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
