CO2 Adsorption Capacities of Gasified Coal Chars

  • Author / Creator
    Sripada, Pavan Pramod
  • Recent interest in the use of post-underground coal gasification (UCG) sites for carbon capture and storage (CCS) has created a need to fundamentally understand the carbon dioxide (CO2) adsorption on gasified and pyrolysed coal chars. More specifically, in this work, the effect of coal properties on the surface area development and subsequently the CO2 adsorption capacities of coal chars are studied. In addition, some design considerations necessary for obtaining reliable adsorption measurements on a volumetric adsorption apparatus have been suggested based on sensitivity analysis on the accuracies on the components of the apparatus. CO2 adsorption isotherms at 45.5oC were obtained for pyrolysed and gasified coal samples. Two pyrolysed chars and four CO2 gasified chars were obtained from different coals at different temperatures. The sorption capacities were in turn compared with the respective raw coal samples. Results indicate that the adsorption capacity of both pyrolysed and gasified char is much higher in comparison to the raw coal samples. In addition, in the case of gasified chars, it was demonstrated that the chars from a sub-bituminous coal (characteristic of very high vitrinite content) had the highest sorption capacity followed by the lignite and bituminous char respectively. Moreover, the pore size distributions indicate enhanced micro and meso-porosity for the chars. The diffusivity decreased with increase in pressure for all the samples. The effective diffusivities in the raw coals were clearly a function of the mesoporosity in the coal. Further, the Dubinin-Astakhov model was found to be consistent with the experimental data.

  • Subjects / Keywords
  • Graduation date
    Fall 2014
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.