A method of hydropyrolysis comprising: a. introducing an oxygenated organic feedstock into the fluidized bed reactor, wherein said feedstock is rapidly heated from ambient temperature to the temperature of the fluidized bed, and is thereby devolatilized; b. introducing a stream of fluidizing gas comprising mostly molecular hydrogen into the fluidized bed reactor, creating conditions under which rapid mixing and heat transfer occur throughout the fluidized bed, and fluidizing the bed to a point where its state is consistent with that of a bubbling fluidized bed; c. maintaining a deep bed of solid particles of catalyst, the depth of which is greater than 2 reactor diameters, in a state of vigorous motion, to promote reactions resulting in deoxygenation and chemical stabilization of vapors produced when the feedstock is devolatilized, wherein solid particles of biomass comprise the feedstock, and wherein the particle size of the catalyst is larger than a particle size of the biomass; d. removing solid residues, remaining after devolatilization and hydropyrolysis of the feedstock, from the fluidized bed reactor via entrainment in the stream of fluidizing gas and product vapors exiting the fluidized bed reactor; e. removing attrited residues of catalyst, but not intact particles of catalyst, or particles of catalyst that have been minimally attrited, from the fluidized bed reactor via entrainment in the stream of fluidizing gas and product vapors exiting the fluidized bed reactor; f. separating the solid residues, entrained in the stream of fluidizing gas and product vapors exiting the fluidized bed reactor, from the stream of fluidizing gas and product vapors exiting the fluidized bed reactor; g. recovering a product stream of hydrocarbon vapors comprising hydrocarbon species with atmospheric-pressure boiling points, consistent with those of at least one of gasoline, kerosene and diesel fuel, from the hydropyrolysis process as condensed liquid; h. releasing enough exothermic heat from the deoxygenation reactions occurring during hydropyrolysis of the feedstock to supply process heat required by endothermic processes occurring during hydropyrolysis of the feedstock, including chemical reactions, heating of feedstock, and evaporation of liquids characterized in that slugging in the fluidized bed is controlled via the use of equipment incorporating lateral obstructions, obstacles or constrictions, an axis or centerline of the equipment intersecting a centerline of the fluidized bed reactor, wherein the obstructions, obstacles, or constrictions, are installed at vertical locations along the fluidized bed reactor that are separated from one another by one to two reactor diameters. a. introducing an oxygenated organic feedstock into the fluidized bed reactor, wherein said feedstock is rapidly heated from ambient temperature to the temperature of the fluidized bed, and is thereby devolatilized; b. introducing a stream of fluidizing gas comprising mostly molecular hydrogen into the fluidized bed reactor, creating conditions under which rapid mixing and heat transfer occur throughout the fluidized bed, and fluidizing the bed to a point where its state is consistent with that of a bubbling fluidized bed; c. maintaining a deep bed of solid particles of catalyst, the depth of which is greater than 2 reactor diameters, in a state of vigorous motion, to promote reactions resulting in deoxygenation and chemical stabilization of vapors produced when the feedstock is devolatilized, wherein solid particles of biomass comprise the feedstock, and wherein the particle size of the catalyst is larger than a particle size of the biomass; d. removing solid residues, remaining after devolatilization and hydropyrolysis of the feedstock, from the fluidized bed reactor via entrainment in the stream of fluidizing gas and product vapors exiting the fluidized bed reactor; e. removing attrited residues of catalyst, but not intact particles of catalyst, or particles of catalyst that have been minimally attrited, from the fluidized bed reactor via entrainment in the stream of fluidizing gas and product vapors exiting the fluidized bed reactor; f. separating the solid residues, entrained in the stream of fluidizing gas and product vapors exiting the fluidized bed reactor, from the stream of fluidizing gas and product vapors exiting the fluidized bed reactor; g. recovering a product stream of hydrocarbon vapors comprising hydrocarbon species with atmospheric-pressure boiling points, consistent with those of at least one of gasoline, kerosene and diesel fuel, from the hydropyrolysis process as condensed liquid; h. releasing enough exothermic heat from the deoxygenation reactions occurring during hydropyrolysis of the feedstock to supply process heat required by endothermic processes occurring during hydropyrolysis of the feedstock, including chemical reactions, heating of feedstock, and evaporation of liquids