Carbon dioxide conversion system used in coal-to-methanol process and working method thereof

Abstract

The invention discloses a carbon dioxide conversion system used in a coal-to-methanol process and a working method thereof, belonging to the technical field of the coal chemical industry. The system comprises a coal preparation unit, a coal gasification unit, a water gas conversion unit, a synthesis gas cooling unit, a low-temperature methanol washing unit, a synthesis gas-to-methanol unit, a water treatment unit, a waste heat power generation unit, an electrolytic hydrogen production unit, a CO2-to-methanol unit, a methanol rectification unit, a hydrogen collection unit, an oxygen collectionunit, an air separation unit and a sulfur recovery unit. According to the invention, CO2 generated in the coal-to-methanol process is converted into a methanol product on site; in-situ conversion of CO2 is realized, and a conversion product is CO2; low-temperature waste heat of the coal gasification and synthesis gas cooling units is adopted for power generation, so electric energy is provided forelectrolytic hydrogen production; pure oxygen generated in the electrolytic hydrogen production process is used for the coal gasification unit; and methanol yield is high, CO2 emission is low, equipment investment and operation cost are reduced, energy in the process is effectively utilized, energy is saved, and good application prospects are achieved.

Description

technical field [0001] The invention belongs to the technical field of coal chemical industry, and particularly relates to a carbon dioxide conversion system and a working method thereof in a coal-to-methanol process. Background technique [0002] With the rapid development of methanol industry, CO in methanol production 2 Emissions are also increasing. In the coal-to-methanol process, the unit product CO 2 Emissions are 3.4 to 5.4 tons of CO 2 / ton of methanol. Under the same production scale, the carbon emission of coal-based methanol production is nearly 8 times higher than that of natural gas production. Carbon emissions from coal-to-methanol production accounted for 53.38%, carbon emissions from fuel combustion in thermal power boilers accounted for 36.25%, and carbon emissions from net purchased electricity consumption accounted for 10.36%. It can be seen that direct carbon emissions are the main CO 2 Emission source, CO 2 There is a lot of room for emission re...

AI Technical Summary

Problems solved by technology

[0003] At present, in large-scale coal-to-synthetic ammonia and coal-to-methanol projects, a large amount of CO in tail gas 2 Due to the low concentration, it is directly vented, which not only causes a large amount of greenhouse gas emissions, but also causes CO 2 waste of resources

In order to recover the CO emitted from the exhaust gas 2 , can be recovered by PSA or MEA, MDEA, etc., and can even be directly compressed and returned to the raw gas, but this requires additional capture equipment and consumes a lot of energy

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