US3347754A - High vacuum distillation - Google Patents

High vacuum distillation Download PDF

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Publication number
US3347754A
US3347754A US372170A US37217064A US3347754A US 3347754 A US3347754 A US 3347754A US 372170 A US372170 A US 372170A US 37217064 A US37217064 A US 37217064A US 3347754 A US3347754 A US 3347754A
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United States
Prior art keywords
zone
vaporiser
vaporising
condenser
trays
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US372170A
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English (en)
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Thomas William Llewelyn
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BP PLC
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BP PLC
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D1/00—Evaporating
    • B01D1/0011—Heating features
    • B01D1/0017—Use of electrical or wave energy
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D1/00—Evaporating
    • B01D1/0082—Regulation; Control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D1/00—Evaporating
    • B01D1/22—Evaporating by bringing a thin layer of the liquid into contact with a heated surface
    • B01D1/222—In rotating vessels; vessels with movable parts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/10—Vacuum distillation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S159/00—Concentrating evaporators
    • Y10S159/01—Electric heat

Definitions

  • Sheets-Sheet l 2616 fric .4 @aa/5* @wif/MM ZAM INVENTOR w
  • ABSTRACT OF THE DISCLOSURE A multi-stage centrifugal still having a series of concentric vaporisation zones and which has the special feature that liquid phase material (input material in the case of the rst zone, otherwise condensate) is added to each zone at the upstream periphery and removed at the downstream periphery.
  • the invention provides a simple and convenient construction in which a rotary vaporiser is divided into a series of concentric vaporisation zones each having a drainage tube at its outer periphery. Above each zone there is situated a condenser tray which slopes downwards towards the next vaporisation zone and which terminates in an edge for dripping condensate into the upstream periphery of that zone.
  • This invention relates to high vacuum distillation apparatus of the type in which a vaporiser having a vaporising surface and a condenser are provided and separated Aby substantially unobstructed space, distilland being spread over the vaporising surface in the form of a thin lm.
  • this invention relates to centrifugal stills of the above type, i.e. stills in which the vaporising surface is in the form of a rotatable disc so that distilland introduced onto the surface is dispersed in lm form over the surface by centrifugal action.
  • Distillation apparatus of the above type is well known and is particularly suitable for distilling, under a high vacuum of the order of 1 micron Hg, thermally unstable materials.
  • the distilland is heated for a short time only. Distillate is condensed on the condensing surface and removed from the system; undistilled residue is also cooled and removed.
  • the vaporising surface of the vaporiser is divided into a series of concentric vaporisation zones each zone being provided with a drainage conduit situated near its outer periphery land adapted to remove surplus liquid from the zone, the inlet conduit is positioned so as to introduce distilland near the inner boundary of the inner zone and the condenser comprises a series of condensing trays, one for each vaporising zone, the trays sloping downward towards the outer circumference of the vaporiser and having an outer edge positioned, in the case of all trays except the last, over the next succeeding vaporisation zone near its inner ⁇ boundary and, in the -case of the last tray, over a collecting zone, each tray being adapted, in the use of the apparatus, to condense vapour from its associated vaporising zone and to deposit said condensate from its outer edge.
  • the distance between the vaporising and condensing surface preferably approaches the molecular mean free path of the vapour molecules at the operating pressure. Desirably this distance is less than the molecular mean free path.
  • the vaporisation zones may be defined by rings or corrugations formed on the vaporising surface.
  • the condensing trays mounted on the condensing surface are preferably inclined as steeply as possible consistent with the mechanical limitations imposed by the distance between the vaporising and condensing surfaces, by the height of the rings defining the distillation zones and by the angles of inclination of the vaporising and condensing surfaces themselves.
  • the vaporising surface may be horizontal although preferably this surface is inclined upwardly from the centre, the angle of inclination to the horizontal increasing with the diameter of the vaporising surface.
  • the maximum practical diameter for horizontal vaporisers is of the order of one foot. At greater diameters the centrifugal force tends to pull the distilland into a series of radial streaks so that the total area of the rotary vaporisng surface is not utilised ediciently. Reducing the speed of rotation of the vaporiser or increasing the flow of distillant, although ensuring a continuous film at the periphery of the vaporiser, gives rise to poor conditions in the central area where the distilland forms thick layers.
  • the vaporiser preferably takes the form of a circular disc and any convenient means of heating the vaporser may be employed.
  • a hot medium such as oil may be circulated through the disc.
  • an electrical heating element is incorporated in the disc.
  • each vaporisation zone is equal to or greater than that of the next succeeding vaporisation zone.
  • the factor determining the optimum areas in each Case is the liquid loading in each zone. It is desirable that the evaporating area of a zone should be directly proportioned to the liquid loading in that zone so as to maintain the film thickness and residence time constant over the entire vaporising surface.
  • the condenser may be cooled by any convenient means. Preferably, however, means are provided to allow for the circulation of a coolant medium such as air or particularly water through the condenser.
  • a coolant medium such as air or particularly water
  • Temperatures may be measured in such parts of the apparatus as may be required by any suitable means, for example by means of thermocouples.
  • FIGS. 1 and 2 One embodiment of the present invention is illustrated with reference to the accompanying FIGS. 1 and 2.
  • FIG. 1 is a front view, partially in section, of a distillation apparatus according to the present invention having a horizontal vaporiser.
  • FIG. 2 is a side view of the apparatus of FIG. 1.
  • FIG. 3 is a front view of a vaporiser and condenser which are inclined as hereinbefore described.
  • the apparatus comprises a glass vessel 1 having formed in it a gutter 2 which has a slight downwards inclination towards a tap 3.
  • Tap 3 is of a two-way type which permits passage of liquid entering from upper limb 4 either back to the vessel via lower lim'b 5 or to a receiver (not shown) via limb (a.
  • tube 7 is provided at the base of the vessel for charging feedstock to the apparatus and for draining the apparatus when required.
  • the vessel is provided with a top plate 9 and is sealed against this by a rubber gasket 10. Pipe 8 passes through the top plate 9 and is connected in the normal manner to a diliusion pump backed by a rotary vacuum pump (not shown).
  • the vessel contains a circular, rotary, castaluminium vaporiser 11 incorporating an electrical resistance heating element 12.
  • the vaporiser 11 is connected by shaft 14 to a motor (not shown). Leads 13 connect heating element 12 through the shaft 14 to slip rings (not shown) outside the vessel.
  • Shaft 14 is sealed from top plate 9 by vacuum seal 15.
  • Concentric rings 16a, b, c are formed on the upper surface of the vaporiser 11 dividing the vaporiser into annular zones. Duets 17a, b, c pass through the vaporiser at a number of points around the outer periphery of each annular zone.
  • Circular condenser 1S is located above and parallel to the vaporiser land is provided with a central hole 18 through which shaft 14 passes.
  • Inlet and outlet tubes 19 and 2t respectively are provided to permit circulation of coolant water through the condenser 18.
  • Concertric trays 21a, b, c are formed on the underside of condenser 18 to form condensing zones corresponding with the distillation zones of the vaporiser. The outer edges of the trays 21 project slightly over the tops of the corresponding rings 16, the end of the linal tray projecting over gutter 2.
  • Feed pump 22 is located in the base of the vessel 1 and is driven by shaft 23 which is itself enclosed in tube 24 and passes through top plate 9 via vacuum seal 25.
  • Tube 24 serves to conduct liquid from the pressure outlet side of pump 22 up the annulus between the drive shaft 23 yand the tube 24 and has an inlet conduit 26 which extends to a point near the centre of vaporiser 11 at 27.
  • Residue receiver 28 is supported by tube 24 and has 'ball valve 29 at its base.
  • Ball valve 29 is operated by plunger 30 which passes through a vacuum seal in top plate 9 and is connected to the ball valve 29 by lever arm 31.
  • Ball valve 29 normally closes the upper end of receiver drain pipe 29'.
  • Funnel 32 is ⁇ placed under vaporiser 11 and is supported by residue receiver 28.
  • Vessel 1 is evacuated to l0 microns Hg or less via pipe 8 and feedstock is introduced slowly via tube 7, degassing of feedstock taking place at this time.
  • Feed pump 22 and vaporiser 11 are set in motion and feedstock is circulated over the vaporiser. Application of heat to the vaporiser at this stage assists degassing.
  • the temperature of the vaporiser is so low that no vaporisation occurs and the entire distilland passes over the inner zone of the vaporising surface of the vaporiser in a thin film to the inner ring or corrugation 16e then falls under gravity through the ducts 17e around the outer periphery of the inner distillation zone iir-stly into the funnel 32, then into the residue receiver 28 and thence through receiver drain pipe 29 into the base of the vessel 1.
  • the vaporiser temperature increases, some distillation, particularly of the more volatile components of the feedstock, occurs and the vapours formed con dense on the inner tray 21C. The condensate runs down the surface of the tray and drops on to the middle distillation zone near its inner periphery.
  • This liquid passes in a thin lilm covering the middle distillation zone, to the middle ring 16b and is heated in the process. Some vaporisation, particularly of the more volatile components of the feed, occurs and these vapours condense on the middle tray 2lb.
  • the unvaporised liquid from the middle distillation zone passes through the ducts 17b around the outer periphery of this zone, irstly into the funnel 32, then into the residue receiver 28, and finally into the base of the vessel 1.
  • the condensed vapours from the middle tray run down the surface of this tray and drop on to the outer distillation zone near its inner periphery.
  • This liquid pas-ses in a thin film covering the outer distillation zone, to the outer ring 16a and is heated in the process, Some vaporisation, particularly of the more volatile components of the liquid, again occurs and these vapours condense on the outer tray 21a.
  • the unvaporised liquid from the outer distillation zone passes through the ducts 17a around the outer periphery of this zone, firstly into the funnel 32 then into the residue receiver 28, and thence into the base of the vessel 1.
  • the condensed vapours from the outer tray run down the surface of this tray and drop into the gutter 2.
  • the distillate that collects in the gutter runs down by gravity to the upper limb 4 which leads to the tap 3.
  • the tap is adjusted so that the distillate passes back to the vessel 1 through the lower limb S. Gradually the temperatures rise, and when they have reached their desired values the tap 3 is turned so that distillate runs through tube 6 into an external distillate receiver (not shown).
  • the ball valve 29 is now shut so as to collect the residue from vaporiser 11 in the receiver 28. Distillation is continued until all the feedstock has been pumped from the lower part of the vessel 1. The distillation may be terminated at this stage, if desired. If required, however, a series of distillate fractions may be prepared by repeated distillation, at successively higher temperatures, of the residue remaining in the still after the iirst distillation.
  • the procedure then is to replace the lirst distillate receiver with another after all the feedstock has been pumped from the vessel 1.
  • the ball valve 29 is opened, allowing residue to pass to the base of the vessel.
  • This residue now forms the distilland for the next stage of the distillation which is carried out at a somewhat higher temperature than before.
  • the second distillate is collected in the distillate receiver and the second residue is collected in the residue receiver 28.
  • This procedure is repeated as many times as necessary.
  • the distillation is terminated, the power is switched off, the still is allowed to cool, the vacuum is released, and the final residue is run olf from the residue receiver 2S into a sample container.
  • the still may then be cleaned out with a suitable solvent.
  • the vaporiser 11 is inclined upwardly from the center, the condenser 18 being correspondingly inclined upwardly.
  • the vaporiser 11 By thus inclining the vaporiser, its upper or vaporising surface is correspondingly inclined and a thin tilm of distilland can be maintained on the entire vaporising surface without the distilland film being pulled into a series of radial streaks and Without the distilland being formed into thick layers in the central area.
  • a high vacuum centrifugal distillation apparatus comprising a rotatable vaporiser having a vaporising surface, a condenser and an inlet conduit for introducing distilland to said vaporising surface, said vaporiser and condenser being separated by substantially unobstructed space, and wherein said vaporising surface is divided into a series of concentric vaporisation zones, each zone being provided with a drainage conduit situated near its outer periphery and adapted to remove surplus liquid from the zone, and wherein said inlet conduit is positioned so as to introduce distillaud near the inner boundary of the inner zone and the condenser comprises a series of condensing trays, one for each vaporising zone, the trays sloping downwardly towards the outer circumference of the vaporiser and having an outer edge positioned, in the case of all trays except the last, over the next succeeding vaporisation zone near its inner boundary and, in the case ⁇ of the last tray over a collecting zone, each tray being adapted, in the use of the apparatus, to
  • An apparatus as claimed vaporising surface is inclined upwardly from the centre -at an angle of between 15 and 85 to the horizontal.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
US372170A 1963-06-21 1964-06-03 High vacuum distillation Expired - Lifetime US3347754A (en)

Applications Claiming Priority (1)

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GB24778/63A GB1062032A (en) 1963-06-21 1963-06-21 Improvements relating to high vacuum distillation

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BE (1) BE649513A (el)
DE (1) DE1519557A1 (el)
FR (1) FR1398381A (el)
GB (1) GB1062032A (el)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837491A (en) * 1972-11-03 1974-09-24 Pollution Control Inc Liquid purification apparatus and process
US4575404A (en) * 1982-09-10 1986-03-11 Yamato Scientific Co., Ltd. Pure water tank assembly for water distillation equipment
US4666564A (en) * 1984-04-21 1987-05-19 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Method of and apparatus for distilling a monoazeotropic liquid mixture
US4759825A (en) * 1985-07-25 1988-07-26 Bela Medvey Rotary evaporator
US4822455A (en) * 1986-01-08 1989-04-18 Chas. Hude Distilling and desalination apparatus
US20080230366A1 (en) * 2007-02-09 2008-09-25 Yuzuru Ito Liquid condensation system
US20090159419A1 (en) * 2007-11-09 2009-06-25 Chemchamp Llc Solvent recycler
US20130319845A1 (en) * 2002-12-03 2013-12-05 Todd S. Parkhurst Contaminated Solvent Recycling System
WO2018111548A1 (en) 2016-12-14 2018-06-21 Carbon, Inc. Methods and apparatus for washing objects produced by stereolithography

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE17324T1 (de) * 1981-10-30 1986-01-15 Kou Toung Laio Kolonne zur kontinuierlichen molekulardestillation.
GB8308134D0 (en) * 1983-03-24 1983-05-05 Ici Plc Rotary evaporation process

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2234166A (en) * 1939-11-03 1941-03-11 Distillation Products Inc Vacuum distillation
US2298377A (en) * 1939-11-03 1942-10-13 Distillation Products Inc Vacuum distillation from moving surfaces and apparatus therefor
US2313175A (en) * 1941-03-20 1943-03-09 Carbide & Carbon Chem Corp Vacuum distillation process and apparatus
US2446997A (en) * 1943-03-11 1948-08-17 Atomic Energy Commission Molecular distillation process and apparatus for the separation of isotopes, etc.
US2614973A (en) * 1947-12-19 1952-10-21 Vickers Electrical Co Ltd Short path fractionating stills
US2617760A (en) * 1947-12-19 1952-11-11 Vickers Electrical Co Ltd Short path fractionating centrifugal still

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2234166A (en) * 1939-11-03 1941-03-11 Distillation Products Inc Vacuum distillation
US2298377A (en) * 1939-11-03 1942-10-13 Distillation Products Inc Vacuum distillation from moving surfaces and apparatus therefor
US2313175A (en) * 1941-03-20 1943-03-09 Carbide & Carbon Chem Corp Vacuum distillation process and apparatus
US2446997A (en) * 1943-03-11 1948-08-17 Atomic Energy Commission Molecular distillation process and apparatus for the separation of isotopes, etc.
US2614973A (en) * 1947-12-19 1952-10-21 Vickers Electrical Co Ltd Short path fractionating stills
US2617760A (en) * 1947-12-19 1952-11-11 Vickers Electrical Co Ltd Short path fractionating centrifugal still

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837491A (en) * 1972-11-03 1974-09-24 Pollution Control Inc Liquid purification apparatus and process
US4575404A (en) * 1982-09-10 1986-03-11 Yamato Scientific Co., Ltd. Pure water tank assembly for water distillation equipment
US4666564A (en) * 1984-04-21 1987-05-19 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Method of and apparatus for distilling a monoazeotropic liquid mixture
US4759825A (en) * 1985-07-25 1988-07-26 Bela Medvey Rotary evaporator
US4822455A (en) * 1986-01-08 1989-04-18 Chas. Hude Distilling and desalination apparatus
US20130319845A1 (en) * 2002-12-03 2013-12-05 Todd S. Parkhurst Contaminated Solvent Recycling System
US20080230366A1 (en) * 2007-02-09 2008-09-25 Yuzuru Ito Liquid condensation system
US8034217B2 (en) * 2007-02-09 2011-10-11 Hitachi Plant Technologies, Ltd. Liquid condensation system
US20090159419A1 (en) * 2007-11-09 2009-06-25 Chemchamp Llc Solvent recycler
WO2018111548A1 (en) 2016-12-14 2018-06-21 Carbon, Inc. Methods and apparatus for washing objects produced by stereolithography

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Publication number Publication date
FR1398381A (fr) 1965-05-07
BE649513A (el)
DE1519557A1 (de) 1969-08-21
GB1062032A (en) 1967-03-15

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