Resid hydrotreating catalyst containing titania
Improved catalyst supports, supported catalyst, and method of preparing and using the catalysts for the hydrodesulfurization of a residuum hydrocarbon feedstock are disclosed. The catalyst supports comprise titania alumina having 5 wt % or less titania and have greater than 70% of their pore volume in pores having a diameter between 70 Å and 130 Å and less than 2% in pores having a diameter above 1000 Å. Catalysts prepared from the supports contain Groups 6, 9 and 10 metals or metal compounds, and optionally phosphorus, supported on the titania alumina supports. Catalysts in accordance with the invention exhibit improved sulfur and MCR conversion in hydrotreating processes.
1. A process for preparing a porous support material for supporting catalytically active metals suitable for the hydrodesulfurization of residuum hydrocarbon fractions under hydrotreating conditions, which process comprises:
a) preparing a co-precipitated titania alumina powder having 5 wt % or less titania, based on the total weight of the titania alumina powder; wherein the titania alumina is co-precipitated from an aqueous alumina and titanyl salt composition at a temperature of 63° C. to 80° C.;
b) peptizing the titania alumina powder;
c) extruding the titania alumina powder to form a titania alumina extrudate; and
calcining the extrudate at a temperature from about 500° C. to about 900° C. for about 1 hour to about 3 hours to obtain a titania alumina support having 5 wt % or less titania, based on the total weight of the support, wherein the support is characterized as having:
(i) a total pore volume from about 0.5 to about 1.1 cubic centimeters per gramas determined by nitrogen porosimetry;
(ii) at least 70% of the total pore volume in pores having a diameter of about 70 Å to about 130 Å as determined by nitrogen porosimetry;
(iii) less than 5% of the total pore volume in pores having a diameter above 300 Å, as determined by nitrogen porosimetry, and
(iv) less than 2% of the total pore volume in pores having a diameter above 1000 Å, as determined by mercury penetration porosimetry.
2. The process of claim 1 wherein the support comprises at least 90 wt % of co-precipitated titania alumina.
3. The process of claim 1 wherein the co-precipitated titania alumina powder is formed by co-precipitating aluminum sulfate and titanium sulfate with sodium aluminate while using an amount of titanium sulfate sufficient to provide a final support comprising titania alumina.
4. The process of claim 1 wherein the support is calcined at a temperature from about 650° C. to about 870° C.
5. A catalyst support prepared by the process according to claim 1 .
6. The catalyst support of claim 5 , wherein the support comprises at least 90 wt % of co-precipitated titania alumina.