Heat integration in coal gasification and methanation reaction process

A combined Gasification, methanation and power island with steam turbine system, the system comprising:

• a methanation portion, the methanation portion including:
• a first methanation reactor having an input configured to receive synthesis gas and an output;
• a second methanation reactor having an input coupled to output of the first methanation reactor and an output;
• a third methanation reactor having an input coupled to the output of the second methanation reactor and an output;
• and
• a low-pressure superheater coupled between the second reactor and the third reactor that heats low-pressure steam;
• a steam turbine portion, the steam turbine portion including:
• a low-pressure steam turbine having an input coupled to an output of the low-pressure superheater.