Method for preparing hydrogen by coal gasification

Abstract

The invention relates to a method for preparing hydrogen by coal gasification. The method for preparing hydrogen includes the following steps: (1) thermal cracking of coal is carried out under the condition of isolating from air and at the temperature of 900 DEG C to essentially obtain coal thermal cracking gas, tarre and coal coke, and the coal thermal cracking gas and the tarre are removed to obtain the coal coke; (2) at the temperature below 800 DEG C, a gasifying agent is used for gasifying the coal coke obtained from the step (1) to obtain coal coke gas, and the obtained coal coke gas is purified to obtain a target object. In the invention, a 'two-stage type' gasifying method is adopted for gasifying coal, and the obtained coal coke gas (the coal coke gas contains about 70v / v% of hydrogen, less than 3v / v% of carbon monoxide and no methane) is used as the 'raw material gas' for preparing hydrogen. Therefore, a methane catalytic reforming technique and a carbon monoxide conversion process in a post treatment process can be omitted, and a beforehand desulfuration process required in these techniques can also be omitted, that is to say, pure hydrogen can be prepared only after the processes of removing acidic gas and purifying a little residual gas.

Description

technical field [0001] The invention relates to a method for preparing hydrogen, in particular to a method for preparing hydrogen by gasification of coal. Background technique [0002] The key process of coal hydrogen production is the coal gasification process. Existing coal gasification technologies (or devices) include: Lurgi moving bed gasifier, Winkler fluidized bed gasifier, Kopper-Totzek and Shell entrained bed with dry feed Gasifier, as well as Texaco with wet feed and entrained bed gasifier developed by Huatong East China University of Science and Technology and other units. [0003] The gas products obtained by the above-mentioned coal gasification technology (or device) contain hydrogen, carbon monoxide, carbon dioxide, methane, nitrogen and a small amount of hydrogen sulfide gas, etc., and the content of hydrogen is very low. Therefore, in order to produce hydrogen with higher purity, a conversion and separation process with lengthy steps and harsh process cond...

AI Technical Summary

Problems solved by technology

Although this method improves the purity of hydrogen, its disadvantages are: the conversion rate of coal char is low, and the methane content in the gas product is high (methane will generate carbon monoxide in the catalytic reforming conversion process)

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