ESB-R05A-KW Standalone Biomass Gasifier Without Canopy The gasifier we offer here is downdraft gasifier. Downdraft gasifier is the most common type of gasifier. In downdraft gasifiers, the pyrolysis zone is above the combustion zone & the reduction zone is below the combustion zone. Fuel is fed from the top. The flow of air and gas is downwards through the combustion & reduction zones. A downdraft gasifier is designed which is produced in the pyrolysis zone travels through the combustion zone where it is burnt. As a result the mixture gases in the exit stream are relatively clean