The separator C is merely a device for quickly and auto matically separating the oil and water. The mixture enters at inlet 30, and the clean oil rises and flows away to the delivery tanks through outlet 31, while the water drops and is discharged through pipe 32 in a clear stream. As in the case of the wetted septum trap, the height of outlet 32 is so adjusted as to make the flow self-regulating, the controlling factor being the water-level in the lower element of the trap.
2. Dehydrating by Direct Heat. There are many variations of this method in use, but the principal objection to most of them is the lack of provision for preventing loss by evaporation. A system which has been patented, however, overcomes this objection and can be used at a cost of 3 to 4 c. per barrel including a royalty of 1 c. per barrel, the cost of installing the separator being about $1500. The oil to be treated enters a series of four or six 12-in. pipes connected by return bends and placed in sets of two about 30 in. above the furnace floor. The back ends of the inside walls have a flue space 12 in. wide and the heat runs the entire length of the furnace through the flue space and up around the evaporator which is bricked in, leaving an open space of about 6 inches. The evaporator is a cylinder 4 by 20 ft. of i n . steel having a conical bottom and resting upon a foundation of brick. The oil is heated in the retort to a temperature of from 375 to 425° F. and passes through a 4-in. line into the top of the evaporator. Inside the latter are five baffle plates made of gal vanized iron, having deeply serrated edges and projecting within 1 in. of the side of the evaporator. The baffle plates are held in the centres by lock nuts on a 6-in. pipe which has four large open ings immediately below each plate. The latter are perforated with /-in. holes except the top one, which is solid. The oil, upon being introduced into the evaporator, strikes the top plate, spreads to the sides and runs down the evaporator in a thin film, the perforated plates preventing the oil from entering the openings in the 6-in. pipe. At such temperatures as 400° F. the volatile parts of the oil and the water are in the form of vapors, and enter the openings in the 6-in. pipe as such, while the non volatile parts, including the mineral salts, continue their downward course and are drawn off at the bottom of the evaporator. The 6-in. column has three take-offs which convey the vapors out the side of the evaporator and into the discharge-lines. Both the outgoing oil and the vapors are run through pipes which are enveloped with larger-sized lines which convey the oil entering the retorts. Thus the heat of the outgoing fluid is absorbed largely by the incoming fluid, effecting a considerable saving in heat units, at the same time effectually cooling the treated product. The
vapors are further condensed by being gravitated through a water jacket and enter a tank separate from the residuum, where the water and emulsion can readily be drawn off. The 'tops' or lighter portions, can then be mixed with the residuum and the whole shipped to the purchaser. A unit plant will readily clean 1500 or 2000 bbls. of oil a day, leaving no traces of emulsion, and it will be found that the gravity has been raised from to due to the fact that the emulsions have been eliminated. The temperature should not exceed 450° F., the latter heat being more than sufficient to break up the emulsions and vaporize the water. The treated oil should be gravitated after entering the evaporator, as the latter should never have a pressure exceeding 25 lbs. per square inch. The retorts and larger lines can be made up from discarded casing to reduce cost, and tees should be used in place of elbows when the percentage of mineral salt is large, as the latter is apt to clog the lines at the turns after being liberated from the water. A steam connection at each tee will keep the bends clear. This system can be used successfully on any emulsified oil with an oc casional replacement of the retorts which burn out in time.
3. Dehydrating by Compressed Air. The Milliff dehydrating system has met with success in treating emulsion by the use of com pressed air. An air pressure sufficient to overcome the weight of the oil is maintained by an air compressor through a 3-in. line which passes under a boiler furnace at which it is heated to a temperature of 1000° F. The heated air is conveyed through an insulated line to a tank 8 ft. diameter and 20 ft. high at which it enters at the bottom. A fire screen is used in the line to prevent hot cinders or sparks from coming in contact with the oil, and a thermometer is placed near the tank for temperature readings. The air enters the tank at the bottom through a spider with four 3-in. wings having holes and intermingles with the oil in the form of globules of varying size. The heat from the air attacks the water, turning it into steam, at the same time liberating the oil from the emulsion globule and carry ing the steam upward to the surface, where it is dissipated into the atmosphere, at the same time dropping the excess water to the bottom in a free state where it can be drawn off. One set of heater pipes in the boiler-furnace cleaned 140,000 barrels of oil at the Port Costa pumping station of the Associated pipe line. The oil contained an emulsion of 30 to 60% and tested less than 1% after treating by this process.