Treatment of liquids with corona wind discharge

摘要

In the separation of a water-in-oil emulsion into its component parts, the emulsion is introduced into a vessel 1 through a conduit 2 and passes upwardly through a metal screen 7 toward a downwardly directed corona wind discharge developed by an electrode assembly 11. A baffle 3 assists in dispersing the emulsion which is confined to a central position 6 by an annular baffle 4. The electrode assembly is charged oppositely to the baffles 3, 4, the screen 7 and the vessel 1. Loosely held water may separate out within the central portion 6 but water particles in the emulsion which pass through the screen are urged by the wind discharge on to the screen where they coalesce and gravitate to the bottom of the vessel 1. The oil flows outwardly, from the portion 6, substantially without turbulence, and the remaining water drops also gravitate to the bottom of the vessel. The separated-out water forms a layer 24 of which the level is maintained by electrodes 20, 21 and a valved take-off conduit 19. The oil flows over a weir 8 into a basin 9 and out of a spout 10. A hood 16, preferably of a synthetic resin, encloses the electrode assembly and forms a gas-seal with the oil in the basin 9. Air may be evacuated through a conduit 23 and replaced by another gas, e.g. hydrocarbon gas contained in the incoming emulsion. In the construction shown in Fig. 2, the emulsion is admitted through a conduit 31 and flows upwardly through an aperture 38 in a baffle 37 and through a screen 35. A plurality of such units may be enclosed for parallel operation in a single vessel. Alternatively, a number of units may be used in series or in parallel-series. In Fig. 4 the plate 77 of the electrode assembly is perforated to aid circulation of the atmosphere under the hood (not shown), and an additional screen 80 is placed closer to the discharge electrodes 70 than a screen 78, which is coarser than screen 78. The action of the wind discharge on the water remaining in the region of the screen 80 is more severe thus accelerating coalescence and gravitation. A potential of from 10,000 to 100,000 volts is specified for the electrodes which may be of tungsten or stainless steel. The method is applicable to liquids other than water-in-oil emulsions. Carbon dioxide, nitrogen, helium and argon are also specified for surrounding the electrode assembly. Alternating current may be used to energize the electrodes but uni-directional current is preferred.