A fixed bed study of formation and reduction of nitric oxide over different sand materials at fluidized bed temperatures and concentrations

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

OSTI ID:287946

Olanders, B; Stroemberg, D ^[1]

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1. Chalmers Univ. of Technology and Univ. of Goeteborg (Sweden). Dept. of Inorganic Chemistry

There are several homogeneous and heterogeneous reactions that are of importance for the formation and reduction of nitric oxide at fluidized bed conditions. This investigation concerns three heterogeneous processes, namely the reduction of nitric oxide with carbon monoxide, the formation of nitric oxide from ammonia and oxygen and the oxidation of carbon monoxide. The reactions were studied in a fixed-bed quartz reactor with quartz, silver sand, olivine sand as bed materials in the temperature range 600--950 C. The residence time within the bed was 50--380 ms and the gas concentrations 380--1,000 ppm nitric oxide, 400--7,600 ppm carbon monoxide, 1,000 ppm NH{sub 3} and 1% oxygen. The gases were diluted in argon. The natural sands have more catalytic effect than the quartz of analytical grade. Olivine sand was the most active of the sands investigated. The crystalline structure of olivine sand changed under oxidizing and reducing conditions. Olivine sand contains iron oxide, which gives a more catalytic surface compared to the natural quartz sand. Drying of the gases reduced the oxidation of carbon monoxide substantially on quartz and silver sand, but only a few percent on olivine sand, probably because of the high iron content of olivine sand. The activation energy and preexponential factor for the reduction of nitric oxide with carbon monoxide over olivine sand were determined to 76.5 kJ/mole and 1,905 m{sup 3}/kmole s respectively.

• OSTI ID: 287946
• Report Number(s): CONF-950522--; ISBN 0-7918-1305-3
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
40 CHEMISTRY
54 ENVIRONMENTAL SCIENCES
AMMONIA
CATALYTIC EFFECTS
CHEMICAL REACTION YIELD
COMBUSTION KINETICS
DOLOMITE
FLUIDIZED-BED COMBUSTION
FLUIDIZED-BED COMBUSTORS
LIMESTONE
NITRIC OXIDE
OXIDATION
REDUCTION
SILICATE MINERALS
SORBENT INJECTION PROCESSES