System and process for production of synthesis gas

A process for production of a synthesis gas, comprising:

• in a synthesis gas generation reactor producing a first synthesis gas from a hydrocarbon feed stream;
• supplying a CO2 rich gas stream into a mixing zone of a post converter via a conduit, where said post converter comprises a shell housing a catalyst, where said CO2 rich gas stream in said conduit upstream said mixing zone is in heat exchange relationship with gas flowing over catalyst prior to mixing said CO2 rich gas stream with at least part of the first synthesis gas in said mixing zone,
• supplying said at least a part of the first synthesis gas from said synthesis gas generation reactor into a mixing zone of said post converter via a pipe, thereby combining said at least part of the first synthesis gas and said CO2 rich gas stream to a mixed gas, where said post converter, said catalyst being active for catalyzing steam methane reforming, methanation and reverse water gas shift reactions, and where said mixing zone is upstream said catalyst,
• producing a product synthesis gas from said mixed gas by carrying out steam methane reforming, methanation and reverse water gas shift reactions over said catalyst, and
• outletting said product synthesis gas from said post converter.