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Title: Diagnosing causes of increased NO{sub x} at Potomac River Unit 4

Conference ·
OSTI ID:427873
;  [1];  [2]
  1. Lehigh Univ., Bethlehem, PA (United States). Energy Research Center
  2. Potomac Electric Power Co., Alexandria, VA (United States)

Potomac River Unit 4, a 108 MW unit, has a corner-fired boiler with conventional burners. Through the use of combustion optimization techniques, the NO{sub x} emissions had been reduced from baseline levels of 0.6 lb/MBtu to values below 0.45 lb/MBtu over the load range, and had been routinely dispatched at this reduced emissions level for extended periods of operation. After a scheduled outage in Fall 1995 for boiler maintenance, windbox modifications and a superheater replacement, the unit was returned to service, and it was found that the full-load NO{sub x} level had increased by approximately 0.1 lb/MBtu. A week of tests was performed and pre- and post-outage data analyzed to determine the factors contributing to the increase in NO{sub x} emissions. The principal cause was found to be a reduction in the amount of boiler air in-leakage arising from boiler casing repairs, and leading to higher air-to-fuel ratios in the furnace. Other, secondary, causes were also determined. Results from the analysis indicate the windbox modifications were actually effective in reducing NO{sub x}, although the benefits were obscured due to the intervening circumstances. This paper describes the diagnostic process which was followed and discusses the findings from the investigation.

OSTI ID:
427873
Report Number(s):
CONF-961006-; ISBN 0-7918-1795-4; TRN: IM9708%%200
Resource Relation:
Conference: 1996 international joint power generation conference, Houston, TX (United States), 13-17 Oct 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the 1996 international joint power generation conference -- Volume 1: Environmental control/fuels and combustion technologies. EC-Volume 4; FACT-Volume 21; Smouse, S.M. [ed.] [Dept. of Energy, Pittsburgh, PA (United States). Pittsburgh Energy Technology Center]; Gupta, A. [ed.] [Univ. of Maryland, College Park, MD (United States)]; PB: 516 p.
Country of Publication:
United States
Language:
English