Kinetic combustion experiments in a pressurized fluidized bed

Conference · Thu Feb 14 23:00:00 EST 1991

OSTI ID:6089996

Wallman, P H ^[1]; Carlsson, R C.J. ^[2]

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1. Chalmers Univ. of Tech., Goeteborg (Sweden). Dept. of Energy Conversion Lawrence Livermore National Lab., CA (USA)
2. Chalmers Univ. of Tech., Goeteborg (Sweden). Dept. of Energy Conversion

Batch combustion experiments have been performed in a bench-scale pressurized fluidized bed with the objective of establishing combustion rates under typical pressurized fluidized bed conditions. Resulting combustion conversion vs. time relationships show that pressure has no significant effect on the combustion rates of a medium-volatile bituminous coal over a wide range of practically important combustion conditions: fluidized bed temperature 700-800 C, coal particle size 0.3-4.8mm, and O{sub 2} concentration 3-7%. Pressures of 0.2, 1 and 2 MPa are studied. The explanation of the lack of a pressure effect on the overall combustion kinetics derives from mass-transfer controlled kinetics: pressure increases the driving force for O{sub 2} mass transfer by increasing O{sub 2} partial pressure but reduces diffusivity at the same time. Pressure-insensitive combustion kinetics are predicted to lead to relatively high char concentrations in pressurized beds. This in turn can lead to low combustion efficiency (by excessive loss of attrited char) but also to low emissions of NO{sub x} (high char concentrations favor NO{sub x} reduction). Measured burning particle temperatures are also relatively low, further promoting low levels of NO{sub x}. 15 refs., 7 figs., 1 tab.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• Sponsoring Organization: DOE; SENEA; USDOE, Washington, DC (USA); Statens Energiverk, Stockholm (Sweden)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6089996
• Report Number(s): UCRL-JC-106115; CONF-9103145--1; ON: DE91009734; CNN: 276 398-1
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010800 -- Coal
Lignite
& Peat-- Waste Management
014000* -- Coal
Lignite
& Peat-- Combustion
AIR POLLUTION ABATEMENT
BENCH-SCALE EXPERIMENTS
BITUMINOUS COAL
BLACK COAL
CARBONACEOUS MATERIALS
CARBONATE ROCKS
CHALCOGENIDES
CHARS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL
COMBUSTION
COMBUSTION KINETICS
COMBUSTORS
DEVOLATILIZATION
ELEMENTS
ENERGY SOURCES
FLUIDIZED-BED COMBUSTION
FLUIDIZED-BED COMBUSTORS
FOSSIL FUELS
FOSSIL-FUEL POWER PLANTS
FUELS
HIGH TEMPERATURE
KINETICS
LIMESTONE
LOW PRESSURE
MASS TRANSFER
MATERIALS
MEDIUM PRESSURE
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PARTICLE SIZE
POLLUTION ABATEMENT
POWER PLANTS
PRESSURIZATION
PYROLYSIS PRODUCTS
REACTION KINETICS
ROCKS
SEDIMENTARY ROCKS
SIZE
SORBENT INJECTION PROCESSES
TEMPERATURE DEPENDENCE
THERMAL POWER PLANTS
THERMOCHEMICAL PROCESSES
TIME DEPENDENCE
VERY HIGH TEMPERATURE