GB360530A - An improved process and apparatus for the purification of hydrocarbon oils - Google Patents

Abstract

<PICT:0360530/III/1> Gasoline and distillate oils containing mainly light naphtha fractions are purified by treating them with hydrogen at a temperature above 850 DEG F. (preferably 900-1000 DEG F.) and under a pressure in excess of 20 atmospheres. The time of contact of the oil with the hydrogen is preferably adjusted so that not less than 5 per cent by weight of the oil is converted into fixed hydrocarbon gas, and preferably does not exceed 10 minutes. The oil is fed by a pump 1 through a pipe 2 and heat exchanger 3 to a heating coil 8 and retort tubes 5 packed with catalysts, e.g. chromium and molybdenum oxides dried in lump form or mixed with a carrier, e.g. fuller's earth, pumice, &c. The tubes 5 are of greater diameter than the coil 8, the respective diameters being 8-12 ins. and 2-4 ins. for a throughput of 1000 barrels of oil per day. The products pass through the exchanger 3 to a cooler 13 and separator 14 from which the condensate is led off through a line 15 while gases pass off through a line 16 to a purification system 17 from which they are re-circulated by a pump 18, fresh hydrogen being added by a pump 19. The temperature of the furnace 6 is regulated by recirculating part of the flue gases through ducts 10 by a fan 11. The furnace may alternatively be heated by lead or mercury vapour baths. In starting up the process the retorts are preferably first heated by injecting controlled amounts of carbon dioxide which reacts with the hydrogen to form steam and methane with the evolution of heat. The carbon dioxide may be added throughout the reaction. A cracked distillate of 46,4 DEG A.P.I. gravity obtained from Smackover crude and containing ,395 per cent sulphur is passed with hydrogen through a retort heated to 875-920 DEG F. at a pressure of 200 atmospheres and provided with a catalyst, the time of treatment being 6-45 minutes. 88 per cent of the oil is recovered in liquid form. 10-15 per cent of oils boiling between 400 and 600 DEG F. are preferably mixed with the naphtha.