MONITORING POWER PLANT EFFICIENCY USING THE MICROWAVE-EXCITED PHOTOACOUSTIC EFFECT TO MEASURE UNBURNED CARBON

Brown, Robert C. ; Weber, Robert J. ; Sweterlitsch, Jeff

Iowa State University (United States)

关键词: Monitoring;    Lock-In Amplifiers;    Photoacoustic Effect;    Diaphragm;    Efficiency;   

DOI  :  10.2172/831075
RP-ID  :  NONE
RP-ID  :  FC26-01NT41220
RP-ID  :  831075

美国|英语

来源: UNT Digital Library

【 摘 要 】

Three test instruments are being evaluated to determine the feasibility of using photoacoustic technology for measuring unburned carbon in fly ash. The first test instrument is a single microwave frequency system previously constructed to measure photoacoustic signals in an off-line configuration. A second off-line instrument was constructed based in part on lessons learned with the first instrument, but which also expands the capabilities of the first instrument. Improvements include a control loop to allow more constant microwave power output and an ability to operate over a range of microwave frequencies. The third instrument, the on-line version of the fly ash monitor, has been designed, constructed, and initial efficiency tests have been conducted on the monitor's electrical components. This quarter focused on improving the signal strength of the accelerometer by increasing the power level of the microwaves that induced the thermo-elastic effect, and also to conduct repeatability experiments. Efforts this quarter were spent improving the coupling of the accelerometer with the diaphragm, detecting and eliminating microwave leakage, isolating stray electrical current within the laboratory, specifically within the ground, and replacing a faulty lock-in amplifier.