Method for producing methane by catalytic gasification of coal and device thereof

A process for preparing methane by catalytically gasifying coal, comprising steps:

• (a) providing a gasifier comprising a syngas generation section, a coal methanation section, a syngas methanation section and a coal pyrolysis section, and carrying out methanation reaction by reacting the coal with a syngas-including gas stream coming from the syngas generation section in the presence of coal methanation catalyst in the coal methanation section, so as to generate a methane-containing gas stream and reacted char;
• (b) the reacted char enters downwardly the syngas generation section and reacts with a gaseous oxidant introduced into the syngas generation section, producing the syngas-including gas stream and ash residues, wherein the syngas-including gas stream enters upwardly the coal methanation section to carry out step (a), while the ash residues exit the gasifier;
• (c) the methane-containing gas stream from step (a) enters upwardly the syngas methanation section, and the syngas is subjected to methanation reaction in the presence of a syngas methanation catalyst to produce additional methane, so as to obtain a gaseous product containing more methane;
• and,
• (d) the gaseous product containing more methane enters upwardly the coal pyrolysis section and heats the coal introduced into the coal pyrolysis section to pyrolyze the coal and produce additional methane, and all gases in this section exit the gasifier, while the pyrolyzed coal moves downwardly along the gasifier,
• wherein solid materials move from top to bottom, and finally exit the gasifier via an ash residue exit at the bottom of the gasifier, while gaseous materials move from bottom to top, and finally exit the gasifier via a gas exit at the top of the gasifier;
• in the gasifier the solid materials contact with the gaseous materials basically in counter current mode.

A gasifier for preparing methane by catalytically gasifying coal, which comprises a syngas generation section, a coal methanation section and a syngas methanation section in the order from bottom to top, wherein,

• the coal methanation section is used to carry out methanation reaction by reacting the coal with a syngas-including gas stream coming from the syngas generation section in the presence of coal methanation catalyst, so as to generate a methane-containing gas stream and reacted char;
• the syngas generation section is used to react the reacted char from coal methanation section with a gaseous oxidant introduced into the syngas generation section, producing the syngas-including gas stream and ash residues, wherein the syngas-including gas stream enters upwardly the coal methanation section, while the ash residues exit the gasifier;
• the syngas methanation section is used to let the syngas in the methane-containing gas stream from the coal methanation section to be subjected to methanation reaction in the presence of a syngas methanation catalyst to produce additional methane, so as to obtain a gaseous product containing more methane, wherein solid materials move from top to bottom, and finally exit the gasifier via an ash residue exit at the bottom of the gasifier, while gaseous materials move from bottom to top, and finally exit the gasifier via a gas exit at the top of the gasifier;
• in the gasifier the solid materials contact with the gaseous materials basically in counter current mode.