Modeling a fluidized-bed coal gasification reactor

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5633307

Ma, R P

A steady-state model has been developed to simulate the North Carolina State University pilot-scale fluidized bed coal gasification reactor. The model involves instantaneous devolatilization of coal in the free-board region and char combustion and gasification in the fluidized bed. A two-phase representation of the fluidized bed incorporates the phenomena of jetting, bubbling, slugging, and mass and heat transfer between phases. The model has the ability to predict both concentration and temperature profiles, the latter being useful in the prediction of possible clinker formation at hot spots within the bed. The model has been successfully used to simulate the gasification of a devoltailized Western Kentucky bituminous coal and a New Mexico subbituminous coal. Effects of the molar steam/carbon feed ratio, molar oxygen/carbon feed ratio, fluidized bed height, and pressure on gasifer performance have been studied parametrically with the two-phase model. The molar steam/carbon feed ratio has moderate negative effects on the reactor performance. The approach to water-gas shift equilibrium is favored by lowering the steam/carbon ratio and/or raising oxygen/carbon ratio. The effects of moderate change sin bed height and pressure on the gasifier performance are small, implying that the reactor can be operated at any bed height and pressure near the targeted operating conditions without significantly affecting the gasifier output. Organic sulfur distributions in a New Mexico subbituminous coal and a Texas lignite have been determined by a nonisothermal technique. A three-stage well-mixed bed model incorporating the hydrodesulfurization kinetics of Yergey et al. was used to correlate the evolution rate of H{sub 2}S from coal or char during gasification.

• Research Organization: North Carolina State Univ., Raleigh, NC (USA)
• OSTI ID: 5633307
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
BITUMINOUS COAL
BLACK COAL
BROWN COAL
BUBBLES
CARBON
CARBON COMPOUNDS
CARBON OXYSULFIDE
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHARS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL
COAL GASIFICATION
COMBUSTION
DESULFURIZATION
DEVOLATILIZATION
DIMENSIONS
ELEMENTS
ENERGY SOURCES
ENERGY TRANSFER
FEDERAL REGION IV
FEDERAL REGION VI
FLUIDIZED BEDS
FOSSIL FUELS
FUELS
GAS GENERATORS
GASIFICATION
HEAT TRANSFER
HYDROGEN COMPOUNDS
HYDROGEN SULFIDES
KENTUCKY
KINETICS
LIGNITE
MASS TRANSFER
MATERIALS
MATHEMATICAL MODELS
NEW MEXICO
NONMETALS
NORTH AMERICA
NORTH CAROLINA
OXIDATION
OXYGEN
PERFORMANCE TESTING
PRESSURE DEPENDENCE
PYROLYSIS PRODUCTS
QUANTITY RATIO
REACTION KINETICS
STEAM
SUBBITUMINOUS COAL
SULFIDES
SULFUR COMPOUNDS
SULFUR CONTENT
SYNTHESIS
TEMPERATURE DISTRIBUTION
TESTING
TEXAS
THERMOCHEMICAL PROCESSES
USA