Analysis on bed temperature operational characteristics of 450 t/h CFB boiler

Presently the control level of bed temperature of circulating fluidized bed (CFB) boiler is comparatively low, it is difficult to put automatic control into operation. On the basis of the operating data of a commercial 450 t/h CFB boiler, the authors systematically analyze the main factors which influence the change of bed temperature. The record of the operation data shows that the lag of the bed temperature is a common phenomenon while fuel supply is changed; coal quality and its grain diameter spectrum also have notable influence on bed temperature; primary air rate has different influences on bed temperature in different operating conditions; the change of oxygen concentration can reflect combustion conditions in the furnace; the change of dense zone height will result in the change of bed temperature; bed temperature is one of the main factors which lead to load variation. The conclusions can provide references for the design of control system and safe operation of CFB boiler.