AN ADVANCED COAL FIRED HEAT EXCHANGER/GAS TURBINE TOPPING CYCLE FOR A HIGH EFFICIENCY POWERPLANT

SIGNIFICANT IMPROVEMENTS IN EFFICIENCY FOR COAL-FIRED POWERPLANTS CAN BE ACHIEVED BY CYCLES THAT EMPLOY A HIGH TEMPERATURE, HIGHLY RECUPERATIVE GAS TURBINE TOPPING CYCLE. THE PRINCIPAL DIFFICULTY IN EMPLOYING A GAS TURBINE IN A COAL FIRED POWER GENERATION SYSTEM IS THE POSSIBLE EROSION AND CORROSION OF THE HIGH TEMPERATURE ROTATING GAS TURBINE COMPONENTS CAUSED BY THE COAL'S INORGANIC AND ORGANICALLY BOUND CONSTITUENTS (ASH, SULFUR, AND ALKALI METALS). ONE ROUTE TO OVERCOMING THIS PROBLEM IS TO DEVELOP AN EXTERNALLY FIRED GAS TURBINE SYSTEM. THE KEY TECHNOLOGY ISSUE IS, THEN, THE DEVELOPMENT OF METHODS TO FIRE A HIGH TEMPERATURE CERAMIC HEAT EXCHANGER WITH COAL IN SUCH A WAY AS TO MINIMIZE THE POTENTIAL DAMAGE FROM THE INORGANIC CONSTITUENTS. THE SOLUTION OFFERED IN THIS PROJECT IS THE DESIGN OF A HIGH TEMPERATURE ADVANCED FURNACE (HITAF) WITH A PROPRIETARY HEAT EXCHANGER THAT ALLOWS HEAT EXCHANGE FROM A COAL FLAME BUT WITHOUT CONTACT OF THE ASH COMPONENT. THE OBJECTIVE OF PHASE I IS TO TEST THE PROPOSED HITAF/HEAT EXCHANGER COMBINATION IN A WELL-INSTRUMENTED LABORATORY FACILITY AND ASSESS ITS ADVANTAGES IN A POWER GENERATING SYSTEM. THE WORK WILL BE PERFORMED IN THE 0.5 MILLION BTU/HR COAL COMBUSTION FACILITY PREVIOUSLY EMPLOYED FOR COAL WATER SLURRY FUELS. ON THE BASIS OF THESE TESTS, THE PERFORMANCE OF THE PROPRIETARY HEAT EXCHANGER IN A POWER GENERATING SYSTEM WILL BE ASSESSED.