Boiler combustion in three forms: layer burning (fire bed combustion), room burning (suspended combustion), boiling combustion. Various types of combustion have their own corresponding combustion equipment. Fixed grate, chain grate, reciprocating grate, vibrating grate, etc. belong to the layer type, suitable for burning solid fuel. Pulverized coal boilers, oil boilers, gas boilers, etc. belong to the room-burning type, suitable for powdered solid fuel, liquid fuel and gas fuel. Bubbling fluidized bed, circulating fluidized bed is a boiling combustion method, suitable for burning particulate solid fuel. Pulverizer chain grate, both stratospheric and chamber combustion combustion, a mixture of combustion.