직접 황 회수 공정으로 유입되는 재생가스에 함유된 미량산소의 촉매활성저하 원인 규명

국문 초록 (Abstract)

재생공정에서 황화 된 탈황흡수제의 재생을 위하여 산소는 산화제로 사용되었다. 재생공정에서 미량의 미 반응 산소는 직접 황 회수 공정으로 유입된다. 그러나, SO₂ 환원을 위한 반응성은 미 반응 산소의 다양한 이유에 의해서 저하된다. SO₂ 환원을 위한 반응성 실험을 위해 Sn-Zr계 촉매가 사용되었으며, SO₂와 O₂는 각각 5.0 vol%와 4.0 vol%로 고정하였고 300-450 ℃와 1-20 atm에서 수행되었다. 본 연구에서는 고온건식 탈황공정의 직접 황 회수공정에 유입되는 미 반응산소에 의한 촉매반응성 저하에 미치는 영향을 조사하였다. SO₂ 환원으로 생성된 원소 황은 미 반응산소에 의해서 재산화되고, redox반응기구에서 Sn-Zr계 촉매의 빈 격자 산소자리가 미 반응산소에 의해서 재산화되므로 SO₂ 전화율은 감소되는 것으로 판단된다. 한편 환원제로써 공급된 CO는 미 반응산소에 의해서 산화되어 연소열에 의해 촉매 충전 층 온도가 상승되기도 한다. 결과적으로 충전 층의 빠른 온도상승은 활성 물질을 소결시켜 촉매의 비활성화를 초래하게 된다.

다국어 초록 (Multilingual Abstract)

In order to regenerate the sulfidated desulfurization sorbent, oxygen is used as the oxidant agent on the regeneration process. The small amount of oxygen un-reacted in regeneration process is flowed into direct sulfur recovery process. However, the reactivity for SO₂ reduction can be deteriorated with the un-reacted oxygen by various reasons. In this study, the deactivation effects of un-reacted oxygen contained in the off-gas of regeneration process flowed into direct sulfur recovery process of hot gas desulfurization system were investigated. Sn-Zr based catalysts were used as the catalyst for SO₂ reduction. The contents of SO₂ and O₂ contained in the regenerator off-gas used as the reactants were fixed to 5.0 vol% and 4.0 vol%, respectively. The catalytic activity tests with a Sn-Zr based catalyst were for SO₂ reduction performed at 300-450 ℃ and 1-20 atm. The un-reacted oxygen oxidized the elemental sulfur produced by SO₂ catalytic reduction and the conversion of SO₂ was reduced due to the production of SO₂. However, the temperature for the oxidation of elemental sulfur increased with increasing pressure in the catalytic reactor. Therefore, it was concluded that the decrease of reactivity at high pressure is occurred by catalytic deactivation, which is the re-oxidation of lattice oxygen vacancy in Sn-Zr based catalyst with the un-reacted oxygen on the catalysis by redox mechanism. Meanwhile the un-reacted oxygen oxidized CO supplied as the reducing agent and the temperature in the catalyst packed bed also increased due to the combustion of CO. It was concluded that the rapidly increasing temperature in the packed bed can induce the catalytic deactivation such as the sintering of active components.

목차 (Table of Contents)

• 요약
• Abstract
• 1. 서론
• 2. 실험
• 3. 결과 및 고찰
• 4. 결론
• References

참고문헌 (Reference)

1 박정윤, "고압조건에서 Sn-Zr계 촉매상에서 SO2 촉매환원 반응특성" 한국화학공학회 48 (48): 316-321, 2010

2 Han, G. B., "Synergistic Catalysis Effect in SO2 Reduction by CO over Sn-Zr Based Catalysts" 337 : 29-, 2008

3 이태진, "Sn-Zr계 촉매 상에서 CO와 H2를 이용한 SO2 환원 반응특성" 한국화학공학회 44 (44): 356-362, 2006

4 Liu, W., "Reduction of Sulfur Dioxide by Carbon Monoxide to Elemental Sulfur over Composite Oxide Catalysts" 4 : 167-, 1994

5 Khalafalla, S. E., "Kinetics of Carbothermal Reduction of Quartz Under Vacuum" 55 : 414-, 1972

6 Haas L. A, "Kinetic Evidence of a Reactive Intermediate in Reduction of SO2 with CO" 29 (29): 264-269, 1973

7 Han, G. B., "Investigation of Catalytic Reduction of Sulfur Dioxide with Carbon Monoxide over Zirconium Dioxide Catalyst for Selective Sulfur Recovery" 47 : 1427-, 2008

8 Han, G. B., "Direct Reduction of Sulfur Dioxide to Elemental Sulfur with Hydrogen over Sn-Zr-based Catalysts" 47 : 4658-, 2008

9 Liu, W., "Development of Novel Metal Oxide Composite Catalysts for Complete Oxidation Reactions" Massachusetts Institute of Technology 1995

10 Piéplu, A., "Claus Catalysis and H2S Selective Oxidation" 40 : 409-, 1998

11 Lepsoe, R., "Chemistry of Sulfur Dioxide Reduction" 32 : 910-, 1940

12 Park, N.-K., "Catalytic Reduction of SO2 over Sn-Zr Based Catalysts for DSRP Under High Pressure" 174 (174): 46-53, 2011