GB1505886A - Process for the catalytic hydrodesulphurisation of vanadium-and nickel-containing residual hydrocarbon oils - Google Patents

Abstract

1505886 Hydrodesulphurization of residual oils SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 3 April 1975 [20 May 1974] 13668/75 Heading C5E A process for the catalytic hydrodesulphurization of vanadium- and nickel-containing residual hydrocarbon oils without catalyst replenishment, carried out in the presence of a quantity of water corresponding with a water vapour partial pressure during the process of 0À5 to 30 bar and wherein the hydrocarbon oil is consecutively contacted with a catalyst I and a catalyst II which satisfy the requirements: (a) each of the individual catalysts I and II has a total pore volume in excess of 0À30 ml/g of which less than 10% is present as pores having a diameter in excess of 100 nm; (b) catalyst II has a specific average pore diameter p and a specific average particle diameter d such that where P H2 is the hydrogen partial pressure applied; (c) when two catalysts are used, catalyst I has a p and d such that while, when more than two catalysts are used, the above requirement of the quotient [p/(d)<SP>0À9</SP>] cat. I applies to the average p/(d)<SP>0À9</SP> of catalyst I which is determined as the weight average of the values of p/(d)<SP>0À9</SP> of each of the individual catalysts of catalyst I; (d) the percentage of the total catalyst volume which is taken up by catalyst II is between 10 and 90% and such that wherein S F is the sulphur content of the feed and S P the required sulphur content of the desulphurized product; and (e) when more than two catalysts are used, each of the individual catalysts of catalyst I has a p and d such that the quotient p/(d)<SP>0À9</SP> of each of these catalysts is greater than [p/(d)<SP>0À9</SP>] cat. II (p is expressed in nm, d in mm, P H2 in bar, and S P and S F in percentage by weight. The designation catalyst II refers to the second catalyst when two catalysts are used and to the final catalyst when more than two catalysts are used; the designation catalyst I refers to the first catalyst when two catalysts are used and to all but the last catalyst when more than two catalysts are used. The hydrodesulphurization may be effected at a temperature between 300 and 475‹ C., a hydrogen partial pressure of 30 to 200 bar, a space velocity of 0À1 to 10 parts by weight of fresh feed per part by volume of catalyst per hour and a hydrogen/feed ratio of 150 to 2000 NL of H 2 /kg. of feed using a catalyst containing Ni and/or Co together with Mo and/or W on a support such as alumina or alumina/silica. The hydrodesulphurization can be preceded by a demetallization by catalytic hydrogenation in which the metal content of the oil is reduced from M 1 to M 2 , the degree of demetallization being selected in dependence on the desired extension of the life of the desulphurization catalysts such that M 2 =(1À05 Œ 0À20)ÎM 1 Î(L 1 /L 2 )<SP>0À5</SP> where L 1 and L 2 are the lives of the desulphurization catalysts when they are used for the non-demetallized oil with a metal content M 1 and for the demetallized oil with a metal content M 2 respectively and wherein: (1) 25#M 1 #1500; (2) 2000#L 2 #16,000; (3) 0À10#M 2 /M 1 #0À75; and (4) 2Î10<SP>5</SP>#M 1 ÎL 2 #3 x 10<SP>6</SP>, (L 1 and L 2 are expressed in hours and M 1 and M 2 in ppmw).