Conversion of Organic Waste to Fuel Gas

The feasibility of a single-step process for the direct production of a synthetic natural gas from solid organic waste was investigated. Conversions were effected by injecting steam into a heated fixed bed of the organic waste that had been previously mixed with an alkali carbonate and nickel methanation catalyst. The alkali catalyzes the steam-carbon reaction while the nickel catalyzes hydrocracking and methanation reactions. Reaction conditions have been 550 to 725°C and 32 to 265 psia with various organic wastes and steam feed rates. No noticeable pressure effect upon product composition was observed. The product gas was composed predominately of methane, carbon dioxide, and hydrogen with a CO₂-free heating value generally in excess of 850 Btu/SCF. Carbon conversions of 50 to 90% were obtained with accompanying volume contractions of the solid wastes of 40 to 95%.