NOVELTY - System (1) for processing carbonaceous in-feed material comprises pyrolyzer kiln (3) for pyrolysis of carbonaceous in-feed material, in which in-feed material is pyrolyzed in the kiln in order to produce primarily gaseous output fraction; steam reformer positioned downstream of kiln to which combustion gases from pyrolyzer kiln are fed; water scrubber (7) positioned gas flow-wise downstream of steam reformer; a methanation stage; carbon dioxide scrubbing stage; where system includes unit for splitting gas and directing portion of split gas back to pyrolyzer kiln.    USE - For processing carbonaceous in-feed material, particularly for processing of solid carbonaceous material e.g. carbonaceous waste such as biomass, mixed municipal waste, organic waste, coal or refuse-derived-fuel (RDF), to produce synthetic natural gas (SNG).    ADVANTAGE - The system results in the evolution of gaseous product that has sufficiently high calorific value to enable its use as fuel such as synthetic natural gas (Syngas or SNG) fuel. The system is highly efficient and suitable for application in relatively small scale situations e.g. for producing fuel for use in generation systems of the order of 10MW. This efficiency is achieved by splitting proportion of processed gas and diverting to the gas burner of kiln, also by using indirect fired rotary kiln, and closely controlling process parameters to ensure that sufficient moisture is present in the material to enable steam reforming using moisture content of the gas alone without the need to add steam at the reformer stage.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for processing carbonaceous in-feed material involving feeding carbonaceous in-feed material into pyrolyzer kiln; slow pyrolyzing in-feed material in the kiln in order to produce primarily gaseous output fraction; directing the out-feed gas from the pyrolyzer kiln to steam reformer positioned downstream of the pyrolyzer kiln; directing out-feed gas via water scrubber stage, methanation stage and carbon dioxide scrubbing stage, each of which is positioned gas flow-wise downstream of steam reformer; splitting the gas and directing portion of split gas back to pyrolyzer kiln.    DESCRIPTION OF DRAWING(S) - The figure shows schematic flow diagram of process and system.    Processing system (1)    Pre-dryer (2)    Kiln pyrolyzer (3)    Scrubber (7)    Methanation stage (8)