NOVELTY - The comminuted cellulosic is soaked in inorganic alkali solution. It is introduced into a conveyor (6), where it is heated to 250degreesC forming a foamed carbonaceous material, which is finely-ground. This is burned together with gases formed, in preheated air under reducing conditions, to produce a carbon monoxide-, hydrogen- and hydrocarbon-rich synthesis gas which is cooled and cleaned in a scrubber (9).    USE - To make synthesis gas from cellulosics, optionally producing electrical energy. The term cellulosics covers a wide range, e.g. wood, agricultural waste, straw, brush- or coppice wood, sludges, shells, stones, yeasts, vegetation, waste paper and card.    ADVANTAGE - The plant produces high quality synthesis gas and electrical energy from renewable, raw or waste materials. Heat and alkali are recycled in the process as described, for economical operation. The foamed cellulosic material produced is readily comminuted to fine size, for excellent entrainment into the rich combustion process forming gases. Quenching the gases, mitigates against dioxin formation.    DETAILED DESCRIPTION - Preferred features: The cellulosics are steeped in 25% (or stronger) potassium carbonate and/or potassium bicarbonate solution, added cold in the ratio 300-500 ml/kg. Treated material is transferred by a screw conveyor, comminuted and heated in countercurrent, using recycled heat. The foamed hydrocarbon is comminuted to granules, 10 mum to 100 mum in size. Temperature following combustion, is controlled by air fed along the casing of the combustion chamber (8). Cooling takes account of the desired water gas- and Boudourard reaction processes. Air so preheated, is used for combustion. Cooled, cleaned synthesis gas is supplied to an internal combustion engine (10) driving an electrical generator, the waste heat being used to heat the wood. Comminution takes place in at least two stages (1, 2), to a grading of 10 mm - 50 mm. Metallic and other inorganic content is removed ahead of comminution. Solids are separated from the wash fluid which is used to steep the comminuted cellulosic, forming the inorganic alkaline solution cited. The hot synthesis gas is fed to a quencher.    DESCRIPTION OF DRAWING(S) - The plant schematic selected, clearly reveals the process, and is accompanied by a block flow diagram in the disclosure.    initial two-stage comminution (1, 2)    hot conveyor (6)    combustion chamber (8)    internal combustion engine (10)    scrubber (9)