Evaluation of erosion-oxidation and ash deposition in the convective section of an industrial watertube boiler retrofitted to fire coal-water fuel
- Pennsylvania State Univ., University Park, PA (United States)
The feasibility of directly firing coal-water fuel in an oil-designed industrial watertube boiler is being determined for possible deployment at Department of Defense facilities. Erosion of carbon steel by particles and deposition of ash were measured in the convective section of the boiler while cofiring coal-water fuel and natural gas. Erosion was enhanced by directing a small jet of nitrogen, air, or oxygen toward the surface of a test coupon mounted on an air-cooled tube. The temperature and oxygen dependencies of the erosion rate were explained by a model for simultaneous erosion and oxidation. Extrapolation, using the experimentally determined coefficients for metal and oxide erosion, provided estimates of the erosion rate as functions of the gas velocity and angular position about the circumference of a heat exchanger tube in the convective section of the boiler. Under the conditions of metal temperature, oxygen concentration in the gas, particle size, and particle loading investigated, erosion of carbon steel is expected to be slower than 0.05 {mu}m/hour when the gas velocity in the convection section is less than approximately 8 m/s. A measurement in the convective section at 4 m/s gas velocity showed a pattern of ash deposits covering the circumference at positions on the tube surface where no erosion is predicted.
- DOE Contract Number:
- FC22-89PC88697; FC22-92PC92162
- OSTI ID:
- 41614
- Report Number(s):
- CONF-940320--
- Country of Publication:
- United States
- Language:
- English
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