AN ADVANCED CONCEPT FOR COST-EFFECTIVE PRESSURIZED FLUIDIZED BED COMBUSTION SYSTEMS

MTCI'S ALTERNATIVE SECOND-GENERATION ADVANCED PFBC CONCEPT EMPLOYS A PULSE COMBUSTION-BASED COMBUSTOR ISLAND IN THE TOPPING CYCLE. THE PULSE COMBUSTOR ACTS AS A VITIATED AIR BURNER AND SERVES TO INCREASE THE FLUE GAS TEMPERATURE FROM ABOUT 1600 DEGREES FAHRENHEIT AT THE EXIT OF THE PFBC TO ABOUT 2000 DEGREES FAHRENHEIT AT THE INLET TO THE GAS TURBINE. THE COMBUSTOR ISLAND INCLUDES A COMBINED SULFUR CAPTURE AND ASH AGGLOMERATION CHAMBER (CSA), A HOT CYCLONE, AND A HOT GAS CLEANUP SYSTEM FOR PARTICULATE REMOVAL AND EMISSIONS CONTROL. COAL FINES OBTAINED BY CLASSIFICATION AND EQUIVALENT TO STAND GRIND PULVERIZED COAL ARE BURNED IN THE PULSE COMBUSTOR. COARSE COAL AND WASTE FUEL, IF ANY, ARE COMBUSTED IN THE PFBC. THE SULFUR RELEASED IN THE PULSE COMBUSTOR ALONG WITH THE RESIDUAL SULFUR SPECIES IN THE FLUE GAS FROM THE PFBC ARE CAPTURED BY DOLOMITE SORBENT IN A SONIC-ENHANCED MODE IN THE CSA. ADDITIONALLY, SONIC-ENHANCED BIMODAL AGGLOMERATION TAKES PLACE IN THE CSA. THIS MAKES IT POSSIBLE TO OBTAIN HIGH COLLECTION EFFICIENCY USING A HOT CYCLONE. A HOT GAS CLEANUP SYSTEM IS PROVIDED TO PROTECT THE TURBINE DURING UPSET CONDITIONS. POTENTIAL EXISTS FOR USING ALKALI GETTERING MATERIAL SUCH ASEMATHLITE. THE PROPOSED MTCI CONCEPT RESOLVES MANY OF THE TECHNICAL BARRIERS ANTICIPATED FOR THE FOSTER WHEELER SECOND-GENERATION PFBC SYSTEM. THE ADVANTAGES INCLUDE RELATIVELY HIGH VOLUMETRIC HEAT RELEASE RATE, COMPACT SIZE, LOW NOX EMISSIONS, COMBUSTION-INDUCED PRESSURE BOOST, SONIC-ENHANCED AGGLOMERATION AND SULFUR CAPTURE, AND FUEL FLEXIBILITY. THE SYSTEM SHOWS PROMISE FOR ACHIEVING HIGHER CYCLE EFFICIENCY ( 45%) AND LOWER COST OF ELECTRICITY AS COMPARED TO COMPETING TECHNOLOGIES. THE PROPOSED SYSTEM IS INITIALLY INTENDED FOR INDUSTRIAL COGENERATION APPLICATIONS WITH SUBSEQUENT SCALE-UP TO THE UTILITY SECTOR.