GB1062032A - Improvements relating to high vacuum distillation - Google Patents

Abstract

1,062,032. High-vacuum distillation apparatus. BRITISH PETROLEUM CO. Ltd. and W. L. THOMAS. May 25, 1964 [June 21, 1963], No. 24778/63. Heading BIB. In a high-vacuum distillation apparatus comprising a heated, rotary disc 11 having, on its upper surface, concentric rings 16a, b, c forming a series of annular vaporization zones which are separated by a narrow overhead space from a corresponding series of condensation trays 21a, b, c arranged so that the distillate from each condensation tray flows down to the next vaporization zone, the outer periphery of each vaporization zone is provided with several circumferentially-spaced ducts 17 for the removal of liquid which has not been vaporized in that zone. The residual liquid fractions from all the vaporization zones are collected in receiver 28. The condensation trays 21 are formed concentrically on the underside of condenser 18, the end of each tray projecting slightly over the top of the corresponding ring 16, and the end of the final tray 21a projecting over gallery 2. The vaporization disc 11, which is made of aluminium and contains an electrical heating element 12, is rotated on shaft 14. The feedstock is slowly introduced into the base of the apparatus through tube 7, degassing of the liquid taking place at this time. Rotary pump 22 is set in motion so that the distilland is pumped up through tube 24 and conducted to the inner periphery of the innermost vaporization zone through tube 27. Initially, the temperature is so low that no vaporization occurs, the entire distilland flows as a thin film over the first vaporization zone to the ring 16c, and then flows through ducts 17c into funnel 32 and receiver 28. The liquid flows out of the receiver through ball-valve 29 into the base of the apparatus, whence it is recirculated to the first vaporization zone. As the temperature rises, distillation of the more volatile components of the feedstock occurs and the vapours condense on tray 21c. The condensate runs down into the middle vaporization zone where it flows outwards as a film, while some vaporization of the more volatile components occurs. The unvaporized liquid flows through ducts 17b, funnel 32 and receiver 28 into the base of the apparatus. The vapours evolved in the middle vaporization zone condense on tray 21b, and the condensate flows into the outer vaporization zone, where further vaporization of volatile components from the outwardly-flowing film of liquid occurs. The unvaporized liquid flows through ducts 17a, funnel 32, and receiver 28 into the base of the apparatus. The vapours evolved from the outer vaporization zone condense on tray 21a, and the condensate runs down into gallery 2, and then to a three-way tap (not shown). At the beginning of a run the tap is adjusted so that the distillate passes back to the base of the apparatus. When the temperatures in the vaporization zones have attained the desired values, the tap is turned so that the distillate runs into a distillate-receiver. Ball-valve 29 is now shut so as to collect the residue in receiver 28. In a modified construction, the vaporization surface is inclined upwardly from the centre at an angle between 15 degrees and 85 degrees to the horizontal.