Performance of natural gas cofiring on a coal-fired spreader stoker
- Acurex Corp., Mountain View, CA (United States)
- Coen Co., Burlingame, CA (United States)
- Gas Research Inst., Chicago, IL (United States)
- East Ohio Gas, Cleveland, OH (United States)
- Dover Light and Power, Dover, OH (United States)
Tightening environmental regulations create special challenges with coal fired stoker boilers where the moving bed firing configuration greatly limits operational flexibility. For stokers, gas cofiring is an efficient way to achieve compliance, enhance performance and treat operational problems. Firing from 5 to 30% of total heat input through side-wall gas burners offers a spectrum of benefits including faster and cleaner warmup and light-off, reduced opacity, recovered derate, coal flexibility, and improved turndown and load following. In this project, the4 165,000 lb/hr Babcock and Wilcox spreader stoker boiler at Dover Light and Power was retrofit with dual Coen gas fired burners rated at 37 MWBtu/hr each. The burners were positioned on opposite sidewalls 6 feet above the grate and offset 8 feet. A high-pressure drop burner design with a small throat opening was used to increase flame penetration into the combustion gases and minimize pressure part modifications. The gas burners in this staggered configuration promote better mixing and heat distribution and reduce the load per unit area on the grate. The unit has been operated since August 4, 1995, cofiring gas a majority of the time. Test results show significant improvement in emissions efficiency, and operability. Particulate emissions at the electrostatic precipitator inlet were reduced by an average of 25% with 10% cofire. Firing from 8 to 10% of total heat input from gas increased boiler efficiency 2 to 3% due to improved carbon utilization and reduced excess air. Carbon in flyash was reduced by 35 to 40% by cofiring. Excess oxygen was a function of coal quality and was reduced up to 2 to 3% with gas cofiring.
- OSTI ID:
- 550010
- Report Number(s):
- CONF-961006--; ISBN 0-7918-1796-2
- Country of Publication:
- United States
- Language:
- English
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