GB1199740A - Process for Separating Black Oil Conversion Product - Google Patents

Abstract

1,199,740. Purifying hydrocarbons. UNIVERSAL OIL PRODUCTS CO. 28 Dec., 1967 [30 Dec., 1966], No. 58818/67. Heading C5E. A process for separating a mixed-phase hydrocarbonaceous conversion product effluent containing hydrocarbons boiling above 566‹ C. comprises the steps of (a) separating said effluent in a first separation zone at a temperature above 371‹ C. and a pressure above 68 atmospheres gauge to provide a first vapour phase and a first liquid phase; (b) cooling said first vapour phase, introducing the same into a second separation zone at a temperature below 60‹ C. and a pressure substantially the same as in said first separation zone, and separating therein a hydrogen-rich second vapour phase and a second liquid phase principally comprising propane and heavier normally liquid hydrocarbons; (c) introducing at least a portion of said first liquid phase, at a pressure less than 13À6 atmospheres gauge, into a third separation zone at a point below a mesh blanket which extends across an upper section of said third separation zone, and therein separating a third vapour phase and third liquid phase containing hydrocarbons boiling above 566‹ C.; (d) introducing said third liquid phase into a fourth separation zone at a temperature above 371‹ C. and at a sub-atmospheric pressure and therein separating a residuum fraction containing hydrocarbons boiling above 566‹ C., and a heavy gas oil fraction boiling below 566‹ C.; and (e) introducing a portion of said heavy gas oil fraction into said third separation zone at a point above said mesh blanket. The mesh blanket serves to prevent the entrainment of asphalts in the third vapour phase, the heavy gas oil wash removing the entrapped asphalts from the blanket. The process is particularly applicable to black oil conversion products. The second liquid phase and the cooled third vapour phase may be combined to form a product stream containing more than 60% of butanes and heavier hydrocarbons. Apart from that part of the heavy vacuum gas oil which is not recycled, the products from the final separation stage may also include a light vacuum gas oil.