| 摘要 |
Metallic contaminants present as complex organic chelate compounds of the porphyrin type are removed from petroleum oils having constituents boiling above 950 DEG F. by contacting the oil at a temperature of 100 DEG F.-550 DEG F. with from 0,01 to 2 volumes of liquid hydrofluoric acid per volume of oil, thereby precipitating the contaminants, and thereafter separating the oil from the acid phase and the precipitated contaminants. The hydrofluoric acid may be employed as a 10% to 99% aqueous solution or in the anhydrous form. Boron trifluoride may be added to the acid to increase its effectiveness. The process may be applied to an undeasphalted topped petroleum crude oil, which may be deasphalted with a hydrocarbon having <PICT:0915601/III/1> 3-8 carbon atoms, and the demetallized oil may thereafter be cracked. In the Figure, a crude oil is distilled in zone 1, and a heavy gas oil fraction boiling between 950 DEG F. and 1300 DEG F. is withdrawn via line 6. Bottoms are withdrawn via line 7. These two fractions may be treated, either together or separately, in zone 10, which is equipped with heating and agitating means. Aqueous hydrofluoric acid is introduced into this zone, which is desirably maintained at 200 DEG F. to 400 DEG F. and 15 p.s.i.g. to 1,200 p.s.i.g., and the oil and acid remain in contact for 2 to 120 minutes, after which the mixture passes to settling zone 17, from where withdrawn acid is recycled to zone 10. The demetallized oil is passed through pressure release valve 19 to flash zone 20, from which acid vapours are withdrawn via line 21. The oil passes through filter 24 and the desired oil of low metal content is recovered via line 25. The oil may be washed with water or caustic to complete removal of acid. |
