Abstract: Spent or inactive alumina-supported catalysts removed from a catalytic hydrotreating process and having carbonaceous and metallic deposits thereon are reactivated. After a solvent wash to remove process oils, the spent catalyst is treated with an organic solvent, such as N-methyl-2-pyrrolidone, at a temperature of 200.degree. to about 500.degree. F. for a period of about 1 to about 12 hours to form the reactivated catalyst suitable for reuse in a catalytic hydrotreating process. Optionally, the solvent treated catalyst can be regenerated by contact with an oxygen-containing gas at a temperature of about 700.degree. to about 900.degree. F. to remove carbon deposits from the catalyst, or, alternatively, the solvent treated catalyst can be acid leached to remove undesired metals and then contacted with an oxygen-containing gas at an elevated temperature to remove carbon deposits.

Abstract: Spent hydrotreating catalyst having carbonaceous and metallic deposits and of regular geometric shape after being stripped of process oil is fluidized by flowing air upwardly through the catalyst at a velocity sufficient to expand the bed thereby segregating the catalyst particles into a high activity, upper, less-contaminated fraction and a lower, more-contaminated fraction and recycling the high activity fraction to a hydrotreating process. Optionally, the high activity fraction can be regenerated with carbon burnoff or rejuvenated by acid leaching followed by regeneration with carbon burnoff to further improve catalyst activity.

Abstract: A hydrocarbon conversion process to yield product of improved properties is effected in the presence of a zeolite characterized by increased Secondary Pore Volume, decreased Lattice Constant, Secondary Pore Mode, Secondary Pore Diameter, increased Secondary Pore Volume, Surface Silicon to Aluminum Atom Ratio, and Acid Site Density.

Abstract: A hydrocarbon conversion process to yield product of improved properties is effected in the presence of a zeolite characterized by increased Secondary Pore Volume, decreased Lattice Constant, Secondary Pore Mode, Secondary Pore Diameter, increased Secondary Pore Volume, Surface Silicon to Aluminum Atom Ratio, and Acid Site Density.

Abstract: A catalyst composition useful in the hydroprocessing of a sulfur- and metal-containing hydrocarbon feedstock comprises 1.0-5.0 weight percent of an oxide of nickel or cobalt and 10.0-25.0 weight percent of an oxide of molybdenum, all supported on a porous alumina support in such a manner that the molybdenum gradient of the catalyst has a value of less than 6.0 and 15-30% of the nickel or cobalt contained in the catalyst is in an acid extractable form. The catalyst is further characterized by having a total surface area of 150-210 m.sup.2 /g, a total pore volume of 0.50-0.75 cc/g, and a pore size distribution such that pores having diameters of less than 100A constitute less than 25.0%, pores having diameters of 100-160A constitute 70.0-85.0% and pores having diameters of greater than 250A constitute 1.0-15.0% of the total pore volume of the catalyst.

Abstract: A novel treated charge zeolite is prepared by treating charge zeolite (which is essentially free of Secondary Pores) with steam for 5-60 hours at 1000.degree. F.-1500.degree. F. Product is particularly characterized by increased Secondary Pore Volume (pores of diameter of 100A-600A) in amount of as high as 0.20 cc/g.

Abstract: A novel treated charge zeolite is prepared by treating charge zeolite (which is essentially free of Secondary Pores) with steam for 5-60 hours at 1000.degree. F.-1500.degree. F. Product is particularly characterized by increased Secondary Pore Volume (pores of diameter of 100A-600A) in amount of as high as 0.20 cc/g.

Abstract: A catalyst composition useful in the hydroprocessing of a sulfur- and metal-containing hydrocarbon feedstock comprises 1.0-5.0 weight percent of an oxide of nickel or cobalt and 10.0-25.0 weight percent of an oxide of molybdenum, all supported on a porous alumina support in such a manner that the molybdenum gradient of the catalyst has a value of less than 6.0 and 15-30% of the nickel or cobalt contained in the catalyst is in an acid extractable form. The catalyst is further characterized by having a total surface area of 150-210 m.sup.2 /g, a total more volume of 0.50-0.75 cc/g, and a pore size distribution such that pores having diameters of less than 100A constitute less than 25.0%, pores having diameters of 100-160A constitute 70.0-85.0% and pores having diameters of greater than 250A constitutes 1.0-15.0% of the total pore volume of the catalyst.

Abstract: A process for the hydrotreatment of a sulfur and metal-containing hydrocarbon feed comprises contacting said feed with hydrogen and a catalyst in a manner such that the catalyst is maintained at isothermal conditions and is exposed to a uniform quality of feed, where said catalyst has a composition comprising 3.0-5.0 wt. % of an oxide of a Group VIII metal, 14.5-24.0 wt. % of an oxide of a Group VIB metal and 0-2.0 wt. % of an oxide of phosphorus supported on a porous alumina support, and said catalyst is further characterized by having a total surface area of 150-210 m.sup.2 /g and a total pore volume of 0.50-0.75 cc/g with a pore diameter distribution such that micropores having diameters of 100-160A constitute 70-85% of the total pore volume of said catalyst and macropores having diameters of greater than 250A constitute 5.5-22.0% of the total pore volume of said catalyst.