Suspended combustion: suspended combustion, also known as fire chamber combustion, for solid, liquid or gas fuels, is the main combustion method of medium-sized and large boilers. Suspension combustion without grate, fuel and air contact area is large, rapid ignition, high burnout rate, combustion efficiency and high thermal efficiency of the boiler, automatic control can be realized. However, there are many equipments, complex system and high energy consumption.