Treatment of gas-containing oil-water emulsions flowing from oil wells whereby the emulsions are broken

摘要

PICT:0654369/III/1 PICT:0654369/III/2 PICT:0654369/III/3 PICT:0654369/III/4 Crude water- and gas-containing oil obtained from oil wells is treated to separate gas, then stratified into a water layer and water-oil emulsion layer, and the emulsion is passed into a body of heated water, thereby breaking the emulsion, the whole process being carried out in a closed system to prevent escape of hydrocarbon-bearing condensible vapours to the atmosphere, while arrangements are made in the emulsion-breaking step to condense any such vapours which separate and to return the condensed vapours to the oil. In Figs. 1, 2 and 4 (the transverse vertical sectional view of the upper part of the apparatus shown in Fig. 2 being taken at right angles to that shown in Fig. 1), the crude oil enters preheater 60 through inlet pipe 61 and then passes through pipe 28 to tower 26. Diverter box 29 causes the crude oil entering tower 26 to take a circumferential and helical course round the inner wall of the tower, so that the oil is scrubbed and gas separation results. Gases pass through openings 31 into shell 30 where any liquid entrained with the gases drops down drain pipe 33 while the gases are drawn off through pipe 32. The scrubbed crude oil drops on to spreader 34 and falls therefrom in a sheet into the upper chamber 25 of tank 20. Tank 20 is divided into an upper and lower chamber by means of partition 23. Further scrubbing of the oil results from its fall from spreader 34, while in chamber 25 the crude oil stratifies into a water layer and a water-oil emulsion layer. Agitation and churning are substantially reduced by the fact that spreader 34 lies below the liquid level in chamber 25. The emulsion layer overflows sleeve 99 and runs down pipe 741 through perforations 431 into the lower chamber of tank 20 containing a body of heated salt water. Heat is supplied by return-bend firebox 48. The oil emulsion is broken by the heated salt water and the oil rises past baffles 52 and is discharged through pipe 62 into the preheater 60. Oil leaves the preheater through line 63. The upper and the lower chambers of tank 20 are provided with filters 35 and 111 formed of excelsior or other suitable material to break up water-oil globules. Gas pressure equalization pipes are provided at 591 and 64 while condensation of hydrocarbon vapours may occur on the lower surface of partition 23, the condensed vapours dropping back into the oil. Water is drawn off from the upper chamber through pipes 101 and 102 and from the lower chamber through pipe 42 and discharged down water leg 46. In Fig. 3, an alternative form of the upper chamber of tank 20 is shown. Crude oil from the preheater 60 enters the upper chamber through pipe 28 and is diverted round the circumference of the chamber by means of diverter 29. The scrubbed crude oil drops on to shield 93 and is further scrubbed as it runs down depending skirt 95. Stratification occurs below shield 93 and the shield serves to protect the stratified liquids from undue agitation. Filter 109 aids stratification by breaking up oil-water globules. Emulsion overflows sleeve 99 and runs down pipe 741 into the lower chamber. Gases liberated enter shell 90 through louvres 92, any entrained liquid dropping down drain pipe 98. U.S.A. Specifications 1,755,527, 2,181,685, 2,181,688 and U.S.A. Reissue Specification 17983 are referred to. The Specification as open to inspection under Sect. 91 contains additional drawings corresponding to Figs. 1-8 of U.S.A. Specification 2,297,297. This subject-matter does not appear in the Specification as accepted.