Natural gas combustion in a bed of sand

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:357890

Bulewicz, E M; Kandefer, S; Pilawska, M ^[1]

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1. Cracow Univ. of Technology (Poland)

The combustion of natural gas in a bed of sand has been studied using a laboratory size quartz reactor. Visual observations confirmed earlier qualitative descriptions of the process: above about 900 C the bed material glowing uniformly orange and with sufficient oxygen, efficient combustion. In this work, the effect of changing bed particle size, bed height (mass), mixture stoichiometry and bed temperature, measured at two levels, has been studied and the concentrations of O{sub 2}, CO, NO and NO{sub 2} above the bed were recorded. As expected, the CO concentration rises sharply on the fuel rich side and the NO concentration always peaks close to stoichiometry. With O{sub 2} in excess, the CO is very sensitive to temperature in the neighborhood of 900 C, falling rapidly at higher temperatures. This is attributed to radical chain branching via H + O{sub 2} = OH + O becoming faster than the three body radical recombination reaction leading to the formation of the HO{sub 2} radical. The NO concentration appears to increase with the bed height and not with bed temperature, to which it is quite insensitive. This eliminates the thermal mechanism of NO formation, leaving prompt NO as the only possibility. In the 800--900 C range, when CO oxidation appears to be slow, NO{sub 2} can also be present. This can be accounted for if NO is oxidized mainly by reaction with HO{sub 2}. The results have implications for fluidized bed coal combustion.

• OSTI ID: 357890
• Report Number(s): CONF-9705116--; ISBN 0-7918-1557-9
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
03 NATURAL GAS
AIR POLLUTION
CARBON MONOXIDE
COAL
COMBUSTION KINETICS
FLUIDIZED-BED COMBUSTION
NATURAL GAS
NITROGEN OXIDES
PARAMETRIC ANALYSIS
SAND