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WO1996032998A1 - Evaporateur a flux tombant pour liqueur residuaire de cuisson de pate chimique, et procede permettant de fabriquer des lamelles tubulaires dans l'evaporateur - Google Patents

Evaporateur a flux tombant pour liqueur residuaire de cuisson de pate chimique, et procede permettant de fabriquer des lamelles tubulaires dans l'evaporateur Download PDF

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Publication number
WO1996032998A1
WO1996032998A1 PCT/SE1996/000411 SE9600411W WO9632998A1 WO 1996032998 A1 WO1996032998 A1 WO 1996032998A1 SE 9600411 W SE9600411 W SE 9600411W WO 9632998 A1 WO9632998 A1 WO 9632998A1
Authority
WO
WIPO (PCT)
Prior art keywords
tubes
falling
lamellae
film
liquor
Prior art date
Application number
PCT/SE1996/000411
Other languages
English (en)
Inventor
Lars Olausson
Original Assignee
Kvaerner Pulping Ab
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kvaerner Pulping Ab filed Critical Kvaerner Pulping Ab
Priority to EP96911135A priority Critical patent/EP0821611A1/fr
Publication of WO1996032998A1 publication Critical patent/WO1996032998A1/fr

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C11/00—Regeneration of pulp liquors or effluent waste waters
    • D21C11/10—Concentrating spent liquor by evaporation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D1/00—Evaporating
    • B01D1/04—Evaporators with horizontal tubes
    • 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

Definitions

  • the present invention relates to a further development of the known type of apparatus for evaporating spent liquor from chemical pulp cooking, so- called black liquor, which operates in accordance with the falling-film principle, i.e. that a film of the liquid which is to be evaporated is arranged to flow down along a surface which is heated with steam, with water in the film evaporating during its progress downwards.
  • the invention relates, on the one hand, to a further development of the method of achieving evaporation and, on the other, to a method for manufacturing tube lamellae down which the falling film is to flow.
  • Spent liquor from the cooking and bleaching departments of the chemical pulp industry consists mainly of water. Most of this water must be evaporated off, and the liquor concentrated, since, in a later stage, organic material in this liquor will be combusted and thermal energy and chemicals collected.
  • This water can be evaporated in different ways, in different types of apparatus, one of which ways is by means of so-called falling film evaporation, in which the liquor is arranged to flow down in the form of a film on a heated surface.
  • This surface can consist of a wall having outwardly directed bulges, with two walls being welded together to form lamellae. It can also consist of a series of pipes. Steam for heating flows inside the lamellae, and the falling film flows down on the outside of these lamellae. In the case of pipes or tubes, these are placed vertically adjacent to each other and steam for heating is arranged to flow inside the pipes, and the falling film to flow down along the outside of these pipes.
  • a falling- film evaporator for evaporating spent liquor from chemical pulp cooking, so-called black liquor which consists of an elongate, upright container which has inlet and outlet openings for steam and spent liquor, and a tube system in the container through which evaporation steam is intended to flow and which is surrounded on the outside by a falling film of black liquor, which evaporator is characterized in that the tube system consists of horizontal tubes.
  • the tubes prefferably be arranged in the form of lamellae with parallel tubes lying above each other, which tubes are connected to, and open out into, a vertical, pipe-shaped box at the ends of the tubes.
  • the tubes in the lamellae can be arranged n groups with, for example, three tubes in each group, which tubes are bent at 180° two or more times at the boxes so that steam in these tubes is obliged to pass backwards and forwards three or more times between the boxes.
  • the tube lamellae it is expedient for the tube lamellae to be coupled together in one or more cassettes.
  • the invention furthermore includes a process for manufacturing tube lamellae as described above, and the process is characterized in that the tubes are firmly welded, at their ends, in an elongate sheet metal wall which is plane or curved in cross-section and which has cutouts for the tubes, after which the sheet metal wall is welded to the remaining part of the box so that the weld between the tubes and the box ends up inside the box.
  • F g. 1 shows, diagrammatically and n section, a falling-film evaporator according to the invention
  • Fig. 2 shows one embodiment of a tube lamellae according to the invention
  • F g. 3 shows another embodiment of a tube lamella according to the present invention.
  • Figure 1 shows, diagrammatically and in vertical section, a falling-film evaporator according to the invention. It consists of a closed, cylindrical container 1 which has a length of some 10 metres and a diameter of 4-5 metres. The gable ends are dome-shaped in order to be able to withstand pressure. Naturally, the container 1 can be of another design. At its lower part, it is provided with an inlet pipe 2 for liquor which is to be evaporated. This liquor mixes with liquor which has already finished being evaporated and which is present in the bottom part of the container 1.
  • the liquor which is reintroduced into the evaporator through the pipe 6 is distributed in a distribution box 7 immediately above the tube system 8.
  • This distribution box 7 can be of a conventional type and has the task of spreading the liquor in a uniform stream over the whole of the tube system 8.
  • the liquor then flows uniformly as a film over the surfaces in the tube system 8 and eventually drips down into the lower part of the container 1.
  • the aqueous steam which is to heat the pipe system 8 to evaporation temperature enters, under suitable pressure, through a supply pipe 9 and is distributed, in a pipe or box 10 which is arranged transversely in relation to the supply pipe 9, to the tube lamellae, which are placed adjacent to each other, in the tube system 8.
  • the tube system 8 consists of tube lamellae which are arranged adjacent to each other and which, in turn, consist of horizontal tubes which open out, at each end, into two boxes 11. Only one lamella is shown in Figure 1, and the box on the right of the figure serves as the box for feeding the steam to the tubes, while the box on the left constitutes a discharge box for condensate and steam which then flows out into the outlet pipe 12 at the lower part of the container 1.
  • the liquor which is fed in at the upper part of the tube system 8 flows down, as has been mentioned above, along the tube system as a film. Due to the fact that the tubes are horizontal and arranged transversely in relation to the direction in which the liquor is flowing, the film will alter during the whole of its passage downwards and consequently acquire a new surface for each pipe. This facilitates evaporation and promotes heat transfer.
  • FIG. 2 shows a tube lamella according to the invention. It consists, in this embodiment, of straight tubes 14 which lie above each other and which are firmly welded into the boxes 11 at either end.
  • the boxes 11 have openings which coincide with the ends of the tubes so that free passage can be provided for the steam, which flows into the tubes 14 through one box and out into the other box.
  • the outlet for condensate and steam at the lower part of the left-hand box 11 is arranged in the same manner as the supply through the distribution box 10.
  • the collecting box 15 is somewhat narrower than the distribution box 10 since some of the steam has condensed and consequently does not need to be conducted out through the collecting box 15.
  • FIG 3 shows a design of the tubes 14 which is different from that in Figure 2, the arrangement is otherwise the same.
  • the tubes 14 have, as is evident from the figure, been arranged in groups of three and have been bent at 180° (or 2 x 90°) at the opposite box, so that they pass back towards the first box, the feed-in box, where they have been bent in the same manner, and pass back to the outlet box on the left of the figure, where they are connected to this box.
  • the steam which enters a tube from the feed-in box consequently has to pass three times between the boxes 11 before it flows out into the collecting box on the left- hand side.
  • the boxes 11 can be square, rectangular, circular or oval in cross-section.
  • a special procedure can be implemented for connecting the tubes 14 to the boxes 11.
  • a long strip of sheet metal which is straight or curved in cross-section and which is provided with openings corresponding to the external diameter of the tubes, is first firmly welded to these tubes. This weld is then executed on the inside of the proposed box. It is a simple operation, which can readily be automated, to weld the pipes firmly to this elongate sheet metal strip in this manner. After the tubes have been firmly welded in this manner, the sheet metal strip, which includes the tubes and which is to be a part of the whole box, is then firmly welded to the remaining part of the box.
  • This procedure consists of only two longitudinal external welds, and this operation, too, can readily be automated. As a result, it is very simple and cheap to manufacture the tube system 8 with tubes 14 and boxes 11.
  • both the temperature gradient and the concentration gradient of the film will be equalized every time the liquor film flows over to a new tube.
  • the liquor film will, therefore, be equalized every 50 to 100 mm, while, in the case of tube lamellae having vertical tubes, the liquor film will flow undisturbed over the whole of the length of the tube (10 - 15 metres) .
  • This improvement in the heat transfer is of interest both for achieving high dry matter contents in the liquor, since processing of the liquor film by means of the continual rearrangements affords great improve- ments, and for evaporating very dilute solutions, for example bleaching department effluent, where very high heat transfer numbers are sought for economic reasons.
  • the invention is not limited to spent liquors from chemical pulp cooking but can also be applied to bleaching department spent liquors and the like.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)

Abstract

L'invention porte sur un évaporateur à flux tombant conçu de préférence pour évaporer la liqueur résiduaire provenant de la cuisson de pâte chimique. L'invention se caractérise par le fait que le système tubulaire (8) est constitué de tubes horizontaux (14) à la différence des évaporateurs à flux tombant classique. L'invention comprend également un procédé permettant de fabriquer des lamelles tubulaires qui devront être utilisées dans l'évaporateur à flux tombant de l'invention. Le procédé est basé sur les tubes (14) que l'on va fermement souder à la paroi interne d'une partie du caisson, à la suite de quoi, l'autre partie du caisson (11) est fermement soudée à la première partie lors de la deuxième phase.
PCT/SE1996/000411 1995-04-18 1996-03-29 Evaporateur a flux tombant pour liqueur residuaire de cuisson de pate chimique, et procede permettant de fabriquer des lamelles tubulaires dans l'evaporateur WO1996032998A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP96911135A EP0821611A1 (fr) 1995-04-18 1996-03-29 Evaporateur a flux tombant pour liqueur residuaire de cuisson de pate chimique, et procede permettant de fabriquer des lamelles tubulaires dans l'evaporateur

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9501388A SE504232E (sv) 1995-04-18 1995-04-18 Fallfilmsindunstare för indunstning av avlut från cellulosakokning samt förfarande för tillverkning av tublameller i fallfilmsindunstaren
SE9501388-4 1995-04-18

Publications (1)

Publication Number Publication Date
WO1996032998A1 true WO1996032998A1 (fr) 1996-10-24

Family

ID=20397962

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1996/000411 WO1996032998A1 (fr) 1995-04-18 1996-03-29 Evaporateur a flux tombant pour liqueur residuaire de cuisson de pate chimique, et procede permettant de fabriquer des lamelles tubulaires dans l'evaporateur

Country Status (3)

Country Link
EP (1) EP0821611A1 (fr)
SE (1) SE504232E (fr)
WO (1) WO1996032998A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999000484A1 (fr) * 1996-03-13 1999-01-07 Jean De Surrel De Saint Julien Procede de concentration d"une solution telle que mouts de raisin a basse temperature et pression atmospherique
WO2018143886A1 (fr) * 2017-02-03 2018-08-09 Valmet Ab Tube de transfert de chaleur, et procédé de fabrication de tube de transfert de chaleur

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2261983A1 (en) * 1974-02-21 1975-09-19 Aerocyclic Distillation Glass-tubed vapour compression (sea water) distn plant - utilising same pressure in all evapn stages to raise efficiency
DE2511144A1 (de) * 1975-03-14 1976-09-23 Rheinstahl Ag Folienwaermetauscher fuer das eindampfen von loesungen
EP0110545A1 (fr) * 1982-11-04 1984-06-13 Secretary of State for Trade and Industry in Her Britannic Majesty's Gov. of the U.K. of Great Britain and Northern Ireland Procédé de transfert de chaleur

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2261983A1 (en) * 1974-02-21 1975-09-19 Aerocyclic Distillation Glass-tubed vapour compression (sea water) distn plant - utilising same pressure in all evapn stages to raise efficiency
DE2511144A1 (de) * 1975-03-14 1976-09-23 Rheinstahl Ag Folienwaermetauscher fuer das eindampfen von loesungen
EP0110545A1 (fr) * 1982-11-04 1984-06-13 Secretary of State for Trade and Industry in Her Britannic Majesty's Gov. of the U.K. of Great Britain and Northern Ireland Procédé de transfert de chaleur

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999000484A1 (fr) * 1996-03-13 1999-01-07 Jean De Surrel De Saint Julien Procede de concentration d"une solution telle que mouts de raisin a basse temperature et pression atmospherique
WO2018143886A1 (fr) * 2017-02-03 2018-08-09 Valmet Ab Tube de transfert de chaleur, et procédé de fabrication de tube de transfert de chaleur
WO2018143880A1 (fr) * 2017-02-03 2018-08-09 Valmet Ab Tube de transfert de chaleur et procédé de fabrication de tube de transfert de chaleur
WO2018143885A1 (fr) * 2017-02-03 2018-08-09 Valmet Ab Tube de transfert de chaleur, et procédé de fabrication de tube de transfert de chaleur
US10926189B2 (en) 2017-02-03 2021-02-23 Valmet Ab Heat transfer tube and method for manufacturing a heat transfer tube
US10933342B2 (en) 2017-02-03 2021-03-02 Valmet Ab Heat transfer tube and method for manufacturing a heat transfer tube
US10981080B2 (en) 2017-02-03 2021-04-20 Valmet Ab Heat transfer tube and method for manufacturing a heat transfer tube

Also Published As

Publication number Publication date
EP0821611A1 (fr) 1998-02-04
SE9501388D0 (sv) 1995-04-18
SE9501388L (sv) 1996-10-19
SE504232C2 (sv) 1996-12-09
SE504232E (sv) 2003-02-11

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