System and process for preparing olefin by taking coal and coke-oven gas as raw materials

Abstract

The invention belongs to the technical fields of energies and chemical industry, and discloses a system and a process for preparing olefin by taking coal and coke-oven gas as raw materials. The system for preparing olefin by taking coal and coke-oven gas as raw materials comprises a water-coal-slurry preparation unit, a coal gasification unit, a synthesis gas purification unit, a methanol synthesis unit, an olefin synthesis unit, a coke-oven gas separation unit, a methane dry-reforming unit, a methane vapour reforming unit and a gas mixer. By using the system for preparing olefin, hydrogen separated by the coke-oven gas separation unit, methane dry reforming synthesis gas, methane vapour reforming synthesis gas and the clean synthesis gas generated by the coal gasification unit can be mixed, the hydrogen-carbon ratio of the synthesis gas is adjusted to meet the requirements of methanol synthesis so as to synthesize methanol, and then olefin is synthesized. By adopting the device and the process disclosed by the invention, the emission amount of CO2 during the existing coal-to-olefin process can be decreased, the energy utilization ratio can be increased, and the exhaust emission of the industrial coal coking industry can be reduced.

Description

technical field [0001] The invention belongs to the technical field of energy and chemical industry, and specifically relates to a system and process for producing olefins by using coal and coke oven gas as raw materials. Background technique [0002] Alkenes are important platform chemicals. In recent years, the world's olefin production capacity and demand have grown rapidly, especially in China. However, China's ethylene self-sufficiency rate is only about 50%, and the supply of olefins is seriously insufficient. The olefin production process is mainly the cracking or pyrolysis of alkanes, naphtha and gasoline, so olefin production is heavily dependent on petroleum, and the proportion of olefin production from naphtha accounts for 85% of the world's olefin production. Petroleum accounts for 16.2% of China's energy structure, while coal accounts for 74.7%. Therefore, the development of coal to replace petroleum to olefins technology is the main development trend in the f...

AI Technical Summary

Problems solved by technology

[0004] There are two main problems in the existing coal-to-olefins process: first, the energy consumption of the coal-to-olefins process is twice that of the traditional petroleum cracking route; second, the CO 2 Emissions are 5-6 times higher than conventional petroleum routes

China's annual output of coke oven gas is about 35 billion standard cubic meters. However, except for 20% being directly burned as fuel, most of the coke oven gas is directly discharged into the atmosphere, wasting a lot of resources

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