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

Brown, Robert C. ; Weber, Robert J. ; Suby, Andrew A.

Iowa State University (United States)

关键词: Fossil-Fuel Power Plants;    Air Pollution Monitors;    01 Coal, Lignite, And Peat;    Performance Testing;    Efficiency;   

DOI  :  10.2172/809200
RP-ID  :  NONE
RP-ID  :  FC26-01NT41220
RP-ID  :  809200

美国|英语

来源: UNT Digital Library

【 摘 要 】

Three test instruments are being evaluated to determine the feasibility of using photo-acoustic technology for measuring unburned carbon in fly ash. The first test instrument is a single microwave frequency system previously constructed to measure photo-acoustic signals in an off-line configuration. This system was assembled and used to test parameters thought important to photo-acoustic signal output. A standard modulation frequency was chosen based upon signal to noise data gained from experimentation. Sample heterogeneity was tested and found not to be influential. Further testing showed that sample compression and photo-acoustic volume do affect photo-acoustic signal. Many tests were performed in the third quarter, which included the effects of ambient temperature and humidity, as well as sample moisture content, and signal linearity. Conclusions regarding the data for sample bulk density and temperature are pending further review and may require further testing. Simultaneously, a second instrument is being 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. To date, all of the components for the second instrument have been received and most of them tested with the exception of the broadband impedance transformers, as they will be incorporated into the second instrument test chamber. The third instrument will be designed based on the experiences of the first two instruments and will operate in an on-line carbon-in-ash monitoring system for coal-fired power plants.