A study of factors influencing NO/sub x/ emissions from spreader-stoker wood-residue fired boilers
Parameters influencing NO/sub x/ emission rates from spreader-stoker, wood-residue fired, industrial boilers were investigated at 4 units. The major operating conditions affecting wood-residue fired boiler NO/sub x/ emission were excess air, fuel nitrogen content, the amount of air supplied through the grate, and the fuel moisture content. Excess air use had the greatest effect on NO/sub x/ emissions from wood-residue fired boilers. NO/sub x/ emissions were proportional to the square-root of the flue gas oxygen concentrations. The minimum practical excess air use was limited by the production of high CO and smoke emissions that developed at low excess air use. Minimum CO emission rates occurred at boiler exit gas oxygen concentrations between 3 and 6 percent, on a dry gas basis. High fuel nitrogen contents increased NO/sub x/ emissions at all practical excess air levels. Fuel moisture contents between 40 and 50 percent diminished the formation of NO/sub x/. Dry fuels with high nitrogen contents produced high NO/sub x/ emission rates. Higher emission rates also occurred when the fuel moisture content was greater than 50 percent. At low excess air levels, undergrate air equivalence ratios (oxygen available/stoichiometric oxygen required) increasing from 0.2 to 0.9, increased NO/sub x/ emissions. At higher excess air levels, NO/sub x/ emission rates increased with increasing equivalence ratios until a ratio of 0.75 was reached, and then, at one boiler burning high nitrogen content fuel, decreased. The reasons these operating conditions influence NO/sub x/ emission levels are discussed.
- Research Organization:
- NCASI, Corvallis, OR
- OSTI ID:
- 5904987
- Report Number(s):
- CONF-850612-
- Journal Information:
- Proc., Annu. Meet., Air Pollut. Control Assoc.; (United States), Vol. 4; Conference: Air Pollution Control Association annual meeting and exhibition, Detroit, MI, USA, 16 Jun 1985
- Country of Publication:
- United States
- Language:
- English
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42 ENGINEERING
54 ENVIRONMENTAL SCIENCES
CARBON MONOXIDE
AIR POLLUTION MONITORING
FUEL-AIR RATIO
OPTIMIZATION
INDUSTRIAL PLANTS
REFUSE-FUELED BOILERS
NITROGEN OXIDES
FLUE GAS
PERFORMANCE TESTING
SMOKES
WOOD
COMBUSTION
AIR
COMPARATIVE EVALUATIONS
MOISTURE
NITROGEN
QUANTITY RATIO
STOKERS
WOOD WASTES
AEROSOLS
BOILERS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
COLLOIDS
DISPERSIONS
ELEMENTS
FLUIDS
FUEL FEEDING SYSTEMS
FUEL SYSTEMS
GASEOUS WASTES
GASES
NITROGEN COMPOUNDS
NONMETALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
RESIDUES
SOLID WASTES
SOLS
TESTING
THERMOCHEMICAL PROCESSES
WASTES
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140504 - Solar Energy Conversion- Biomass Production & Conversion- (-1989)
421000 - Engineering- Combustion Systems
500200 - Environment
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