Biogas purification method and system

Abstract

The invention relates to a marsh gas purification method and a system thereof. The method comprises the following steps: keeping pressure below the pressure for the production of methane hydrate for the purpose of enabling carbon dioxide to react with sulfureted hydrogen to produce hydrate, and then separating methane gas from marsh gas. The marsh gas purification system comprises a marsh gas separating tank 6 and a marsh gas storage tank 1; liquid water is stored in the marsh gas separating tank 6; the marsh gas storage tank 1 is communicated with a compressor 2 through a pipeline equipped with a valve; the compressor 2 is communicated with the marsh gas separating tank 6 through a pipeline equipped with a valve; a refrigeration pipe 7 is coiled on the inner wall of the marsh gas separating tank 6; two ends of the refrigeration pipe 7 are mounted respectively on a refrigerator 8 positioned outside the marsh gas separating tank 6; the marsh gas separating tank 6 is communicated with a methane storage tank 9 through a pipeline equipped with a valve; and a marsh gas sampler A, a pressure sensor P, and a temperature sensor T are separately mounted on the marsh gas separating tank 6.

Description

Technical field [0001] The invention relates to a purification and separation technology of biogas. Background technique [0002] Biogas is a high-quality, high-efficiency, green, and environmentally friendly fuel. Its main components are 60 to 70% methane, 30 to 40% carbon dioxide, and 0.5 to 1.5% hydrogen sulfide. Carbon dioxide is a greenhouse gas and affects the combustion efficiency of biogas; hydrogen sulfide is a highly toxic gas, which not only causes corrosion of pipelines and equipment, but also endangers people's health. [0003] At present, a step-by-step purification method is generally used to prepare high-purity methane gas from biogas, that is, first remove one of carbon dioxide and hydrogen sulfide gas, and finally remove the remaining other. The pressure swing adsorption method and the water washing method are commonly used to remove carbon dioxide from the biogas. The main methods for removing hydrogen sulfide in biogas include dry, wet, and biological removal ...

AI Technical Summary

Problems solved by technology

Carbon dioxide is a greenhouse gas that affects the combustion efficiency of biogas; hydrogen sulfide is a highly toxic gas that not only causes corrosion of pipelines and equipment, but also endangers people's health

However, due to the large difference in the physical properties of carbon dioxide and hydrogen sulfide gas, it is impossible to use a technical method to remove hydrogen sulfide and carbon dioxide at one time to obtain high-purity methane gas

The prior art methods and devices not only need to be carried out step by step, the process is relatively complicated, the consumption of water resources is large, and the separation effect is not ideal, which limits the large-scale industrial application of biogas

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