Catalytic reduction of SO2 over supported transition-metal oxide catalysts with C2H4 as a reducing agent |
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Authors: | Ching-Huei Wang Shiow-Shyung Lin Pei-Chang Sung Hung-Shan Weng |
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Affiliation: | a Department of Chemical Engineering, Kao Yuan Institute of Technology, Kaohsyung 821, Taiwan b Department of Environmental Engineering and Health, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan c Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan |
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Abstract: | This work investigates performances of supported transition-metal oxide catalysts for the catalytic reduction of SO2 with C2H4 as a reducing agent. Experimental results indicate that the active species, the support, the feed ratio of C2H4/SO2, and pretreatment are all important factors affecting catalyst activity. Fe2O3/γ-Al2O3 was found to be the most active catalyst among six γ-Al2O3-supported metal oxide catalysts tested. With Fe2O3 as the active species, of the supports tested, CeO2 is the most suitable one. Using this Fe2O3/CeO2 catalyst, we found that the optimal Fe content is 10 wt.%, the optimal feed ratio of C2H4/SO2 is 1:1, and the catalyst presulfidized by H2+H2S exhibits a higher performance than those pretreated with H2 or He. Although the feed concentrations of C2H4:SO2 being 3000:3000 ppm provide a higher conversion of SO2, the sulfur yield decreases drastically at temperatures above 300 °C. With higher feed concentrations, maximum yield appears at higher temperatures. The C2H4 temperature-programmed desorption (C2H4-TPD) and SO2-TPD desorption patterns illustrate that Fe2O3/CeO2 can adsorb and desorb C2H4 and SO2 more easily than can Fe2O3/γ-Al2O3. Moreover, the SO2-TPD patterns further show that Fe2O3/γ-Al2O3 is more seriously inhibited by SO2. These findings may properly explain why Fe2O3/CeO2 has a higher activity for the reduction of SO2. |
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Keywords: | Reduction of SO2 Conversion of SO2 Yield of elemental sulfur Fe2O3/CeO2 TPD |
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