TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: In converting the biomass feedstock into the product hydrocarbon, generating at least a portion of the hydrogen comprises generating substantially all of the hydrogen needed for step (b) by reaction between steam and a portion of the pyrolysis gas. The method further comprises generating at least a portion of the hydrogen at a reaction temperature T( degrees C), and at a reaction total pressure P(bara) correlated with the reaction temperature T by the relation: log10P=A(T-To), where To is in the approximate range of 400 degrees C less than To less than 600 degrees C, and empirical parameter A is in the approximate range of 0.05 less than A less than 0.10, where A is about 0.06 and To is about 540 degrees C. The product hydrocarbon is mainly methane and converting at least a portion of the pyrolysis gas to product hydrocarbon and carbon dioxide comprises a methanation step performed over a catalyst. Generating at least a portion of the hydrogen comprises a steam reforming step performed over the same catalyst as in the methanation step. The method as well comprises regenerating the catalyst to remove coke, where generating the catalyst comprises contacting the catalyst with steam or superheated steam. Regenerating the catalyst comprises an oxidative regeneration step performed by contacting the catalyst with steam and air or enriched oxygen. The method also comprises providing the catalyst in any of the following reactor configurations so that the catalyst will cycle between reaction zones for steam reforming, methanation and regeneration steps: (a) moving bed with granular catalyst; (b) fixed bed with granular packing or monolithic catalyst, and rotary or directional valve logic for cyclically switching beds between reaction and regeneration steps; and (c) bubbling or circulating fluidized bed. In the cyclic catalytic method for converting the biomass feedstock into the product hydrocarbon, the higher temperature is 600-900 degrees C. The lower temperature is 400-600 degrees C. The catalyst contained in any of the following reactor configurations so that the catalyst cycles between reaction zones for steam reforming, methanation and oxidative regeneration steps: (a) moving bed with granular catalyst; (b) fixed bed with granular packing or monolithic catalyst, and rotary or directional valve logic for cyclically switching beds between reaction and regeneration steps; and (c) bubbling or circulating fluidized bed. The biomass feedstock is converted into the product hydrocarbon by: (a) subjecting the feedstock to rapid pyrolytic heating in substantial absence of oxygen in order to generate fractions of pyrolysis gas and char; (b) catalytically converting at least a portion of the pyrolysis gas to the product hydrocarbon and carbon dioxide in the presence of hydrogen and steam; (c) generating substantially all of the hydrogen for converting at least a portion of the pyrolysis gas to the product hydrocarbon and carbon dioxide by reaction between steam and a portion of the pyrolysis gas or the hydrocarbon; (d) separating the carbon dioxide; and (e) separating recycle hydrogen from the hydrocarbon product. Preferred System: In the system, the fast pyrolysis means includes a hydrogen sweep gas. A portion of the hydrogen is produced in a steam reforming zone. The hydrocarbons converted over the catalyst are mainly methane, and the catalyst is in a methanation zone. The same catalyst is used in the steam reforming and methanation zones. The regeneration means for heating and regenerating the catalyst in a regeneration zone. The system has means for cyclically circulating or switching the catalyst between the steam reforming, methanation and regeneration zones. The catalyst is supported in fixed beds with switching valves to establish the steam reforming, methanation and regeneration zones to which each bed is cycled. The fixed beds containing the catalyst are mounted in a rotor with rotary valve ports sealingly engaged with fixed ports to establish the steam reforming, methanation and regeneration zones to which each bed is cycled. Substantially all of the hydrogen is produced in the steam reforming zone. EXAMPLE - No suitable example given.