Improvements in or relating to an electrical process for breaking emulsions and apparatus therefor

摘要

PICT:0731606/III/1 PICT:0731606/III/2 PICT:0731606/III/3 A process for the breaking of an emulsion, particularly an aqueous oil emulsion, comprises passing the emulsion through an electrical field in a plurality of vertically superimposed inverted V-streams, whereby the heavier particles of the emulsified phase tend to move downwardly and outwardly relative to the lighter particles thereof. The emulsion may be a water emulsion of a salt-containing hydrocarbon oil, especially one obtained by washing crude petroleum with water to remove such salts as the chlorides of sodium, calcium and magnesium, and the bromides, sulphates, carbonates and bicarbonates of potassium, strontium, vanadium and iron. In Fig. 1, a feed oil to be desalted is introduced into the system by means of line 60, heated to the desired temperature (e.g. 150-350 DEG F.) in heating zone 61 and mixed with a neutralizing agent (e.g. caustic soda or other caustic alkali or alkali carbonate solution) which is introduced by means of line 62. A de-emulsifier (e.g. sodium hydroxide or the material known under the Trade name "Tretolite T.424"; the word "Tretolite" is a Registered Trade Mark) is added to the oil stream by means of line 63. Alternatively, the de-emulsifier may be added via line 64 to line 65, through which hot water is added to the oil stream. The mixture is then passed either through mixer 66, or mixing valve 82 and line 83, and the emulsion obtained is passed through line 67 to the emulsion breaking vessel 72. In this vessel, the emulsion is jetted between inverted V-shaped electrodes 69 and 70 (see also Fig. 2) by means of jets 68. A voltage of 5000-35,000 volts or higher may be employed between the electrodes and the treated emulsion then passes between the surfaces of the inverted V-shaped elements 71 (see also Fig. 3), which form a settling zone. Lips 81 prevent the back-flowing of water into the electrical zone, while flow-restricting means in the form of a header element 80 prevents the free flow of the respective streams between the elements 71. The header element has a plurality of openings 811 immediately below each element 71, the number of such elements being so adjusted so as to secure a uniform pressure drop between all elements. The desalted oil leaves vessel 72 through line 73, while the aqueous saltcontaining layer is withdrawn from a plurality of points at the bottom of the vessel by means of line 74. Unbroken emulsion may be withdrawn by pump 86 from an intermediate point above the water withdrawal level and re-introduced by means of lines 75 and 76 at a level adjacent the water withdrawal level. Some or all of this unbroken emulsion may be re-introduced into line 67 by means of line 77. Emulsion breaking may be aided by the introduction of steam or hot water into the bottom of vessel 72 at a plurality of points 78 by means of line 79, pump 85 and line 84.