Novel Adsorbents for Acid Gas Treatment in Process Streams

• Author / Creator

  Rezaei, Sabereh

• The objective of this dissertation was to find novel adsorbents addressing problems associated with acid gases. They are the most common contaminants in multiple aspects of petroleum processing and combustion gas clean up, which reduce the efficiency of petroleum refining and product quality. This refers to any gas stream containing significant amount of acidic gases such as hydrogen sulfide (H2S) or carbon dioxide (CO2). Engelhard Titanosilicate-2 (ETS-2) has shown to be a promising substrate to load active metal sites for deep H2S removal (to sub-ppm levels) for gas purification applications at room temperature. Because of the high external surface area and the cation exchange capacity of ETS-2, active sites can be highly dispersed and very accessible to H2S molecules making it a novel support material for active metal sites. Copper supported ETS-2 has been found to be a superior H2S scavenger, outperforming the Ag, Ca, and Zn exchanged ETS-2 and a fully developed commercial H2S adsorbent (BASF). A dynamic model based on the rigorous mass balance equations applied to the fixed-bed has analyzed H2S column breakthrough experiments. Temperature-programmed desorption tests provided insight on the material characterization as well as on the relative magnitudes of the H2S-material interactions. Sorption capacity of ETS-2 for Cu2+ ions from aqueous solution through the batch technique was also investigated. It was experimentally shown that ion exchange is the major removal mechanism and up to 89% copper removal was achieved. Low energy input regenerable moisture removal from CO2 streams, which would be generated from a post-combustion capture (PCC) system, has been also studied. A desired desiccant for CO2 drying should have a high moisture capacity at low partial pressure and high selectivity to provide through drying. It also needs to be economically efficient by being regenerable with waste heat and humid air. Engelhard Titanosilicate-10 (ETS-10) materials have been shown to reserve all of these characteristics. Ca-ETS-10 showed the highest moisture capacity for a temperature swing of 30-70 °C and a CO2 feed stream of 50–100% relative humidity compared to that of commercial silica and 4A zeolite.

• Subjects / Keywords

  • H2S
  • ETS-10
  • Gas separation
  • Acid gas treatment
  • Desiccant
  • CO2
  • ETS-2
  • Modelling

• Graduation date

  Spring 2015

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3DR2PN0Q

• 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.