Method and device for continuous separation of methane, carbon dioxide and hydrogen sulfide from biogas by hydrate method

Abstract

The present invention provides a method for continuous separation of methane, carbon dioxide and hydrogen sulfide from biogas by hydrate method, and a three-stage gas separation device for implementing the method. High purity methane is separated by a first stage hydrate dissociation tower working at the temperature of 273.7K-283.1K and under the pressure of 1.324MPa-4.502MPa, high-purity carbon dioxide is separated by a second stage hydrate dissociation tower working at the temperature above 272.8K-288.7K and under the pressure of 0.093MPa-0.499MPa; high-purity hydrogen sulfide is separated by a third stage hydrate dissociation tower working at the temperature above room temperature and under the pressure above atmospheric pressure, and the three-stage gas separation device can be controlled by a written program by a computer to run automatically and select the proper working condition. The gas-liquid contact efficiency, hydrate formation rate, separation process target gas recovery rate and gaseous product purity are improved, hydrate formation heat removal is enhanced, high pressure hydrate system gas, liquid and solid three-phase automatic separation can be achieved, and the method can replace the existing technology, and can be used in production of continuous separation of methane, carbon dioxide and hydrogen sulfide from biogas by industrialized hydrate method.

Description

technical field [0001] The invention relates to the separation and purification of mixed gas, and more to a method and a device for continuously separating and purifying methane, carbon dioxide and hydrogen sulfide from biogas by using a hydrate method. technical background [0002] The main component of biogas produced by biogas digesters is methane. Biogas is composed of 50% to 80% methane (CH 4 ), 20% to 40% carbon dioxide (CO 2 ), 0% to 5% nitrogen (N 2 ), less than 1% hydrogen (H 2 ), less than 0.4% oxygen (O 2 ) and 0.1% to 3% hydrogen sulfide (H 2 S) and other gases. Hydrogen sulfide (H 2 S) has many uses, 0.1% ~ 3% hydrogen sulfide (H 2 S), although the content of biogas per cubic meter is only 1-12 grams, it forms sulfuric acid with water to corrode our gas equipment, and when its concentration in the air exceeds 0.1%-0.2%, it can quickly cause death , is a highly toxic gas, so the existing biogas technology must desulfurize it. carbon dioxide (CO 2 ) is ...

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Problems solved by technology

Hydrogen sulfide (H 2 S) has many uses, 0.1% ~ 3% hydrogen sulfide (H 2 S), although the content of biogas per cubic meter is only 1-12 grams, it forms sulfuric acid with water to corrode our gas equipment, and when its concentration in the air exceeds 0.1%-0.2%, it can quickly cause death , is a highly toxic gas, so the existing biogas technology must desulfurize it

carbon dioxide (CO 2 ) is chemically non-combustible and does not support combustion. It is used as a fire extinguishing agent, gas fertilizer, medicine, etc. It is one of the main gases that cause the greenhouse effect. It accounts for a large percentage of it, although it will not corrode our gas equipment, but if it is not separated from the biogas for utilization, in addition to causing waste of resources and emitting greenhouse gases, it will also take away a large amount of heat from the combustion of biogas, which is not conducive to energy conservation and emission reduction

The method and biogas digester for industrialized large-scale production of biogas have been researched, but the existing separation technology cannot meet the requirements. How to solve the four major technical problems and design a matching separation device to continuously industrialize the separation of methane, carbon dioxide, and hydrogen sulfide in biogas It has become an urgent technical problem for human beings to solve

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