Patent GB-360358-A (GB)
Title: Improvements relating to the refining of hydrocarbon oils
IPC: C10G67/02
Filed: 1930-07-28
Abstract: <PICT:0360358/III/1> <PICT:0360358/III/2> A process for refining hydrocarbons of low boiling point such as benzol or cracked hydrocarbons and removing gum-forming constituents therefrom, consists in treating the hydrocarbons with a mixture of ferric sulphate and a microporous earth, as described in Specification 269,242, [Class 91, Oils &c.], in which the refining agent is fed into the mixing zone at a controlled rate and admixed with the oil for a pre-determined time, the oil being then separated by filtration, neutralized and distilled. Crude benzol is pumped into a washer z, Fig. 1a, and the refining agent is added through a tube 2, by a screw conveyer or a pump, in the form of a dry powder or in admixture with oil or spirit as a slurry.  The washer z is heated to about 50 DEG  C. and is provided with an agitator.  When refining is complete the mixture passes through a filter 3, to yield a purified oil passing to the neutralizer 4, and a residue of refining agent which is dried by treatment with compressed air.  The neutralizer 4 contains caustic alkali or ammonia whereby traces of tar acids, &c. are removed. The neutral oil then passes to a tank 5 from which it is raised to a tank 7 by a pump 6, to maintain a constant level of oil. The tank 7 feeds a column 8 of a still 9, and oil distilling up to 115 DEG  C. passes through a condenser 10, and water trap 11 to a motor spirit tank 12.  The residue in the still 9 flows to a tank 13 from which it is forced by a pump 14 to a still 15, having a column 18, a dephlegmator 19, condenser 20, and a water separator 21.  The lighter fractions up to 145 DEG  C. are returned to the motor spirit tank 12, a second fraction 145-165 DEG  C. passes to a light solvent tank 16 and a third fraction 165-195 DEG  C. passes to a heavy solvent tank 17.  The refining and neutralizing agents are supplied from overhead tanks and the spent materials drawn off by syphon tube, whereby a constant pressure head is maintained.  In the purification of benzines or cracked petroleum products, the distillation of the residue obtained from first fractionation is omitted.  In the purification of crude benzol containing naphthalene, heavy ends and sulphur compounds, these may be removed before the main purification. For example, crude heavy benzol is pumped into a tank b, Fig. 1, from which it flows through a pipe e, a heat exchanger f, exhaust heater g, and a pipe h to a column d of a topping still k, where it meets ascending vapours at about 85 DEG  C. from the still.  The resulting mixture of vapours containing carbon disulphide &c. is condensed and collects in the sulphide washer m, and after extraction passes through a separator n and washer o to a tank p.  The topped oil from the still k passes downwards through a column i, which is packed with Raschig rings, and is treated with steam in countercurrent.  The resulting vapours pass through a dephlegmator q, condenser r and water separator s to the tank p.  This fraction has an end point about 195 DEG  C.  The residue in the still column i flows through the separator j, and heat exchanger f to trays in which the naphthalene is crystallized.  The benzol in the tank p is forced by a pump v into a tank w from which it flows through pyridine washers x, and a separator y in which the bases are separated, before the main treatment.