The single section gasifier is also called single section gasifier. It is manufactured by adopting the long points of various similar enterprises and is consequently advanced in design and reasonable in construction. Two kind of slag/ash discharging methods are adopted, i.e. discharging slag with wet ash pan driven by worm and worm gear or removing ash with water-seal jacket equipped with screws driven by conical gear, both of these two methods are stable and reliable in operation. The furnace body adopts the complete water jacket structure. The self-produced steam can satisfy the requirement of both coal gasification and steam sealing for poking hole. Coal-feeding adopts manual or electrical drum-type double bell jars.