You, Xiaozhou
(2002)
Activated Carbon Sulfur Impregnation through Hydrogen Sulfide Oxidation.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Activated carbon adsorption is a most promising technology for reducing mercury emissions from coal-fired power plants (CFPPs) because of its high efficiency to remove gas-phase mercury, especially when activated carbon is impregnated with elemental sulfur.The present study provides preliminary information about activated carbon impregnation with sulfur through H2S oxidation. Impregnation conducted in the temperature range of 20-200C showed that the maximum sulfur loading can be achieved at 100C (up to 27% after 10 minutes), but the reaction at room temperature achieved 13% sulfur loading, which is also considered sufficient for enhanced mercury uptake. Sulfur loading increased with prolonged reaction time in the range from 5 to 30 minutes. 10 minutes was found to be sufficient to achieve substantial sulfur deposition using 25% H2S in the influent. The presence of excess oxygen is essential to promote the reaction and can increase sulfur loading up to 3 times at room temperature. Furthermore, sulfur content of impregnated carbon increased with the increase in H2S concentration from 2.5% to 25%. However, impregnation with low H2S concentration (2.5%) resulted in more efficient conversion. Carbons impregnated under all experimental conditions investigated in this study exhibited high thermal stability below 210C, which demonstrates the potential of these sorbents to be applied for mercury adsorption under realistic process conditions. Sulfur deposited on activated carbon through H2S oxidation can be completely removed by heat treatment above 400C.Hydrogen treatment was found to substantially remove acidic functional groups from BPL carbon surface and inhibit active sites from catalyzing H2S oxidation at room temperature. Other surface modifications such as oxidation and acid washing showed limited impact on H2S oxidation.Performances of five virgin carbons tested in this study (BPL, PCB, F400, BD, and Centaur) varied greatly with the highest sulfur loading at room temperature achieved by Centaur (above 40%) and the lowest by BD (below 5%). No direct relationship was found between sulfur loading and surface properties, such as total acidity, functional group types, basicity, and total surface area.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
1 April 2002 |
| Date Type: |
Completion |
| Defense Date: |
19 March 2002 |
| Approval Date: |
1 April 2002 |
| Submission Date: |
27 March 2002 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Civil and Environmental Engineering |
| Degree: |
MSCE - Master of Science in Civil Engineering |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Activated carbon; Adsorption; Coal-fired power plants; Hydrogen sulfide; Mercury; Sulfur impregnation |
| Other ID: |
http://etd.library.pitt.edu:80/ETD/available/etd-03272002-185859/, etd-03272002-185859 |
| Date Deposited: |
10 Nov 2011 19:33 |
| Last Modified: |
15 Nov 2016 13:37 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/6601 |
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