US3616835A - Evaporators having hollow platelike vertical heat transfer elements and overhead nozzles - Google Patents

Evaporators having hollow platelike vertical heat transfer elements and overhead nozzles Download PDF

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US3616835A
US3616835A US798339A US3616835DA US3616835A US 3616835 A US3616835 A US 3616835A US 798339 A US798339 A US 798339A US 3616835D A US3616835D A US 3616835DA US 3616835 A US3616835 A US 3616835A
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crystals
solution
elements
installation
exchanger
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Francois Laurenty
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D9/0006—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the plate-like or laminated conduits being enclosed within a pressure vessel
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0018—Evaporation of components of the mixture to be separated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0036—Crystallisation on to a bed of product crystals; Seeding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0059—General arrangements of crystallisation plant, e.g. flow sheets
    • 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
    • Y10S159/25—Decant, press, centrifuge

Definitions

  • the present invention relates to installations provided for the continuous evaporation of a solvent of any kind and/ or for the continuous concentration of at least one substance in solution in a solvent, with or without extraction of the said substance.
  • a conventional installation for the continuous evaporation and/or concentration comprises generally, in a closed circuit, a circulation pump, a heater, an evaporator independent of the said heater, and connecting pipe-work.
  • An intake pipe introduces into this circuit the liquor to be thickened and an outlet piping system for the extraction of the thickened liquor.
  • the whole assembly forms a treatment stage.
  • the condensed liquor is the end product desired or obtained; in others, there is crystallization of one or more substances, and the crystals thus formed which constitute the finished product desired or obtained, are extracted either in drying circuits individually associated with the various stages of the installation, or in a terminal drying circuit common to all the stages of the installation.
  • the heating of the liquor in the heater is not uniform; there is a formation of bubbles of vapour even inside the said liquor.
  • the bubbles thus formed burst and cause the production of droplets of liquid which are mechanically carried away by the vapour thus liberated. This phenomenon, known as leading, adversely affects the efficiency of the installation and may result in the elimination of a not-negligible quantity of liquor.
  • the temperature difference existing between the primary and the secondary fluids is substantial, of the order of 5 to C., both for a heater and for an evaporator, so
  • the present invention has for its object an installation for the continuous evaporation of any particular solvent and for the continuous concentration of at least one substance in solution in the said solvent, which is free from the above drawbacks and which furthermore offers other advantages.
  • the installation according to the invention which comprises a heat exchanger in which circulate, on the one hand, the solution to be treated and, on the other hand, a heat-exchange fluid
  • the said heat exchanger comprises a body, a plurality of similar exchange elements arranged in parallel at a distance from each other inside the said body and each formed by two thin walls arranged at a small distance from each other, a primary intake introducing the said exchange fluid between the said Walls and a secondary intake causing the said solution to stream over the said walls, the said secondary intake comprising as many outlet nozzles as there are exchange elements, and each of the said nozzles being arranged directly above one of the said exchange elements.
  • the heating of the solution and its partial evaporation are effected, in accordance with the invenition, and contrary to the usual installations, in a single apparatus, namely the heat exchanger, which already eliminates one of the causes of bubbling and therefore of overheating and leading or priming.
  • this exchanger in addition, by virtue of the structure of this exchanger, the introduction of heat is effected through a very small thickness of solution and therefore the evaporation of the solution is also effected without bubbling and therefore without priming.
  • this structure has the advantages of permitting conjointly an increase in surface area of the exchanger walls and a reduction of the thdickness of the walls and, in consequence, a substantial reduction of the variation of temperature introduced by any particular stage of treatment.
  • FIG. 1 is a general view with parts broken away of a crystallization installation in accordance with the invention
  • FIG. 2 is a view in cross-section taken along the line lI-II of FIG. 1, of an evaporator utilized in this installation;
  • FIG. 3 is a view in transverse section, to a larger scale, of one of the unitary elements of this evaporator;
  • FIG. 4 is a view in elevation with parts broken away, of a dryer employed in the installation according to the invention.
  • FIG. 5 is a half-view in cross-section of this dryer, taken along the line V-V of FIG. 4;
  • FIG. 6 is a general View of an installation with several stages, according to the invention.
  • FIG. 7 is a view similar to FIG. 2 and relates to an alternative form of construction
  • FIG. 8 is a view in elevation of this alternative form, partly dismantled
  • FIG. 9 is a view in cross-section taken along the line IX-lX of FIG. 8, of one of the elements of this alternative construction;
  • FIGS. 10A, 10B are partial views in cross-section, to a larger scale, taken respectively along the lines XA-XA and XB-XB of FIG. 9;
  • FIG. 11 is a partial view in cross-section, to a different scale, taken along the line XI-XI of FIG. 10A;
  • FIG. l2 shows a crystallization diagram, given by way of example
  • FIG. 13 is an elevational view similar to FIG. 8 and relates to another alternative form of heat exchanger in accordance with the invention.
  • FIG. 14 is an end view of the exchanger shown in FIG. 13, looking in the direction of the arrow XIV of this ligure;
  • FIG. l is a view in transverse section of this exchanger, taken along the line XV-XV of FIG. 13;
  • FIG. 16 is a detail plan View of one of the components of this exchanger, looking in the direction of the arrow XVI of FIG. 13;
  • FIG. 17 is a partial, elevational, cross-sectional view, to a larger scale, of this exchanger
  • FIG. 18 is a detail View, in elevation of another alternative form of construction, shown in elevation;
  • FIG. 19 is a detail, elevational, cross-sectional view of another alternative form of construction.
  • FIG. 20 is a view in axial section of a dryer capable of being utilized in an installation according to the invention.
  • FIG. 21 is a half-view plan of this dryer taken along the line XXI-XXI of FIG. 20;
  • FIG. 22 is similar to FIG. 21 and concerns an alternative form of construction.
  • an installation according to the invention in conformity with the form of embodiment chosen and shown in FIG. 1, comprises an evaporation circuit and a drying circuit 11.
  • the evaporation circuit 10 comprises a single heat exchanger 12, described in detail below, and a centrifugal separation chamber 13 in which rotates a circulating pump with a wheel, helix or the like, driven by a motor 14.
  • the exchanger 12 is coupled to the separation chamber 13, on the one hand by a pipe and on the other hand by a conduit 16, on which there may be mounted, as shown, a crystallizer 17.
  • this latter is constituted by a simple section of diameter larger than the pipe 16, and can also be interposed equally well in the same way on the pipe 15.
  • Each element 21 is as shown in FIG. 3 composed of two thin walls 22A, 22B, each having a depression zone of small depth, 23A, 23B respectively, limited by a peripheral edge 24A, 24B respectively.
  • the walls 22A, 22B are faced by their peripheral edges 24A, 24B, and these edges are rigidly iixed in a fluid-tight manner to each other, for example by welding.
  • the walls 22A, 22B are provided here and there with stiening bosses 122A, 122B respectively, supported in pairs between one wall and the other, and ixed to each other rigidly if so required.
  • These walls 22A, 22B may be made of metal or synthetic material. They form conjointly an elongated pocket of which two main coplanar dimensions are substantially greater than the corresponding transverse dimension.
  • the exchange elements 21 are arranged vertically in the body 20 and this latter is slightly inclined to the horizontal, so that the upper edge of each of the elements 21 is slightly inclined to the horizontal.
  • each of the elements 21 is engaged a distributor pipe 25 provided for that purpose at its lower portion with a slot 26 formed along a generator line.
  • the pipes 25 are horizontal or inclined to the horizontal at an angle diierent from that of the body 20, so that they are engaged more and more deeply over the upper edges of the element 21, in the direction of the free extremities of these latter.
  • the pipes 25 are coupled in parallel to the conduit 16 leading from the separation chamber 13.
  • the body 20 of the exchanger 12 is provided with a collecting cone 27 coupled by a pipe 28 to a compression vessel 29.
  • This compression vessel 29 is connected at its base by a pipe 30 to a vacuum pump 31, which may be for example of the liquid-ring type.
  • the compression vessel 29 is further connected by a discharge nozzle 32 to the various exchange elements 21 of the exchanger 12 by nozzles 35 (FIG. 3), connected in parallel and each discharging into the upper portion of a respective one of the said elements.
  • nozzles 35 In the discharge nozzle 32 is engaged a pipe 37 fed with live steam and controlled by a regulating valve 38. It would of course be possible to use any other type of steam compressor, mechanical or the like..
  • each exchange element 21 of the exchanger 12 is connected by a pipe 39 to the vacuum pump 31.
  • pipes 33 and 34 are branched to the elbows of the conduit 16.
  • the drying circuit 11, shown in FIG. 1, comprises a circulating pump 40, the suction of which is connected by a pipe 41 to the separation vessel ⁇ 13 at the base of this latter, while the delivery side of the pump supplies a separation hydro-cyclone 43 through a pipe 42.
  • the delivery side of the pump 40 is also connected to the separation vessel 13 by a return pipe 44 controlled by a valve 45.
  • valve 45 is preferably always slightly open. This arrangement maintains a desirable agitation in the bottom of the separation vessel 13. In addition, it enables part of the delivery of the pump 40 tol be absorbed, this delivery being in general greater than that of the drying circuit 11.
  • the hydro-cyclone sends a liquor, which is saturated but free from crystals, to the separation vessel '13, through a pipe y416.
  • the dryer 48 is shown in detail in FIGS. 4 and 5. It comprises, in known manner, a conical sieve 52 rotatably mounted in a chamber or tank 54.
  • the liquor to ⁇ be dried is from hydro-cyclone 43 at 47 along the axis of the sieve 52 and this latter ensures the separation or sifting of the desired crystals, which fall at 53, from a practically liquid paste forming the drying reflux, the latter being evacuated from the chamber 54 by a conduit 58.
  • the Scrapers which may be employed if so desired, in drying machines of this type.
  • This conduit 58 connects the dryer 48 to the separation vessel 13 in which, after the junction of conduit 58 with the pipe 46, the outlet of conduit 58 forms the intake 70 for previously established crystals, as will be explained below; this intake 70 is preferably arranged as close as possible to the point at which the conduit 15 opens into the separation vessel 13, so as to take advantage of the high upward speed resulting from the large flow-rate in this latter conduit.
  • a fractionating means 65 for crystals which for example may be a ball grinding mill or preferably a simple mixer of the type utilized for example for domestic purposes. It is also possible to place any other fractionating means at any other point of the installation which contains crystals.
  • the liquor contained in the evaporation circuit 1'0 carries crystals, the latter being introduced at 70 ⁇ into the separation vessel 13 as will be explained below.
  • This liquor is kept in continuous circulation in the circuit by the pump of the vessel 13v and, after passing into the crystallizer 17, this liquor is distributed by the pipes 25 over the elements 21 of the exchanger 12; it constitutes the secondary fluid of this exchanger, the primary heating fluid of which is steam introduced into the elements 21, as will be explained below.
  • the pipes 25 should preferably be constructed in such manner as to comply with the two following essential features:
  • the distribution of the liquid to be spread over the elements 21 must be as uniform as possible over each element and no crystal should be capable of blocking the slots 26, shown in FIG. 3.
  • the distributed liquor is subjected to a partial vaporization but, as has been explained above, this vaporization is advantageously carried out without bubbling, and therefore without priming and without local overheating.
  • This vaporization results in a concentration of the liquor and, if this concentration is carried sufficiently far, causes a subsequent increase in size of the previously formed crystals which are carried by the said liquor, as will be explained below.
  • 'Such increase 1n size may also be produced upstream and/or downstream of the heat exchanger, for example in the crvstallizer 17.
  • the non-vaporized liquor is taken by the conduit and returned to the separation vessel 13.
  • vapour liberated in the exchanger 12 above the treated liquid is collected by the cone 27 and dlrected by this latter to the compression vessel 29; then, by means of the discharge nozzle 32 and conjointly with a pressurized solvent vapour coming-in through the pipe 37, it is introduced into the elements 2.1 of the exchanger 12, of which it constitutes the primary fluid.
  • the condensed solvent vapour is removed by the pump 31.
  • the crystals are classified, or sorted, due especially to the rising ilow induced 1n this vessel by the pump which it contains.
  • the concentrated liquor loaded with crystals is taken by the pump 40 of the drying circuit 11 and is directed by this pump to the hydro-cyclone 43.
  • the spent liquor can be extracted by the pipe 33 and/ or by the pipe '34, this liquor being easily separated from the large crystals by the hydro-cyclone 43 for example, by the cyclone action resulting from the connection of these tubes in the elbows of the conduit 16, or by appropriate filtration.
  • This spent liquor returns to the associated preparation unit, preferably after ltration.
  • the thick mass of crystals leaving the hydrocyclone 43 passes into the drying apparatus which removes the largest crystals by sifting; these crystals fall at 53 and constitute in the present case the lfinal product.
  • the liquid paste which passes through the basket of the drying apparatus, and which still contains crystals of small size, is directed through the conduit 58 to the separation vessel 13 of the evaporation circuit.
  • the crystals conveyed by this paste constitute for this circuit, a source of supply of pre-formed crystals.
  • these crystals are brought to the desired dimensions by the fractionating means 65.
  • These dimensions may for example be of the order of 1D0/i.
  • the use of crystals split-up in this way is of particular advantage, since experience has shown that such crystals generally grow faster than naturally-formed crystals.
  • the fresh liquor is the concentrated 4filtered under-saturated liquor introduced into the drying apparatus 48 by the pipes 61 and 62.
  • the corresponding points of introduction of this liquor as described above have been chosen so as to ensure a systematic elimination of the nuclei, which without this arrangement, would have a tendency to develop spontaneously in the vicinity of these points.
  • the liquor introduced through the pipe 62 mechanically carries away the crystals which would have a tendency to be decanted in the tank 54 of the drying apparatus shown in FIG. 4.
  • the controlled preferential growth of pre-formed crystals enables, by a judiciously arranged extraction, a production of crystals of the desired size and in particular large crystals.
  • the number, as large as possible, and the size of the pre-formed crystals introduced into the treated solution, are of course chosen in such manner that the presence of these crystals is compatible with a suitable circulation of the product in question.
  • the fresh solution is introduced into the drying apparatus 48.
  • lFIG. l2 is a concentration-temperature diagram, on which there has been transferred a typical solubility curve C1 of the products for which the solubility of the crystals increases with the temperature-in most cases these are hydrated crystals-and a typical solubility curve C2 of the products for which the solubility of the crystals diminishes with increasing temperature, and in most cases these are anhydrous crystals.
  • These curves intersect at D on a vertical line having an abscissa tD.
  • a newly-formed fresh solution ⁇ which is slightly undersaturated has its characteristic point at S1, having an ordinate c1, corresponding to a concentration which is as high as possible; its temperature is t1, which is relatively high.
  • this fresh solution is introduced into the centrifuge, with the following advantages:
  • the under-saturated liquor conveyed by the pipe 62 axially through, but isolated from the suspension outlet conduit 58 of the centrifuge attacks the nuclei first in tank 54 in preference to the crystals which are located in this conduit after having passed through the basket of the centrifuge.
  • the supply of pre-formed crystals to the vessel 13 would be ensured, either by increasing the flow taken by the valve 45 from the delivery of the pump 40, or by connecting the said delivery to the inlet 70 through a regulating valve 76 interposed on a branch circuit 77 on the one hand, as shown in broken lines in *FIG. 1, and on the other hand through the fractionating means 65.
  • This fractionating means has the purpose of maintaining constant the number of crystals'contained in the crystallization unit and of replacing the number of crystals extracted by an equal number of broken crystals introduced into this crystallization unit.
  • the fractionating means is operative in the liquid phase.
  • FIG. 6 relates, by way of example, to an installation with three stages or eifects A, B and C.
  • the elements previously described have been given the same reference numbers, to which is added however the letter A, B, or C corresponding to the effect or stage to which they belong.
  • Each effect A, B and C comprises an evaporation circuit 10A, 10B, 10C respectively; in order to simplify the drawing, it has been assumed that a single product is crystallized in the installation, and there is therefore only a single centrifuge circuit 11.
  • the fresh solvent vapour coming in through the pipe 37 is directed inside the elements 21A of the exchanger 12A of the effect A or first effects; the secondary vapour collected by the cone 27A of this exchanger 12A is directed inside the elements 21B of the exchanger 12B of the effect B, or second effect; and then similarly, the tertiary vapour collected by the cone 27B of the exchanger 12B is directed inside the elements 21C of the exchanger 12C of the effect C, or third effect; finally, the fourth vapour collected by the cone 27C of the exchanger 12C is directed over a condenser 80 connected by a conduit 31 to a vacuum pump (not shown). This same conduit 81 also collects the vapours condensed in the various exchangers.
  • the spent liquor passes out at 146 and can for example be conveyed to a cooling circuit for the subsequent deposit of another solid.
  • FIGS. 7 to 1l relate to an alternative form of construction of the heat exchanger 12 according to the invention.
  • the body 1.20 of this exchanger is as shown in FIGS. 7 and 8 horizontal and is provided laterally with rollers 121 intended to roll on rails 122.
  • This arrangement makes it possible to have very easy access to the exchange elements 21 in case of need.
  • the body terminates in ange 123 intended for fixing it rigidly, for example by bolting, to a cover 124 to which are connected the vapour outlet 13.2 with a discharge nozzle or the like, and the evacuation pipe 13-9.
  • the arrangement also includes steam inlet 142 and condensate outlet 143.
  • the distributor pipes 25 of the previous embodiment are replaced in this alternative form by a unit 125 in the form of a comb (FIGS. 7-10).
  • This unit 125 is shown in FIGS. 9, 10A, 10B and ll to comprise an upper closure plate 126 and a plurality of parallel channels 1,27.
  • Each channel 127 is convergent horizontally between an inlet 1.28 at one end of unit 125 and an outlet 129 arranged at the other end thereof, but has always the same dimension in the vertical direction.
  • Each channel 127 is formed by two vertical Walls 130, 131, which Agradually approach each otherand which are directed towards each other by horizontal returns 133, 134 respectively, forming conjointly a slot 135 of constant width.
  • the slots 135 of the unit 125 are engaged over the upper edges of the exchange elements 21 and substantially overlap these latter.
  • a unit of this -kind ensures a very uniform distribution and permits a considerable delivery of vapour. Any liquid which is delivered to unit 125 and which does not leave via slots 135, simply exits via outlet 129, falls to the bottom of body 120, and is removed with the other liquid.
  • heat exchanger described above may equally serve as a cooler in the case especially where a crystallization is desired and this crystallization necessitates a cooling action.
  • FIGS. 13 to 17 relate to an alternative form of construction of this exchanger.
  • this latter comprises as shown in FIGS. 13 and 15 a cylindrical body or casing 220 ⁇ with a horizontal axis, provided laterally with rollers 221 for moving on rails 222.
  • 'Ihe body 220 ⁇ is terminated by a flange 223 for fixing, for example by bolting, to a cover 224.
  • the body 220 is shown removed from the cover 224 to a distance from this latter, in order to show the nest of tubes 225 of the exchange elements 226 which the body is intended to protect.
  • Each of the heat exchange elements 226 has, in a plane perpendicular to the axis of body 120, a substantially rectangular contour (see FIGS. 14 and l5) and in prole an undulating contour as shown in FIGS. 13 and 17. It is composed of two similar thin walls 227, 228, which are spaced uniformly apart by a distance D. Each of these walls has corrugations, the period, amplitude and number of which are chosen so that, taking account of its thickness, it is capable of resisting without permanent deformation, the difference in pressures capable of existing on each side. These walls 227, 228 are then simply welded to each other at their periphery without mutual intermediate supports.
  • the walls 227, 2281 of an element 226 are provided with a sharp edge 229, the purpose of which will become apparent below.
  • This edge may be added, for example by welding.
  • the exchange elements 226 extend transversely with respect to the longitudinal axis of the body 220, so that when the latter is withdrawn the edges of elements 2.26 are on the outside. This arrangement facilitates cleaning of these elements by a jet of water, and also provides for the possible addition of supplementary elements at the end of those previously incorporated, with the corresponding addition of a cylindrical portion to the body 2.20.
  • the assembly of the elements 226 permits the formation peripherally between them and the body 220I of the chambers V1, V2, V3 ⁇ and V4, the chamber V1 being the extreme left-hand chamber on the said figures and the chambers V2 to V4 being then spaced apart and distributed around elements 226 in the clockwise direction.
  • the exchange elements 226 are mounted to project in the same way as the teeth of a comb (see FIG. 16) from a common vertical distribution casing 230i arranged inside the chamber V1 defined above.
  • the internal volume of this casing communicates with the internal space 231 of each element,
  • the elements 226 are shown in a rectilinear manner, detached from each other for the sake of clearness of the drawing. However, as shown in FIG. 17, these elements are preferably slightly reentrant in each other.
  • the distribution casing ⁇ 230 is provided with a supply conduit 232 which passes through the cover 224, and at the same time the elements 226 are connected together at their lower portion by an evacuation conduit 233, which also passes through the cover 224, as shown in FIGS. 13 and 16.
  • the assembly can easily be made dismantlable.
  • This distributor unit which is preferably but not necessarily of the same type as that described in French Patent No. 1,531,361, comprises a respective transverse discharge nozzle 236 (FIGS. 13 and 17) located vertically above the sharp edge 229 of each element 226.
  • This distribution unit 2315 which advantageously ensures a smooth projection of the treated solution and not a spraying effect, is coupled to a supply pipe 237 which passes through the cover 224, preferably in a removable manner.
  • This cover 224 is also traversed by a vapor removal conduit 2381 opening into chamber V3 which is at right angles to the chamber V2, and by a concentrate removal conduit 239 leading from chamber V4.
  • an exchanger of this kind may also serve as a crystallization body, whether this crystallization is effected by cooling or by evaporation.
  • the distribution unit 235 supplied from the pipe 237, causes the mother solution to stream in thin dilms over the walls of the exchange elements 226, the sharp edges of these latter ensuring a good distribution of this solution over each of their walls.
  • the elements 226 are supplied with live steam by the pipe 232 and the distribution casing 230.
  • the steam condensed at 231 in the elements 2126 is evacuated by the pipe 233, while the solution which has streamed over the elements 226 is collected in the chamber V4, from which it is evacuated by the pipe 2-39.
  • the solution treated becomes concentrated under the most favorable conditions of micro-agitation, advantageously avoiding any excess heating.
  • This micro-agitation is due to the turbulent streaming of the solution over the elements 226 and is facilitated by the corrugated profile of these latter, or more generally, by the changes in slope of the said profile.
  • this is collected in the chamber V3 and evacuated by the tube 238, for example towards a condenser or a. vacuum ejector.
  • the most upstream nozzle 236, that is to say the nozzle 236 which is nearest to the co'ver 224, is preferably wider than the others so as to permit the passage of all the crystals which may travel into the pipe 237, thus avoiding a possible obstruction of the other nozzles.
  • the exchange elements 226 may equally well have a zig-zag profile.
  • spacing members are preferably provided at the overhanging extremities of the elements 226.
  • These spacing members which are preferably adjustable, have a double purpose: on the one hand to compensate for the effects of the differential expansion of the two longitudinal walls of the casing 230, and on the other hand to regulate the positions of the sharp edges 229 of the elements 226 in the axes of the corresponding nozzles 236 of the distribution unit 235.
  • FIG. 19 relates to an alternative form, in which the sharp edge 229 of an element 226 is formed by an extension of one of the walls 227, 228 of this element to form a tongue, this extension being preferably deformable with respect to its connection or coupling line to the other wall.
  • the spacing members referred to above enable the regulation by deformation of the position of this extension with respect to the associated nozzle 236 (not shown in the drawing), as indicated in broken lines.
  • the crystallization concerned was effected by evaporation.
  • this crystallization is effected by cooling, that 1s to say in the case where the heat exchanger accordmg to the invention is utilized as a cooler, the refrigerating fluid necessary may be introduced through the pipe 232 and passes out heated through the pipe 233, although it is preferable from the thermal point of view to introduce it at 233 and to evacuate it at 232.
  • the fresh solution may be introduced at a point other than into the centrifuge
  • centrifuge 260 provided in accordance with the invention with arrangements adopted precisely for that purpose.
  • the perforated basket 26'1 of this centrifuge is carried by a skirt 262 keyed for rotation on a driving shaft 263.
  • a driving shaft 263 In a manner known per se, there is associated therewith one or a plurality of helical Scrapers 264 carried by a support 265, and this support is keyed for rotation with a shaft 266 mounted in the interior of the shaft 263 and coaxial therewith.
  • the shaft 266 may be fixed or it may rotate at the same speed as the basket 261 or it may rotate at a different speed by braking or by a motor.
  • the crystals to be centrifuged are introduced into the mouth 267 of the basket 261, and, after sliding along the internal wall of this backet under the control of the v11 scraper or scrapers 264, they are evacuated at 268.
  • the basket 261 is extended laterally by a plate 270 and is capped by a bell 271.
  • This slot are adjusted so that its flow-rate is at most equal to the theoretical liquid flowrate of the centrifuge.
  • the outlet of liquid is effected along a ring, as shown diagrammatically at 277.
  • the above outlet slot 276 is replaced by a plurality of peripheral nozzles 278 oriented tangentially and uniformly spaced apart around the periphery.
  • An installation for the continuous evaporation of any solvent and for the continuous concentration of at least one substance in solution in said solvent comprising an indirect heat exchanger through which circulate, on the one hand, the solution to be treated and, on the other hand, a heat exchange uid, in which said heat exchanger comprises a housing body, a plurality of similar exchange elements arranged in parallel and spaced apart from each other inside said body, each said element being closed and composed of two substantially vertical thin walls disposed at a short distance from each other, a primary heating vapor intake adapted to introduce said exchange fluid between said Walls, and a secondary solution intake causing said solution to stream over said walls, said secondary intake comprising as many substantially horizontal elongate discharge outlet nozzles as there are heat exchange elements, and each of said nozzles being arranged directly above the upper edge of a respective one of said exchange elements, said secondary intake being constituted by a unit having the shape of a comb and comprising a plurality of elongate channels converging in their longitudinal direction and longitudinally
  • each of said exchange elements is provided with a tapering edge 12 facing the corresponding outlet nozzle of the intake for said solution.
  • thermoelectric fluid in which said heat exchanger comprises a housing body in the form of a circular cylinder having a substantially horizontal axis, a plurality of similar, vertical exchange elements arranged in parallel, spaced apart from each other inside said body, and disposed transversely with respect to the axis of said body, each said element being closed and composed of two thin substantially vertical walls disposed at a short distance from each other, a primary heating vapor intake adapted to introduce said exchange uid between said walls, and a secondary solution intake causing said solution to stream over said walls, said secondary intake comprising as many outlet nozzles as there are exchange elements, and each of said nozzles being arranged directly above the upper edge of one of said exchange elements.
  • An installation for the continuous evaporation of any solvent and for the continuous concentration of at least one substance in solution in said solvent comprising an indirect heat exchanger through which circulate, on the one hand, the solution to be treated and, on the other hand, a heat-exchange uid, in which said heat exchanger comprises a housing body, a plurality of similar exchange elements arranged in parallel and spaced apart from each other inside said body, each said element being closed and composed of two substantially vertical thin walls disposed at a short distance from each other, a primary heating vapor intake adapted to introduce said exchange fluid between said walls, and a secondary solution intake causing said solution to stream over said walls, said secondary intake comprising a distributor unit having its bottom provided with as many elongate discharge outlet nozzles as there are exchange elements, each of said nozzles being arranged directly above and parallel to the upper edge of a respective one of said exchange elements, said distributor conveying solution in a direction transverse to said nozzles, and that one of said secondary solution nozzles which is in the far
  • An installation for the continuous evaporation of any solvent and for the continuous concentration of at least one substance in solution in said solvent and the extraction of crystals of said substance, of the ⁇ kind comprising an indirect heat exchanger through which circulate, on the one hand, the solution to be treated and, on the other hand, a heat-exchange fluid, in which said heat exchanger comprises a housing body, a plurality of similar exchange elements arranged in parallel and spaced apart from each other inside said body, each said element being composed of two substantially vertical thin walls disposed at a short distance from each other, a primary heating vapor intake adapted to introduce said exchange iluid between said walls, and a secondary solution intake causing said solution to stream over said Walls, to cause part of said solution to be evaporated by thermal exchange with said exchange fluid and the remainder of said uid to remain in its liquid state and to fall to the bottom of the interior of said body after traversing said walls, said secondary intake comprising as many elongate discharge outlet nozzles as there are exchange elements, and each of said nozzles being

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Centrifugal Separators (AREA)
US798339A 1968-02-20 1969-02-11 Evaporators having hollow platelike vertical heat transfer elements and overhead nozzles Expired - Lifetime US3616835A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR140468 1968-02-20
FR6900106A FR2028623A6 (fr) 1968-02-20 1969-01-08

Publications (1)

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US3616835A true US3616835A (en) 1971-11-02

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Country Link
US (1) US3616835A (fr)
AT (1) AT309391B (fr)
BE (1) BE728588A (fr)
CH (1) CH491657A (fr)
DE (1) DE1908252A1 (fr)
FR (2) FR1583698A (fr)
GB (1) GB1247771A (fr)
NL (1) NL6902624A (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3724522A (en) * 1971-05-10 1973-04-03 Boeing Co Constant velocity uniform flow evaporator header
US4106555A (en) * 1976-10-21 1978-08-15 Yvan Quintal Ground heat exchanger
US4372996A (en) * 1972-05-09 1983-02-08 Massachusetts Institute Of Technology Method for metallizing aluminum pads of an integrated circuit chip
US4671856A (en) * 1984-04-26 1987-06-09 Superstill Technology, Inc. Method for recyclying energy in counterflow heat exchange and distillation
US4769113A (en) * 1982-09-02 1988-09-06 Superstill Technology, Inc. Method for recycling energy in counterflow heat exchange and distillation
US4869067A (en) * 1982-09-02 1989-09-26 Superstill Corporation Method of generating power
US5340443A (en) * 1988-08-26 1994-08-23 Aquamax Oy Distillation apparatus with paired membrane units
WO2014187690A1 (fr) * 2013-05-23 2014-11-27 Siemens Aktiengesellschaft Unité de séparation et procédé pour séparer des sels d'une substance détergente
CN105597646A (zh) * 2015-11-20 2016-05-25 如皋市中如化工有限公司 单氰胺水解脱溶系统装置
CN107053453A (zh) * 2017-04-19 2017-08-18 宁波北新建材有限公司 一种石膏板生产线原料冷却球磨一体化系统

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2552340B1 (fr) * 1983-09-28 1988-02-19 Swenson Sa Procede et dispositif de cristallisation a recyclage axial de niveau reglable
CN108759548A (zh) * 2018-07-18 2018-11-06 北京化工大学 一种嵌有增强骨架轴芯的螺旋扭带
CN115414685B (zh) * 2022-07-22 2024-02-20 广西糖业集团大新制糖有限公司 一种三效汁汽升温系统
CN116391478A (zh) * 2023-05-06 2023-07-07 海南大学三亚南繁研究院 一种可调节种植间距的瓜类作物幼苗栽种装置

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3724522A (en) * 1971-05-10 1973-04-03 Boeing Co Constant velocity uniform flow evaporator header
US4372996A (en) * 1972-05-09 1983-02-08 Massachusetts Institute Of Technology Method for metallizing aluminum pads of an integrated circuit chip
US4106555A (en) * 1976-10-21 1978-08-15 Yvan Quintal Ground heat exchanger
US4769113A (en) * 1982-09-02 1988-09-06 Superstill Technology, Inc. Method for recycling energy in counterflow heat exchange and distillation
US4869067A (en) * 1982-09-02 1989-09-26 Superstill Corporation Method of generating power
US4671856A (en) * 1984-04-26 1987-06-09 Superstill Technology, Inc. Method for recyclying energy in counterflow heat exchange and distillation
US5340443A (en) * 1988-08-26 1994-08-23 Aquamax Oy Distillation apparatus with paired membrane units
WO2014187690A1 (fr) * 2013-05-23 2014-11-27 Siemens Aktiengesellschaft Unité de séparation et procédé pour séparer des sels d'une substance détergente
CN105597646A (zh) * 2015-11-20 2016-05-25 如皋市中如化工有限公司 单氰胺水解脱溶系统装置
CN107053453A (zh) * 2017-04-19 2017-08-18 宁波北新建材有限公司 一种石膏板生产线原料冷却球磨一体化系统

Also Published As

Publication number Publication date
CH491657A (fr) 1970-06-15
NL6902624A (fr) 1969-08-22
GB1247771A (en) 1971-09-29
FR1583698A (fr) 1969-11-28
DE1908252A1 (de) 1969-09-11
AT309391B (de) 1973-08-10
FR2028623A6 (fr) 1970-10-09
BE728588A (fr) 1969-08-01

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