LOW COST FIBER-OPTIC PROBE FOR ON-LINE EMISSION CONTROL OF PARTICULATE LADEN FLOWS

LOW COST, REMOTE SENSING OF PARTICLE-LADEN PROCESS STREAMS REQUIRES CONTINUING INSTRUMENTATION DEVELOPMENT TO MEET THE THE NEEDS OF FOSSIL ENERGY AND OTHER INDUSTRIAL APPLICATIONSPARTICULATE EMISSIONS CONTROL WHICH IS CONSISTENT WITH PROCESS OPTIMIZATION IS HIGHLY DEPENDENT ON THE ENTERING PARTICLE SIZE DISTRIBUTION AND CONCENTRATION. ON-LINE ANAL-YSIS AND FEEDBACK CONTROL DEVELOPMENT WILL PERMIT INTEGRATEDAUTOMATIC CONTROL OF THESE INDUSTRIAL PROCESSES. THE SPECIFIC MOTIVATION FOR THIS WORK IS BASED ON THE NEED FOR SIMPLE, LOW COST INSTRUMENTS FOR "SET-POINT" CONTROL OF INDUSTRIAL PROCESSES. SUCH INSTRUMENTS COULD PROVIDE AN INTEGRATED TYPE OF MEASUREMENT THAT REPRESENTS AN OVERALL PROCESS AND EMISSIONS SUMMARY. A LARGE NUMBER OF THESE LOW COST, FIBER-OPTIC-BASED PROBES CAN BE MULTIPLEXED INTO A SINGLE SIGNAL PROCESSOR AND COMPUTER SYSTEM WHICH PERIODI-CALLY INTERROGATES ALL PROBES. THE INTEGRATED MEASUREMENT CAN THEN BE USED IN A FEEDBACK CONTROL SYSTEM TO 1) MAINTAINSTEADY PROCESS CONDITIONS AROUND AN EMPIRICALLY DETERMINED OPTIMUM CONDITION OR 2) TO DETECT UNDESIRABLE PROCESS AND EMISSIONS CONDITIONS. FOR DENSE FLOWS, THE INSTRUMENT CAN BE FIGURED TO HANDLE ENSEMBLE SCATTERING IN EITHER FORWARD BACKSCATTER CONFIGURATIONS. ENSEMBLE (MANY SCATTERS) TECH- NIQUES HAVE THE ADVANTAGE OF FAST TIME RESPONSE AND CAN BE USED IN STEADY STATE OR TRANSIENT PROCESSES. THE END RESULT OF PHASE I AND II IS THE DEVELOPMENT OF A COMMERCIAL INSTRUMENT FOR LOW-COST, REMOTE SENSING OF PARTI-CLE-LADEN STREAMS. AN ON-LINE, IN SITU PARTICLE MEASUREMENTDEVICE WILL HAVE APPLICATIONS IN THE ANALYSIS OF A WIDE RANGE OF GAS AND LIQUID STREAMS: MONITORING ABSOLUTE LEVELSOF SOLIDS TRANSPORT IN PROCESS AND CLEANUP SYSTEMS, AND MON-ITOREING HIGH TEMPERATURE AND PRESSURE COMBUSTION SYSTEMS. STUDIES OF PARTICULATE EROSION IN GAS TURBINES ALSO REQUIRE A FAST, IN SITU MEASUREMENT TECHNIQUE. OTHER AREAS OF POTENTIAL APPLICATION INCLUDE REMOTE SENSING OF PARTICULATES IN RADIOACTIVE ENVIRONMENTS ANS ON-LINE MONITORING AND CONTROL OF PARTICLE SIZE DISTRIBUTIONS FOR POWDER METALLURGY.