مدل‌سازی و بهینه‌سازی گزینش‌پذیری و فعالیت کاتالیست Co/Al2O3 در سنتز فیشرتروپش

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار مهندسی شیمی، دانشگاه سیستان و بلوچستان

2 دانشجوی کارشناسی ارشد مهندسی شیمی، دانشگاه سیستان و بلوچستان

چکیده

در این مقاله با استفاده از روش سطح پاسخ و تجزیه‌های آماری، اثرهای اصلی و متقابل مشخصه‌های عملیاتی در حضور کاتالیزور کبالت بر پایۀ آلومینای صنعتی در رآکتور مخلوط‌ شونده، بررسی شد. تجزیۀ‌ واریانس نشان داد که مدل­های چندجمله­ای مرتبۀ دو، به­ خوبی داده­های تجربی را برازش کرده است. با کاهش سرعت جریان گاز سنتز گزینش‌پذیری دی­اکسیدکربن، متان و درصد تبدیل منواکسیدکربن افزایش یافت. افزایش فشار به bar 22 سبب افزایش همزمان درصد تبدیل منواکسیدکربن و گزینش ­پذیری دی‌اکسیدکربن شد که نشان‌دهندۀ تقویت واکنش جابه‌جایی آب-گاز در محدودۀ فشار متوسط است. افزایش سرعت جریان گاز سنتز موجب کاهش درصد تبدیل منواکسیدکربن و افزایش گزینش­ پذیری +C5 شد. براساس نتایج بهینه‌سازی چندهدفه، در شرایط سرعت جریان گاز  Nl/h8/47 و فشار bar 15 کمترین مقدار دی­اکسیدکربن (2%) و متان (4/16%) و بیشترین میزان درصد تبدیل منواکسیدکربن (8/53%) و محصولات سنگین (3/68%) +C5به‌دست می­ آید.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Modeling and Optimization of Selectivity and Activity of Co/Al2O3 Catalyst in the Fischer Tropsch Synthesis

نویسندگان [English]

  • S. H. Zohdi 1
  • S. Mansouri 2
1 Assistant Professor of Chemical Engineering, University of Sistan and Baluchestan
2 M. Sc. Student of Chemical Engineering, University of Sistan and Baluchestan
چکیده [English]

In this paper, main effects and the interactions of operating conditions were investigated using response surface methodology and statistical analysis in the presence of Co/Al2O3 catalyst in a CSTR reactor. Analysis of variance demonstrated that the second-order polynomials adequately predicted the responses. The selectivity of CO2, CH4, and CO conversion increased by the decrement of syngas flow rate. Increasing the pressure to 22 bar led to the increasing of CO conversion and CO2 selectivity; indicating the promotion of the water-gas-shift reaction in these conditions. Rising syngas flow rate caused decreasing the CO conversion and increasing C5+ selectivity. Minimum CO2 selectivity was achieved at the syngas flow rate and pressure of 61.9 Nl/h and 15 bar, respectively. Multi-objective optimization showed that minimum CO2 selectivity (2%) and methane selectivity (16.4%), as well as maximum CO conversion (53.8 %) and C5+ selectivity (68.3%) obtained at the syngas flow rate and pressure of 47.8 Nl/h and 15 bar, respectively.

کلیدواژه‌ها [English]

  • Modeling
  • Selectivity
  • Response Surface Methodology
  • Fischer Tropsch Synthesis
  • Alumina
  • Cobalt
[1] De La Osa, A., De Lucas, A., Romero, A., Valverde, J., & Sánchez, P. (2011). Fischer–Tropsch diesel production over calcium-promoted Co/alumina catalyst: Effect of reaction conditions. Fuel, 90(5), 1935-1945.
[2] Ernst, B., Bensaddik, A., Hilaire, L., Chaumette, P., & Kiennemann, A. (1998). Study on a cobalt silica catalyst during reduction and Fischer–Tropsch reaction: in situ EXAFS compared to XPS and XRD. Catalysis today, 39(4), 329-341.
[3] Ghiasi, Y., Atashi, H., Zamaniyan, A., & Nakhaei Pour, A. (2019). Determination of the Product Selectivity Model from the Fischer Tropsch Synthesis in a Fixed Bed Reactor. Physical Chemistry Research, 7(3), 499-510.
[4] Hammache, S., Goodwin Jr, J. G., & Oukaci, R. (2002). Passivation of a Co–Ru/γ-Al2O3 Fischer–Tropsch catalyst. Catalysis today, 71(3-4), 361-367.
[5] Jalama, K., Ma, W., Jacobs, G., Sparks, D., Qian, D., & Davis, B. H. (2020). Fischer-Tropsch synthesis over Pt/Co/Al2O3 catalyst: Improvement in catalyst stability by activation with diluted CO. Applied Catalysis A: General, 117645.
[6] Khorashadizadeh, M., Atashi, H., & Mirzaei, A. A. (2017). Process conditions effects on Fischer–Tropsch product selectivity: Modeling and optimization through a time and cost-efficient scenario using a limited data size. Journal of the Taiwan Institute of Chemical Engineers, 80, 709-719.
[7] Ma, W., Jacobs, G., Keogh, R. A., Bukur, D. B., & Davis, B. H. (2012). Fischer–Tropsch synthesis: Effect of Pd, Pt, Re, and Ru noble metal promoters on the activity and selectivity of a 25% Co/Al2O3 catalyst. Applied Catalysis A: General, 437, 1-9.
[8] Ma, W., Jacobs, G., Qian, D., Ji, Y., Klettlinger, J. L., Hopps, S. D., & Davis, B. H. (2020). Fischer-Tropsch synthesis: Synergistic effect of hybrid Pt-Cd additives on a 15% Co/Al2O3 catalyst. Applied Catalysis A: General, 117610.
[9] Marion, M. -C., & Hugues, F. (2011). Modification of cobalt catalyst selectivity according to Fischer-Tropsch process conditions. Natural Gas Conversion VIII: Proceedings of the 8th Natural Gas Conversion Symposium, May 27-31, 2007, Natal, Brazil,
[10] Martinelli, M., Gnanamani, M. K., LeViness, S., Jacobs, G., & Shafer, W. D. (2020). An overview of Fischer-Tropsch Synthesis: XtL processes, catalysts and reactors. Applied Catalysis A: General, 608, 117740.
[11] MohammadRezapour, M., Mirzaei, A. A., & Zohdi-Fasaei, H. (2018). Optimizing the preparation conditions of silica supported Fe-Co-Ce ternary catalyst for the fixed-bed Fischer-Tropsch synthesis: Taguchi experimental design approach. Physical Chemistry Research, 6(2), 387-397.
[12] Pendyala, V. R. R., Gnanamani, M. K., Jacobs, G., Ma, W., Shafer, W. D., & Davis, B. H. (2013). Fischer–Tropsch synthesis: effect of ammonia impurities in syngas feed over a cobalt/alumina catalyst. Applied Catalysis A: General, 468, 38-43.
[13] Riyahin, M., Mohebbi-Kalhori, D., Zohdi-Fasaei, H., Mirzaei, A. A., & Atashi, H. (2020). Proposing innovative modeling for Fischer–Tropsch synthesis product selectivity over Cobalt catalyst and skewness analyzing. Petroleum Science and Technology, 38(4), 411-419.
[14] Sage, V., Sun, Y., Hazewinkel, P., Bhatelia, T., Braconnier, L., Tang, L., Chiang, K., Batten, M., & Burke, N. (2017). Modified product selectivity in Fischer-Tropsch synthesis by catalyst pre-treatment. Fuel Processing Technology, 167, 183-192.
[15] Savost'yanov, A. P., Yakovenko, R. E., Narochniy, G. B., Sulima, S. I., Bakun, V. G., Soromotin, V. N., & Mitchenko, S. A. (2017). Unexpected increase in C5+ selectivity at temperature rise in high pressure Fischer-Tropsch synthesis over Co-Al2O3/SiO2 catalyst. Catalysis Communications, 99, 25-29.
[16] Visconti, C. G., & Mascellaro, M. (2013). Calculating the product yields and the vapor–liquid equilibrium in the low-temperature Fischer–Tropsch synthesis. Catalysis today, 214, 61-73.
[17] Xu, R., Hou, C., Xia, G., Sun, X., Li, M., Nie, H., & Li, D. (2020). Effects of Ag promotion for Co/Al2O3 catalyst in Fischer-Tropsch synthesis. Catalysis Today, 342, 111-114.
[18] Zarin Torang, H., Atashi, H., Zohdi‐Fasaei, H., & Meshkani, F. (2021). Investigating catalytic performance of Ag/Ce promoted Fe/Al2O3 catalyst in the CO hydrogenation process: Selectivity modeling and optimization using response surface methodology. International Journal of Energy Research, 45(10), 14518-14529.
[19] Zohdi-Fasaei, H., Atashi, H., Farshchi Tabrizi, F., & Mirzaei, A. A. (2016). Exploiting the effects of catalyst geometric properties to boost the formation of light olefins in Fischer-Tropsch synthesis: Statistical approach for simultaneous optimization. Journal of Natural Gas Science and Engineering, 35, 1025-1031.
[20] Zohdi-Fasaei, H., Atashi, H., Tabrizi, F. F., & Mirzaei, A. A. (2017). Modeling and optimization of Fischer-Tropsch synthesis over Co-Mn-Ce/SiO2 catalyst using hybrid RSM/LHHW approaches. Energy, 128, 496-508.