Modeling studies in fixed-bed coal gasification

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5967676

Bhattacharya, A

A dynamic model of a fixed bed coal gasification reactor has been developed and coded into a simulation program. The model incorporates radial and axial variations of temperature and composition within the reactor, and may also be used to simulate moving bed reactors. Results from the model have been compared with experimental data from a fixed bed unit operating at Washington University. Reasonable agreement at initial times is obtained with the temperature profiles measured in the laboratory reactor. In the past, verification of models was limited to matching flow rates and compositions of outlet gas. These variables are not very sensitive to the actual profiles inside the gasifier. This work attempts to fill this gap by matching experimental temperature data to simulation values. Several aspects are investigated to explain the mismatch of temperature profiles at large times. This deterioration is attributed to the changing solid conversion profile with time, which depend heavily on effective reaction rates. Uncertainty in the effective reaction rates for the char + oxygen and char + steam reactions is caused by an uncertainty in the value of the mass transfer coefficient through the gas film. The effect of including axial dispersion of energy is also investigated, and is found to be marginal compared with the above effect.

• Research Organization: Washington Univ., St. Louis, MO (USA)
• OSTI ID: 5967676
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
COAL GASIFICATION
MATHEMATICAL MODELS
GAS GENERATORS
CHARS
CHEMICAL REACTION KINETICS
MASS TRANSFER
OXYGEN
SIMULATION
STEAM
TEMPERATURE DISTRIBUTION
ELEMENTS
GASIFICATION
KINETICS
NONMETALS
PYROLYSIS PRODUCTS
REACTION KINETICS
THERMOCHEMICAL PROCESSES
010404* - Coal
Lignite
& Peat- Gasification