Reduction of N{sub 2}O over char and bed material from CFBC

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:287945

Johnsson, J E; Dam-Johansen, K ^[1]

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1. Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering

The decomposition and reduction of N{sub 2}O over char and bed material from a CFBC burning wood chips, bituminous coal and coke was measured in a laboratory fixed bed reactor. The char was very active for N{sub 2}O decomposition and reduction in inert atmosphere, and especially the char from burning wood chips had a high activity and a large BET-surface area. The addition of O{sub 2} or CO to the feed gas had only minor influence on the activity of the chars. Bed material (sand + ash) had a low activity for N{sub 2}O decomposition in inert atmosphere, although the activity increased at temperatures above 1,150 K. However, bed material from all three fuels showed at least a 10-fold increase in activity at reducing conditions. The catalytic activity of bed material decreases if oxygen is present, even if the gas mixture is fuel rich. At stoichiometric conditions (0.5 vol% O{sub 2} and 1.0 vol% CO) the activity is low, about the same as in inert atmosphere. It was estimated that char and bed material both contribute to the heterogeneous decomposition and reduction of N{sub 2}O in a CFBC. At staged conditions and no limestone addition, decomposition of N{sub 2}O over bed material and reduction by char will be of importance in the reducing regions, but reduction by char will dominate in oxidizing regions.

• OSTI ID: 287945
• Report Number(s): CONF-950522--; ISBN 0-7918-1305-3
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
09 BIOMASS FUELS
ASHES
BITUMINOUS COAL
CATALYTIC EFFECTS
CHARS
CIRCULATING SYSTEMS
COCOMBUSTION
COKE
COMBUSTION KINETICS
DECOMPOSITION
EXPERIMENTAL DATA
FLUIDIZED-BED COMBUSTION
NITROUS OXIDE
REDUCTION
STAGED COMBUSTION
WASTE PRODUCT UTILIZATION
WOOD WASTES