High-efficiency underground coal synthesis gas ground treatment process

Abstract

The invention belongs to the technical field of underground coal synthesis gas treatment processes, and particularly relates to a high-efficiency underground coal synthesis gas ground treatment process, wherein the process comprises the steps: step 1, removing dust and oil, introducing synthesis gas into a gravity cyclone separator to separate solid impurities and coal tar in the synthesis gas, and washing in a water washing tower with water to obtain raw material gas; step 2, absorbing CO2 in the raw material gas by adopting an MDEA decarbonization device to obtain decarbonized gas; step 3, recycling acid gas generated by the MDEA decarbonization device in the step 2 to obtain sulfur and liquid carbon dioxide; step 4, pressurizing the decarburized gas obtained in the step 2 to obtain pressurized gas; step 5, dehydrating the pressurized gas by adopting a two-tower isobaric molecular sieve dehydration process to obtain dehydrated gas; and step 6, cooling the dehydrated gas, carrying out dehydrogenation treatment, after dehydrogenation treatment, condensing and liquefying the dehydrated gas into liquefied natural gas, and recovering the hydrogen-containing mixed gas after dehydrogenation to obtain a methanol raw material. The process has the advantages of being low in energy consumption, high in overall resource utilization rate and remarkable in economic benefit.

Description

technical field [0001] The invention belongs to the technical field of underground coal synthesis gas treatment technology, and in particular relates to a high-efficiency underground coal synthesis gas surface treatment process. Background technique [0002] Underground coal gasification technology is the controlled combustion of underground coal, which generates combustible gas (mainly composed of H 2 , CO, CO 2 、CH 4 etc.), which integrates the three major processes of well construction, coal mining, and surface gasification, and changes traditional physical coal mining into chemical coal mining. Underground coal gasification technology can not only recover abandoned coal resources in mines, but also can be used for thin coal seams, deep coal seams, "three-down" coal pressure and high sulfur, high Ash and high-gas coal seams; underground gasification ash remains in the gasification area, which reduces surface subsidence, no solid matter discharge, and the gas can be pur...

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Problems solved by technology

[0003] The main characteristics of underground coal synthesis gas: the temperature of incoming gas from the wellhead is high (>200°C), the saturated water content is large (above 50%), sewage needs to be recycled and reused, and the components are complex (high content of CO 2 , high H 2 , containing coal tar, containing dust impurities, etc.), of which CO 2 If the content exceeds 50%, it is difficult to decarbonize; the current underground coal synthesis gas treatment process is not perfect, the energy consumption of the device is high, the overall utilization rate of resources is low, and the economic benefits are not good

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