Method and device for separating carbon dioxide in marsh gas compression and filling system

Abstract

The invention relates to a method for separating carbon dioxide in a marsh gas compression and filling system, which comprises steps as follows: an existing reciprocating marsh gas compressor is utilized to control the temperature in the first-stage cylinder to be higher than the critical temperature and partial pressure of carbon dioxide when the marsh gas filling system is separating carbon dioxide; the pressurized marsh gas gets out of a four-stage cooler, enters a cooling coil device to be cooled and liquified, and enters a high-pressure gas-liquid separator together with gas-state methane so as to be subjected to gas-liquid separation; and the separated carbon dioxide is diverted into a steel cylinder to be collected, and the methane gas enters a filling guide tube to be canned. The removal rate of the carbon dioxide by the method for separating carbon dioxide in a marsh gas compression and filling system is up to more than 99%; the marsh gas which is purified and compressed can achieve the quality of natural gas; and meanwhile, the industrial raw material carbon dioxide is provided, so that the natural resource is fully utilized. The invention has the advantages of simple equipment structure and energy saving, is convenient to operate, lowers the cost, and is beneficial to popularization.

Description

technical field [0001] The invention relates to a biogas purification and utilization technology, in particular to a method and a device for separating carbon dioxide in a biogas compression filling system. Background technique [0002] With the rapid economic development, the supply of energy is becoming increasingly tense. As a renewable biomass energy, biogas has attracted more and more attention. The main component of biogas is methane, which is similar to natural gas. Therefore, it is possible to purify and compress biogas, make it meet the quality standard of natural gas, fill it into bottles, and replace natural gas and liquefied petroleum gas for residents to use. This is beneficial to energy conservation and environmental improvement. important strategic significance. The main tasks of biogas concentration and purification include: removal of hydrogen sulfide, removal of carbon dioxide, dehydration, pressurization and transportation. Since the content of carbon d...

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Problems solved by technology

The solvent absorption method is mainly suitable for the treatment of gas sources with low carbon dioxide content in the gas. Its separation effect is good, and high-purity carbon dioxide gas of 99.99% can usually be obtained, but the investment cost is large, the energy consumption is high, and the economy is poor; low temperature distillation The method is suitable for treating gas sources with high carbon dioxide content in the gas (generally, the carbon dioxide content is greater than 60%), but the investment in the process equipment is large, the energy consumption is high, and the separation effect is not good, so this method is rarely used at present; the membrane separation method The process is simple, easy to operate, advanced technology, low energy consumption, good economy, the investment is only half of the solvent absorption method, but the purity of carbon dioxide obtained by this method is low

Pressure swing adsorption (PSA), the process is simple, low energy consumption, and no major corrosion problems, when the carbon dioxide content is less than 50%, the operation process of PSA technology is more economical, but the initial investment is high, when the carbon dioxide content is greater than 90% %, it is far beyond the economic use range of pressure swing adsorption, and it is not suitable to use PSA technology

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