NOVELTY - Non-catalytic thermal decomposition of solid feedstock involves providing solid feedstock to thermal decomposition unit, moving feedstock through one or more gasification zone in the thermal decomposition unit with a moving device, and providing oxygen and optionally additional gas to the gasification zone. The feedstock is moved through the gasification zone, and oxygen is provided to the gasification zone at rate effective for maintaining a material bed temperature of 2300 degrees F or less at any point in the material bed, and for maintaining a material bed temperature of 500-2000 degrees F.    USE - Non-catalytic thermal decomposition of solid feedstock e.g. sewage sludge, animal waste, carbonaceous material, carbonaceous liquid product, polymer, waste polymer, polyethylene terephthalate, polystyrene, recycled carbonaceous industrial liquid, carbonaceous municipal solid waste, carbonaceous urban waste, carbonaceous agricultural material, carbonaceous forestry material, carbonaceous wood waste, carbonaceous construction material, carbonaceous vegetative material, carbonaceous industrial waste, carbonaceous fermentation waste, carbonaceous petrochemical co-product, carbonaceous alcohol production co-product, carbonaceous coal, tire, plastics, waste plastics, coke oven tar, fiber soft, lignin, black liquor, crop residue, energy crop, forest processing residue, wood processing residue, livestock waste, poultry waste, food processing residue, fermentative process waste, ethanol co-product, spent grain and spent microorganisms, for preparing syngas (all claimed) used as fuel source and intermediate for producing synthetic natural gas, ammonia and methanol.    ADVANTAGE - The method enables effective non-catalytic thermal decomposition of solid feedstock by reducing formation of agglomerate and hot spots, controlling amount of oxygen and residence time of feedstock material, and improving oxygen dispersion. The carbonaceous material feed is treated with molecular oxygen to initiate and facilitate chemical transformation of carbonaceous material. The syngas prepared by non-catalytic thermal decomposition of solid feedstock has excellent quality.