ABSTRACT
In this work, methods for preparing alumina-titania and ceria-titania mixed oxide
supports were studied. In one method, alumina or ceria were precipitated on the
surface of a commercial titanium oxide,. In the second method, alumina or ceria
were impregnated on the surface of titania followed by drying and calcination as with
the first method .The metal oxide couples used in this study contains NiO and
MoO3. In this study,the catalyst content of NiO is3 wt% while MoO3 is8 wt.% while 89
wt.% is the support material.
Surface area and pore volume measurements for the supports and catalysts were
determined. Al, Ce, Ni and Mo contents as well as the coke percentage the spent
catalyst were determined by chemical analysis. Characterization of the prepared
support samples have been studied by DTA and XRD.
The HDS activities of the prepared catalyst samples have been studied in
comparison with titania and alumina catalysts. Two types of catalytic tests were
used.One type of measurement was a screening test using the pulse technique while
the second type was focused on studying the effect of important process variables
as reaction temperature, hydrogen pressure and liquid hourly space velocity (LHSV)
on the extent of HDS of gas oil (GO) feadstock and simultaneous HDS and HDN of
GO + Pyridine on the selected screened catalysts by using the continuous flow highpressure
fixed bed cata –test unit.
The results revealed that these catalysts are much more active than the conventional
NiMo/Al2O3 catalysts on HDS and HDN reactions.
The results revealed that these catalysts are much more active than the conventional
NiMo/Al2O3 catalysts on HDS and HDN reactions.They also demonstrate high
aromatic saturation capabilities.
The inhibiting effect of pyridine on gas oil HDS was found to be similar for all
catalysts, i.e.: was independent on the support composition.In general, diesel fuel
quality improved as the temperature and pressure increased or space velocity
decreased.