GB756629A - Integrated process for the production of high quality heating oils - Google Patents

Abstract

<PICT:0756629/III/1> A process for the production of petroleum products comprises hydrofining a virgin naphtha under mild conditions such that the hydrogen consumption is below 200 standard cubic feet per barrel of oil feed in an initial mild hydrofining zone, removing the hydrofined product from this zone and separating liquid and gaseous constituents therefrom, recycling at least a portion of the gaseous constituents, which comprise hydrogen, to the initial hydrofining zone, hydroforming the liquid constituents to obtain hydrogen at least a portion of which is passed with a hydrocarbon fraction boiling in the heating oil boiling range to a secondary mild hydrofining zone, removing the hydrofined product and separating liquid hydrocarbons from gaseous constituents comprising hydrogen, recycling at least a portion of the gaseous constituents to the initial hydrofining zone, whereby a hydrofined heating oil product and a desirable feed for the hydroformer are obtained. The process preferably also includes mildly hydrofining a virgin naphtha lighter than the above mentioned virgin naphtha, separating the product into liquid hydrocarbons and gaseous constituents comprising hydrogen; at least a portion of the gaseous constituents of the products from the light and heavier virgin naphtha hydrofining zones and the heating oil fraction hydrofining zone being recycled to the two virgin naphtha hydrofining zones. A light virgin naphtha boiling in the motor fuel boiling range (100 DEG F. to 275 DEG F.) is introduced in a line 2, heated in a furnace 1, mixed with recycle hydrogen introduced in line 4, hydrofined in a zone 5 with a catalyst of cobalt molybdate on alumina, cooled and passed to a stripping zone 25 after removal of hydrogen and vaporous constituents in a flash drum 9. A product stream boiling in the range from 100 DEG F. to 275 DEG F. is removed from the stripper 25, cooled, and removed by line 34 while hydrogen and hydrocarbon constituents boiling below 100 DEG F. is removed by line 26 and returned by line 10 with hydrogen from drum 9 to the hydrofining zone 5. A heavier virgin naphtha boiling in the range 250 DEG F. to 375 DEG F. is introduced by a line 16, heated in a furnace 15, mixed with recycle hydrogen introduced by a line 18, and hydrofined in a zone 19, having a catalyst of cobalt molybdate on alumina cooled, and passed to a stripper 23. Hydrogen and hydrocarbons boiling below 100 DEG F. are removed and passed via a distillate drum 37 to line 10 for recycle to hydrofining zones 5 and 19, while a liquid product is removed and passed by a line 59 to a hydroforming zone 60 containing as catalyst platinum or molybdenum on alumina. Hydrogen formed in zone 60 is removed by a line 61, a port being introduced by a line 62 to stipper 23 for use as a stripping medium, the remainder passing along a line 44 and mixed with a hydrocarbon fraction boiling in the heating oil boiling range (350 DEG F. to 650 DEG F.) introduced by a line 41 and heated in a furnace 42. The mixture is passed into a hydrofining zone 45 containing a catalyst comprising molybdenum oxide on alumina. The hydrofined stream is cooled and passed into a stripper 49, steam being introduced by a line 50. Hydrogen and hydrocarbons boiling below 500 DEG F. are removed by a line 51, cooled, and passed to a distillate drum 53 where water is removed by a line 54, a hydrocarbon condensate is removed by a line 55 and recycled to stripper 49, while hydrogen and hydrocarbon constituents boiling below 100 DEG F. are passed by a line 55 to recycle line 10, and thence to hydrofining zones 5 and 19. The three hydrofining operations are "mild," i.e. the hydrogen consumptions per barrel of feed are below 200 standard cubic feet, preferably below 60. The heating oil feed may be a blend containing 10 to 60 per cent of stocks derived from cracking operations.