A novel technique for simultaneous reduction of nitrous- and nitrogen oxides emissions from a bubbling fluidized-bed combustor

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:288010

Hosoda, Hideo; Hirama, Toshimasa ^[1]; Nakanishi, Osamu; Ninomiya, Yoshihiko ^[2]

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1. Hokkaido National Industrial Research Inst., Sapporo (Japan). Dept. of Resources and Energy Engineering
2. Chubu Univ., Kasugai, Aichi (Japan). Dept. of Industrial Chemistry

A new technology to reduce nitrous oxide (N{sub 2}O) emission, the Improved Three-Stage Combustion System (ITS System), is proposed based on the experiences of two-stage combustion and fuel gas reburning in bubbling fluidized bed coal combustion (BFBC). In the ITS System, the primary combustion zone is kept in an oxygen-deficient condition, the secondary zone consists of fuel gas reburning in an oxygen-deficient condition, and the tertiary zone is in a condition of oxygen excess. The performance of the ITS System under coal combustion conditions was examined with an experimental BFBC having an inner diameter of 0.16 m and a height of 3.0 m. Propane gas mixed with air was fed through a secondary air injection port to accelerate the thermal decomposition reaction of N{sub 2}O by raising freeboard temperature and to promote chemical reduction reactions of N{sub 2}O and nitrogen oxides (NO{sub x}) in an oxygen-deficient condition. At a maximum freeboard temperature of approximately 925 C, the ITS System made it possible simultaneously to reduce N{sub 2}O by over 85% and NO{sub x} by 60% in comparison with emission levels of those gases in single-stage combustion.

• OSTI ID: 288010
• Report Number(s): CONF-950522--; ISBN 0-7918-1305-3
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
AIR POLLUTION ABATEMENT
COAL
COCOMBUSTION
COMBUSTION PRODUCTS
DESIGN
FLUIDIZED-BED COMBUSTION
FLUIDIZED-BED COMBUSTORS
FUEL-AIR RATIO
NITROGEN OXIDES
NITROUS OXIDE
OPERATION
PROPANE
RECYCLING
STAGED COMBUSTION