Abstract: The invention provides processes and systems for generating heat from a carbon-containing material or converting a carbon-containing material to a combustible gaseous fuel, comprising (a) pyrolysing the material in a reactor to produce a carbon-enriched solid and a first gaseous product, (b) burning at least part of the first gaseous product and/or a second gaseous product obtained by reacting the carbon-enriched solid with water vapour to generate heat, and (c) returning combustion products from the burning step to the reactor and/or removing part of the first gaseous product and/or the second gaseous product as a combustible fuel.