation pretreatment tank, 13-heat evaporation crystallizer, 14-solidification device. DETAILED DESCRIPTION

[0025] The present application will be described in detail below so that the advantages and features of the present application can be more easily understood by those skilled in the art, and the scope of protection of the present application can be more clearly defined.

[0026] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0027] As Figure 1As shown, a waste power plant leachate zero discharge and compressed air production system, including waste incineration boiler 1, bag dust collector 2, flue gas heat exchanger 3, chimney 4, steam turbine 5, air compressor 6, air tank 7, deaerator 8, air blower 9, waste heat exchanger 10, steam air preheater 11, wastewater evaporation pretreatment tank 12, waste heat evaporation crystallizer 13 and solidification device 14, wherein the waste incineration boiler 1, bag dust collector 2, flue gas heat exchanger 3, chimney 4 are sequentially communicated, the waste incineration boiler 1 is also communicated with the deaerator 8, the waste heat exchanger 10, the steam air preheater 11, the air blower 9 is communicated with the waste heat exchanger 10, the high temperature outlet of the flue gas heat exchanger 3 is communicated with the steam inlet of the steam turbine 5, the steam turbine 5 is communicated with the low temperature inlet of the flue gas heat exchanger 3, the water outlet of the air compressor 6 is communicated with the water inlet of the deaerator 8, the air compressor 6 is also communicated with the steam turbine 5 and the air tank 7, the leachate outlet of the wastewater evaporation pretreatment tank 12 is communicated with the liquid inlet of the waste heat evaporation crystallizer 13, the condensed water outlet of the waste heat evaporation crystallizer 13 is communicated with the cooling water inlet of the air compressor 6, the heat source inlet of the waste heat evaporation crystallizer 13 is communicated with the outlet of the steam air preheater 11, the driving heat source of the waste heat evaporation crystallizer 13 adopts high temperature hot water (steam air preheater 11 steam drain), the outlet of the secondary steam Q2 of the waste heat evaporation crystallizer 13 is respectively communicated with the steam inlet of the steam turbine 5, the high temperature side inlet of the waste heat exchanger 10 and the steam recirculation inlet of the waste heat evaporation crystallizer 13, the waste heat evaporation crystallizer 13 is also communicated with the solidification device 14, the outlet of the recirculation heating condensed water N of the waste heat evaporation crystallizer 13 and the outlet of the condensed water N of the waste heat exchanger 10 are respectively communicated with the process raw water pipe in the plant, the outlet of the high concentration water or crystalline salt of the waste heat evaporation crystallizer 13 and the outlet of the fly ash S generated by the waste incineration boiler 1 are respectively communicated with the feeding port of the solidification device 14.

[0028] The waste incineration boiler 1 includes a waste incineration furnace on the left side and a waste incineration waste heat boiler on the right side, the waste heat exchanger 10 and the steam air preheater 11 are communicated with the waste incineration furnace, the air compressor 6 is communicated with the waste incineration waste heat boiler through the deaerator 8.

[0029] The waste heat evaporation crystallizer 13 adopts graphene vertical anti-fouling evaporation heat exchange and salt crystallization structure.

[0030] The solidification device 14 adopts fly ash chelation solidification facility or ceramic pelletizing device.

[0031] A waste power plant leachate zero discharge and compressed air production method, comprising the following steps:

[0032] The waste power plant leachate Q0 is sent into the wastewater evaporation pretreatment tank 12, and the required weight reduction and other pretreatments such as metal reduction are carried out, and the concentrated water Q1 after pretreatment is sent into the waste heat evaporation crystallizer 13;

[0033] The concentrated water Q1 is heated, evaporated, concentrated or crystallized in the waste heat evaporation crystallizer 13 by the driving heat source, which uses the steam drain of the steam air preheater 11, and the steam drain of the steam heating side of the steam air preheater 11 is used to heat, evaporate, concentrate or crystallize the pretreated leachate concentrated water Q1, and the condensed water generated by the steam heat release enters the air compressor 6 to cool the compressed air, and the hot water after heat absorption is sent to the waste incineration boiler 1 through the deaerator 8; the high-concentration water or crystallized salt of the waste heat evaporation crystallizer 13 is sent to the solidification device 14 together with the fly ash S, and is converted into building material raw materials or landfill solid waste E;

[0034] The secondary steam of the waste water side of the waste heat evaporation crystallizer 13 is divided into three parts, the first part enters the waste heat exchanger 10 to preheat the combustion-supporting air of the waste incineration furnace to improve the temperature of the combustion-supporting air, the second part is recycled and returned to the waste heat evaporation crystallizer 13 to assist in heating, evaporating, concentrating or crystallizing the pretreated leachate concentrated water, and the condensed water generated by the two parts is returned to the process make-up water in the plant through the plant process raw water pipe, and the third part enters the steam turbine 5 to do work and drive the air compressor 6 to make compressed air required in the plant and sent to the air storage tank 7.

[0035] The exhaust steam of the steam turbine 5 enters the flue gas heat exchanger 3, and the steam generated by the waste heat of the tail flue gas (the flue gas discharged from the waste incineration boiler 1 after being dedusted by the bag-type dust collector 2) and the third part of the steam generated by the leachate concentrated water waste water is mixed into the steam turbine 5 to continue to do work and drive the air compressor 6 to make compressed air and send it to the air storage tank 7.

[0036] The parts or structures not specifically described in the present application can use existing technologies or existing products, which are not described here.

[0037] The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the present application specification, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A waste power plant leachate zero discharge and compressed air making system, characterized in that, The system includes a waste incineration boiler, a flue gas heat exchanger, a steam turbine, an air compressor, a waste heat exchanger, a steam air preheater, a wastewater evaporation pretreatment tank, and a waste heat evaporation crystallizer. The waste incineration boiler is connected to the flue gas heat exchanger, the air compressor, the waste heat heat exchanger, and the steam air preheater. The waste heat evaporation crystallizer is connected to the steam turbine, the air compressor, the waste heat heat exchanger, the steam air preheater, and the wastewater evaporation pretreatment tank. The steam turbine is connected to the flue gas heat exchanger and the air compressor. The driving heat source for the waste heat evaporation crystallizer is the steam condensate of the steam air preheater. The high-temperature outlet of the flue gas heat exchanger is connected to the steam inlet of the steam turbine, and the exhaust steam outlet of the steam turbine is connected to the low-temperature inlet of the flue gas heat exchanger. The leachate outlet of the wastewater evaporation pretreatment tank is connected to the feed liquid inlet of the waste heat evaporation crystallizer. The condensate outlet of the waste heat evaporation crystallizer is connected to the cooling water inlet of the air compressor. The heat source inlet of the waste heat evaporation crystallizer is connected to the outlet of the steam air preheater. The secondary steam outlet of the waste heat evaporation crystallizer is connected to the steam inlet of the steam turbine, the high-temperature side inlet of the waste heat heat exchanger, and the steam recirculation inlet of the waste heat evaporation crystallizer, respectively. The secondary steam on the wastewater side of the waste heat evaporation crystallizer is divided into three parts: the first part enters the waste heat exchanger to preheat the combustion air of the waste incinerator to increase the temperature of the combustion air; the second part is recirculated and returned to the waste heat evaporation crystallizer to assist in heating, evaporating, concentrating or crystallizing the concentrated leachate after pretreatment; the third part enters the steam turbine to do work, driving the compressed air required by the air compressor manufacturing plant and sending it into the air storage tank.

2. A waste power plant leachate zero-emission and compressed air production system according to claim 1, characterized in that, The system also includes a bag filter and a chimney, and the waste incineration boiler, bag filter, flue gas heat exchanger and chimney are connected in sequence.

3. The system of claim 1, wherein the system further comprises a compressor for compressing the air. The system also includes an air storage tank and a deaerator. The outlet of the air compressor is connected to the inlet of the deaerator and then to the waste incineration boiler. The air compressor is connected to the air storage tank.

4. The waste power plant leachate zero-emission and compressed air making system according to claim 1, characterized in that, The system also includes a blower connected to a waste heat exchanger.

5. The system of claim 1, wherein the system further comprises a compressor for compressing the air. The system also includes a solidification device, wherein the outlet of the high-concentration water or crystalline salt of the waste heat evaporation crystallizer and the outlet of the fly ash S generated by the waste incineration boiler are respectively connected to the feed inlet of the solidification device.

6. The system of claim 1, wherein the system further comprises a compressor for compressing the air. The outlet of the recirculated heated condensate N of the waste heat evaporation crystallizer and the outlet of the condensate N of the waste heat exchanger are respectively connected to the raw process water pipe in the plant.

7. A method for making zero discharge of leachate from a waste power plant and compressed air, characterized by, Includes the following steps: The leachate Q0 from the waste-to-energy plant is sent to the wastewater evaporation pretreatment tank for pretreatment, and the concentrated water Q1 after pretreatment is sent to the waste heat evaporation crystallizer. In the waste heat evaporation crystallizer, concentrated water Q1 is heated by the steam condensate generated on the steam heating side of the steam air preheater for evaporation, concentration or crystallization. The condensate generated after the steam releases heat enters the air compressor to cool and compress the air. The hot water after absorbing heat is sent to the waste incineration boiler through the deaerator. The high-concentration water or crystallized salt from the waste heat evaporation crystallizer is sent together with fly ash S into the solidification device to be converted into building material raw materials or landfill solid waste E. The second steam of the waste heat evaporation crystallizer on the sewage side is divided into three parts: the first part enters the waste heat exchanger to preheat the combustion-supporting air of the garbage incinerator to increase the temperature of the combustion-supporting air; the second part is recycled and returned to the waste heat evaporation crystallizer to assist in heating, evaporating, concentrating or crystallizing the concentrated water of the pretreated leachate; and the third part enters the steam turbine to work to drive the air compressor to produce compressed air required in the factory and to be sent into the air storage tank. The exhaust steam of the steam turbine enters the flue gas heat exchanger, mixes with the third part of the steam generated by the concentrated water of the leachate and the steam generated by the waste heat of the tail flue gas discharged by the garbage incinerator, and then enters the steam turbine to continue working to drive the air compressor to produce compressed air and to be sent into the air storage tank.

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