Thermochemical technologies employ high temperature, and use of oxidizing agents or catalysts to break down the biomass polymers into liquid or gaseous fuels. These include combustion, gasification, pyrolysis, liquefaction, and hydrogenation. The most noteworthy difference among these processes is the target products that these processes are used to produce. Heat (or power) is the main direct product of combustion. Gaseous fuel (synthesis gas or producer gas) is the direct product of gasification; whereas, the direct product of pyrolysis, liquefaction and hydrogenation is a liquid (bio-oil) or solid (char) depending on the process operating conditions. In some situations, two or more biomass thermochemical processes are applied in series to increase conversion efficiency, obtain desired chemicals, or reduce environmental emissions. For example, biomass gasification followed by combustion of syngas (or producer gas) provides an opportunity to remove contaminants from the gaseous fuels and to use a gas turbine and other gaseous fuel-based technologies.