Patent GB-420909-A (GB)
Title: Improvements in or relating to the treatment of hydrocarbon oils
IPC: C10G19/00
Filed: 1933-06-02
Abstract: Hydrocarbon oils are freed from impurities by passing oil vapours through contact zones at a temperature of 250 to 500 DEG  C., each containing a flowing stream of a molten anhydrous mixture of free active metal and one or more compounds thereof, and subsequently condensing the vapours.  The contact zones differ <PICT:0420909/III/1> in the temperature used, or in the composition of the treating agent.  Suitable agents consist of metals having one unpaired electron such as the alkali or alkaline earth metals, or aluminium in admixture with compounds of these metals such as sodium or potassium hydroxide, sodamide or aluminium chloride.  Such mixtures may be formed in the electrolytic cell described in Specification 408,819 in which caustic soda for example is dehydrated and partially electrolyzed to form an amount of free sodium in admixture with anhydrous caustic soda.  A dispersion of sodium in oil is made in a vessel 1 from which it flows into a vessel 3 containing the oil such as lubricating oil, to be treated.  The vessel 3 maintained under reduced pressure is heated to 250 to 300 DEG  C., by an electric winding 8 and is provided with a heavy agitator the blades 7 of which just scrape the inside of the vessel.  Oil vapours rise through a pipe 11 and pass through a vessel 12 filled with metal turnings and may be mixed with light hydrocarbons such as cracking gas admitted through a pipe 14.  Any polymerized material is removed through an outlet 15, and the hot vapours pass through a pipe 16 into the bottom of the first treating tower 17, down which a stream of molten sodium mixed with sodium hydroxide at a temperature of 350--400 DEG  C., flows from a distributer 18.  The treating period is preferably short for example a few seconds.  A further quantity of light vapours may be admitted through a pipe 34.  The treated vapours pass to a second tower 37<1> in which it is treated in concurrent with a similar treating agent at a temperature of 300--350 DEG  C., but containing a higher proportion of free metal for example from a few per cent up to nearly pure sodium.  The vapours are then fractionally condensed in condensers 54, 55 and the fractures drawn off from separators 56, 57.  The spent reagent flows from the treating tower 17 into a settling tank 21 where it is washed with oil, which is discharged together with impurities through a pipe 23. The partially purified molten mass is then subjected to electrolysis in an electrolytic cell 24 to form about 1 per cent of free sodium, and the mixture then flows into a tank 28 from which it is returned to the distributer 18.  Oil or inert gas may be admitted to the tank 28 through a pipe 33.  A similar regenerating plant is provided for the treatment of the spent reagent passing from the second treating tower 37<1>. The preliminary treatment in vessels 1, 3 and 12 may be replaced by treatment with an alkali hydroxide, aluminium chloride, aluminium, calcium or salts thereof, or the preliminary treatment may be dispensed with and the oil vapours admitted to the main treating towers of which a series is then preferably employed.