Gasification converts wood chips or crop residues into a combustible gas mixture.
In gasification, biomass is heated at high temperature with a controlled amount of oxygen, air, or steam rather than being burned completely. The process produces synthesis gas, commonly called syngas, containing mainly carbon monoxide and hydrogen, along with carbon dioxide, methane, water vapor, and impurities in varying amounts.
Syngas can be burned in an engine or boiler to produce heat and electricity. After cleaning and conditioning, it can also serve as a feedstock for chemicals or synthetic fuels. The exact gas composition depends on the feedstock, temperature, gasifying agent, and reactor design.
Gasification differs from pyrolysis, which heats material without oxygen and produces char, oil, and gas. It also differs from anaerobic digestion, in which microorganisms break down wet organic matter without oxygen to produce biogas. These technologies all use biomass, but their chemistry, products, and suitable feedstocks are not the same.