Patent GB-518263-A (GB)
Title: Improvements in or relating to cracking and refining hydrocarbon oils
IPC: C10G11/04
Filed: 1938-07-12
Abstract: 518,263. Cracking oils hydrocarbons. OCON, E. A. July 12, 1938, No. 20593. [Class 32] [Also in Group IV] Bituminous oils are cracked to produce gasoline of good antiknock value by preheating the oil and injecting it into a vaporizing zone where it is distilled by direct contact with hot cracked vapours produced in the process, subjecting the residual oil to cracking, separating the vapours thus formed, purifying them from tarry &c. materials by passage through absorbent contact materials, and utilising. the purified vapours as the distillation agent for the crude oil. The formation of vapours in the cracking reaction is increased by the introduction of gases, e.g., hydrogen, steam, carbon monoxide, and the vapours formed are subjected to pyrolitic and catalytic conversion to produce anti-knock fuels containing alkylated and oxygenated derivatives. The contact agents are regenerated by treatment with steam and oxidizing gases to produce hydrogen and carbon monoxide which together with other gases produced in the process are treated catalytically to produce hydrocarbons. Crude oil preheated in heat exchanger 2 is fed from tank 1 through line 3 and spray 4 into the flashing tower 5 where with the aid of heat supplied by vapours injected through spray 6 it is fractionated into (a) gasoline fractions taken overhead through line 11, heat exchanger 2 and cooler 72 to tower 73 ; (b) a naphtha fraction withdrawn through line 10 which is reformed by passage through coil 14 and a catalytic chamber 92 ; (c) a gas oil fraction which is withdrawn through line 9 and cracked at 900-950‹F. in a coil 13 ; (d) a heavy oil withdrawn through line 8 ; (e) residues withdrawn through line 7. The heavy oil is cracked mildly in coil 12 and passed into one of two flash towers A, B used alternately so that while one is in use the catalysts in the other may be regenerated. The towers are provided in their upper parts with contact masses 22 for removing tar from the vapours comprising activated clay, charcoal, firebrick, bauxite, coke &c. which may be coated with metal or metallic oxide catalysts and in their lower parts with coal or coke beds 24. The cracked products are delivered tangentially to a pool of oil on trays 28 so that a swirling movement is set up. Superheated steam, hydrogen, or gaseous hydrocarbons may be injected through lines 15, 17 and sprays 18, and also through line 16 into the coil 12. The purified vapours pass off through lines 29, 30 and are introduced in part through line 32 and spray 6 into the tower 5 to vaporize the crude. The vapours are also passed in part through line 33 and spray 42 into tower 93 into which the products of the cracking and reforming coils 13, 14 are led through lines 47, 40 the vapours formed being passed to a tower 61 while the residual oil is removed through line 51 and may be recycled through line 34 to the coil 12 or to the towers A, B. The reforming in the chamber 92 is carried out in the presence of mild oxidizing gases, e.g., steam or diluted oxygen fed through line 46 and in presence of catalysts comprising oxides of copper, titanium, chromium, tungsten, vanadium, germanium, cerium, or silica, or other silicious materials in which the metal oxides are incorporated. Vapours passing off from the tower 61 are passed through a catalytic alkylization zone 71 and after treatment are mixed with the vapours taken off from the tower 5 and the mixture is passed through a cooler 72 to a separator 73 from which the finished gasoline is withdrawn through line 75 while a lower layer containing alkylated and oxygenated products is recycled through line 76. The gases separated through line 74 are recovered in part by compression and fractionation in towerÀ77 the residual gases comprising hydrogen, methane, ethane &c. flowing through line 78 and a purifier 79 (where sulphur .impurities, carbon dioxide and moisture are removed) to a synthesizing zone 81 in which they are mixed with gases obtained in the generation of the contact agents in the towers A, B led through line 52. In the zone 81 the gases are treated to obtain synthetic alcohols and hydrocarbons in presence of catalysts comprising iron or cobalt activated with weak alkaline oxides, e.g., zinc, chromium oxides or alkline carbonates. Mixed catalysts comprising cobalt-copper-manganese, cobalt-thorium, cobalt-thorium-copper, cobalt-manganese may be employed with carriers, e.g., magnesia, pumice, bauxite &c. The synthesized products are cooled and fractioned in tower 83 the vapours being fed through line 85 to mix with those in line 70 passing from the tower 61 while the liquid products are recycled to the line 9. The contact agents in the reactor 71 comprise organo metallic compounds, alkylated metal compounds, e.g., tetraethyl lead, alumina, thoria, silica &c. Specification 502,799 is referred to.