Lanthanum oxide-based catalysts for the Claus process

Baglio, J.; Susa, Thomas J.; Wortham, David W.; Trickett, E. A.; Lewis, T. J.

doi:10.1021/i300007a011

Cited by 6 publications

(7 citation statements)

References 2 publications

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“…Various reducing agents such as H 2 , CO, CH 4 , and carbonaceous materials have been used for the reduction of SO 2 . – Especially, mechanistic studies for the reduction of SO 2 using H 2 have been conducted for dry SO 2 treatment. For the SO 2 reduction using H 2 , the reaction pathway involving hydrogenation and the Claus reaction havse been suggested as the conventional mechanism, as follows: – ,– First, the hydrogenation proceeds, leading to the formation of H 2 S used in the Claus reaction. Second, the Claus reaction proceeds over a catalyst having Lewis and Brönsted acidic sites (SO 2 + 2H 2 S → 3S + 2H 2 O).…”

Section: Introductionmentioning

confidence: 99%

Direct Reduction of Sulfur Dioxide to Elemental Sulfur with Hydrogen over Sn−Zr-Based Catalysts

Han

Park

Yoon

et al. 2008

Ind. Eng. Chem. Res.

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We conducted the SO 2 reduction with H 2 over Sn-Zr-based catalysts for the direct sulfur recovery process. The reaction temperature was varied from 250 to 550°C while using SnO 2 -only, ZrO 2 -only, and SnO 2 -ZrO 2 (Sn/Zr ) 2/1) catalysts. The highest reactivity was obtained using the SnO 2 -ZrO 2 (Sn/Zr ) 2/1) catalyst at 550°C, for which the SO 2 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 SO 2 according to the redox mechanism (SO 2 + 2H 2 f S + 2H 2 O). (2) The produced sulfur is partially converted into H 2 S with the hydrogenation (H 2 + S f H 2 S). (3) Finally, the Claus reaction proceeds through Lewis and Brönsted acidic sites (SO 2 + 2H 2 S f 3S + 2H 2 O). 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.

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Section: Introductionmentioning

confidence: 99%

Direct Reduction of Sulfur Dioxide to Elemental Sulfur with Hydrogen over Sn−Zr-Based Catalysts

Han

Park

Yoon

et al. 2008

Ind. Eng. Chem. Res.

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“…The overall reduction of SO 2 through CO to sulfur element can be written as SO 2 + 2 CO → 2 CO 2 + [ S ] where [S] represents the various forms of sulfur products (S 2 , S 6 , S 8 ). Under fuel-rich conditions, COS is the major byproduct . Several types of catalysts, including alumina-supported transition metals, perovskite, and mixed oxides, have been reported to mediate the reduction of SO 2 by CO.…”

Section: Introductionmentioning

confidence: 99%

“…Under fuel-rich conditions, COS is the major byproduct. 7 Several types of catalysts, including aluminasupported transition metals, 8 perovskite, 9 and mixed oxides, 10 have been reported to mediate the reduction of SO 2 by CO. However, all these catalysts have their limitations.…”

Section: Introductionmentioning

confidence: 99%

“…Aluminasupported transition metals typically need to be activated by reducing gases at high temperature. 11 Perovskite, for example, La 1−x Sr x CoO 3 , 9 essentially loses its perovskite structure, which contributes to the catalyst activity, 7 after a short period under reaction conditions and becomes a mixture of metal sulfides and oxysulfides. Mixed oxides require a high reaction temperature to complete the conversion of SO 2 .…”

Section: Introductionmentioning

confidence: 99%

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Catalytic Reduction of SO₂ by CO over Pt_lAu_m(CO)_n: A First-Principles Investigation

2012

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The catalytic activities, to the reduction of SO 2 by CO, of clusters Pt l Au m (l + m = 2) with or without preadsorbing CO molecules are investigated using firstprinciples density functional theory. We find that the PtAu(CO) n (n = 1−3) clusters show more excellent catalytic properties than either pure metallic catalysts. Preadsorption of CO to the catalysts could effectively avoid platinum-based catalyst sulfur poisoning; as more CO molecules preadsorbed to the catalysts, the energy barriers for the carbonyl sulfide (COS) molecule's desorption from the catalyst are remarkably decreased. We propose an ideal catalytic cycle to simultaneously get rid of SO 2 and CO over the catalysts PtAu(CO) 3 .

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“…Hot gas desulfurization (HGD), which consists of two processes, sulfidation (MO + H 2 S → MS + H 2 O) and regeneration (MS + O 2 → MO + SO 2 ) with a metal oxide sorbent, is a dry process for the sorption and removal of H 2 S. In the regeneration part of the HGD process, SO 2 is produced, which should be removed because SO 2 is an air pollutant that can be injurious to health and produce acid rain. The direct sulfur recovery process (DSRP) is a catalytic SO 2 treatment process used to convert SO 2 into elemental sulfur with various reducing agents such as CO, H 2 , CH 4 , carbonaceous materials, and so on. − In the IGCC system, the DSRP can be combined with the regeneration part of the HGD process for the effective and efficient removal of sulfur compounds.…”

Section: Introductionmentioning

confidence: 99%

Effect of O₂ on SO₂ Reduction with CO or H₂ over SnO₂−ZrO₂ Catalyst

Han

Park

Lee

2009

Ind. Eng. Chem. Res.

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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.

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Lanthanum oxide-based catalysts for the Claus process

Cited by 6 publications

References 2 publications

Direct Reduction of Sulfur Dioxide to Elemental Sulfur with Hydrogen over Sn−Zr-Based Catalysts

Direct Reduction of Sulfur Dioxide to Elemental Sulfur with Hydrogen over Sn−Zr-Based Catalysts

Catalytic Reduction of SO₂ by CO over Pt_lAu_m(CO)_n: A First-Principles Investigation

Effect of O₂ on SO₂ Reduction with CO or H₂ over SnO₂−ZrO₂ Catalyst

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Lanthanum oxide-based catalysts for the Claus process

Cited by 6 publications

References 2 publications

Direct Reduction of Sulfur Dioxide to Elemental Sulfur with Hydrogen over Sn−Zr-Based Catalysts

Direct Reduction of Sulfur Dioxide to Elemental Sulfur with Hydrogen over Sn−Zr-Based Catalysts

Catalytic Reduction of SO2 by CO over PtlAum(CO)n: A First-Principles Investigation

Effect of O2 on SO2 Reduction with CO or H2 over SnO2−ZrO2 Catalyst

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Catalytic Reduction of SO₂ by CO over Pt_lAu_m(CO)_n: A First-Principles Investigation

Effect of O₂ on SO₂ Reduction with CO or H₂ over SnO₂−ZrO₂ Catalyst