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

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