Mechanisms of ash fouling during low-rank coal combustion
- Univ. of North Dakota, Grand Forks, ND (United States). Energy and Environmental Research Center
Four low-rank coals were investigated for fouling severity using bench and pilot combustion testing and microanalytical examination of fouling deposits. The coals contained varying levels of alkali and alkaline-earth elements that are commonly associated with initiating and accelerating ash fouling, including Na, Mg, K, Ca, and Fe. Combustion testing revealed that fouling deposits generated from these coals shared common chemical and physical properties. Four test coals from western US coal fields were selected, including the Beulah and Gascoyne lignites from western North Dakota and the Colstrip subbituminous coal from Montana, and the Utah Wasatch from Utah. Deposits were ranked from low-fouling to severe-fouling based on deposit build-up rate, deposit strength, and liquid-phase viscosity, which was calculated based on the chemistry and the gas temperature near the deposits at the time of quenching. Microanalysis of the deposits using scanning electron microscopy revealed that the gluing material or phase that was responsible for the cementing of the severe-fouling deposits that the gluing material or phase that was responsible for the cementing of the severe-fouling deposits was a low-melting-point sodium-calcium-rich silicate.
- Research Organization:
- Engineering Foundation, New York, NY (United States)
- OSTI ID:
- 305666
- Report Number(s):
- CONF-9507274--PROC.; ISBN 0-306-45376-2
- Country of Publication:
- United States
- Language:
- English
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