NO sub x and N sub 2 O formation in pressurized fluidized-bed combustion tests
- Chalmers Univ. of Tech., Goeteborg (Sweden). Dept. of Energy Conversion Lawrence Livermore National Lab., CA (USA)
- Chalmers Univ. of Tech., Goeteborg (Sweden). Dept. of Energy Conversion
Batch combustion tests have been performed in a small bubbling fluidized-bed reactor with the objective of establishing process variable effects on the formation of NO{sub x} (NO and NO{sub 2}) and N{sub 2}O in the combustion of coals of various rank. The reactor has been operated both in a differential mode with once-through gas flow for the purpose of studying primary production of nitrogen oxides, and in an integral mode with recycle-gas flow for the purpose of studying secondary heterogeneous reactions of the nitrogen oxides. The pressure range studied extends from atmospheric pressure to 20 bar. Net NO{sub x} production is found to decrease significantly with increasing pressure at least for moderate fuel concentrations in the bed. Increasing fuel concentration reduces strongly net NO{sub x} production for all pressures, implying that heterogeneous contact of the primary NO{sub x} with burning fuel surfaces is an important reduction mechanism for NO{sub x}. In a sulfated limestone bed N{sub 2}O formation is found to be almost an order of magnitude lower than the levels reported in recent field measurements on circulating fluidized-bed (CFB) boilers. In a quartz bed however, much higher N{sub 2}O levels are obtained. Consequently it is concluded that heterogeneous decomposition of N{sub 2}O over the limestone surface is an important contributor to the N{sub 2}O chemistry. Experiments performed with NO-doped combustion air show that most of the N{sub 2}O formation is from the heterogeneous NO{sub x} reduction over burning fuel surfaces. Another, and generally smaller source of N{sub 2}O is the volatiles combustion. 15 refs., 9 figs., 1 tab.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- Sponsoring Organization:
- SENEA; Statens Energiverk, Stockholm (Sweden)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5970244
- Report Number(s):
- UCRL-JC-105150; CONF-910424--4; ON: DE91008737; CNN: 276 362-2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010800* -- Coal
Lignite
& Peat-- Waste Management
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL
COMBUSTION
COMBUSTORS
ENERGY SOURCES
FLUIDIZED BEDS
FLUIDIZED-BED COMBUSTION
FLUIDIZED-BED COMBUSTORS
FOSSIL FUELS
FUELS
MATERIALS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
NITROUS OXIDE
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE TESTING
SYNTHESIS
TESTING
THERMOCHEMICAL PROCESSES