Environment-friendly and efficient landfill gas collection, purification and power generation process
阅读说明：本技术 一种环保高效的垃圾填埋气收集净化发电工艺 (Environment-friendly and efficient landfill gas collection, purification and power generation process ) 是由 刘田田 于 2020-05-07 设计创作，主要内容包括：本发明公开了一种环保高效的垃圾填埋气收集净化发电工艺,包括垃圾填埋气收集、固气分离和气液分离、吸附除湿、脱硫塔脱硫、水洗脱碳、冷凝干燥、精滤、储存、发电等步骤,本发明公开的垃圾填埋气收集净化发电工艺流程精炼,净化效果好,废气产生少。(The invention discloses an environment-friendly and efficient landfill gas collecting, purifying and power generating process which comprises the steps of landfill gas collection, solid-gas separation and gas-liquid separation, adsorption dehumidification, desulfurization by a desulfurizing tower, water washing decarburization, condensation drying, fine filtration, storage, power generation and the like.)
1. An environment-friendly and efficient landfill gas collection, purification and power generation process is characterized by comprising the following steps:
a. collecting landfill gas: collecting landfill gas through gas collecting devices uniformly distributed in a landfill site and collecting the landfill gas to a collecting station through a pipeline;
b. solid-gas separation and gas-liquid separation: introducing the landfill gas raw material of the collection station into a separator for solid-gas separation and gas-liquid separation;
c. adsorption and dehumidification: introducing the separated landfill gas into an adsorption dehumidification device for primary drying to remove part of water vapor;
d. desulfurizing in a desulfurizing tower: introducing the landfill gas from which part of water vapor is removed in the previous step into a desulfurizing tower for desulfurization and purification;
e. washing with water for decarburization: introducing the desulfurized landfill gas into a water washing tower for water washing to remove most of carbon dioxide;
f. condensation and drying: introducing the decarbonized landfill gas into a condensation drying device, and reducing the temperature of the landfill gas to be below the dew point temperature by a refrigeration system to condense water vapor in the landfill gas, wherein the condensation heat is taken away by the refrigeration device;
g. fine filtering, namely introducing the dried landfill gas into a fine filter for fine filtering;
h. and (3) detection: the detector detects that the landfill gas is qualified and then enters the next step;
i. and (3) storage: storing the qualified landfill gas into a double-layer membrane gas storage cabinet;
j. generating electricity: after being pressurized, the gas enters a gas power generation system to generate power, and the concentration of the waste gas is detected.
2. The environment-friendly and efficient landfill gas collecting, purifying and power generating process of claim 1, wherein the step a specifically comprises: the vertical collecting shafts are arranged in the vertical collecting shafts of the pipelines with holes in the landfill vertical shaft at intervals of 20-30 m, each 6-8 collecting shafts are provided with a gas collecting cabinet to form a group of conveying systems, and each gas collecting cabinet is provided with an independent pipeline connected to a collecting station.
3. The environment-friendly and efficient landfill gas collecting, purifying and power generating process as claimed in claim 1, wherein the separator in the step b is a defoaming separator, the landfill gas output by the collecting station enters the defoaming separator from the upper part of the defoaming separator, impurities such as soil dust and sewage are discharged from the lower outlet of the defoaming separator, and the separated landfill gas is output from the upper part of the defoaming separator.
4. The environment-friendly and efficient landfill gas collecting, purifying and power generating process of claim 1, wherein the step c specifically comprises: introducing landfill gas into an adsorption bed formed by stacking solid adsorbents, and adsorbing water gas on the solid adsorbents by utilizing the capillary action; the solid adsorbent is selected from one or more of activated carbon, zeolite, calcium chloride and silica gel.
5. The environment-friendly and efficient landfill gas collecting, purifying and power generating process of claim 1, wherein the step d specifically comprises: the landfill gas enters from the bottom of the desulfurization tower and is in countercurrent contact reaction with sodium hydroxide liquid, the purified landfill gas is discharged from the top of the tower, and oxygen is used for regenerating the absorption liquid.
6. The environment-friendly and efficient landfill gas collection, purification and power generation process according to claim 1, wherein the step e specifically comprises: and (3) compressing the desulfurized landfill gas, compressing the gas to be more than 2.5MPa by using a compressor, entering the lower part of the water absorption washing tower, and carrying out heat and mass exchange by countercurrent contact with cooling water sprayed from the upper part of the water absorption washing tower to absorb carbon dioxide until the concentration of the carbon dioxide in the landfill gas is lower than 2%.
7. The environment-friendly and efficient landfill gas collecting, purifying and power generating process of claim 1, wherein a multi-layer membrane filtering structure is arranged in the fine filter in the step g.
8. The environment-friendly and efficient landfill gas collecting, purifying and power generating process of claim 7, wherein the multi-layer membrane filtering structure is a polydimethylsiloxane membrane, a polysulfone membrane, a cellulose acetate membrane, an ethyl cellulose membrane, and a polycarbonate membrane in sequence.
9. The environment-friendly and efficient landfill gas collecting, purifying and power generating process of claim 1, wherein the landfill gas qualification standard of the step h is as follows: methane content above 95%, carbon dioxide content below 2%, sulfide content below 10mg/m3Hereinafter, the relative humidity is 75% or less.
10. The environment-friendly and efficient landfill gas collecting, purifying and power generating process of claim 1, wherein the exhaust emission in the step j has HC below 40pm, CO below 0.010%, and NOx below 100 ppm.
Technical Field
The invention relates to the field of landfill gas power generation, in particular to an environment-friendly and efficient landfill gas collection, purification and power generation process.
Technical Field
The Landfill gas is a mixed gas containing methane and carbon dioxide as main components, which is generated by decomposing domestic garbage by microorganisms in a Landfill after the Landfill, and LFG is english abbreviation (Landfill gas) of the Landfill gas. According to different sources and compositions of landfill garbage, landfill gas contains 30-55% of methane by volume, 30-45% of carbon dioxide by volume, and a small amount of air, malodorous gas and other trace gases. Each cubic meter of landfill gas corresponds to about 0.5m3The natural gas or the fuel oil with the heat value of 0.5L, namely the untreated landfill gas has the heat value of 27.8-30.5 MJ/kg, and has high fuel recovery value. In order to solve the problem of the pollution of the buried garbage in the garbage enclosed city and the saturated garbage landfill, the garbage incineration power generation technology is becoming the mainstream, but the garbage incineration power generation technology urgently needs to solve the problems of purification of the garbage landfill gas and serious pollutant emission after the garbage landfill gas is combusted.
Disclosure of Invention
Aiming at the defects, the invention provides the environment-friendly and efficient landfill gas collection, purification and power generation process, which has the advantages of refined process flow, good purification effect and less waste gas generation.
In order to achieve the purpose, the invention provides the following technical scheme:
an environment-friendly and efficient landfill gas collection, purification and power generation process is characterized by comprising the following steps:
a. collecting landfill gas: collecting landfill gas through gas collecting devices uniformly distributed in a landfill site and collecting the landfill gas to a collecting station through a pipeline;
b. solid-gas separation and gas-liquid separation: introducing the landfill gas raw material of the collection station into a separator for solid-gas separation and gas-liquid separation;
c. adsorption and dehumidification: introducing the separated landfill gas into an adsorption dehumidification device for primary drying to remove part of water vapor;
d. desulfurizing in a desulfurizing tower: introducing the landfill gas from which part of water vapor is removed in the previous step into a desulfurizing tower for desulfurization and purification;
e. washing with water for decarburization: introducing the desulfurized landfill gas into a water washing tower for water washing to remove most of carbon dioxide;
f. condensing and drying, namely introducing the decarbonized landfill gas into condensing and drying equipment, and reducing the temperature of the landfill gas to be lower than the dew point temperature by a refrigerating system to condense water vapor in the landfill gas, wherein the condensation heat is taken away by the refrigerating equipment;
g. fine filtering, namely introducing the dried landfill gas into a fine filter for fine filtering;
h. a detector: the detector detects that the landfill gas is qualified and then enters the next step;
i. and (3) storage: storing the qualified landfill gas into a double-layer membrane gas storage cabinet;
j. generating electricity: after being pressurized, the gas enters a gas power generation system to generate power, and the concentration of the waste gas is detected.
Further, according to the environment-friendly and efficient landfill gas collection, purification and power generation process, the step a specifically comprises the following steps: the vertical collecting shafts are arranged in the vertical collecting shafts of the pipelines with holes in the landfill vertical shaft at intervals of 20-30 m, each 6-8 collecting shafts are provided with a gas collecting cabinet to form a group of conveying systems, and each gas collecting cabinet is provided with an independent pipeline connected to a collecting station.
Furthermore, according to the environment-friendly and efficient landfill gas collecting, purifying and power generating process, the separator in the step b is a defoaming separator, landfill gas output by the collecting station enters the defoaming separator from the upper part of the defoaming separator, impurities such as soil dust and sewage are discharged from the lower part of the defoaming separator, and the separated landfill gas is output from the upper part of the defoaming separator.
Further, according to the environment-friendly and efficient landfill gas collection, purification and power generation process, the step c specifically comprises the following steps: introducing landfill gas into an adsorption bed formed by stacking solid adsorbents, and adsorbing water gas on the solid adsorbents by utilizing the capillary action; the solid adsorbent is selected from one or more of activated carbon, zeolite, calcium chloride and silica gel.
Further, according to the environment-friendly and efficient landfill gas collection, purification and power generation process, the step d specifically comprises the following steps: the landfill gas enters from the bottom of the desulfurization tower and is in countercurrent contact reaction with sodium hydroxide liquid, the purified landfill gas is discharged from the top of the tower, and oxygen is used for regenerating the absorption liquid.
Further, in the environment-friendly and efficient landfill gas collection, purification and power generation process, the step e specifically comprises the following steps: and (3) compressing the desulfurized landfill gas, compressing the gas to be more than 2.5MPa by using a compressor, entering the lower part of the water absorption washing tower, and carrying out heat and mass exchange by countercurrent contact with cooling water sprayed from the upper part of the water absorption washing tower to absorb carbon dioxide until the concentration of the carbon dioxide in the landfill gas is lower than 2%.
Further, in the environment-friendly and efficient garbage landfill gas collecting, purifying and power generating process, the fine filter in the step g is provided with a multilayer film filtering structure.
Further, according to the environment-friendly and efficient garbage landfill gas collecting, purifying and power generating process, the multilayer film filtering structure sequentially comprises a polydimethylsiloxane film, a polysulfone film, a cellulose acetate film, an ethyl cellulose film and a polycarbonate film.
Further, in the environment-friendly and efficient landfill gas collection, purification and power generation process, the qualified standard of the landfill gas in the step h is as follows: methane content above 95%, carbon dioxide content below 2%, sulfide content below 10mg/m3Hereinafter, the relative humidity is 75% or less.
Further, in the environment-friendly and efficient landfill gas collecting, purifying and power generating process, HC in the exhaust gas emission in the step j is lower than 40pm, CO is lower than 0.010%, and NOx is lower than 100 ppm.
The scheme shows that the invention at least has the following beneficial effects: the invention discloses an environment-friendly and efficient landfill gas collection, purification and power generation process, which effectively removes water, sulfur and carbon dioxide impurities in landfill gas in a landfill site through steps of landfill gas collection, solid-gas separation and gas-liquid separation, adsorption dehumidification, desulfurization by a desulfurizing tower, water washing for decarbonization, condensation drying, fine filtration, storage, power generation and the like, and has good purification effect, the obtained gas has a methane content of more than 95 percent, a carbon dioxide content of less than 2 percent and a sulfide content of 10mg/m3The relative humidity is less than 75%, the requirements of gas power generation on gas quality are met, power generation equipment is protected, waste gas generated after power generation can meet the environmental protection standard for emission, the whole purification process flow is refined, the requirements on equipment are low, the cost is low, and the environment is protected.
Drawings
Fig. 1 is a flow chart of an environment-friendly and efficient landfill gas collection, purification and power generation process described in examples 1-3.
Detailed Description
The invention will be further elucidated by means of several specific examples, which are intended to be illustrative only and not limiting.