ACOUSTICAL RESONANCE MEASUREMENT FOR MONITORING AND CONTROL OF PNEUMATICALLY CONVEYED PULVERIZED COAL

INSTRUMENTATION BASED ON ACOUSTICAL RESONANCE MEASUREMENT WILL BE DEVELOPED TO MONITOR THE FLOW RATE OF PNEUMATICALLY CONVEYED PULVERIZED COAL AND TO CONTROL COMBUSTION STOICHIOMETRY. AN INSTRUMENT CONFIGURATION WILL BE IMPLEMENTED AND TESTED IN A CLOSED-LOOP LABORATORY TEST RIG AND AT A COAL-FIRED ELECTRICAL UTILITY POWERPLANT. THIS EFFORT ALSO INCLUDES A FIRST ORDER ACOUSTICAL ANALYSIS TO INTERPRET THE FUEL SIGNAL FROM THE ACOUSTICAL RESONANCE MEASUREMENT AND APPLICATION OF THIS ANALYTICAL ANALYSIS TO THE EXPERIMENTAL CONDITIONS. THE ACOUSTICAL RESONANCE MEASUREMENT TECHNIQUE PROVIDES A NONINTRUSIVE AND REAL-TIME MEASUREMENT OF MASS LOADING AND SIZING OF PARTICLES FLUIDIZED BY A GAS PHASE. THE SOUND SPEED OF A TWO-PHASE MIXTURE OF PARTICLES IN GAS DECREASES AS THE MASS DENSITY OF THE PARTICLES INCREASES. BY MEASURING THE DECREASE IN THE RESONANT FREQUENCIES, WHICH ARE LINEARLY RELATED TO THE SOUND SPEED, THE MASS DENSITY OF THE PARTICLES CAN BE DETERMINED. BECAUSE THE SOUND SPEED IS DISPERSIVE WITH THE FREQUENCY OF THE ACOUSTICAL WAVES, THE FREQUENCY DEPENDENCE OF THE SOUND SPEED PROVIDES A METHOD OF DETERMINING THE PARTICLE SIZING BY MEASURING THE RESONANCE FREQUENCIES OF DIFFERENT MODES. DESIGN VERIFICATION TESTING REQUIRED FOR A PROTOTYPE WILL BE PERFORMED, AND THE FEASIBILITY OF USING THE ACOUSTICAL RESONANCE MEASUREMENT FOR PULVERIZED COAL FUEL SYSTEM AIR/FUEL MONITORING AND CONTROL WILL BE DETERMINED.