CONTROLLING FLUIDISED BED COMBUSTION

摘要

The specification describes a method and means for controlling operation of a fluidized bed combustion apparatus. In the proposals embodied in the invention the supply of combustion air fed to the fluidized bed is augmented by inert gas (preferably waste gas taken from a low temperature outlet of the apparatus) and the proportion of inert gas used to augment the combustion supporting air is variable in dependence upon the temperature of the fluidized bed in the apparatus and/or the thermal demand placed upon the apparatus. In described embodiments of means enabling the invention to be effected arrangements are described including an induced draft fan, coupled to the outlet for waste gas of the apparatus, for feeding waste gas to a mixer and the use of a two input mixer fan coupled to both atmosphere and a waste gas supply line connected to a waste gas outlet. The volume of waste gas supplied is controllable in dependence upon the temperature of the bed in the apparatus and/or the thermal demand placed on the apparatus. The rate at which fuel is fed to the apparatus may also be controlled in dependence upon the thermal demand placed on the apparatus.