NOVELTY - The apparatus comprises: a riser reactor (10) having a mixing zone (12), an intermediate zone (13) located above the mixing zone and forming interface with the mixing zone, and an upper zone (14) located above the intermediate zone, where a biomass feed is mixed with a heat carrier material to produce a reaction mixture comprising the heat carrier material and a reaction product, which comprises oxygenated hydrocarbons; a biomass feed conduit (18) connected in fluid flow communication with the mixing zone for introducing the biomass feed to the riser reactor.    USE - The apparatus is useful for conversion of biomass to produce chemicals, fuels or bio-oils, which are useful for clean, controlled combustion in boilers and in diesel and stationary turbines.    ADVANTAGE - The apparatus ensures rapid conversion of the biomass thus efficiently producing the bio-oil from the biomass.    DETAILED DESCRIPTION - The apparatus comprises: a riser reactor (10) having a mixing zone (12), an intermediate zone (13) located above the mixing zone and forming interface with the mixing zone, and an upper zone (14) located above the intermediate zone, where a biomass feed is mixed with a heat carrier material to produce a reaction mixture comprising the heat carrier material and a reaction product, which comprises oxygenated hydrocarbons; a biomass feed conduit (18) connected in fluid flow communication with the mixing zone for introducing the biomass feed to the riser reactor; a lift gas conduit connected in fluid flow communication with the mixing zone for introducing the lift gas to the riser reactor to assist in producing a general upward flow in the riser reactor; a heat carrier material conduit connected in fluid flow communication with the mixing zone for introducing the heat carrier material into the riser reactor; a first quench stream conduit connected in fluid flow communication with the riser reactor at a location just above the interface of the mixing zone and the intermediate zone resulting in a lower temperature in the intermediate zone as compared to the mixing zone; and a disengager connected in fluid flow communication with the upper zone such that the reaction mixture is received in the disengager. A portion of the reaction product is separated from the heat carrier material within the disengager. The apparatus further comprises: other quench stream conduit connected in fluid flow communication with the riser reactor at the location within the intermediate zone, the upper zone, or both the intermediate zone and the upper zone; a product conduit connected in fluid flow communication with the disengager for receiving reaction product; a stripper connected in fluid flow communication with the disengager such that heat carrier material from the disengager is introduced into the stripper; and a regenerator connected in fluid flow communication with the stripper and the heat carrier material conduit such that the heat carrier material from the stripper is introduced into the regenerator, and heat carrier material from the regenerator is introduced into the heat carrier material conduit. Two other quench stream conduits are connected at the location within the intermediate zone, and the quench stream conduit is connected at the location within the upper zone. The lift gas conduit is connected to the mixing zone below the locations, where the biomass feed conduit and the heat carrier material conduit are each connected to the mixing zone.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of an apparatus for a biomass conversion.    Riser reactor (10)    Mixing zone (12)    Intermediate zone (13)    Upper zone (14)    Biomass feed conduit. (18)