افزایش بازده تولید بنزین در فرآیند شکست کاتالیستی VGO توسط اصلاح پسا- سنتز زئولیت USY

نوع مقاله : مقاله پژوهشی

نویسندگان

پژوهشکده پتروشیمی، پژوهشگاه پلیمر و پتروشیمی، تهران، ایران

چکیده

زئولیت USY به‌عنوان جزء اصلی و مهم در کاتالیزور فرآیند کراکینگ کاتالیزی بستر- سیال به منظور دست‌یابی به سطح تماس و دسترسی حفره بالاتر به‎روش پساسنتز توسط اسیدهای مختلف شامل استیک اسید، اکسالیک اسید و هیدروکلریک اسید تحت دو شرایط دمای محیط و رفلاکس اسیدشویی شد. این فرآیند ضمن حفظ شبکه بلوری زئولیت منجر به خروج آلومینیوم‎های خارج شبکه‌ای زئولیت شد. جهت اثبات این امر آنالیزهای XRDا، SEMا،اICP-OES و جذب و واجذب نیتروژن انجام شد. آنالیز عنصری افزایش نسبت سیلیس به آلومین در زئولیت اصلاح شده را نشان داد. اندازه‎گیری مساحت سطح زئولیت و حجم حفره‌ها به روش‌های BET-BJH و t-plot نشان از افزایش مساحت سطح و حجم حفره‌های مزو در زئولیت‌های اصلاح شده داشت. سطح حفره‌های مزو بر اثر اسیدشویی از 62/52 در زئولیت اولیه به m2/g 09/115 و مساحت سطح کلی زئولیت از 684 به m2/g 743 در نمونه زئولیت اسیدشویی شده توسط اکسالیک اسید در دمای محیط افزایش یافت. زئولیت‌های اصلاح شده در تهیه کاتالیزگر FCC به‌کار گرفته شدند. بررسی فعالیت کاتالیزورها در فرآیند شکست کاتالیستی VGO نشان از افزایش چشمگیر در بازده تولید بنزین برای کلیه کاتالیزورهای اصلاح شده در مقایسه با زئولیت اولیه دارد. بازده تولید بنزین از 18% وزنی برای کاتالیزور حاصل از زئولیت USY اولیه به 40% وزنی در کاتالیزور اصلاح شده توسط اکسالیک اسید در دمای محیط افزایش یافته است.
 

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Maximizing Gasoline Yield in Catalytic Cracking of VGO through Post-synthesis Modification of USY Zeolite

نویسندگان [English]

  • Sara Tarighi
  • Nafise Modanlou Juibari
Faculty of Petrochemicals, Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran
چکیده [English]

USY zeolite as a crucial component in FCC catalyst has been modified via post-synthesis acid treatment applying acetic acid, oxalic acid, and hydrochloric acid in order to increase mesoporosity and more pore accessibility. Acid leaching was performed under two different conditions including room temperature and reflux. Extra-framework Al atoms were removed which was confirmed through XRD, SEM, ICP-OES and N2 adsorption-desorption isotherm analyses. Elemental analysis showed increasing in SiO2 to Al2O3 ratio. Examining surface area and pore volume through BET-BJH and t-plot methods showed that total surface area, as well as mesoporous volume, were increased by acid-treating in all modified zeolites. The mesoporous surface was increased from 52.62 in primary zeolite to 115.09 m2/g in the sample which was acid leached through oxalic acid at room temperature. Moreover, the total surface area of the zeolite was increased from 684 to 743 m2/g. All modified zeolites were applied in the preparation of FCC catalyst. Catalytic cracking of VGO indicated a considerable increase in gasoline yield upon modified catalysts. Gasoline yield was increased from 18 wt.% over FCC to 40 wt.% in acetic acid-modified zeolite at room temperature.
 

کلیدواژه‌ها [English]

  • USY zeolite
  • Post-synthesis Modification
  • FCC Catalyst
  • Catalytic Cracking
  • Gasoline
[1]. Dehghan R., and Anbia M., “Zeolites for adsorptive desulfurization from fuels: A review,” Fuel Process. Technol., Vol. 167, pp. 99-116, 2017.##
[2]. Moshoeshoe M., Nadiye-Tabbiruka M. S. and Obuseng V., “A review of the chemistry, structure, properties and applications of zeolites,” Am. J. Mater. Sci., 7(5), pp. 196-221, 2017.##
[3]. Liang J., Liang Z., Zou R. and Zhao Y., “Heterogeneous catalysis in zeolites, mesoporous silica, and metal–organic frameworks,” Adv. Mater. doi:10.1002/adma.201701139, 2017. ##
[4]. Taufiqurrahmi N., Mohamed A. R. and Bhatia S., “Nanocrystalline zeolite Y: synthesis and characterization,” IOP Conf. Ser.: Mater. Sci. Eng. Vol. 17, No. 1, DOI: 10.1088/1757-899X/17/1/012030, 2011. ##
[5]. Feng R., Yan X., Hu X., Qiao K., Yan Z. and Rood M. J., “High performance of H3BO3 modified USY and equilibrium catalyst with tailored acid sites in catalytic cracking,” Microporous Mesoporous Mater., Vol. 243, pp. 319-330, 2017.##
[6]. García-Martínez J., Johnson M., Valla J., Li K. and Ying J. Y., “Mesostructured zeolite Y-high hydrothermal stability and superior FCC catalytic performance,” Catal. Sci. Technol., Vol. 2, No. 5, pp. 987-994, 2012.##
[7]. Etim U. J., Xu B., Zhang Z., Zhong Z., Bai P., Qiao K. and Yan Z., “Improved catalytic cracking performance of USY in the presence of metal contaminants by post-synthesis modification,” Fuel, Vol. 178, pp. 243-252, 2016.##
[8]. Liu H., Zhao H., Gao X. and Ma J., “A novel FCC catalyst synthesized via in situ overgrowth of NaY zeolite on kaolin microspheres for maximizing propylene yield,” Catal. Today, Vol. 125, No. 3, pp. 163-168, 2007.##
[9]. Ka¨rger J. and Ruthven D. M., “Diffusion in zeolites and other microporous solids,” Wiley & Sons: New York, 1992.##
[10]. Chen N. Y., Degnan T. F. and Smith C. M., “Molecular Transport and Reaction in Zeolites,” VCH: New York, 1994.##
[11]. Müller M., Harvey G. and Prins R., “Comparison of the dealumination of zeolites beta, mordenite, ZSM-5 and ferrierite by thermal treatment, leaching with oxalic acid and treatment with SiCl4 by 1H, 29Si and 27Al MAS NMR,” Microporous Mesoporous Mater., Vol. 34, No. 2, pp. 135-147, 2000.## 
[12]. Maier S. M., Jentys A. and Lercher J. A., “Steaming of zeolite BEA and its effect on acidity: A comparative NMR and IR spectroscopic study,” J. Phys. Chem. C, Vol. 115, No. 16, pp. 8005-8013, 2011.##
[13]. Groen J. C., Jansen J. C., Moulijn J. A. and Pérez-Ramírez J., “Optimal aluminum-assisted mesoporosity development in MFI zeolites by desilication,” J. Phys. Chem. B, Vol. 108, No. 35, pp. 13062-13065, 2004.##
[14]. Vafi L. and Karimzadeh R., “A novel method for enhancing the stability of ZSM-5 zeolites used for catalytic cracking of LPG: Catalyst modification by dealumination and subsequent silicon loading,” Chin. J. Catal., Vol. 37, No. 4, pp. 628-635, 2016.##
[15]. Gomes A. L., S-Aguiar E. F., Menezes S. C. and Cardoso D., “Influence of combined acid treatment on physico-chemical characteristics of ultrastable zeolite Y and on its catalytic properties in the disproportionation of ethylbenzene,” Appl. Catal. A: Gen., Vol. 148, No. 2, pp. 373-385, 1997.##
[16]. Agudelo J. L., Hensen E. J. M., Giraldo S. A. and Hoyos L. J., “Influence of steam-calcination and acid leaching treatment on the VGO hydrocracking performance of faujasite zeolite,” Fuel Process. Technol., Vol. 133, pp. 89-96, 2015.##
[17]. Zhang J., Ding H., Zhang Y., Yu C., Bai P. and Guo X., “An efficient one-pot strategy for synthesizing hierarchical aluminosilicate zeolites using single structure directing agent,” Chem. Eng. J., Vol. 335, pp. 822-830, 2018.##
[18]. Zhao Y., Lv W., Lu N., Shi X., Fan B. and Li R., “Hierarchical zeolite Y as hosts for encapsulation of Fe-Schiff base complexes,” Microporous Mesoporous Mater., Vol. 257, pp. 35-41, 2018.##
[19]. Feliczak-Guzik A., Sprynskyy M., Nowak I., Jaroniec M. and Buszewski B., “Application of novel hierarchical niobium-containing zeolites for synthesis of alkyl lactate and lactic acid,” J. Colloid Interface Sci., Vol. 516, pp. 379-383, 2018.##
[20]. Gola A., Rebours B., Milazzo E., Lynch J., Benazzi E., Lacombe S. and Fernandez C., “Effect of leaching agent in the dealumination of stabilized Y zeolites,” Microporous Mesoporous Mater., Vol. 40, No. 1, pp. 73-83, 2000.##
[21]. Yan Z., Ma D., Zhuang J., Liu X., Liu X., Han X. and Liu Z., “On the acid-dealumination of USY zeolite: a solid state NMR investigation,” J. Mol. Catal. A: Chem., Vol. 194, No. 1, pp. 153-167, 2003.##
[22]. Corma A., Fornes V., Kolodziejski W. and Martineztriguero L. J., “Orthophosphoric acid interactions with ultrastable zeolite-Y: infrared and NMR studies,‘’ J. Catal., Vol. 145, No. 1, pp. 27-36, 1994.##
[23]. Xin-Mei L. and Zi-Feng Y., “Optimization of nanopores and acidity of USY zeolite by citric modification,” Catal. Today, Vol. 68, No. 1, pp. 145-154, 2001.##
[24]. Lippens B. C. and De Boer J. H., “Studies on pore systems in catalysts: V. The t method,” J. Catal., Vol. 4, No. 3, pp. 319-323, 1965.##
[25]. Agudelo J. L., Hensen E. J., Giraldo S. A. and Hoyos L. J., “Effect of USY zeolite chemical treatment with ammonium nitrate on its VGO hydrocracking performance,” Energy Fuels, Vol. 30, No. 1, pp. 616-625, 2015.##
[26]. Pu X., Liu N. W. and Shi L., “Acid properties and catalysis of USY zeolite with different extra-framework aluminum concentration,” Microporous Mesoporous Mater., Vol. 201, pp. 17-23, 2015.##
[27]. Afshar Ebrahimi A. and Tarighi S., “Microactivity instrument for evaluation of FCC catalysts,” Iranian Patent, 91915, 1396##
[28]. Chaouati N., Soualah A., Hussein I., Comparot J. D. and Pinard L., “Formation of weak and strong Brønsted acid sites during alkaline treatment on MOR zeolite,” Appl. Catal. A: Gen., Vol. 526, pp. 95-104, 2016.##