Method for purification and recovery of methane from refuse landfill gas

A landfill gas and landfill gas technology, applied in organic chemistry, adsorption purification/separation, waste fuel, etc., can solve the problem of difficult removal of trace impurities, achieve considerable social and economic benefits, be conducive to environmental protection, and broad The effect of market prospects

Active Publication Date: 2006-10-11
SOUTHWEST RES & DESIGN INST OF CHEM IND
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

[0007] At present, countries around the world are also actively developing landfill gas purification methods. Due to the difficulty

Method used

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  • Method for purification and recovery of methane from refuse landfill gas

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Embodiment 1

[0023] The invention is composed of technical processes such as compression, desulfurization, freezing liquid separation, temperature swing adsorption and pressure swing adsorption (both are two beds). Its process is shown as figure 1 :

[0024] The specific content of the present invention is described as follows.

[0025] Compression: Landfill gas at atmospheric pressure is compressed to the pressure required by the subsequent process in order to overcome sufficient resistance drop and meet the C0 of PSA 2 Removal rate and CH 4 Requirements for recovery rate, compressed landfill gas pressure is 0.2MPa(G) or 1.5MPa(G) or 2.5MPa(G).

[0026] Desulfurization: The desulfurization process uses modified activated carbon and iron oxide composite desulfurizer, and the ratio is 1:1~10 (volume ratio). The landfill gas with a pressure of 0.2MPa(G) or 1.8MPa(G) or 2.5MPa(G) is sent to the desulfurization process for desulfurization, so that the sulfur content in it is ≤20mg / m 3 , t...

Embodiment 2

[0045] This example adopts a 2-bed system of temperature swing adsorption process and a 4-bed secondary pressure equalization system of pressure swing adsorption process. The TSA adsorption bed is filled with alumina and silica gel with a volume ratio of 1:6, and the PSA adsorption bed is filled with alumina and silica gel with a volume ratio of 1:7.

[0046] The landfill gas composed as shown in Table 1 is compressed to 0.5MPa by the compressor, and enters the desulfurization system for desulfurization. The desulfurization system adopts a two-tower series-parallel process, and the desulfurizer uses modified activated carbon and iron oxide composite desulfurizer, and the ratio is 1. : 2 (volume ratio), remove sulfur from landfill gas to ≤20mg / m 3 Then it enters the freezing liquid separation system. The operating temperature of the freezing liquid separation system is 5°C, and most of the water and high boiling point impurities in the landfill gas are separated. The prelimina...

Embodiment 3

[0050] This example adopts a 2-bed system of temperature swing adsorption process and a 6-bed three-time pressure equalization system of pressure swing adsorption process. TSA is attached with tower to install alumina and activated carbon, the volume ratio is 1:2, PSA is attached with tower to install alumina and silica gel, and the volume ratio is 1:9.

[0051] The landfill gas with the composition shown in Table 1 is compressed to 0.7MPa(G) by the compressor, and then enters the refrigerated liquid separation system. The operating temperature of the refrigerated liquid separation system is 6°C, and most of the water and high-boiling point impurities are condensed and separated out of the garbage. Landfill gas and landfill gas enter the desulfurization system for desulfurization. The desulfurizer uses modified activated carbon and iron oxide composite desulfurizer. The ratio is 1:5 (volume ratio), and the sulfur is desulfurized to ≤20mg / m 3 The preliminarily purified landfill...

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Abstract

Disclosed is a method for purification and recovery of methane with purity of 80-90 %, yield of 80-95% from refuse landfill gas, comprising compression, desulfurization, refrigerating liquid separation, temperature swing adsorption (TSA) and pressure swing adsorption (PSA). The desulfurization procedure adopts special type active carbon and iron oxide compounding desulfurizer, the total sulfur after desulfurization is less than or equal to 20mg/m3; the refrigerating liquid separation system temperature is 4-10íµ, most of water and high boiling point substances are removed; the adsorbent in TSA adopts alumina and silica gel or alumina and active carbon in a volume ratio of 1:2-10, wherein the alumina is filled in the entry end of the adsorbent bed, the silica gel or active carbon is filled in the exit end of the adsorbent bed, the adsorbent in TSA will also adopt alumina, silica gel and active carbon in a volume ratio of 1:2-10:2-10. Evacuation desorption technology is used in PSA, the adsorbent uses alumina and silica gel with a volume ratio of 1:3-10, an adsorbent pressure of 0.2-2.5 MPa(G), an evacuation pressure of -0.05- -0.09 MPa(G). The product methane is obtained in the adsorption step, and the method is suitable for purification and recovery of methane with higher purity from refuse landfill gas.

Description

Technical field: [0001] The invention relates to the method for separating, purifying and recovering mixed gas, in particular to the method for purifying and recovering methane from landfill gas. Background technique: [0002] Garbage is concentrated in the landfill, poured with bacterial starter and then covered with mucous membrane and soil. The gas produced by the degradation of organic matter in the garbage is called landfill gas (LFG). The composition of LFG is complex and varies with factors such as the stabilization process of the garbage, the degree of compaction, the composition and characteristics of the garbage, the hydrological quality of the landfill area, and the landfill method. The main component is CH 4 , N 2 , CO 2 and H 2 O, there are more than 140 other trace impurities. Typical composition table 1: [0003] main component Content v% Microcomponent Component Content (V10 -6 ) Component Content (V10...

Claims

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Application Information

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IPC IPC(8): C07C9/04C07C7/12
CPCY02E50/30
Inventor 李克兵殷文华刘丽王键武立新
Owner SOUTHWEST RES & DESIGN INST OF CHEM IND
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