Biomass gasifier for converting solid biomass into gaseous fuelusing thermo-chemical conversion

摘要

An open-topped reactor allows air and biomass to be drawn in from the top of the reactor. Air nozzles are placed at around 1/3 of the way up the reactor to bring in additional air. A grille holds the biomass in the reactor. The air supply from the top maintains a high temperature, which supports the devolatilisation of the biomass and partial gasification of carbon. The biomass can be alight when passing the air nozzles. Gasification is finished near the bottom of the reactor where the additional air is introduced through the air nozzles. The reactor is ceramic coated or has two sections: a lower one in soft steel covered with ceramic bricks and aluminium tiles and an upper ring section in stainless steel covered with aluminium. The hot gas leaves through the upper ring section of the reactor to dry the biomass. The cooled gas is filtered through a filter made of a quartz bed on a matrix of polymer fibres. The gas is drawn in by a ventilator and fed to a motor in a controlled manner to generate power and the ventilator is protected from the high temperatures by injection of water into the ventilator. A compact two-lobe burner is used to burn the gas without leaving any trace of unburned fuel. A pool of water or a lifting table are at the bottom of the reactor. The grille is operated by a motor and contains a carbon recovery unit in the base of the reactor to recover charcoal.