ST2-05: Production of transportation fuels from biomass - the thermochemical approach illustrated by the DOE supported project “Green Gasoline from Wood using Carbona Gasification and Topsoe TIGAS Processes”

The thermochemical conversion of biomass into transportation fuels involves a number of unit operations. First of all, the biomass should be crushed into a suitable size and dried before being gasified in a preferentially pressurised process.  The gas from the gasifier then needs to be treated for impurities and possibly also unconverted hydrocarbons (tars) must be eliminated to provide a clean synthesis gas, consisting of essentially hydrogen and carbon monoxide, suitable for downstream catalytic conversion. This synthesis gas can be converted into transportation fuel.

Depending on the desired product the H₂/CO ratio may have to be adjusted. For gasoline and DME synthesis, a ratio of 1 is favoured whereas for FT diesel and methanol a ratio of 2 is favoured.

The conversion processes are all well known in the industry. Some developments in the gasification/tar reforming technology need to be confirmed before the overall process becomes fully commercial. In 2010 Topsoe, together with partners, obtained a $25 million grant from the Department of Energy to produce 20-25 bbl/d of green gasoline from woody biomass by combining the Carbona gasification and Topsøe TIGAS processes. The project represents the entire value chain from wood suppliers to gas stations and will be executed at the premises of project partner, Gas Technology Institute in Des Plaines, IL, already hosting the gasification facilities.