Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Coal-water mixture combustion using oxygen-enriched air and staged firing

Conference · · Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States)
OSTI ID:5994613

Coal-water mixture (CWM) combustion experiments using oxygen-enriched air were conducted in an oil-designed 700-hp watertube boiler using a bituminous CWM. The results indicated that the use of oxygen-enriched air increased carbon burnout, reduced uncontrolled fly ash emissions, and reduced combustion air preheating requirements. The boiler efficiency increased because of reduced flue gas heat losses. The improvement in boiler performance compared to an experiment without oxygen enrichment was significant when using only 2-3 percent enrichment of air (23-24 volume percent oxygen). Using combustion air enriched to 22.7 percent oxygen by volume, the required air preheating temperature was reduced to 192/degree/F as compared to 325/degree/F required with no oxygen enrichment, while the carbon conversion efficiency at full boiler load was increased from 95.0 percent to 97.4 percent. Experiments on CWM combustion were also conducted using staged firing with and without oxygen-enriched air. The NO/sub x/ reduction achieved at a first-stage air/fuel stoichiometric ratio of 0.76 was about 33 percent, but it was accompanied by a reduction in combustion efficiency and an increase in particulate emissions. The use of oxygen-enriched air in the burner zone increased flame stability and carbon burnout while maintaining the effectiveness of staged combustion; however, additional experiments are needed to optimize burner-operating parameters to achieve significant NO/sub x/ reduction.

Research Organization:
Department of Energy, Pittsburgh, PA (USA)
OSTI ID:
5994613
Report Number(s):
CONF-870802-
Journal Information:
Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States), Journal Name: Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States) Vol. 32:4; ISSN ACFPA
Country of Publication:
United States
Language:
English