STUDIES OF VARYING THE BED DEPTH TO MATCH LOAD CHANGES IN PRESSURIZED FLUIDIZED BED COMBUSTION SYSTEMS.

ONE POTENTIAL METHOD OF CHANGING LOAD IN A COMBINED CYCLE POWER PLANT USING A PRESSURIZED FLUIDIZED BED (PFB) COMBUSTION SYSTEM IS TO CHANGE THE BED DEPTH. THIS ALTERS THE AMOUNT OF STEAM GENERATING SURFACE WHICH IS IMMERSED IN THE HIGH HEAT FLUX CONDITIONS OF THE BED AND THUS ALTERS THE OUTPUT OF THE STEAM TURBINE. AT THE SAME TIME, THE VARIATION IN THE AMOUNT OF SURFACE ABOVE THE BED ALTERS THE TEMPERATURE AND THECOMBUSTION GASES AND THUS THE OUTPUT OF THE GAS TURBINE. PILOT-SCALE INVESTIGATIONS IN THE EXPERIMENTAL PFB COMBUSTOR HAVE SHOWN THAT THIS IS AN EFFECTIVE METHOD OF LOAD-CHANGING AND LOAD-FOLLOWING.