Gas generator /oal gasifier is a kind of coal or coke as raw material, with air and water vapour as the gasification agent, oxidation and reduction reaction in the fixed bed mixed gas produced by the special equipment.

Coal gasifier is the process of producing coal gas, a type of syngas–a mixture of carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2) and water vapour (H2O)–from coal and water. Coal gas, which is a combustible gas, was traditionally used as a source of energy for municipal lighting and heat before the advent of industrial-scale production of natural gas, while the hydrogen obtained from gasification can be used for various purposes such as making ammonia, powering a hydrogen economy, or upgrading fossil fuel