Process of converting hydrogen sulfide and carbon dioxide to methane and solid sulfur on carbon-based catalysts under milder conditions with reduced carbon footprint

A method for producing methane gas and solid sulfur, comprising:

• separating a feed stream comprising mixed hydrocarbons to produce a liquid stream comprising liquid mixed hydrocarbons and a gas mixture stream comprising carbon dioxide, methane, and hydrogen sulfide;
• separating the gas mixture stream using an acid gas removal system to produce a methane product stream and a reactant gas stream, wherein the reactant gas stream comprises carbon dioxide and hydrogen sulfide;
• reacting the carbon dioxide and the hydrogen sulfide from the reactant gas stream in a catalytic reactor using a carbon-based catalyst, producing an effluent methane stream, an effluent sulfur stream, and a waste stream, wherein the waste stream comprises produced sulfur dioxide, and unreacted carbon dioxide and unreacted hydrogen sulfide;
• producing an effluent stream comprising hydrogen sulfide, carbon dioxide and sulfur dioxide and a recovered sulfur stream using a sulfur recovery system downstream of the catalytic reactor configured to receive the waste stream;
• receiving the effluent stream comprising hydrogen sulfide, carbon dioxide and sulfur dioxide and producing a recycle stream comprising hydrogen sulfide and carbon dioxide and a residual sulfur dioxide stream using a tail gas treatment system downstream of the sulfur recovery system;
• incinerating the residual sulfur dioxide stream before venting to atmosphere using an incinerator unit downstream of the tail gas treatment system;
• and
• receiving, with a hydrogen sulfide-methane reforming system downstream of the catalytic reactor, the methane product stream and a portion of the waste stream comprising sulfur dioxide, unreacted carbon dioxide, and unreacted hydrogen sulfide.

A system for producing methane and sulfur, comprising:

• a first separation system configured to receive an inlet gas stream comprising methane, hydrogen sulfide, water vapor, and oxygen and separate the water vapor and the oxygen to produce a separated hydrogen sulfide stream comprising a first portion of separated hydrogen sulfide and a second portion of separated hydrogen sulfide, a separated methane stream, and a separated carbon dioxide stream;
• a catalytic reactor configured to react the separated carbon dioxide stream and the first portion of separated hydrogen sulfide using a carbon-based catalyst, producing a produced methane stream and a produced sulfur stream;
• and
• a hydrogen sulfide-methane reforming system downstream of the catalytic reactor configured to receive the produced methane stream, and the second portion of separated hydrogen sulfide.