Cofiring coal-water slurry fuel with pulverized coal as a NOx reduction strategy
- Pennsylvania State Univ., University Park, PA (United States)
A low solids, low viscosity coal-water slurry fuel (CWSF) was formulated and produced from impounded bituminous coal fines and burned in a utility-scale boiler to investigate NOx emissions reduction during the cofiring of CWSF with pulverized coal. Tests were conducted at the Pennsylvania Electric Company (Penelec) Seward Station, located near Seward, Pennsylvania in a Babcock and Wilcox (B and W), front-wall fired, pulverized coal boiler (34 MWe). Two B and W pulverizers feed coal to six burners (two burner levels each containing three low-NOx burners). Approximately 20% of the thermal input was provided by CWSF, the balance by pulverized coal. There was a significant reduction of NOx emissions when cofiring CWSF and pulverized coal as compared to firing 100% pulverized coal. The level of reduction was dependent upon the cofiring configuration (i.e., cofiring in the upper three, lower three, or all six burners), with NOx emissions being reduced by as much as 26.5%. The reduction in NOx emissions was not due to the tempering effect of the water in the CWSF, because a greater reduction in NOx occurred when cofiring CWSF than when injecting the same quantity of water at the same boiler firing rate. This paper discusses the tests in detail and the proposed reburn mechanism for the NOx reduction. In addition, combustion test results from the front-wall fired unit at the Seward Station will be compared to CWSF cofire tests that have been conducted at cyclone-fired units at Tennessee Valley Authority`s (TVA) Paradise Station (704 MWe), Drakesboro, Kentucky and Southern Illinois Power Cooperative`s (SIPC) Marion, Illinois Station (33 MWe).
- OSTI ID:
- 324731
- Report Number(s):
- CONF-970931--
- Country of Publication:
- United States
- Language:
- English
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