Abstract: A solid fuel conversion system feeds solid fuel to a burning area at a controlled and metered rate. In the burning area, the solid fuel is dried before it reaches a burning bed of coals. Once it reaches the bed of coals, it is advanced at a controlled rate from said drying means through the area of the burning bed of coals to an ash area. The fuel-drying and advancing is carried out by a series of grates having controlled amounts of grate movement. The drying grate is set at a relatively steep angle (here, 60.degree.) which breaks the free-fall of an incoming curtain of solid fuel. The fuel-advancing is accomplished by a series of grates which are set at less than a free-fall angle (here, 15.degree.). A reciprocating feeder moves the fuel-advancing grates back and forth by the controlled amounts. The controlled rate of advance causes the solid fuel to gasify in the area over the burning bed. An air delivery system controls the flow of gaseous fuel from the solid fuel burning area to a gaseous burning area.