Basic research on natural gas combustion phenomena--catalytic combustion. Annual report 1986. Report for 15 January 1986-14 January 1987
The intrinsic activity of a series of lanthanum perovskite catalysts for catalytic methane oxidation was determined by temperature-programmed reaction and stationary-state order of reaction experiments. The catalysts were prepared by conventional precipitation of nitrate salts, calcined in oxygen, and characterized by x-ray diffraction, BET surface area, and temperature-programmed evolution of oxygen. The rates of catalytic methane oxidation were first order in methane partial pressure and half-order in oxygen partial pressure. The kinetic studies suggested that methane oxidation occurred in two parallel reaction paths over different active centers. The greatest influence on the performance of the perovskite catalysts was loss of surface area by sintering at elevated temperature. When normalized to surface area, the activity of the first-row transition-metal lanthanates increased in the order LaCrO/sub 3/ < LaFeO/sub 3/ < LaMnO/sub 3/ < LaCoO/sub 3/ < LaNiO/sub 3/ which inversely correlates with their phase stability. Changes in metal oxide stoichiometry, increased oxygen anion vacancy concentration, and changes in the transition-metal cation valence state had lesser influence on combustion activity.
- Research Organization:
- SRI International, Menlo Park, CA (USA)
- OSTI ID:
- 6272700
- Report Number(s):
- PB-87-213153/XAB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
33 ADVANCED PROPULSION SYSTEMS
GAS TURBINE ENGINES
CATALYTIC COMBUSTORS
METHANE
OXIDATION
NATURAL GAS
COMBUSTION PROPERTIES
EFFICIENCY
ALKANES
CHEMICAL REACTIONS
COMBUSTORS
ENERGY SOURCES
ENGINES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
HEAT ENGINES
HYDROCARBONS
INTERNAL COMBUSTION ENGINES
ORGANIC COMPOUNDS
034000* - Natural Gas- Combustion
330103 - Internal Combustion Engines- Turbine