Modeling of wood reburning for NO{sub x} control

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:427875

Adams, B R; Harding, N S

This study examines the use of wood reburning for NO{sub x} reduction in a cyclone-fired boiler. Reburning is an in-furnace NO{sub x} control technology that uses fuel injected above the main firing system to reduce NO formed in the main heat release zone. Bench- and pilot-scale work done over the past several years suggest that NO{sub x} reductions up to sixty percent are possible using reburning under the right conditions. The practical implementation of reburning technology depends upon the ability to contact the reburning fuel with NO formed in the cyclone barrel at the optimum stoichiometry for the maximum time. Thus, reburning effectiveness in practical systems is determined by the performance of the mixing system. This paper describes the results of a computer modeling study of the TVA Allen Station Unit No. 2 to evaluate various reburning fuel injection and overfire air injection designs and estimate the NO{sub x} reduction potential using wood as a reburning fuel. Results of this study showed the best mixing was obtained using opposed fired reburning injectors located as close to the cyclone barrels as possible with opposed wall overfire air injectors operating at as high a velocity as pressure drop constraints allow. Under these conditions, NO{sub x} reductions of {approximately}45% are expected. When the wood carrier air is replaced by flue gas, the expected NO{sub x} reduction increases to {approximately}55%. Further NO{sub x} reduction was possible if the stoichiometric constraints in the reburning zone could be relaxed to allow deeper staging.

• OSTI ID: 427875
• Report Number(s): CONF-961006--; ISBN 0-7918-1795-4
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
09 BIOMASS FUELS
20 FOSSIL-FUELED POWER PLANTS
AIR POLLUTION CONTROL
COAL
COMPUTERIZED SIMULATION
FOSSIL-FUEL POWER PLANTS
NITROGEN OXIDES
STAGED COMBUSTION
WOOD WASTES