NOVELTY - Pyrolysis of feedstock involves supplying it into an inner hopper; introducing the feedstock into and moving the feedstock through a reactor tube by a rotating auger; and heating the feedstock within the reactor tube to a temperature, such that pyrolysis occurs to produce a residual carbonized feedstock. The generated heat is transferred to the incoming feedstock within a hopper through which feedstock is introduced into reactor tube.    USE - For pyrolysis of feedstock, e.g. biomass including wood chips, newspaper, mixed waste paper, peat, energy crops, agricultural residues, coal, tire chips, plastics, or RDF (claimed) to convert to more valuable gaseous liquid or solid form for energy generation, medical applications, food process applications or production of solvents, colorants, disinfectants, fumigants or other specialty chemicals.    ADVANTAGE - The novel method provides simple indirect heating of the solid fuel which is to be gasified.    DETAILED DESCRIPTION - Pyrolysis of feedstock involves supplying the feedstock into an inner hopper; introducing the feedstock into and moving the feedstock through a reactor tube (2) by a rotating auger; heating the feedstock within the reactor tube to a temperature such that pyrolysis occurs to produce a residual carbonized feedstock, where the heat is generated by a combustion chamber (6), gas heat, electric coil oven, or electric tube furnace; and collecting the residual carbonized feedstock exiting the reactor tube in a pressure vessel. The feedstock comprises biomass including wood chips, newspaper, mixed waste paper, peat, energy crops, agricultural residues, coal, tire chips, plastics, or refuse derived fuel (RDF). The feedstock is introduced into the reactor tube from the inner hopper. The residual carbonized feedstock exits the reactor tube via an exit orifice of the reactor tube and enters the pressure vessel. The pressure generated in the pressure vessel forces the flow of gases of pyrolysis upward through the reactor tube and through the incoming feedstock in the inner hopper, such that the feedstock in the inner hopper acts as a filter and heat generated by the heat source is transferred to the incoming feedstock within the inner hopper.    DESCRIPTION OF DRAWING(S) - The figure shows a gasifier incorporating a pressure vessel char-ash collector, as used in the above method.    Reactor tube (2)    Reactor tube walls (3)    Combustion chamber (6)    Grate (7)    Blower (9)    Ash receptacle (11)    Inner tube (21)    Separator (27)    Outlet (28)    Exit orifice (29)    Valve (32)    Outer surface of gasifier (40, 41)    Flame guard plenum (42)    Opening (43)    Funnel wall (44)    Outlet (50)    Under-fire air (52)    Pipes (53)    Apertures (54)    Burner (55)