H2S’ÜN ELEMENTEL KÜKÜRDE SEÇİCİ OKSİDASYONUNDA Ti-V-Cr ve Ti-V-Fe KATALİZÖRLERİ

Abstract

Bu çalışmada kompleksleştirme yöntemiyle eşmolar oranda Ti-V-Fe ve Ti-V-Cr katalizörleri sentezlenmiş ve H₂S’ün seçici oksidasyon reaksiyonuyla elementel kükürt eldesindeki aktiviteleri incelenmiştir. Katalizörlerin katalitik aktiviteleri dolgulu kolon reaktör sisteminde farklı sıcaklık (200°C, 250°C, 300°C) ve stokiyometrik gaz (O₂/H₂S:0,5) bileşiminde incelenmiştir. Katalizörlerin yapısal özellikleri N₂ adsorpsiyon-desorpsiyon, XRD, TPR, SEM-EDS analizleri ile belirlenmiştir. Sentezlenen katalizörlerin mezogözenekli yapıya sahip olduğu tespit edilmiştir. Ti-V-Cr katalizörünün kristal yapısı TiO₂’in rutile fazı ve Cr₂O₃ bileşiklerinden oluşurken, Ti-V-Fe katalizörü kompleks bir kristal yapı sergilemiştir. Bu katalizörün yapısında Fe₂TiO₅, V₂O₅, FeV₂O₄, rutile TiO₂ ve Fe₂O₃ bileşikleri görülmüştür. Sentezlenen her iki katalizörle de 250°C reaksiyon sıcaklığında % 100 H₂S dönüşümü elde edilmiştir. Reaksiyon sıcaklığındaki artış ve azalış katalizörlerde elde edilen H₂S dönüşümünde azalmaya sebep olmuştur. Bunun yanı sıra çalışılan tüm şartlarda her iki katalizörle de oldukça yüksek (≥% 97) elementel kükürt seçiciliği elde edilmiştir.  Özellikle 200°C sıcaklıkta, yapısında kompleks bileşikleri içeren Ti-V-Fe katalizörü ile (% 73 H₂S dönüşümü) Ti-V-Cr katalizörüne kıyasla (% 51 H₂S dönüşümü) daha yüksek dönüşüm elde edilmiştir. 

Keywords

• Katalizör,H2S,Seçici oksidasyon,elementel kükürt

Ti-V-Cr and Ti-V-Fe Catalysts for H2S Selective Oxidation to Elemental Sulfur

Abstract

In this study, Ti-V-Fe and Ti-V-Cr catalysts were synthesized by complexation method and their activities were investigated for H₂S selective oxidation reaction to elemental sulfur. Structural properties of the catalysts were determined by N₂ adsorption-desorption, XRD, TPR, SEM-EDS analyzes. According to the analysis results, it has been found that the synthesized catalysts have a mesoporous structure. Ti-V-Fe catalyst exhibits a complex crystal structure, while the crystal structure of the Ti-V-Cr catalyst is comprised of the rutile phase of TiO₂ and Cr₂O₃ compounds. In this catalyst structure, Fe₂TiO₅, V₂O₅, FeV₂O₄, rutile TiO₂ and Fe₂O₃ compounds were observed. The catalytic activities of the catalysts were investigated in a packed column reactor system at different temperatures (200°C, 250°C, 300°C) and stoichiometric gas composition (O₂/H₂S:0.5). 100% H₂S conversion was obtained at 250°C reaction temperature with both catalysts synthesized. The increase and decrease in the reaction temperature led to a decrease in the conversion of H₂S obtained with the catalysts due to the increase in sulfur deposition in the catalyst structure. In addition, under all conditions studied, elemental sulfur selectivity was high (≥ 97%) with both catalysts. Espe,cially at 200°C, a higher conversion was obtained with Ti-V-Fe (73% H₂S conversion) catalyst which has complex compounds in the structure compared to Ti-V-Cr catalyst (51% H₂S conversion).

Keywords

• Catalyst,H2S,Selective oxidation,Elemental sülfür

References

1. Brundle, C.R., Evans, C.A. (1992) Materials characterization series, In: I.E. Wachs (ed.), Characterization of catalytic materials, Boston.
2. Caceres, C.V., Fierro, J.L., Agudo, A.L., Soria, J. (1990) Effect of support on the surface characteristics of supported molybdena catalysts, Journal of Catalysis, 122,113-125. https://doi.org/10.1016/0021-9517(90)90265-L
3. Chun, S.W., Jang, J.Y., Park, D.W., Woob, H.C., Chung, J.S. (1998) Selective oxidation of H2S to elemental sulfur over TiO2/SiO2 catalysts. Applied Catalysis B: Environmental, 16, 235–243. https://doi.org/10.1016/S0926-3373(97)00078-7
4. Eslek, D.D., Yasyerli, S. (2009) Selectivity and stability enhancement of iron oxide catalyst by ceria incorporation for selective oxidation of H2S to sulfur, Industrıal & Engineering Chemistry Research, 48, 5223–5229. DOI: 10.1021/ie8017059
5. Ilieva, L.I., Andreeva, D.H. (1995) Investigation of the chromium oxide system by means of temperature-programmed reduction, Thermochim Acta, 265,223-31. https://doi.org/10.1016/0040-6031(95)98772-Q
6. Jiang, F., Wei, X., Niu, L., Xiao, G. (2013) Vanadium-chromium oxide: Effective catalysts for ammoxidation of 3-picoline, Advanced Materials Research, 634-638, 624-627. DOI: 10.4028/www.scientific.net/AMR.634-638.624
7. Jung, S.J., Kim, M.H., Chung, J.K., Moon, M.J., Chung, J.S., Park, D.W., Woo, H.C. (2003) Catalytic oxidation of H2S to elemental sulfur over mesoporous Nb/Fe mixed oxides, Studies in Surface Science and Catalysis, 146, 621–624. https://doi.org/10.1016/S0167-2991(03)80460-3
8. Keller, N., Huu, C.P., Ledoux, M.J. (2001) Continuous process for selective oxidation of H2S over SiC-supported iron catalysts into elemental sulfur above its dewpoint, Applied Catalysis A: General, 217, 205–217. https://doi.org/10.1016/S0926-860X(01)00601-9

9. Kim, M., Ju, W.D., Kim, K.H., Park, D.W., Hong, S.S. (2006) Selective oxidation of hydrogen sulfide to elemental surfur and ammonium thiosulfate using VOx/TiO2 catalysts, Studies in Surface Science and Catalysis, 159, 225-228. DOI:10.1016/S0167-2991(06)81574-0
10. Kirk-Otmer. (1992) Encyclopedia of Chemical Technology, 4.Basım, New York.
11. Kohl, A.L., Nielsen, R.B. (1997) Gas Purification, 5.Basım, Texas.
12. Li, K.T., Wu, K.S. (2001) Selective oxidation of hydrogen sulfide to Sulfur on vanadium-based catalysts containing tin and antimony, Industrial Engineering Chemistry Research, 40, 1052-1057. DOI: 10.1021/ie0007015
13. Li, K.T., Huang, C.H. (2006) Selective oxidation of hydrogen sulfide to sulfur over LaVO4 catalyst: Promotional effect of antimony oxide addition, Industrial Engineering Chemistry Research, 45, 7096-7100. DOI: 10.1021/ie060384n
14. Li, K.T., Huang, C.H. (2011) Hydrogen sulfide oxidation on RE (RE = Sm, Y, La)–V–Sb catalysts: Effects of RE size and electronegativity, Catalysis Today, 174, 25–30. doi:10.1016/j.cattod.2011.03.070
15. Li, K.T., Yen, C.S., Shyu, N.S. (1997) Mixed-metal oxide catalysts containing iron for selective oxidation of hydrogen sulfide to sulfur, Applied Catalysis A: General, 156, 117–130. https://doi.org/10.1016/S0926-860X(96)00417-6
16. Liao, S.J., Chen, T., Miao, C.X., Yang, W.M., Xie, Z.K., Chen, Q.L. (2008) Effect of TiO2 on the structure and catalytic behavior of iron-potassium oxide catalyst for dehydrogenation of ethylbenzene to styrene, Catalysis Communication, 9, 1817-1821. https://doi.org/10.1016/j.catcom.2008.02.009
17. Lowell, S., Shield,J. (1984) Powder surface area and porosity, 2. Basım, New York.
18. Marcilly, C., Courty, P., Delmon, B. (1970). Preparation of highly dispersed mixed oxides and oxide solid solutions by pyrolysis of amorphous precursors, Journal of the American Ceramic Society, 53, 56-57. DOI: 10.1111/j.1151-2916.1970.tb12003.x
19. Nagaraju, P., Lingaiah, N., Balaraju, M., Sai Prasad, P.S. (2008) Studies on vanadium-doped iron phosphate catalysts for the ammoxidation of methylpyrazine, Applied Catalysis A: General, 339, 99–107. https://doi.org/10.1016/j.apcata.2007.09.032
20. Palma, V., Barba, D. (2014) Low temperature catalytic oxidation of H2S over V2O5/ CeO2 catalysts, Int. J. of Hydrogen Energy, 39, 21524-21530. https://doi.org/10.1016/j.ijhydene.2014.09.120
21. Park , D.W., Park , B.K., Park, D.K, Woo, H.C. (2002) Vanadium-antimony mixed oxide catalysts for the selective oxidation of H2S containing excess water and ammonia. Applied Catalysis A: General, 223, 215–224. https://doi.org/10.1016/S0926-860X(01)00760-8
22. Shin, M.Y., Park, D.W., Chung, J.S. (2000) Vanadium-containing catalysts for the selective oxidation of H2S to elemental sulfur in the presence of excess water, Catalysis Today, 63, 405–411. https://doi.org/10.1016/S0920-5861(00)00485-5
23. Sing, K.S.W, Haul, R.A.W, Pierotti, R.A., Siemieniewska, T. (1985) Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity, Pure and Applied Chemistry, 57, 603–619. DOI: https://doi.org/10.1515/iupac.57.0007
24. Smith, D.K., Mrose, M.E., Berry, L.G., Bayliss, P. (1974) Selected Powder Diffraction Data for Minerals, 1.Basım, Pennsylvania.
25. Tasdemir, H.M., Yasyerli, S., Yasyerli, N. (2015) Selective catalytic oxidation of H2S to elemental sulfur over titanium based Ti-Fe, Ti-Cr and Ti-Zr catalysts, Int. J. of Hydrogen Energy, 40, 9989-10001. http://dx.doi.org/10.1016/j.ijhydene.2015.06.056
26. Taşdemir, H.M., Yağızatlı, Y., Yaşyerli, S., Yaşyerli, N., Doğu, G. (2017) Ce-O catalysts for elemental sulfur production via selective oxidation of H2S, Journal of the Faculty of Engineering and Architecture of Gazi University, 32(3), 831-841. DOI: 10.17341/gazimmfd.337632
27. Yasyerli, S., Dogu, G., Ar, İ., Dogu, T. (2003) Breakthrough analysis of H2S removal on Cu-V-Mo, Cu-V and Cu-Mo mixed oxides, Chemical Engineering Communication, 190, 1055-1072, DOI: 10.1080/00986440390207602
28. Yasyerli, S., Dogu, G., Ar, İ., Dogu, T. (2004) Dynamic analysis of removal and selective oxidation of H2S to elemental sulfur over Cu–V and Cu–V–Mo mixed oxides in a fixed bed reactor, Chemical Engineering Science, 59, 4001 – 4009. DOI: 10.1016/j.ces.2004.03.045
29. Yasyerli, S., Dogu, G., Dogu, T. (2006) Selective oxidation of H2S to elemental sulfur over Ce–V mixed oxide and CeO2 catalysts prepared by the complexation technique. Catalysis Today, 117, 271–278. https://doi.org/10.1016/j.cattod.2006.05.030
30. Zhang, X., Tang, Y., Qu, S., Da, J., Hao, Z. (2014) H2S-selectşve catalytic oxidation: Catalysts and processes, ACS Catalysis, 5, 1053-1067. DOI: 10.1021/cs501476p
31. Zhu, H., Qin, Z., Shan, W., Shen, W., Wang, J. (2004) Pd/CeO2-TiO2 catalyst for CO oxidation at low temperature: a TPR study with H2 and CO as reducing agents, Journal of Catalysis, 225, 267-277. https://doi.org/10.1016/j.jcat.2004.04.006