Fueling gasifiers with biomass puts clean spin on conventional generators

Gasifiers are partial oxidation devices that convert low- or negative-value, carbon-based feedstocks such as biomass, coal, or petroleum coke, to synthesis gas. The gas can be used in place of natural gas to generate electricity, or as a basic raw material to produce chemicals and liquid fuels.

Gasification dates back to the 1800s and took off during World War II. In the '40s, more than a million gasifiers in Europe powered civilian cars while the military used most of the precious gasoline supplies. Those systems were inefficient and far from clean.

Biomass-based gasifiers, such as the BioMax units, produce electricity and thermal energy from woody waste including wood chips from hard and soft wood, sawdust pellets, coconut shells, nut shells or corncobs. The units heat these fuels with about one-third of the oxygen necessary for complete combustion to produce a mixture of carbon dioxide and hydrogen, known as syngas. This syngas is combusted in an internal combustion engine, a Stirling engine, a micro-turbine or fuel cell. About three pounds of fuel produces 1 kWh.

The byproduct of biomass gasification is char. Tars and soot are also formed as part of the gasification process but are removed from the gas stream prior to use. Further combustion of the char reduces the material to ash made up of the minerals the plant drew from the soil. This residue can be dispersed in soil with minimal environmental impact.