NOVELTY - Converting biomass feedstock into product hydrocarbon involves subjecting feedstock to fast pyrolysis or hydropyrolysis; converting pyrolysis gas in hydroconversion step to product hydrocarbon and carbon dioxide; generating hydrogen by steam reforming by reaction between steam and product hydrocarbon; separating hydrogen from the hydrocarbon product, and recycling the hydrogen to force hydroconversion of biomass into the hydrocarbon product; and regenerating the sorbent to release the carbon dioxide.    USE - For converting biomass feedstock into product hydrocarbon (claimed).    ADVANTAGE - The method provides high purity methane by the sorption enhanced methanation. The method provides high efficiency conversion of biomass including forestry residues and sawmills waste into SNG, either as fuel commodity or for high efficiency generation of electrical power; provides advantageous integrations with gas turbines and/or solid oxide fuel cells. The method converts biomass into heavier and lighter hydrocarbon liquids. The method used at industrial scale; and at smaller scale in rural or remote areas for combined generation of heat, high heating value fuel gas and electricity.    DETAILED DESCRIPTION - Converting a biomass feedstock into a product hydrocarbon involves subjecting feedstock to fast pyrolysis or hydropyrolysis to generate fractions of pyrolysis gas and char; converting at least a portion of the pyrolysis gas in a hydroconversion step to a product hydrocarbon and carbon dioxide over a catalyst in the presence of hydrogen and steam, while removing carbon dioxide by carbonation of a sorbent; generating at least a portion of the hydrogen by steam reforming by reaction between steam and a portion of the pyrolysis gas or a product hydrocarbon; separating hydrogen from the hydrocarbon product, and recycling the hydrogen to force hydroconversion of biomass into the hydrocarbon product; and regenerating the sorbent in a regeneration step to release the carbon dioxide. INDEPENDENT CLAIMS are included for a system for producing hydrocarbons from biomass comprising fast pyrolysis units operating at a process temperature less than 650 degrees C for producing pyrolysis gas and char; catalytic conversion units operating at a process temperature less than 650 degrees C for converting the pyrolysis gas to hydrocarbons and hydrogen by hydroconversion over a catalyst and in presence of CO2 sorbent; gas separation means for purifying a hydrocarbon product and for recycling hydrogen to the catalytic conversion units; and unitss for regenerating the CO2 sorbent to release the CO2.