Structure: The fixed-bed gasifier sends chopped biomass raw materials into the fixed-bed gasifier through the charging port at the top of the furnace. The materials are basically gasified in layers in the furnace, and the gas generated by the reaction is exhausted through the fan in the furnace. The reaction speed of fixed bed gasifier is slow. According to the flow direction of gas in the furnace, fixed-bed gasifier can be divided into downward suction type, upward suction type, horizontal suction type and open-heart type.
Principle: The gas phase of up-draft gasifier is generally solid. During the operation, the material is pushed from the top, dried by the rising hot air flow, and the water vapor is removed. The dried substance descends, is heated and decomposed by airflow, and then releases volatile substances.
The remaining carbon reacts with rising CO2 and water vapor when it continues to fall. CO2 and H2O can also be CO and H2. The remaining carbon is oxidized in the air entering the bottom, and the released heat provides a heat source for the whole gasification process.
Behind the gasifier
After the gas passes through the pyrolysis layer and the drying layer, the heat it carries is transferred to the material for thermal decomposition and drying, and at the same time, its own temperature is reduced, which greatly improves the thermal efficiency of the furnace.
The pyrolysis layer and drying layer of up-draft gasifier have a certain filtering effect on the gas, so the gas only contains a small amount of ash. Compared with other types of gas, this kind of gas has simple structure, easy processing and manufacturing, and small resistance in the furnace.