GB395709A - Improvements in or relating to electric fluid heating apparatus - Google Patents

Abstract

<PICT:0395709/III/1> <PICT:0395709/III/2> <PICT:0395709/III/3> Apparatus for heating fluids to high temperatures at high pressure, and particularly for use in cracking and distilling oil and in distilling glycerine and acids, comprises a rigid tubular casing enclosing one or more thin-walled metal tubes and electric and thermal insulating material filling the space between the tubes and casing. The fluid is passed rapidly through the tubes and electric connections are made to the tubes and casing so that the current flows through them in opposite directions. The apparatus may be used for treating finely divided solids contained by a fluid vehicle. In Fig. 1 a single tube 35 of nickel chrome is enclosed by a metal casing 20 surrounded by heat insulation 22 and fitted with an inlet 25 and an outlet 27, 31. One end of the tube is mounted in a disc or spider 36 and the other end is secured to a ring 37 connected by a spiral spring 39 to a ring 40 welded to the casing. Loose sections 41 of firebrick or lava are arranged between the tube and casing. Perforations 42 in the tube equalize the internal and external pressures. Three such elements are connected so that the fluid flows in series therethrough. The tubes are connected to a three phase supply through the flanges 28 and the casings are connected to earth through the flanges 26. A voltage regulator 60 is controlled by a thermostat 47, and the main switch 56 is controlled by a device 69 sensitive to the fluid flow and arranged in the inlet pipe 25. Means are provided for introducing hydrogen and a catalyst or other reagents into the inlet pipe. The oil after leaving the heater passes to a reactor, which may be electrically heated, then to an expansion chamber and finally to the usual cooling, condensing or fractioning apparatus. The reactor is fitted with a byepass valve. A loaded valve and a mixing device to facilitate the introduction of cooling fluid are arranged on the inlet side of the expansion chamber. In a modification the single tube 35 is replaced by a number of tubes connected by return bends. A plurality of such heaters may be arranged in series so that vapours may be removed at each stage. In a plant for producing gasoline by cracking high boiling point hydrocarbons, the fluid is pumped through a heat exchanger to the heating apparatus and then returns to the heat exchanger from which it passes through a pressure reducing valve to the usual scrubbing tower and condenser. The main switch is controlled by two thermostats fitted at the outlet, one responsive to the temperature of the heating tube and the other responsive to the temperature of the fluid. The oil cracking plant shown in Fig. 9 employs a heater comprising a plurality of tubes arranged in series in a casing 145. The oil, which may be preheated in a gas or oil fired heater, passes from pump 146 to the heater and then traverses a reactor fitted with a byepass and comprising a series of electrically heated conduits 162 arranged between headers 164, 165 and fitted with valves 163. Carbon settles out in the lower header from which it may be removed. From the reactor the oil passes through a reducing valve 152 to an expansion chamber 156 and fractioning tower 159. Fresh oil is supplied to the system through a mixing device 155 by a pump 153. The Specification as open to inspection under Sect. 91 refers to non-metallic heating tubes of carbon or silicon carbide and to distillation in the manufacture of lubricating oils fatty acids and glycerine. A heater is described comprising three tubes arranged in series in a single outer casing. The inlet and outlet are connected through the casing to earth and current is supplied to the midpoint of two tubes and a return conductor is connected to the midpoint of the third tube. Fig. 12 (Cancelled) shows a plant for use in the distillation of oil products and glycerine, the evaporation of acids and caustic chemicals, and the treatment of fatty acids used in the preparation of edible oils and fats and soap. When distilling cotton seed oil the oil is heated to 720 DEG F. at 750 lbs. per square inch and after passing through a reducing valve 179 is subjected to a vacuum of 2 inches produced by a pump 187. A separator 180, a condenser 183 and heat exchanger 184 are provided. The time taken to pass through the heater 175 is 2 seconds so that there is no formation of decomposition products. When treating fatty acids a metallic catalyst may be supplied by a device 192, and 6 to 8 lbs. of hydrogen per lb. of oil treated may be supplied by a device 193. The fatty acid and the catalyst are withdrawn by a pump 186 and passed through a centrifuge 194 and filter press 195. This subject-matter does not appear in the Specification as accepted.