Pressure fluctuations as a diagnostic tool for fluidized beds. Technical progress report, January 1, 1996--March 31, 1996
Additional pressure fluctuation data was recorded from the ISU power plants two CFB boilers. Absolute pressure fluctuations were measured immediately above the distributor nozzles and near the top of the CFB boilers. The fluctuations measured near the bottom of the bed exhibit a highly oscillatory (0.25-0.3 Hz) phenomena. This {open_quotes}square wave{close_quotes} pressure signal is observed at all times of the day and under different boiler loadings. Steps were taken to insure that abasing was not the cause of the observed pressure dynamics. It is hypothesized that these fluctuations are the result of the coal feed system, and are not related to the CFB hydrodynamics. Pressure fluctuations measured near the top of the bed do not show this dominant periodic behavior attributed to the coal feed system. The Bode plots of pressure fluctuations in this region show a near -40 dB/decade roll-off and a cornering frequency of around 0.07 Hz. This result suggests that the pressure dynamics in industrial scale CFBs may be governed by a wave phenomenon similar to that observed in the laboratory scale circulating fluidized beds. This result cannot be confined until more is known about the boiler control dynamics, and more extensive boiler instrumentation is available.
- Research Organization:
- Iowa State Univ. of Science and Technology, Ames, IA (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
- DOE Contract Number:
- FG22-94PC94210
- OSTI ID:
- 426961
- Report Number(s):
- DOE/PC/94210-T7; ON: DE97002642; TRN: 97:000942
- Resource Relation:
- Other Information: PBD: 20 Apr 1996
- Country of Publication:
- United States
- Language:
- English
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