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

[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 begin testing parameters thought to be influential in the resulting 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. Many other tests were performed during the second quarter. Preliminary results show that compression and photo-acoustic volume have an impact on photo-acoustic signal. Conclusions regarding the data for sample bulk density, temperature, humidity, moisture content, and linearity are pending further review. Conclusions for ambient temperature and humidity are pending further review as well. Simultaneously, a second instrument is to be constructed based in part on lessons learned with the first instrument, and to expand 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, the design of the second instrument has been completed and most of the components received. 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.

[发布日期] 2002-05-13 [发布机构] National Energy Technology Laboratory (U.S.)

[关键词] On-Line Measurement Systems;Fossil-Fuel Power Plants;01 Coal, Lignite, And Peat;Performance Testing;Photoacoustic Effect