Method for using carbon dioxide as delivery gas and back flushing gas of coal powder instead of nitrogen in coal gasification methanol preparation process

Abstract

The invention relates to a method for performing gas delivery and ultrahigh pressure back flushing in a Shell coal gasification methanol preparation process. According to the method, when a methanol synthesis system runs, a low temperature methanol washing working section begins to absorb and concentrate CO2 in the synthesis gas, the absorbed CO2 is released through methanol regeneration, the CO2 is recovered and then sent to a compressor so as to be mixed with the N2 obtained through air separation, the mixed gas is pressurized to be used as the delivery gas and back flushing gas of coal powder, the delivery gas and back flushing gas and the coal powder are sent to a gasification furnace; and along with the increase of the CO2 content of the gasification furnace, the CO2 separated in the low temperature methanol washing working section increases gradually, and the amount of N2 in the compressor mixed gas is reduced gradually until CO2 completely replaces N2 to be used as the delivery gas and back flushing gas of coal powder. By adopting the method, the methanol yield can be increased in the methanol process, the CO2 gas emission can be reduced, simultaneously the problems that as a lot of N2 is involved in the reaction to generate ammonia nitrogen, the sewage treatment difficulty is increased and the environment is influenced can be solved, and the aims of reducing pollution and increasing the productivity and the production efficiency can be realized.

Description

technical field [0001] The invention relates to a coal gasification methanol production process, in particular to a method for gas transportation and ultra-high pressure backflushing in the Shell coal gasification methanol production process. Background technique [0002] In the Shell coal gasification industry, especially in the normal production process of the gasifier, pulverized coal is transported from the pulverization system to the pulverized coal storage bin, and from the pulverized coal storage bin into the pulverized coal discharge tank is by gravity flow. After the work is completed, the pulverized coal discharge tank is isolated from all low-pressure equipment and pressurized until the pressure in the tank is the same as that of the pulverized coal feed tank. After that, the balance valve and connecting valve between the two tanks are opened successively, and the pulverized coal is discharged The pulverized coal discharge tank enters the pulverized coal feed tank...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention: In order to solve the waste and adverse effects caused by the use of a large amount of nitrogen in the initial process of coal gasification to methanol, the present invention provides a Shell coal gasification methanol process that reduces energy consumption and pollution and improves coal gasification efficiency. Methods of Gas Delivery and Blowback

Images