Process and plant for the production of a methane-containing synthetic natural gas stream

Process for the production of a methane-containing synthetic gas stream comprising the steps of:

• a) Providing a feed gas (101) comprising CO and/or CO2 as a carbon source (103) and H2 as a first hydrogen source (105);
• b) Adjusting the temperature of the feed gas (101) of step a) to a temperature T1 between 150° C. and 300° C.;
• c) Reacting the feed gas (110) of step b) in a methanation reactor (111) to produce heat and a raw synthetic gas (115) comprising methane and CO2, wherein the methanation reactor (111) comprises a catalyst (113) comprising a compound selected from the group consisting of Ni, Co, Fe, Pd, Pt, Ru, Rh and combinations thereof;
• d) Transporting the raw synthetic gas (115) to a separation unit 119 comprising an absorption medium, wherein the separation unit is an amine scrubber 121 and the absorption medium is an amine solution (122);
• e) Separating the raw synthetic gas (115) in the separation unit (119) into a methane-enriched synthetic gas stream (125) and a CO2-saturated absorption medium (129);
• f) Regenerating the CO2-saturated absorption medium (129) by increasing the temperature of the CO2-enriched absorption medium (129) using the heat produced in the methanation reactor to produce a regenerated CO2-depleted absorption medium (131) and an exhaust gas stream (127) comprising CO2,
• wherein the heat from the methanation reactor (111) is transferred to the separation unit (119) with the aid of a heat transfer device (133) comprising a heat exchanger (137) and water as a heat transfer medium (141, 143, 145, 147);
• wherein the heat transfer device (133) comprises a first loop (135) connecting the methanation reactor (111) with the heat exchanger (137) and a second loop (139) connecting the separation unit (119) with the heat exchanger (137).