TY - JOUR
T1 - The sulfidation mechanism of NiW/gamma-Al2O3 as a function of the calcination temperature studied with Fe-57-MAS and temperature programmed sulfidation
AU - Reinhoudt, HR
AU - van der Meer, Y
AU - van der Kraan, AM
AU - van Langeveld, AD
AU - Moulijn, JA
PY - 1999/9
Y1 - 1999/9
N2 - Currently the production of low sulfur diesel fuel (< 0.05 wt.% S) is an important topic in oil refineries due to new environmental legislation. Consequently, alternative catalysts for deep HDS processes are required and NiW/gamma-Al2O3 catalysts are a promising option. An important issue in the application of NiW/gamma-Al2O3 catalysts is their activation. In this work a quantitative description of the sulfidation mechanism of W in NiW/gamma-Al2O3 catalysts, as obtained from temperature programmed sulfidation measurements, is presented. It is shown that the calcination temperature has a great influence on the relative importance of the different sulfidation reactions. Especially the WS2 formation at sulfidation temperatures below 600 K is strongly decreased after calcination above 673 K. Fe-57-MAS shows that re-dispersion of Ni-sulfide species occurs after sulfidation at 573 K for a dried catalyst to form the so-called NiWS phase. The NiWS phase is also formed on calcined catalysts but only at sulfidation temperatures of 673 K. It is demonstrated that the formation of WS2 slabs is a prerequisite for the re-dispersion of Ni-sulfide species. (C) 1999 Elsevier Science B.V. All rights reserved.
AB - Currently the production of low sulfur diesel fuel (< 0.05 wt.% S) is an important topic in oil refineries due to new environmental legislation. Consequently, alternative catalysts for deep HDS processes are required and NiW/gamma-Al2O3 catalysts are a promising option. An important issue in the application of NiW/gamma-Al2O3 catalysts is their activation. In this work a quantitative description of the sulfidation mechanism of W in NiW/gamma-Al2O3 catalysts, as obtained from temperature programmed sulfidation measurements, is presented. It is shown that the calcination temperature has a great influence on the relative importance of the different sulfidation reactions. Especially the WS2 formation at sulfidation temperatures below 600 K is strongly decreased after calcination above 673 K. Fe-57-MAS shows that re-dispersion of Ni-sulfide species occurs after sulfidation at 573 K for a dried catalyst to form the so-called NiWS phase. The NiWS phase is also formed on calcined catalysts but only at sulfidation temperatures of 673 K. It is demonstrated that the formation of WS2 slabs is a prerequisite for the re-dispersion of Ni-sulfide species. (C) 1999 Elsevier Science B.V. All rights reserved.
KW - NiW/gamma-Al2O3
KW - Hydrodesulfurisation
KW - Temperature programmed sulfidation
UR - https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=researchintelligenceproject&SrcAuth=WosAPI&KeyUT=WOS:000083324000003&DestLinkType=FullRecord&DestApp=WOS
U2 - 10.1016/S0378-3820(99)00029-6
DO - 10.1016/S0378-3820(99)00029-6
M3 - Article
SN - 0378-3820
VL - 61
SP - 43
EP - 54
JO - Fuel Processing Technology
JF - Fuel Processing Technology
IS - 1-2
ER -