Catalyst for the hydrodesulfurization of residua and heavy crudes

Abstract

A catalyst for hydrotreating, especially hydrodesulfurization, of residua and heavy crudes is prepared by synthesizing the support from titanium and boehmite, to form either a titanium/alumina support (TiO 2 /Al 2 O 3 ) or a titanium-alumina support (TiO 2 —Al 2 O 3 ) that is thereafter provided with at least one hydrogenating metal from group VIB in oxide form and a promoter from group VIII also in oxide form. The (TiO 2 /Al 2 O 3 ) support is prepared from boehmite, which is peptized by using an inorganic acid, then extruded, calcined and impregnated with a solution containing titanium, while the (TiO 2 —Al 2 O 3 ) support is prepared by admixing boehmite with a titanium-containing solution, peptized using an inorganic acid, extruded and calcined to obtain the titanium-alumina support.

1 . A catalyst for the hydrodesulfurization of residua and heavy crudes consisting essentially of a TiO 2 /Al 2 O 3  or TiO 2 —Al 2 O 3  support having a concentration of 3-6 wt % titanium, and active metal concentrations comprising 8-12 wt % molybdenum and 2-6 wt. % nickel. 
     
     
         2 . The catalyst of  claim 1 , wherein said catalyst support is TiO 2 /Al 2 O 3 . 
     
     
         3 . The catalyst of  claim 1 , wherein said catalyst has an acidity of from 70 to 120 mg of pyridine per gram of catalyst, a specific surface area of 90 to 300 m 2 /g, an average pore diameter of from 5.0 to 15.0 nm and a total pore volume of from 0.2 to 0.7 cm 3 /g. 
     
     
         4 . The catalyst of  claim 1 , wherein said catalyst has less than 30% of its pore volume from pores of 0 to 5 nm, 55 to 80% of its pore volume from pores of 5 to 10 nm, and less than 15% of its pore volume from pores with diameters greater than 10 nm. 
     
     
         5 . The catalyst of  claim 3 , wherein said catalyst has less than 30% of its pore volume from pores of 0 to 5 nm, 55 to 80% of its pore volume from pores of 5 to 10 nm, and less than 15% of its pore volume from pores with diameters greater than 10 nm. 
     
     
         6 . The catalyst of  claim 1 , wherein said residua and heavy crudes have been previously treated in a first stage of a hydrotreating process. 
     
     
         7 . A catalyst for the hydrodesulfurization of residua and heavy crudes produced by the process of:
 a. preparing a support from boehmite in which 5-20 wt % of the total boehmite is peptized with an inorganic acid to form a binder and the remainder of the boehmite and deionized water are added to the binder to form a homogenous paste, and forming said paste into extrudates;   b. aging said extrudates at a temperature of 20°-25° C. for 12-18 hours, drying said extrudates at a temperature of 100°-120° C. for 2-6 hours, and calcining said dried extrudates at a temperature of 500°-600° C. for 3-5 hours using a heating ramp of 2° C./min, to obtain gamma alumina;   c. impregnating the gamma alumina with a titanium precursor by the incipient wetness impregnation method using an organic solvent to provide content of 3-6 wt % of titanium;   d. aging the impregnated support at a temperature of 20°-25° C. for 12-18 hours, followed by drying at a temperature of 100°-120° C. and calcining at a temperature of 400°-500° C., to obtain the anatase phase of titanium on the surface of the gamma alumina; and   e. impregnating the resulting titania/alumina support (TiO 2 /Al 2 O 3 ) with a precursor of a metal from group VIB and group VIIIB of the periodic table by spraying or incipient wetness methods, either in simultaneous or sequential form.   
     
     
         8 . The catalyst of  claim 7 , wherein said catalyst consists essentially of a TiO 2 /Al 2 O 3  support having a concentration of 3-6 wt % titanium, 8-12 wt % molybdenum and 2-6 wt % nickel. 
     
     
         9 . The catalyst of  claim 8 , wherein said catalyst has an acidity of from 70 to 120 mg of pyridine per gram of catalyst, a specific surface area of 90 to 300 m 2 /g, an average pore diameter of from 5.0 to 15.0 nm and a total pore volume of from 0.2 to 0.7 cm 3 /g. 
     
     
         10 . The catalyst of  claim 7 , wherein said catalyst has less than 30% of its pore volume from pores of 0 to 5 nm, 55 to 80% of its pore volume from pores of 5 to 10 nm, and less than 15% of its pore volume from pores with diameters greater than 10 nm. 
     
     
         11 . The catalyst of  claim 8 , wherein said catalyst contains from a small amount of metals up to 500 ppm of the total amount of nickel plus vanadium, up to 10 wt % of asphaltenes and a sulfur content of from 0.5 to 5 wt %. 
     
     
         12 . The catalyst of  claim 8 , wherein said catalyst is capable of providing an initial hydrodesulfurization conversion of up to 83% of HDS and a stability of up to 60% of HDS, as well as hydrodemetallization and hydrodenitrogenation conversions of at least 20%, and a hydrodeasphaltenization conversion of at least 25%. 
     
     
         13 . A catalyst for the hydrodesulfurization of residua and heavy crudes produced by the process of:
 a. preparing a support by incorporating a titanium precursor into boehmite, peptizing the mixture of boehmite and titanium precursor using an inorganic acid and deionized water to form a homogenous paste, and extruding said paste to form extrudates;   b. aging the extrudates at a temperature of 20°-25° C. for 12-18 hours, and then said aged extrudates are dried at 100°-120° C. for 2-6 hours, and calcined at 500°-600° C. for 3-5 hours using a heating ramp of 2° C./min to obtain a titania-gamma alumina support; and   c. impregnating said titania-gamma alumina support by spraying or incipient wetness methods, either in simultaneous or sequential form, with a precursor of a metal from group VIB and group VIIIB of the periodic table.   
     
     
         14 . The catalyst of  claim 13 , wherein the inorganic acid used in the support synthesis is nitric acid at a concentration of 5-15 volume %. 
     
     
         15 . The catalyst of  claim 13 , wherein the titanium precursor used in the support synthesis is titanium isopropoxide. 
     
     
         16 . The catalyst of  claim 13 , wherein the simultaneous impregnation is conducted using a basic aqueous solution at pH of 9-9.5, which contains Mo and Ni. 
     
     
         17 . The catalyst of  claim 14 , wherein the simultaneous impregnation is conducted using a basic aqueous solution at a pH of 9-9.5, with ammonium heptamolybdate and hexahydrate nickel nitrate. 
     
     
         18 . The catalyst of  claim 13 , wherein sequential impregnation is used with ammonium heptamolybdate at a basic pH of 9-9.5 followed by aging, drying and calcination, and then impregnation using hexahydrate nickel nitrate at a pH of 5.5. 
     
     
         19 . The hydrodesulfurization catalyst produced by the process of  claim 13 , wherein said catalyst consists essentially of a TiO 2 —Al 2 O 3  support having a concentration of 3-6 wt % titanium, and active metal concentrations comprising 8-12 wt % molybdenum and 2-6 wt % nickel. 
     
     
         20 . The catalyst of  claim 19 , wherein said catalyst has a specific surface area of 90 to 300 m 2 /g, an average pore diameter of from 5.0 to 15.0 nm and a total pore volume of from 0.2 to 0.7 cm 3 /g. 
     
     
         21 . The catalyst of  claim 19 , wherein said catalyst has less than 30% of its pore volume from pores of 0 to 5 nm, 55 to 80% of its pore volume from pores of 5 to 10 nm, and less than 15% of its pore volume from pores with diameters greater than 10 nm. 
     
     
         22 . The catalyst of  claim 19 , wherein said catalyst contains from a small amount of metals up to 500 ppm of the total amount of nickel plus vanadium, up to 10 wt % of asphaltenes and a sulfur content of from 0.5 to 5 wt %. 
     
     
         23 . The catalyst of  claim 19 , wherein said catalyst is capable of providing an initial hydrodesulfurization conversion of up to 83% of HDS and a stability of up to 60% of HDS, as well as hydrodemetallization and hydrodenitrogenation conversions of at least 20%, and a hydrodeasphaltenization conversion of at least 25%.