阅读说明：本技术 一种沼气发电烟气余热回收系统及方法 (Biogas power generation flue gas waste heat recovery system and method ) 是由 申娜 张鹏飞 田永红 王昱凯 王璟 吴莎 刘超 吕媛 于 2019-10-22 设计创作，主要内容包括：本申请属于余热回收利用技术领域,尤其涉及一种沼气发电烟气余热回收系统及方法。餐厨垃圾的沼气发电机发电过程中,产生的烟气温度高达550℃,具有较高热量,因此,沼气发电的烟气余热具有回收利用价值。目前对沼气发电的烟气余热的回收利用绝大部分仅限于供热,回收利用率较低。本申请的沼气发电烟气余热回收系统,包括厌氧处理装置、沼气发电机、双压余热锅炉、换热机组以及换热管道；通过将沼气燃烧产生的烟气输送至双压余热锅炉产生高压蒸汽和低压蒸汽,再将高压蒸汽通入厌氧处理装置,将低压蒸汽通入换热机组。本申请高效回收烟气余热,提高能源利用率；高压蒸汽满足厌氧处理工艺的用汽需求,节约能源；同时满足供热、供冷需求。(The application belongs to the technical field of waste heat recovery and utilization, and particularly relates to a system and a method for recovering waste heat of biogas power generation flue gas. In the power generation process of the methane generator for the kitchen waste, the temperature of the generated flue gas reaches up to 550 ℃, and the generated flue gas has higher heat, so that the flue gas waste heat of the methane power generation has a recycling value. At present, most of the recycling of the flue gas waste heat of the biogas power generation is limited to heat supply, and the recycling rate is low. The system for recycling the flue gas waste heat in the methane power generation comprises an anaerobic treatment device, a methane generator, a double-pressure waste heat boiler, a heat exchange unit and a heat exchange pipeline; flue gas generated by methane combustion is conveyed to a double-pressure waste heat boiler to generate high-pressure steam and low-pressure steam, then the high-pressure steam is introduced into an anaerobic treatment device, and the low-pressure steam is introduced into a heat exchange unit. The method has the advantages that the waste heat of the flue gas is efficiently recovered, and the energy utilization rate is improved; the high-pressure steam meets the steam demand of the anaerobic treatment process, and the energy is saved; and simultaneously, the requirements of heat supply and cold supply are met.)

1. A biogas power generation flue gas waste heat recovery system is characterized by comprising an anaerobic treatment device, a biogas generator, a double-pressure waste heat boiler, a heat exchange unit and a heat exchange pipeline;

the anaerobic treatment device is configured to: anaerobic treatment is carried out on the kitchen waste, and methane generated after the kitchen waste is subjected to anaerobic treatment is conveyed to the methane generator;

the biogas generator is configured to: generating power by using the biogas generated by the anaerobic treatment device, and conveying the flue gas generated by biogas combustion to the double-pressure waste heat boiler;

the dual pressure waste heat boiler is configured to: heating water in a boiler by using smoke generated by the biogas generator to generate high-pressure steam and low-pressure steam, conveying the high-pressure steam to the anaerobic treatment device, and conveying the low-pressure steam to the heat exchanger unit;

the heat exchanger unit is configured to: and the steam generated by the double-pressure waste heat boiler is utilized for heat exchange, and a heat exchange working medium is conveyed to the heat exchange pipeline.

2. The biogas power generation flue gas waste heat recovery system of claim 1, further comprising a biogas purification device configured to: and carrying out dust removal and desulfurization treatment on the biogas generated by the anaerobic treatment device, and conveying the treated biogas to the biogas generator.

3. The biogas power generation flue gas waste heat recovery system of claim 1, further comprising an evacuation processing device configured to: and carrying out denitration and dust removal treatment on the flue gas exhausted by the double-pressure waste heat boiler, and then discharging the flue gas into the atmosphere.

4. The biogas power generation flue gas waste heat recovery system according to claim 1, wherein the high pressure steam generated by the dual pressure waste heat boiler is 1.25Mpa pressure steam, and the low pressure steam generated by the dual pressure waste heat boiler is 0.4Mpa pressure steam.

5. The biogas power generation flue gas waste heat recovery system of claim 1, wherein the heat exchanger unit comprises a lithium bromide refrigeration unit and a corrugated pipe steam-water heat exchanger unit.

6. A method for recovering waste heat of flue gas in biogas power generation is characterized by comprising the following steps:

anaerobic treatment is carried out on the kitchen waste through an anaerobic treatment device to generate methane;

the biogas generator generates electricity by using biogas to generate flue gas;

conveying the flue gas to a double-pressure waste heat boiler, and heating water in the double-pressure waste heat boiler to generate high-pressure steam and low-pressure steam;

introducing high-pressure steam into an anaerobic treatment device, and introducing low-pressure steam into a heat exchange unit for heat exchange;

and conveying the heat exchange medium in the heat exchange unit to a preset place through a heat exchange pipeline.

7. The method for recycling the flue gas waste heat in the biogas power generation according to claim 6, wherein before the step of generating the flue gas by using the biogas in the biogas generator, the method further comprises: and (4) performing dust removal and desulfurization treatment on the biogas by using a biogas purification device.

8. The biogas power generation flue gas waste heat recovery method according to claim 6, further comprising, after the step of delivering flue gas to a dual pressure waste heat boiler, heating water in the dual pressure waste heat boiler to generate steam: and an evacuation treatment device is arranged at the flue gas outlet end of the double-pressure waste heat boiler, and is used for carrying out denitration and dust removal treatment on the evacuated flue gas.

9. The biogas power generation flue gas waste heat recovery method according to claim 6, wherein in the step of delivering the flue gas to the dual pressure waste heat boiler to heat water in the dual pressure waste heat boiler to generate steam, the generated high pressure steam is 1.25Mpa pressure steam, and the generated low pressure steam is 0.4Mpa pressure steam, and the high pressure steam is delivered to the anaerobic treatment device and the low pressure steam is delivered to the heat exchanger unit.

10. The biogas power generation flue gas waste heat recovery method according to claim 6, wherein in the step of introducing the steam into the heat exchanger unit for heat exchange, the steam is introduced into a lithium bromide refrigerator unit for refrigeration and heat exchange, and the steam is introduced into a corrugated pipe steam-water heat exchanger unit for heating and heat exchange.

Technical Field

The application relates to the technical field of waste heat recovery and utilization, in particular to a system and a method for recovering waste heat of biogas power generation flue gas.

Background

The kitchen waste is used as one of main energy sources for biogas power generation, and has wide application and economic value. The kitchen waste contains high-concentration organic wastewater, can generate methane after anaerobic fermentation treatment, and can also produce a large amount of compound organic fertilizer; the biogas slurry can provide a large amount of high-quality biogas slurry organic fertilizer for peripheral fruit forests, vegetables, grains and cotton bases, and the biogas is used for biogas power generation. Therefore, the anaerobic treatment project of the kitchen waste has the practicability and the economical efficiency.

Biogas generated after anaerobic treatment of the kitchen waste is purified, subjected to sulfur and moisture impurity removal, enters a gas storage cabinet for pressure stabilization, and then enters a biogas generator for power generation. The exhaust temperature of the biogas generator is about 550 ℃, and the biogas generator has high heat, so the waste heat of the flue gas generated by biogas generation has recycling value.

At present, most of the recycling of the flue gas waste heat of the biogas power generation is limited to heat supply, namely, the flue gas heat is stored in a fluid medium through a heat exchanger, and then the fluid medium is conveyed to realize the purpose of heat supply. However, the method has a low recovery rate, most of the flue gas waste heat is still dissipated, and how to efficiently recover the flue gas waste heat of the biogas power generation becomes a technical problem to be solved urgently in the industry.

Disclosure of Invention

The application provides a system and a method for recovering waste heat of biogas power generation flue gas, which aim to solve the technical problem of low efficiency of recovering the waste heat of the biogas power generation flue gas at present.

The technical scheme adopted by the application is as follows:

in a first aspect of the application, a biogas power generation flue gas waste heat recovery system is provided, which comprises an anaerobic treatment device, a biogas generator, a double-pressure waste heat boiler, a heat exchange unit and a heat exchange pipeline;

the anaerobic treatment device is configured to: anaerobic treatment is carried out on the kitchen waste, and methane generated after the kitchen waste is subjected to anaerobic treatment is conveyed to the methane generator;

the biogas generator is configured to: generating power by using the biogas generated by the anaerobic treatment device, and conveying the flue gas generated by biogas combustion to the double-pressure waste heat boiler;

the dual pressure waste heat boiler is configured to: heating water in a boiler by using smoke generated by the biogas generator to generate high-pressure steam and low-pressure steam, conveying the high-pressure steam to the anaerobic treatment device, and conveying the low-pressure steam to the heat exchanger unit;

the heat exchanger unit is configured to: and the steam generated by the double-pressure waste heat boiler is utilized for heat exchange, and a heat exchange working medium is conveyed to the heat exchange pipeline.

Optionally, the system further comprises a biogas purification device configured to: and carrying out dust removal and desulfurization treatment on the biogas generated by the anaerobic treatment device, and conveying the treated biogas to the biogas generator.

Optionally, the system further comprises an evacuation processing apparatus configured to: and carrying out denitration and dust removal treatment on the flue gas exhausted by the double-pressure waste heat boiler, and then discharging the flue gas into the atmosphere.

Optionally, the high-pressure steam generated by the double-pressure waste heat boiler is 1.25Mpa pressure steam, and the low-pressure steam generated by the double-pressure waste heat boiler is 0.4Mpa pressure steam.

Optionally, the heat exchanger unit includes a lithium bromide refrigeration unit and a bellows steam-water heat exchanger unit.

In a second aspect of the application, a method for recovering waste heat of flue gas in biogas power generation is provided, which is characterized by comprising the following steps:

anaerobic treatment is carried out on the kitchen waste through an anaerobic treatment device to generate methane;

the biogas generator generates electricity by using biogas to generate flue gas;

conveying the flue gas to a double-pressure waste heat boiler, and heating water in the double-pressure waste heat boiler to generate high-pressure steam and low-pressure steam;

introducing high-pressure steam into an anaerobic treatment device, and introducing low-pressure steam into a heat exchange unit for heat exchange;

and conveying the heat exchange medium in the heat exchange unit to a preset place through a heat exchange pipeline.

Optionally, before the step of generating the flue gas by using the biogas generator to generate electricity by using the biogas, the method further comprises: and (4) performing dust removal and desulfurization treatment on the biogas by using a biogas purification device.

Optionally, after the step of delivering the flue gas to a dual-pressure waste heat boiler and heating water in the dual-pressure waste heat boiler to generate steam, the method further includes: and an evacuation treatment device is arranged at the flue gas outlet end of the double-pressure waste heat boiler, and is used for carrying out denitration and dust removal treatment on the evacuated flue gas.

Optionally, in the step of conveying the flue gas to the dual-pressure waste heat boiler and heating water in the dual-pressure waste heat boiler to generate steam, the generated high-pressure steam is 1.25Mpa pressure steam, the generated low-pressure steam is 0.4Mpa pressure steam, the high-pressure steam is conveyed to the anaerobic treatment device, and the low-pressure steam is conveyed to the heat exchanger unit.

Optionally, in the step of introducing the steam into the heat exchanger unit for heat exchange, the steam is introduced into the lithium bromide refrigerator unit for refrigeration and heat exchange, and the steam is introduced into the bellows steam-water heat exchanger unit for heating and heat exchange.

The technical scheme of the application has the following beneficial effects:

the system for recycling the flue gas waste heat in the methane power generation comprises an anaerobic treatment device, a methane generator, a double-pressure waste heat boiler, a heat exchange unit and a heat exchange pipeline; the anaerobic treatment device carries out anaerobic treatment on the kitchen waste, and methane generated after the kitchen waste is subjected to anaerobic treatment is conveyed to the methane generator; the biogas generator generates electricity by using biogas generated by the anaerobic treatment device, and conveys flue gas generated by biogas combustion to the double-pressure waste heat boiler; the double-pressure waste heat boiler heats water in the boiler by using smoke generated by the biogas generator to generate high-pressure steam and low-pressure steam, the high-pressure steam is conveyed to the anaerobic treatment device, and the low-pressure steam is conveyed to the heat exchange unit; the heat exchange unit exchanges heat by using steam generated by the double-pressure waste heat boiler and conveys a heat exchange working medium to the heat exchange pipeline. The application can efficiently recycle the flue gas waste heat generated by the biogas generator, and improve the energy utilization efficiency; the high-pressure steam is conveyed to the anaerobic treatment device, so that the steam demand of the anaerobic treatment process of the kitchen waste can be met, and the energy is saved; and simultaneously, the heat supply and cold supply requirements of a preset place are met.

Drawings

In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an embodiment of a first aspect of the present application;

FIG. 2 is a schematic structural diagram of another embodiment of the first aspect of the present application;

FIG. 3 is a block flow diagram of an embodiment of the second aspect of the present application.

Detailed Description

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following examples do not represent all embodiments consistent with the present application. But merely as exemplifications of systems and methods consistent with certain aspects of the application, as recited in the claims.

Referring to fig. 1, a schematic structural diagram of an embodiment of the first aspect of the present application is shown to facilitate understanding of technical solutions of the following embodiments.

In a first aspect of the application, a biogas power generation flue gas waste heat recovery system is provided, which comprises an anaerobic treatment device, a biogas generator, a double-pressure waste heat boiler, a heat exchange unit and a heat exchange pipeline;

the anaerobic treatment device is configured to: anaerobic treatment is carried out on the kitchen waste, and methane generated after the kitchen waste is subjected to anaerobic treatment is conveyed to the methane generator;

the biogas generator is configured to: generating power by using the biogas generated by the anaerobic treatment device, and conveying the flue gas generated by biogas combustion to the double-pressure waste heat boiler;

the dual pressure waste heat boiler is configured to: heating water in a boiler by using smoke generated by the biogas generator to generate high-pressure steam and low-pressure steam, conveying the high-pressure steam to the anaerobic treatment device, and conveying the low-pressure steam to the heat exchanger unit;

the heat exchanger unit is configured to: and the steam generated by the double-pressure waste heat boiler is utilized for heat exchange, and a heat exchange working medium is conveyed to the heat exchange pipeline.

In the embodiment, the anaerobic treatment device carries out anaerobic treatment on the kitchen waste to generate biogas, the biogas is conveyed to the biogas generator to be combusted and then to generate power, the combusted product, namely the generated flue gas, is conveyed to the double-pressure waste heat boiler to heat water in the boiler to generate double-pressure steam, and the double-pressure steam comprises high-pressure steam and low-pressure steam; high pressure steam has satisfied the required steam of anaerobic treatment device, and low pressure steam then carries to the heat exchanger unit heat transfer, and the heat transfer includes two kinds: namely cooling and heating. After heat exchange, the heat exchange working medium is conveyed to a target user from the heat exchange pipeline, so that the refrigerating or heating requirements of the target user are met.

Optionally, the system further comprises a biogas purification device configured to: and carrying out dust removal and desulfurization treatment on the biogas generated by the anaerobic treatment device, and conveying the treated biogas to the biogas generator.

Referring to FIG. 2, which is a schematic structural view of another embodiment of the first aspect of the present application, in this embodiment, the biogas generated by the anaerobic treatment device often contains impurities and sulfur components such as SO₂And the substances are not beneficial to methane combustion and are not beneficial to the atmospheric environment, so that the dust removal and the desulfurization treatment are carried out by the methane purification device, the stable combustion of the methane is facilitated, and the methane generator and the atmospheric environment are protected.

Optionally, the system further comprises an evacuation processing apparatus configured to: and carrying out denitration and dust removal treatment on the flue gas exhausted by the double-pressure waste heat boiler, and then discharging the flue gas into the atmosphere.

Referring to fig. 2, in this embodiment, the flue gas of two pressure exhaust heat boiler evacuation directly discharges the atmosphere, causes pollution to a certain extent, in order to be friendly to the environment, sets up evacuation processing apparatus and carries out denitration and dust removal processing to the flue gas of two pressure exhaust heat boiler evacuation, further reduces the pollution to atmosphere, is favorable to the environmental protection.

Optionally, the high-pressure steam generated by the double-pressure waste heat boiler is 1.25Mpa pressure steam, and the low-pressure steam generated by the double-pressure waste heat boiler is 0.4Mpa pressure steam.

Referring to fig. 2, in the embodiment, a dual-pressure waste heat boiler generating a fixed pressure is preferred, the high-pressure steam is 1.25Mpa pressure steam, and the low-pressure steam is 0.4Mpa pressure steam; because the specification and the standard of production exist in present two pressure exhaust-heat boiler products, select the two pressure exhaust-heat boiler of this embodiment from production technology and specification parameter and can also compromise certain economic nature when having satisfied the demand of this application.

Optionally, the heat exchanger unit includes a lithium bromide refrigeration unit and a bellows steam-water heat exchanger unit.

Referring to fig. 2, in the embodiment, the lithium bromide refrigeration unit is used for refrigeration and heat exchange, and the corrugated pipe steam-water heat exchange unit is used for heating and heat exchange; a lithium bromide refrigerating unit is called a bromine refrigerator for short, and is an absorption refrigerating machine commonly used in the world at present. In vacuum state, the lithium bromide absorption refrigerator uses water as refrigerant and lithium bromide water solution as absorbent to prepare low temperature water above 0 deg.C, and is mainly used in central air conditioning system. The lithium bromide refrigerator uses the characteristic that the boiling point of water is lower (only 4 ℃) in a high vacuum state to refrigerate (uses the latent heat of boiling of water). The lithium bromide refrigerator has few moving parts, low failure rate, stable movement, small vibration and low noise; the operation is convenient; the lithium bromide solution is non-toxic and has no damage to the ozone layer; the utilization effect on waste heat, waste heat and other low-grade heat energy is good; the operation cost is low, and the safety is good; the heat energy is used as power, and the electric energy consumption is low. The corrugated pipe steam-water heat exchange unit has compact structure, reasonable layout and small occupied area; high heat transfer coefficient and low resistance loss.

In a second aspect of the application, a method for recovering waste heat of flue gas in biogas power generation is provided, which is characterized by comprising the following steps:

s1001, anaerobic treatment is carried out on the kitchen waste through an anaerobic treatment device to generate biogas;

s1002, generating power by using biogas through a biogas generator to generate flue gas;

s1003, conveying the flue gas to a double-pressure waste heat boiler, and heating water in the double-pressure waste heat boiler to generate high-pressure steam and low-pressure steam;

s1004, introducing high-pressure steam into the anaerobic treatment device, and introducing low-pressure steam into a heat exchange unit for heat exchange;

and S1005, conveying the heat exchange medium in the heat exchange unit to a preset place through a heat exchange pipeline.

Referring to fig. 3, a block flow diagram of an embodiment of the second aspect of the present application is shown. In this embodiment, through adopting two pressure exhaust-heat boilers to let in anaerobic treatment device with the high-pressure steam that two pressure exhaust-heat boilers produced, let in heat exchanger group with low-pressure steam and carry out the heat transfer, on the one hand, high-pressure steam has satisfied the steam that anaerobic treatment device required, and on the other hand utilizes low-pressure steam to realize the heat transfer purpose through heat exchanger group, and resources are saved that this embodiment can the bigger degree, and the flue gas waste heat of marsh gas generator is utilized to the high efficiency.

Optionally, before the step of generating the flue gas by using the biogas generator to generate electricity by using the biogas, the method further comprises: and (4) performing dust removal and desulfurization treatment on the biogas by using a biogas purification device.

Optionally, after the step of delivering the flue gas to a dual-pressure waste heat boiler and heating water in the dual-pressure waste heat boiler to generate steam, the method further includes: and an evacuation treatment device is arranged at the flue gas outlet end of the double-pressure waste heat boiler, and is used for carrying out denitration and dust removal treatment on the evacuated flue gas.

Optionally, in the step of conveying the flue gas to the dual-pressure waste heat boiler and heating water in the dual-pressure waste heat boiler to generate steam, the generated high-pressure steam is 1.25Mpa pressure steam, the generated low-pressure steam is 0.4Mpa pressure steam, the high-pressure steam is conveyed to the anaerobic treatment device, and the low-pressure steam is conveyed to the heat exchanger unit.

Optionally, in the step of introducing the steam into the heat exchanger unit for heat exchange, the steam is introduced into the lithium bromide refrigerator unit for refrigeration and heat exchange, and the steam is introduced into the bellows steam-water heat exchanger unit for heating and heat exchange.

The system for recycling the flue gas waste heat in the methane power generation comprises an anaerobic treatment device, a methane generator, a double-pressure waste heat boiler, a heat exchange unit and a heat exchange pipeline; the anaerobic treatment device carries out anaerobic treatment on the kitchen waste, and methane generated after the kitchen waste is subjected to anaerobic treatment is conveyed to the methane generator; the biogas generator generates electricity by using biogas generated by the anaerobic treatment device, and conveys flue gas generated by biogas combustion to the double-pressure waste heat boiler; the double-pressure waste heat boiler heats water in the boiler by using smoke generated by the biogas generator to generate high-pressure steam and low-pressure steam, the high-pressure steam is conveyed to the anaerobic treatment device, and the low-pressure steam is conveyed to the heat exchange unit; the heat exchange unit exchanges heat by using steam generated by the double-pressure waste heat boiler and conveys a heat exchange working medium to the heat exchange pipeline. The application can efficiently recycle the flue gas waste heat generated by the biogas generator, and improve the energy utilization efficiency; the high-pressure steam is conveyed to the anaerobic treatment device, so that the steam demand of the anaerobic treatment process of the kitchen waste can be met, and the energy is saved; and simultaneously, the heat supply and cold supply requirements of a preset place are met.

The embodiments provided in the present application are only a few examples of the general concept of the present application, and do not limit the scope of the present application. Any other embodiments extended according to the scheme of the present application without inventive efforts will be within the scope of protection of the present application for a person skilled in the art.