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Permanent link (DOI): https://doi.org/10.7939/R35T5K
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Entrained Flow Gasification of Oil Sand Coke Open Access
- Other title
Oil sand coke
- Type of item
- Degree grantor
University of Alberta
- Author or creator
- Supervisor and department
Gupta, Rajender (Department of Chemical and Materials Engineering )
- Examining committee member and department
Wu, Hongwei (Dept of Chemical Engineering, Curtin university)
Gray, Murray R ( Department of Chemical and Materials Engineering, U of A)
Gupta, Rajender (Department of Chemical and Materials Engineering, U of A )
Xu, Zhenghe ( Department of Chemical and Materials Engineering, U of A)
Kumar, Amit (Department of Mechanical Engineering, U of A)
Department of Chemical and Materials Engineering
- Date accepted
- Graduation date
Doctor of Philosophy
- Degree level
The effect of blending woody biomass material with fluid coke and coal on the co-pyrolysis process was investigated in an entrained flow gasifier. The SEM results showed a particle size decrease and shape change from needle to spherical as the temperature was increased. Agglomeration between particles occurred above 1250°C due to the low ash fusion temperature of biomass. The results were verified by particle size distribution analysis. Reactivity of pyrolyzed blended and pure fuels decreased with increasing temperature. No agglomeration was found for blends of coal and coke. Pyrolysis at high temperatures also showed a significant surface area development for coke.
The combined effects of the steam and oxygen concentrations and coal/coke blending ratio were investigated in gasification of fluid coke with sub-bituminous and lignite coals using Response Surface Methodology (RSM). Six response variables were considered: H2, CO and syngas production, H2/CO ratio, gasification efficiency, and carbon conversion. Experiments were conducted over a temperature range of 1000-1400°C, using steam and oxygen to carbon weight ratios of (0.9-4.3) and (0-0.4), respectively. Using RSM, the interactions between different factors were determined. The response variable correlations were employed to determine the experimental conditions under which the H2 production was maximized.
The intrinsic rates for Char-O2, char-CO2, and char-H2O reactions were developed for coke. The validity of thermogravimetric determination of kinetics was discussed in depth. Four surface area measurement techniques were used to normalize the specific reaction rate: N2-BET, GCMC-NLDFT and DR models, and active surface area measured by CO2 chemisorption. The objective was to find the specific surface area which gives the best reduction in the variability of reaction rate r(X) using the regressor variable S(X). Overall ASA was found to be the best regressor.
A numerical simulation was developed for entrained flow gasifier using the underlying physics and the intrinsic rates. The intrinsic rates were successfully implemented into the Fluent CFD code via user defined functions. The energy content of particle on a dry basis was conserved by properly calculating the formation enthalpy of volatile matter. The results were compared to the experiment data for carbon conversion, H2, CH4, CO and CO2 concentrations. In general, a fair agreement between simulation and experiment results were found.
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