GB849977A - Hydrocarbon conversion process - Google Patents

Abstract

<PICT:0849977/III/1> Hydrocarbon stocks having an initial boiling point above 325 DEG F. and an end point below 650 DEG F. are upgraded by contacting the stocks in an isomerisation-cracking zone in the presence of a catalyst comprising a hydrogenating-dehydrogenating component disposed on an active cracking support, with from 1,500 to 30,000 SCF of hydrogen per barrel of total feed to that zone, at a temperature of 700 DEG -900 DEG F. a pressure of at least 600 p.s.i.g. and a LSHV of from 0.2 to 15, and in which at least one normally gaseous fraction, at least one gasoline fraction, an intermediate fraction having an initial boiling point of 375 DEG \sB 50 DEG F. and an end point of 475 DEG \sB 25 DEG F. and a bottoms fraction boiling above said intermediate fraction are recovered from the effluent of said zone, at least a portion of the intermediate fraction being returned to said zone. In a preferred embodiment, a hydrofined catalytically cracked cycle oil of 400 DEG -570 DEG F. boiling range is fed through a pipe 10 to a cracking zone 11 in which the catalyst is 1-5% molybdenum oxide on a carrier of silica-alumina. The hydrogenating-dehydrogenating component of the catalyst can be selected from any one or more of the metals of Group V, VI, VII or VIII excluding the metals of the platinum group, i.e. ruthenium, rhodium, palladium, osenium, iridium and platinum as well as the oxides or sulphides thereof, either alone, or with promoters such as the oxides or sulphides of molybdenum, tungsten, vanadium, or chromium; or metals such as iron, nickel, cobalt or platinum or the oxides thereof. The effluent from the cracking zone is removed through line 12 and is fractionated in zone 13 from which a normally gaseous fraction is recovered by line 14, a gasoline having an initial boiling point of about 60 DEG F. and an end point of 325 DEG -425 DEG F. is recovered from line 15, a heavy cycle oil is removed through line 17, and an intermediate fraction boiling in a range of 325-650 DEG F. is removed in line 16 and passed into the isomerisation-cracking zone 19 together with hydrogen. The product from zone 19 is passed to a high pressure gas-liquid separator 23 and to a low pressure vapour liquid separator 25 and via line 27 to a secondary fractionation zone 28 from which is recovered a relatively light gas fraction by lines 29 and 26, a gasoline fraction by line 30 an intermediate fraction boiling from 400-475 DEG F. via line 31, part of which is returned to the isomerisation-cracking zone 19 and a bottoms fraction boiling above 475 DEG F. by line 32.