A method for continuously separating biogas by pressure swing adsorption

Abstract

A method of continuously separating biogas through pressure swing adsorption (PSA). In the invention, by means of a characteristic that an absorption material has a huge difference on adsorbing capacity of carbon dioxide and methane at room temperature under normal pressure, the biogas can be adsorbed and separated selectively, thereby increasing the value of biogas. The method includes the technical steps of (1) compressing dewatered and desulfurated biogas and storing the biogas in a buffer pot for a short time; (2) feeding the biogas into an absorption column to adsorb and separate the biogas at normal temperature and under normal pressure through the adsorption and separation of a 5A molecular sieve on the biogas inside the absorption column, and continuously producing high-purity methane. In the invention, the 5A molecular sieve is combined with the PSA technology and the method is applied in biogas separation and purification, so that the biogas can be effectively and continuously separated and purified. The method can produce the high-purity methane (98%) which has a potential of being applied as compressed natural gas used in vehicle. The method is high in purification efficiency, is simple in technical process, is low in energy consumption and has a wide application prospect.

Description

(1) Technical field [0001] The invention relates to comprehensive utilization of biogas purification and purification, in particular to a method for continuously separating biogas by pressure swing adsorption and preparing high-purity methane gas. (2) Background technology [0002] In order to improve the environment and alleviate the energy crisis, more and more people pay attention to the green resource—methane (CH 4 ). CH in nature 4 often accompanied by CO 2 Generate and form mixed gases such as natural gas, biogas, landfill gas, and coalbed methane. Studies have shown that the calorific value of natural gas containing 90% methane is 32.95MJ / Nm 3 , while the calorific value of landfill gas containing about 50% methane drops to 19.70MJ / Nm 3 . Not only CO 2 Will reduce the overall calorific value of the gas mixture and, in the presence of water, will also cause corrosion of the pipes. Therefore from CO 2 、CH 4 CO removal from mixed gas 2 is of great significance...

AI Technical Summary

Problems solved by technology

At present, the adsorption materials that have been studied include carbon molecular sieves, zeolite molecular sieves, inorganic or organic metal composites, activated alumina, etc., and there are many methods and devices that can separate and purify biogas, most of which require a pressure of 0.5MPa and above. Adsorption and separation of biogas, compressed gas requires additional energy input, which increases production costs, and a large amount of information found that the methane gas content obtained by purifying biogas is up to about 95%. Further separation and purification are needed to increase the methane concentration and product value, but also increases the cost

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