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Direct reduction of sulfur dioxide to elemental sulfur with hydrogen over Sn-Zr-based catalysts / Gi Bo Han in Industrial & engineering chemistry research, Vol. 47 n°14 (Juillet 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4658–4664 Titre : Direct reduction of sulfur dioxide to elemental sulfur with hydrogen over Sn-Zr-based catalysts Type de document : texte imprimé Auteurs : Gi Bo Han, Auteur ; No-Kuk Park, Auteur ; Suk Hoon Yoon, Auteur ; Tae Jin Lee, Auteur Année de publication : 2008 Article en page(s) : p. 4658–4664 Note générale : Bibliogr. p. 4664 Langues : Anglais (eng) Mots-clés : Sulfur  dioxide;  Redox  mechanism;  Conversion Résumé : We conducted the SO2 reduction with H2 over Sn−Zr-based catalysts for the direct sulfur recovery process. The reaction temperature was varied from 250 to 550 °C while using SnO2-only, ZrO2-only, and SnO2−ZrO2 (Sn/Zr = 2/1) catalysts. The highest reactivity was obtained using the SnO2−ZrO2 (Sn/Zr = 2/1) catalyst at 550 °C, for which the SO2 conversion and sulfur selectivity were 98 and 55%, respectively. Also, the following mechanistic pathway was suggested: (1) The elemental sulfur is produced by the direct conversion of SO2 according to the redox mechanism (SO2 + 2H2 → S + 2H2O). (2) The produced sulfur is partially converted into H2S with the hydrogenation (H2 + S → H2S). (3) Finally, the Claus reaction proceeds through Lewis and Brönsted acidic sites (SO2 + 2H2S → 3S + 2H2O). It was estimated that the lattice oxygen vacancies might be active sites for the redox mechanism and the Lewis and Brönsted acidic sites might be related to the pathway of the Claus reaction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800058v [article] Direct reduction of sulfur dioxide to elemental sulfur with hydrogen over Sn-Zr-based catalysts [texte imprimé] / Gi Bo Han, Auteur ; No-Kuk Park, Auteur ; Suk Hoon Yoon, Auteur ; Tae Jin Lee, Auteur . - 2008 . - p. 4658–4664. Bibliogr. p. 4664 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4658–4664 Mots-clés : Sulfur  dioxide;  Redox  mechanism;  Conversion Résumé : We conducted the SO2 reduction with H2 over Sn−Zr-based catalysts for the direct sulfur recovery process. The reaction temperature was varied from 250 to 550 °C while using SnO2-only, ZrO2-only, and SnO2−ZrO2 (Sn/Zr = 2/1) catalysts. The highest reactivity was obtained using the SnO2−ZrO2 (Sn/Zr = 2/1) catalyst at 550 °C, for which the SO2 conversion and sulfur selectivity were 98 and 55%, respectively. Also, the following mechanistic pathway was suggested: (1) The elemental sulfur is produced by the direct conversion of SO2 according to the redox mechanism (SO2 + 2H2 → S + 2H2O). (2) The produced sulfur is partially converted into H2S with the hydrogenation (H2 + S → H2S). (3) Finally, the Claus reaction proceeds through Lewis and Brönsted acidic sites (SO2 + 2H2S → 3S + 2H2O). It was estimated that the lattice oxygen vacancies might be active sites for the redox mechanism and the Lewis and Brönsted acidic sites might be related to the pathway of the Claus reaction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800058v

Effect of O2 on SO2 reduction with CO or H2 over SnO2−ZrO2 catalyst / Gi Bo Han in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10307–10313 Titre : Effect of O2 on SO2 reduction with CO or H2 over SnO2−ZrO2 catalyst Type de document : texte imprimé Auteurs : Gi Bo Han, Auteur ; No-Kuk Park, Auteur ; Tae Jin Lee, Auteur Année de publication : 2010 Article en page(s) : pp. 10307–10313 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : O2--SO2--Reduction--CO--H2--SnO2−ZrO2--Catalyst Résumé : To investigate the effect of the O2 content on the direct sulfur recovery process (DSRP) combined with the hot gas desulfurization (HGD) process with the unreacted O2 emitted from the regeneration process, either CO or H2 was used as a reducing agent for the reduction of SO2 over SnO2−ZrO2 catalyst with a Sn/Zr molar ratio of 2/1. Then, the reaction conditions, including temperature, CO (or H2)/SO2 molar ratio, and space velocity, were optimized to maximize the sulfur yield in the presence and absence of 1 vol % O2. The temperature, CO (or H2)/SO2 molar ratio, and space velocity were varied in the ranges of 300−600 °C, 1.0−4.0, and 1000−30000 h−1, respectively. In SO2 reduction using CO with 1 vol % O2, the temperature, CO/SO2 molar ratio, and space velocity for the maximum sulfur yield were 600 °C, 3.5, and 10000 h−1, respectively, in which case the SO2 conversion and sulfur yield were about 85% and 77%, respectively. In SO2 reduction using H2 with 1 vol % O2, the temperature, H2/SO2 molar ratio, and space velocity optimized for the maximum sulfur yield were 600 °C, 3.0, and 10000 h−1, respectively, in which case the SO2 conversion and sulfur yield were about 89% and 57%, respectively. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900553s [article] Effect of O2 on SO2 reduction with CO or H2 over SnO2−ZrO2 catalyst [texte imprimé] / Gi Bo Han, Auteur ; No-Kuk Park, Auteur ; Tae Jin Lee, Auteur . - 2010 . - pp. 10307–10313. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10307–10313 Mots-clés : O2--SO2--Reduction--CO--H2--SnO2−ZrO2--Catalyst Résumé : To investigate the effect of the O2 content on the direct sulfur recovery process (DSRP) combined with the hot gas desulfurization (HGD) process with the unreacted O2 emitted from the regeneration process, either CO or H2 was used as a reducing agent for the reduction of SO2 over SnO2−ZrO2 catalyst with a Sn/Zr molar ratio of 2/1. Then, the reaction conditions, including temperature, CO (or H2)/SO2 molar ratio, and space velocity, were optimized to maximize the sulfur yield in the presence and absence of 1 vol % O2. The temperature, CO (or H2)/SO2 molar ratio, and space velocity were varied in the ranges of 300−600 °C, 1.0−4.0, and 1000−30000 h−1, respectively. In SO2 reduction using CO with 1 vol % O2, the temperature, CO/SO2 molar ratio, and space velocity for the maximum sulfur yield were 600 °C, 3.5, and 10000 h−1, respectively, in which case the SO2 conversion and sulfur yield were about 85% and 77%, respectively. In SO2 reduction using H2 with 1 vol % O2, the temperature, H2/SO2 molar ratio, and space velocity optimized for the maximum sulfur yield were 600 °C, 3.0, and 10000 h−1, respectively, in which case the SO2 conversion and sulfur yield were about 89% and 57%, respectively. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900553s