Vol.1, No 5, 1998 pp. 135 - 142
UDC:

STRUCTURAL AND TEXTURAL CHANGES OF HYDRODESULFURIZATION CATALYSTS
IN CONDITIONS OF ACCELERATING AGING
J. Kiurski 1, D. Ž. Obadović 1, A. Kapor 1, E. Kiš 2, R. Marinković-Nedučin 2
1 Faculty of Sciences, Institute of Physics, 21000 Novi Sad, Trg Dositeja Obradovića 4
2 Faculty of Technology, 21000 Novi Sad, Bulevar Cara Lazara 1, Yugoslavia

Abstract. The examination of stability of two types hydrodesulfurization catalysts NiO(CoO)-MoO3/gamma -Al2O3 shows different structural and textural changes originated in deactivation processes. The catalysts were expose to accelerated aging in the laboratory conditions in different atmosphere. The structural changes were follow by X-ray diffraction, diffuse reflectance spectroscopy and scanning electron microscopy. Cobalt based catalyst showed higher thermal stability in comparison to nickel promoted samples. The critical role of oxidizing atmosphere in catalyst aging caused by phase changes and chemical interactions accompanied by sintering is confirmed, with emphasis on steam atmosphere. Transitional appearance of MoO3 phase is attribute to deactivation processes accompanied by partial loosing of active phase and forming a spinel-like structure of Ni(Co) ion.
Key words: Hydrodesulfurization, catalyst, aging, structure, texture

STRUKTURNE I TEKSTURALNE PROMENE KATALIZATORA ZA HIDRODESULFURIZACIJU
U USLOVIMA UBRZANOG STARENJA
Izvršena su ispitivanja stabilnosti dva tipa katalizatora za hidrodesulfurizaciju, NiO(CoO) - MoO3 / gamma - Al2O3 , pri ubrzanom starenju u laboratorijskim uslovima. Strukturne promene, nastale deaktivacijom, registrovane su metodama difrakcije x-zraka, difuzne refleksione spektroskopije i skenirajuće elektronske mikroskopije. Na osnovu struktirnih i teksturalnih promena ustanovljena je relativno veća termička stabilnost katalizatora na bazi kobalta u odnosu na katalizator na bazi nikla. Rezultati ispitivanja su pokazali da je oksidaciona atmosfera kritičan faktor u kinetici strukturnih i teksturalnih promena; posebno je kritična atmosfera vodene pare. Intermedijarno izdvojena faza MoO3  ukazuje na pad aktivnosti katalizatora, praćenim gubitkom aktivne komponente iz sistema i formiranjem spinelne strukture Ni odn. Co-jona.
Ključne reči: hidrodesulfurizacija, katalizator, starenje, struktura, tekstura