TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The heterogeneous catalyst is nickel on silica alumina (Ni-Si/Al) catalyst.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method further comprises: the step of olefinating bio-oil while simultaneously esterifying the bio-oil; olefinating esterified bio-oil; combining the bio-oil with a catalyst and an alcohol to cause a reaction; and promoting a reaction by sonication, microwave excitation or high-shear mixing. The step of combining is performed by mixing. The reaction is caused by injecting or spraying the combined alcohol and catalyst into hot pyrolysis vapor stream produced during pyrolysis of biomass. The step of olefinating esterified bio-oil is performed by reacting olefin and esterified bio-oil mixture with a heterogeneous catalyst. The olefination reaction is: performed by heating the olefin, esterified bio-oil and catalyst mixture; performed at above ambient pressure; and promoted by sonication, microwave excitation or high-shear mixing. The step of olefinating bio-oil while simultaneously esterifying the bio-oil includes heating of the mixture. The step of olefinating bio-oil while simultaneously esterifying the bio-oil is: performed by combining bio-oil, olefin, and alcohol with a heterogeneous catalyst to cause a reaction; caused by sonication, microwave excitation or high-shear mixing; caused by injecting or spraying the olefin, alcohol and heterogeneous catalyst mixture into the hot pyrolysis vapor stream produced during pyrolysis of biomass; and performed by reacting a olefin, an alcohol and heterogeneous catalyst in a heated high-pressure autoclave or a heated packed-bed reactor. The heated olefin, esterified bio-oil mixture is reacted at above ambient pressure. The injection or spraying into the hot pyrolysis vapor stream is performed at a location on the apparatus of the pyrolysis reactor (25) carrying pyrolysis vapors to the reactor condenser (27). The spraying is performed by a sprayer capable of producing small droplets. Preferred Components: The catalyst is an acid or base. The alcohol is comprised of a mixture of alcohols. The olefin is a mixture of olefins.