Dispersive Diffusion of Gas in Coal: An Experimental Investigation into the Fundamentals of Gas Sorption and Diffusion in Coal

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Author(s)
Primary Supervisor
Gray, Evan
Other Supervisors
Webb, Jim
Sakurovs, Richard
Year published
2014
Metadata
Show full item recordAbstract
Gas diffusion in coals plays an important role in enhanced coalbed methane production, but a consistent picture of diffusion behaviour in coals is yet to emerge. There is no agreement on the most appropriate model, pressure dependence of diffusion coefficients, or the physical explanation to why CH4 diffusion is slower than CCh. The aim of the work towards this Thesis is to determine sorption kinetics more accurately, model them more systematically over a wider range of experimental conditions and resolve discrepancies present in the literature to explain (i) why uptake of gas in coal takes a considerable ...
View more >Gas diffusion in coals plays an important role in enhanced coalbed methane production, but a consistent picture of diffusion behaviour in coals is yet to emerge. There is no agreement on the most appropriate model, pressure dependence of diffusion coefficients, or the physical explanation to why CH4 diffusion is slower than CCh. The aim of the work towards this Thesis is to determine sorption kinetics more accurately, model them more systematically over a wider range of experimental conditions and resolve discrepancies present in the literature to explain (i) why uptake of gas in coal takes a considerable amount of time and (ii) why C02 sorbs faster than CH4. A manometric sorption system was constructed that was optimized for uptake rate measurements. This was used to study the effects of coal-type, particle size, gas-type and mixture, and temperature on sorption kinetics. A gravimetric apparatus was also utilised to measure isotherms for different gases at different fractions of the same coaL Further work combined manometric uptake rate measurements with Small Angle X-Ray Scattering (SAXS) along with an analysis of previously obtained sorption-induced coal swelling kinetic data.
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View more >Gas diffusion in coals plays an important role in enhanced coalbed methane production, but a consistent picture of diffusion behaviour in coals is yet to emerge. There is no agreement on the most appropriate model, pressure dependence of diffusion coefficients, or the physical explanation to why CH4 diffusion is slower than CCh. The aim of the work towards this Thesis is to determine sorption kinetics more accurately, model them more systematically over a wider range of experimental conditions and resolve discrepancies present in the literature to explain (i) why uptake of gas in coal takes a considerable amount of time and (ii) why C02 sorbs faster than CH4. A manometric sorption system was constructed that was optimized for uptake rate measurements. This was used to study the effects of coal-type, particle size, gas-type and mixture, and temperature on sorption kinetics. A gravimetric apparatus was also utilised to measure isotherms for different gases at different fractions of the same coaL Further work combined manometric uptake rate measurements with Small Angle X-Ray Scattering (SAXS) along with an analysis of previously obtained sorption-induced coal swelling kinetic data.
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Thesis Type
Thesis (PhD Doctorate)
Degree Program
Doctor of Philosophy (PhD)
School
School of Biomolecular and Physical Sciences
Copyright Statement
The author owns the copyright in this thesis, unless stated otherwise.
Item Access Status
Public
Subject
Gas diffusion
Manometric sorption system
Coal seam gas
CH4 diffusion