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A report of the performance of a hybrid flow monitor used for CEMS and heat rate applications

Technical Report ·
OSTI ID:269620
 [1];  [2]
  1. Sierra Pacific Power Co., Reno, NV (United States)
  2. Scientific Engineering Instruments, Inc., Sparks, NV (United States)
The accurate and reliable measurement of volumetric flow rate in large ducts and stacks still remains one of the least understood aspects of Clean Air Act regulations. The accuracy and reliability of a flow monitor directly determines its allowance metering capabilities and true long term cost effectiveness. A large number of flow monitors have now been installed and certified in the United States as Phase I and Phase II plants continue with the certification and RATA process. The type of flow monitors being installed basically fall into one of three general categories, i.e., thermal dispersion, differential pressure or sonic. This paper reports on a hybrid system that has demonstrated excellent performance over this past year. This system has been installed on North Valmy`s Units No. 1 and No. 2 stacks. It uses sonic principles to measure the average velocity and uses differential pressure to estimate the flow profile. The system then measures the average moisture of the flue gas, stack pressure and temperature and hence provides volumetric flow rate measurements of the flue gas in standard wet gas form for direct CEMS recording. The system measures changes in the stack velocity profile in real time and hence it provides accurate measurements over all load ranges and changing plant conditions. The accuracy of this instrument is described in some detail along with a discussion of its operating and maintenance history. Nearly two dozen of these systems have now been installed in Nevada, Colorado and Texas.
Research Organization:
Electric Power Research Inst., Palo Alto, CA (United States); Encor-America, Inc., Mountain View, CA (United States)
OSTI ID:
269620
Report Number(s):
EPRI-TR--106529; CONF-960524--
Country of Publication:
United States
Language:
English