Elemental sulphur (S<sup>0</sup>) is removed from sour gas deposits (high H<sub>2</sub>S) during refinement. The resulting S<sup>0</sup> is often stored onsite when the costs of shipping S<sup>0</sup> to market exceeds the costs of storing it in large above ground blocks. With the aid of acidiphilic bacteria, atmospheric air and water oxidize S<sup>0</sup> to sulphate (SO<sub>4</sub><sup>2-</sup>). Long term storage is under consideration; however, oxidation rates and the role of each oxygen source (O<sub>2(g)</sub> and H<sub>2</sub>O) is not clear.
S<sup>0</sup> oxidation experiments were conducted over a range of temperatures (6-32¡ãC) to investigate reaction rates and isotopic fractionation of O and S isotopes during oxidation. The experiments also investigated the effect of integrating S<sup>0</sup> oxidizing microorganisms and available nutrients on both the reaction rates and isotope fractionation. Results indicated > 95% of total SO<sub>4</sub><sup>2-</sup> generated can be attributed to autotrophic microbial activity. Experiments conducted in a nutrient rich mineral solution showed rates increase with temperature from 0.16 (6¡ãC) to 0.98 (32¡ãC) ¦Ìg S<sup>0</sup> cm<sup>-2</sup> d<sup>-1</sup> (Q<sub>10</sub> ¡Ö 1.7 - 1.9). Experiments conducted in a nutrient poor solution (deionized water) showed oxidation rates did not increase with temperature (0.06 to 0.08 ¦Ìg S<sup>0</sup> cm<sup>-2</sup> d<sup>-1</sup>) between 12 and 32¡ãC. Oxygen isotope analysis of the generated SO<sub>4</sub><sup>2-</sup> indicated essentially all oxygen incorporated into the SO<sub>4</sub><sup>2-</sup> originated from H<sub>2</sub>O. In addition, effluent samples obtained from S<sup>0</sup> block effluent at SCL indicated ¦Ä<sup>18</sup>O<sub>(SO4)</sub> generally reflected the ¦Ä<sup>18</sup>O<sub>(H2O)</sub> in the system at the time of oxidation. While covering the S<sup>0</sup> blocks with an impermeable cover would undoubtedly minimize total SO<sub>4</sub><sup>2-</sup> accumulation in block effluent, the results of this study suggest ¦Ä<sup>18</sup>O<sub>(SO4)</sub> can also be used to track water movement through the block.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-08292009-180320 |
| Date | 21 September 2009 |
| Creators | Smith, Laura Ann |
| Contributors | Hendry, Jim, Wassenaar, Len, Ansdell, Kevin, Farrell, Richard |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-08292009-180320/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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