The advanced tangentially fired combustion techniques for the reduction of nitrogen oxides (NOx) emissions from coal-fired boilers demonstration project: A DOE assessment

Abstract

This document serves as a DOE post-project assessment of a project in Round 2 of the Department of Energy's Clean Coal Technology (CCT) Program: ``Advanced Tangentially Fired Combustion Techniques for the Reduction of Nitrogen Oxides (NO{sub x}) Emissions From Coal-Fired Boilers Demonstration Project''. In September 1990, Southern Company Services entered into an agreement to conduct the study, with Gulf Power Company providing the 180 megawatt electric (MWe) host site and ABB C-E Services Inc. providing the technology to be demonstrated. This project was undertaken to evaluate the nitrogen oxides (NO{sub x}) reduction potential of several variations of the Low NO{sub x} Concentric Firing System (LNCFS{trademark}) when applied to tangentially fired (T-fired) boilers. The project consisted of replacing the existing coal and air nozzles with new nozzles and adding overfire air. Three versions of the LNCFS system were tested: Level 1 consisted of new coal nozzles and close-coupled overfire air; Level 2 used the same burners but separated the overfire air; and Level 3 used both close-coupled and separated overfire air. The performance objectives were as follows: (1) to determine the short-term and long-term NO{sub x} emissions reduction capabilities and impact on unit performance of the low-NO{sub x} combustion technologies of LNCFS Levels 1, 2, and 3 when implemented in a stepwise manner on a T-fired boiler operating under normal dispatch conditions, the NO{sub x} reduction objective was 50%; (2) to compare the performance and cost effectiveness of these technologies; and (3) to determine the relationship between operating parameters (e.g., unit load, percent overfire air) and NO{sub x} emissions and other unit performance indicators, such as unburned carbon, carbon monoxide (CO) level, and air toxics. All goals were met in the demonstration project, which was conducted at Gulf Power's Plant Lansing Smith Unit No. 2 (rated at 180 MWe, but capable of operation at 200 MWe).