[go: up one dir, main page]

WO2011102761A1 - Procédé et appareil de commande d'incrustations dans un train d'évaporation à étages multiples pour la liqueur noire - Google Patents

Procédé et appareil de commande d'incrustations dans un train d'évaporation à étages multiples pour la liqueur noire Download PDF

Info

Publication number
WO2011102761A1
WO2011102761A1 PCT/SE2010/050182 SE2010050182W WO2011102761A1 WO 2011102761 A1 WO2011102761 A1 WO 2011102761A1 SE 2010050182 W SE2010050182 W SE 2010050182W WO 2011102761 A1 WO2011102761 A1 WO 2011102761A1
Authority
WO
WIPO (PCT)
Prior art keywords
black liquor
particles
fraction
coarse fraction
evaporation stage
Prior art date
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.)
Ceased
Application number
PCT/SE2010/050182
Other languages
English (en)
Inventor
Lars Olausson
Ulf Andersson
Mathias Gourdon
Lennart Vamling
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Valmet Power AB
Original Assignee
Metso Power 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 Metso Power AB filed Critical Metso Power AB
Priority to PCT/SE2010/050182 priority Critical patent/WO2011102761A1/fr
Publication of WO2011102761A1 publication Critical patent/WO2011102761A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • D21C11/106—Prevention of incrustations on heating surfaces during the concentration, e.g. by elimination of the scale-forming substances contained in the liquors

Definitions

  • Our present invention relates to a method for reducing the formation of incrustations during concentration of a black liquor obtained from a chemical pulping process, preferably a kraft or soda pulping process.
  • the invention also relates to an apparatus or plant for carrying out the method of the invention.
  • Yet another object of this invention is to provide a method and apparatus which could be implemented in any kind of process position where the solubility limit of a salt is to be exceeded, and where a local recycling of salt crystals of this salt susceptible for forming incrustations is made.
  • the range of recycled crystals will then form nucleus of crystals for efficient further crystal growth, avoiding formation of incrustations on the wall of the equipment.
  • An effect of the recycling of the salt crystals is that the total amount of crystallizing salt is increased by at least 10%, preferably at least 50%, and in some cases more than 100%, calculated as kg of salts (dissolved + crystals) per kg dry matter content of the black liquor compared to not using the selective recycling of salt crystals.
  • the number of the specific salt crystal particles, whose solubility limit is exceeded in the following evaporation stage, and within the particle range 30-500 ⁇ , is increased at least 50%, preferably 100% or in some cases more than 200%, compared to not using the selective recycling of the salt crystals.
  • Yet another object of this invention is to provide an improved method and apparatus where the modification of the process is made by entirely using particles already naturally being part of the black liquor flow, thus avoiding additions of chemicals or particles that must be readily available for the process to the required extent. Thus no negative impact on the total chemical balance is introduced that may cause problems in other parts of the mill.
  • first predetermined particle size used for the salt crystals in concern, by which is meant any practical minimum particle size possible to separate from the black liquor, while any content of the black liquor having particles below this size is considered and handled as liquid content.
  • second predetermined particle size is also used, by which is meant particles having an excessive size, which could accumulate in the system if recycled and instead is forwarded with the black liquor flow or alternatively is bled out at least in part.
  • the "first predetermined particle size” is thus representing particles with a size smaller than particles of the "second predetermined particle size”.
  • the objectives of the invention are accomplished in accordance with the inventive method for reducing the formation of incrustations during concentration of black liquor obtained from a chemical pulping process which comprises the steps of: subjecting said black liquor to a multiple-effect evaporation in a plurality of evaporation stages to partially concentrate the black liquor in each of said evaporation stages; and when the solubility level of salts in the black liquor, including salts from possible ash mixing, thick liquor recycling and salt crystals (particles) recycling, is exceeded in a specific evaporation stage, extracting at least a part of the concentrated black liquor after having passed at least said specific evaporation stage and subjecting this extracted part of the concentrated black liquor to a first separation process; and in said separation process separating crystals (particles) of said salt with a size above a predetermined particle size; and recycling at least a part of the salt crystals (particles) directly into or to a position before said specific evaporation stage and mixing these salt particles into the black liquor that is to be concentrated in said
  • the inventive method outlined above further comprises the steps of in said first separation process obtaining at least one coarse fraction with a major part of the particles from the concentrated black liquor above the predetermined first particle size and at least one fine fraction with a major part of the particles from the concentrated black liquor below said predetermined first particle size; and in said recycling step recycling at least a part of the coarse fraction directly into or to a position before said specific evaporation stage and mixing this coarse fraction into the black liquor that is to be concentrated in said specific evaporation stage, and further recycling at least a part of the fine fraction to a position after said specific evaporation stage and mixing this fine fraction into the black liquor that is to be forwarded to final treatment and combustion in a boiler.
  • it further comprises the steps of subjecting the first coarse fraction to a second separation process; and in said second separation process obtaining at least one second coarse fraction with a major part of the particles from the first coarse fraction above a predetermined second particle size and at least one second fine fraction with a major part of the particles from the first coarse fraction below said predetermined second particle size; and recycling at least a part of the second fine fraction of salt crystals directly into or to a position before said specific evaporation stage and mixing this second fine fraction of salt crystals (particles) into the black liquor that is to be concentrated in said specific evaporation stage, and recycling at least a part of the second coarse fraction to a position after said specific evaporation stage and mixing this second coarse fraction into the black liquor that is to be forwarded to final treatment and combustion in a boiler.
  • the inventive method instead also comprises the steps of from the salt particles separated in said first separation process obtaining at least one coarse fraction with a major part of the particles from the concentrated black liquor above a second predetermined particle size and at least one fine fraction with a major part of the particles from the concentrated black liquor below said second predetermined particle size; and recycling at least a part of the coarse fraction to a position after said specific evaporation stage and mixing this coarse fraction into the black liquor that is to be forwarded to final treatment and combustion in a boiler, or alternatively bleeding out at least a part of the coarse fraction, subjecting the fine fraction to a second separation process; and in said second separation process obtaining at least one second coarse fraction with a major part of the particles from the first fine fraction above the first predetermined particle size and at least one second fine fraction with a major part of the particles from the first fine fraction below the first predetermined particle size; and recycling at least a part of the second coarse fraction directly into or to a position before said specific evaporation stage
  • inventive method further comprises the steps of performing the extraction and first separation from two different positions in the multiple- effect evaporation process.
  • This alternative is preferably implemented in evaporation processes reaching higher dry matter content in the concentrated black liquor, typically above 80%. Different crystals form in different process positions when the solubility limit is exceeded, and typically is burkeit (2Na 2 S0 4 ,Na 2 C0 3 ) formed earlier in the multiple-effect evaporation plant, while dicarbonate (Na 2 S0 4 ,2Na 2 C0 3 ) is formed later.
  • the inventive method further comprises the steps of performing the extraction and first separation in a position of the multiple-effect evaporation process where the black liquor is still pressurized, and before any pressure reduction of the black liquor to a pressure below 1 ,0 bar (e) is made.
  • a position of the multiple-effect evaporation process where the black liquor is still pressurized, and before any pressure reduction of the black liquor to a pressure below 1 ,0 bar (e) is made.
  • the inventive apparatus for reducing the formation of incrustations during concentration of a black liquor obtained from a chemical pulping process comprises: a plurality of evaporation stages in a multiple-effect evaporation plant receiving black liquor from a feed pipe, said evaporation stages treating the black liquor in succession and increasing the concentration of the black liquor further in each of said evaporation stages; and an extraction pipe connected to the flow of partially concentrated black liquor after having passed at least one specific evaporation stage said extraction pipe being connected to first separation means; and in said separation means separating particles of a salt formed in said specific evaporation stage; and a recycling pipe for at least a part of said separated salt particles connected from the separation means and directly into or to a position before said specific evaporation stage and mixing these separated salt particles into the black liquor that is to be concentrated in said specific evaporation stage.
  • the apparatus further comprises in said first separation means obtaining at least one flow of a first coarse fraction with a major part of the salt particles from the concentrated black liquor above a first predetermined particle size and at least one first fine fraction with a major part of the particles from the concentrated black liquor below said first predetermined particle size; and a recycling pipe for at least a part of the first coarse fraction connected from the separation means and directly into or to a position before said specific evaporation stage and mixing this coarse fraction into the black liquor that is to be concentrated in said specific evaporation stage, and a recycling pipe for at least a part of the first fine fraction to a position connected from the separation means to a position after said specific evaporation stage and mixing this fine fraction into the black liquor that is to be forwarded to final treatment and combustion in a boiler (REC.B)
  • the apparatus further comprises a second separation means (SEP B) connected via a pipe to first separation means (SEP A); said pipe forwarding the first coarse fraction to the second separation means; and in said second separation means obtaining at least one second coarse fraction with a major part of the particles from the first coarse fraction above a second predetermined particle size and at least one second fine fraction with a major part of the particles from the first coarse fraction below said second predetermined particle size; and a recycling pipe for at least a part of the second fine fraction connected from the second separation means (SEP B) directly into or to a position before said specific evaporation stage and mixing this second fine fraction into the black liquor that is to be concentrated in said specific evaporation stage, and a recycling pipe for at least a part of the second coarse fraction connected from the second separation means (SEP B) to a position after said specific evaporation stage and mixing this second coarse fraction into the black liquor that is to be forwarded to final treatment and combustion in a boiler (REC.B).
  • SEP B second separation means
  • SEP A first
  • the apparatus instead further comprises from the salt particles separated in said first separation process obtaining at least one coarse fraction with a major part of the particles from the concentrated black liquor above a second predetermined particle size and at least one fine fraction with a major part of the particles from the concentrated black liquor below said second predetermined particle size; and recycling at least a part of the coarse fraction to a position after said specific evaporation stage and mixing this coarse fraction into the black liquor that is to be forwarded to final treatment and combustion in a boiler, or alternatively bleeding out at least a part of the coarse fraction, a second separation means (SEP B ) connected via a pipe (20) to first separation means (SEP A ); said pipe forwarding the first fine fraction (FFi) to the second separation means; and in said second separation means obtaining at least one second coarse fraction (CF 2 ) with a major part of the particles from the first fine fraction above a first predetermined particle size and at least one second fine fraction (FF 2 ) with a major part of the particles from the first fine fraction below said first pre
  • inventive apparatus further comprises at least two different extraction pipes being connected to the flow of partially concentrated black liquor after having passed different evaporation stages, said extraction pipes each being connected to an individual first separation means (SEP A and SEP B respectively) and wherein recycling pipes from each individual separation means being connected at different positions in the multiple-effect evaporation process.
  • the extraction pipes are connected to the flow of black liquor trough the multiple-effect evaporation process before reducing the pressure of the black liquor in a flash tank, and before the thick liquor storage tank.
  • the invention could be used in the recovery process in any kind of pulping systems. It could be used for pulping hardwood, softwood or annual plants, using different pulping processes such as kraft, sulphite or AQ/PS based delignification processes.
  • the type of separation process used for implementing the selective separation of the salt crystals is not critical to the invention. Any kind of separation process could be implemented, using hydrocylones, filters, centrifuges or sedimentation/settling tanks.
  • FIG. 1 shows a flow-diagram of a conventional multiple-effect evaporation process according to prior art
  • FIG. 2 shows a flow-diagram of a multiple-effect evaporation process according to a first embodiment of the invention
  • FIG. 3 shows a flow-diagram of a multiple-effect evaporation process according to a second embodiment of the invention
  • FIG. 4a, 4b, 4c, 4d and 4e shows five examples of a two-stage separation process used in order to separate out the selected particles for recycling according to the invention
  • FIG. 5 shows an example of the distribution of particles obtained in the separation process according to the invention
  • FIG. 6 shows a flow-diagram of a multiple-effect evaporation process according to a third embodiment of the invention.
  • FIG. 7a and 7b shows two examples of different separation principles possibly used in the invention.
  • a black liquor BL which has been concentrated in part in preceding stages of the evaporation process, supplied in line 1 to final stages 1 C/1 B/1 A.
  • the final stages 1 C/1 B/1 A are typically of a conventional design with falling-film evaporator stages A, B and C, either built as a plate or tube evaporator stage.
  • Fresh low-pressure steam ST LP which heats the black liquor indirectly in said tube or plate evaporators, is supplied in parallel to the last stages (concentrators) 1 A, 1 B and 1 C , as seen in the flow direction of black liquor, and with steam driven off is collected and led to the next effect 2 via line 2a.
  • the black liquor is thus exposed to heating which boils off liquid and increase the concentration of the black liquor.
  • Most often is also ash added to the flow of black liquor, which ash A E SP conventionally is obtained from an electrostatic filter in the flue passage from a recovery boiler.
  • ash A E SP conventionally is obtained from an electrostatic filter in the flue passage from a recovery boiler.
  • the black liquor BL E T having passed the final stage 1 A of the evaporation train is typically having a temperature of about 130 Q C, and after a pressure drop in a flash tank FT the temperature could be about 100-1 10 Q C and with a dry matter concentration of about 75%.
  • the concentrated black liquor is sent to a thick liquor storage tank TLS, before it is pumped to the liquor guns in the recovery boiler (not shown).
  • a recycling of the thick black liquor is done from this thick liquor storage tank as indicated with the dotted flow arrow R.
  • FIG 2 is a first simplest form of the inventive apparatus by which the inventive method could be used. In most parts it resembles the system as shown in figure 1 but for one modification.
  • an extraction pipe 10 connected to the flow of partially concentrated black liquor BL E T after having passed at least one specific evaporation stage, here all of said stages 1 A-1 C, said extraction pipe being connected to first separation means SEP A.
  • Said first separation means SEP A obtaining at least one flow of a first coarse fraction R F R with a major part of the particles from the concentrated black liquor above a predetermined first particle size and at least one first fine fraction sent via line 1 1 with a major part of the particles from the concentrated black liquor below said predetermined first particle size.
  • the recycling pipe 12 for at least a part of the first coarse fraction connected from the separation means and directly into or to a position before said specific evaporation stage, here before all stages 1A-1 C, and mixing this coarse fraction R F R into the black liquor that is to be concentrated in said specific evaporation stage.
  • the recycling pipe 1 1 for at least a part of the first fine fraction is connected from the separation means SEP A to a position after said specific evaporation stage and mixing this fine fraction into the black liquor that is to be forwarded to final treatment and combustion in a boiler (REC.B).
  • the separation means could preferably be a conventional hydrocyclone, which could separate out coarser particles from the flow of black liquor.
  • FIG 2 By this embodiment shown in figure 2 could coarser particles/crystals be recycled that could form nucleus of crystals for further crystal growth, avoiding formation of incrustations on the wall of the equipment for those salts that during the passage of stages 1A-1 C, due to increased concentration of the black liquor, will exceed its solubility limit.
  • FIG 3 is a second form of the inventive apparatus by which the inventive method could be used. In most parts it resembles the system as shown in figure 2 but for one modification as of an additional superconcentrator SC, driven by medium pressure steam ST M p, and thus capable of reaching a higher concentration.
  • an extraction pipe 10 connected to the flow of partially concentrated black liquor BL E T after having passed at least one specific evaporation stage, here after the superconcentrator SC, said extraction pipe being connected to first separation means SEP A.
  • Said first separation means SEP A obtaining at least one flow of a first coarse fraction R F R with a major part of the particles from the concentrated black liquor above a predetermined first particle size and at least one first fine fraction sent via line 1 1 with a major part of the particles from the concentrated black liquor below said predetermined first particle size.
  • the recycling pipe 12 for at least a part of the first coarse fraction connected from the separation means and to a position before said specific evaporation stage, here before all stages 1 A- 1 C, and mixing this coarse fraction R F R into the black liquor that is to be concentrated in said specific evaporation stage.
  • the recycling pipe 1 1 for at least a part of the first fine fraction is connected from the separation means SEP A to a position after said specific evaporation stage and mixing this fine fraction into the black liquor that is to be forwarded to final treatment and combustion in a boiler (REC. B).
  • the separation means could preferably be a conventional hydrocyclone, which could separate out coarser particles from the flow of black liquor.
  • figures 4a, 4b, 4c, 4d and 4e are examples of alternative 2-stage separation processes shown that could be used in figure 2 or 3.
  • FIG 4a is schematically shown a 2-stage particle separation process using screens SCi and SC2 as separation means.
  • the input flow is led to an upper chamber with a lower chamber beneath a screen SCi/SC2, and a fine fraction is passing the screen and accumulates in the lower chamber.
  • a second separation means SEP B is connected via a pipe 20 to first separation means SEP A, said pipe forwarding the first fine fraction FFi to the second separation means.
  • said second separation means is at least one second coarse fraction CF 2 obtained with a major part of the particles from the first fine fraction above a predetermined third particle size and at least one second fine fraction FF 2 with a major part of the particles from the first fine fraction below said predetermined third particle size.
  • a recycling pipe 12 for at least a part of the second coarse fraction CF 2 is connected from the second separation means SEP B to a position R F R before said specific evaporation stage and mixing this second coarse fraction into the black liquor that is to be concentrated in said specific evaporation stage.
  • a recycling pipe 1 1 for at least a part of the second fine fraction FF 2 is connected from the second separation means SEP B to a position after said specific evaporation stage and mixing this second fine fraction into the black liquor BL E T that is to be forwarded to final treatment and combustion in a boiler REC. B.
  • FIG 4b is schematically shown a 2-stage separation process using instead hydrocyclones as separation means.
  • the input flow is led to a top or mid part of the hydrocyclone, and by centrifugal force coarse particles are separated into the lower part of the cyclone.
  • the second separation means SEP B is connected via a pipe 20 to first separation means SEP A , said pipe forwarding the first fine fraction FFi to the second separation means.
  • said second separation means is at least one second coarse fraction CF 2 obtained with a major part of the particles from the first fine fraction above a predetermined third particle size and at least one second fine fraction FF 2 with a major part of the particles from the first fine fraction below said predetermined third particle size.
  • a recycling pipe 12 for at least a part of the second coarse fraction CF 2 is connected from the second separation means SEP B to a position R F R before said specific evaporation stage and mixing this second coarse fraction into the black liquor that is to be concentrated in said specific evaporation stage. Further a recycling pipe 1 1 for at least a part of the second fine fraction FF 2 is connected from the second separation means SEP B to a position after said specific evaporation stage and mixing this second fine fraction into the black liquor BL E T that is to be forwarded to final treatment and combustion in a boiler REC.B.
  • figure 4c is schematically shown a 2-stage separation process similar to that of figure 4a but having the screens so designed that the interesting particle content instead follows the first coarse fraction CFi and instead is sifted out in the second separation means SEP B .
  • figure 4d is schematically shown a 2-stage separation process similar to that of figure 4b but having the hydrocyclones so connected that the interesting particle content instead follows the first coarse fraction CFi and instead is separated in the second separation means SEP B .
  • FIG 4e is schematically shown the principles for an alternative separation process using centrifugal technique with only one separator.
  • the entire separator is typically a vertically oriented cylinder vessel that is rotated around its vertical center axis at considerable speed, typically well above 1000 rpm, and often in the range 2000-5000 rpm.
  • this separation technique could a first coarse fraction CF be separated, due to higher specific weight, at an outer layer and the finest fraction FF be separated, due to lowest specific weight, at the center of the rotating separator, both of them merged and sent to further evaporation and to the recovery boiler in flow BL E T-
  • the interesting particle content could be obtained in an intermediate layer, if the specific weight of the salt crystals is in an intermediate range, and extracted for further use according to the invention. Irrespective of the actual specific weight of the salt crystals, it could be separated similarly in any outlet adapted for the relative volume flows in each respective outlet.
  • each separator means be of any kind of type, i.e. a screening type of separator such as that shown schematically in figure 4a or 4c, or a hydrocyclone such as that shown schematically in figure 4b or 4d or a centrifuge as shown in figure 4e.
  • a screening type of separator such as that shown schematically in figure 4a or 4c
  • a hydrocyclone such as that shown schematically in figure 4b or 4d
  • a centrifuge as shown in figure 4e.
  • other types of separating means could be used, for example decanter centrifuges, sedimentations vessels, as well as separators capable of separating more than 2 fractions in one separator unit.
  • FIG 5 is shown an example of the distribution of particles obtained in the separation process according to the invention if a two stage separation process is used, and typically used for recycling nucleus of burkeit crystals for further crystal growth.
  • the first screen member SCi is equipped with slots that allows all particles with a size below 500 ⁇ to pass into a the lower chamber.
  • all particles in the area III and IV will thus pass out in the first coarse fraction CFi .
  • the second screen member SC 2 is equipped with slots that allows all particles with a size below 30 ⁇ to pass into a the lower chamber.
  • all particles in the area II will thus be recycled in pipe 12, while the second finer fraction, area I in figure, will pass out in pipe 1 1 and merged with the first coarse fraction CFi .
  • the burkeit crystals that promotes further crystal growth be recycled, while the remaining content of liquids and smaller particles is sent on further to the recovery boiler.
  • the 2-stage separation processes as shown in figure 4a and 4b would also separate out all larger particles, which may be grit or gravel and larger fiber bundles that may cause sedimentation and build up in volume of these fractions over time in the specific evaporation stage.
  • the larger particles could in some cases be drained from the system by other means, and the important feature is to be able to avoid recycling of smaller particles and chemicals that may overload the evaporation stage in concern.
  • the particle sizes sifted out could also be modified to the salt crystals being formed in the specific evaporation stage.
  • the lower and upper predefined particle sizes could be adjusted accordingly to any lower and upper predefined particle sizes covering the bulk volume of the salt crystals in concern.
  • the ranges 30-500 ⁇ is representative for covering the bulk volume of burkeit crystals in a typical evaporation process for black liquor obtained from a kraft cooking process.
  • FIG 6 is a third form of the inventive apparatus shown by which the inventive method could be used. In most parts it resembles the system as shown in figure 3 but for two modifications as of an additional evaporation stage 2 located before the evaporation stages 1 A-1 C, and a second extraction and separation process.
  • at least two different extraction pipes 10a/10b being connected to the flow of partially concentrated black liquor after having passed different evaporation stages 1 A and SC respectively.
  • Said extraction pipes 10a/10b each being connected to an individual first separation means, SEPi and SEP 2 respectively and wherein recycling pipes 12a/12b from each individual separation means being connected at different positions in the multiple-effect evaporation process.
  • regulating valves ⁇ and V 2 for controlling the amount of flow that is to be treated in the separation means
  • the part volume treated in this separation equipment could adjustably be set to any range from part flows to the entire output flow volume from the specific evaporation stage, depending upon the efficiency of separating the salt crystals in concern and the required amount of nucleus of crystals needed in the specific evaporation stage avoiding incrustations. This is heavily dependent upon the specific salt in concern.
  • regulating valves V 3 and V 4 for controlling the amount of thick liquor recycled into each separation loop.
  • the extraction pipes for extraction and further separation connected to the flow of black liquor trough the multiple-effect evaporation process before reducing the pressure of the black liquor in a flash tank, and before the thick liquor storage tank. This will maintain some of the easily evaporable liquids in the concentrated black liquor that could escape in the flash tank, which content may be favorable for the separation process.
  • the separation process Once the concentrated black liquor have passed the flash tank and is sent to the thick liquor storage, is the viscosity increased and further handling is made more difficult.
  • the separation process also be implemented on the final thick liquor, but at more difficult conditions for a successful separation process.
  • figure 7a and 7b are two examples shown of different separation principles possibly used in the invention.
  • figure 7a is schematically the separation process outlined as implemented in the method according to claim 4 and the apparatus according to claim 10, and also shown in the two stage separation process according to figure 4a and 4b.
  • figure 7b is schematically the separation process outlined as implemented in the method according to claim 3 and the apparatus according to claim 9. From a separation point of view the difference in approach is that the oversized material is directly sifted out from the bulk flow in figure 7a, and the useful salt particles are sifted out from the remaining flow containing also the undersized material and the bulk volume of liquids.
  • figure 7b is instead the undersized material directly sifted out from the bulk flow, i.e. the bulk volume of liquids, and the useful salt particles are sifted out from the remaining flow containing also the oversized material. What kind of separation process to use is dependent on the type of separation means used.

Landscapes

  • Paper (AREA)

Abstract

La présente invention concerne un procédé et un appareil de réduction de la formation d'incrustations pendant la concentration de liqueur noire au cours d'un processus d'évaporation à multiples effets (1A-1B-1C). Lorsque le niveau de solubilité des sels dans la liqueur noire est dépassé dans un étage d'évaporation spécifique, au moins une partie de la liqueur noire concentrée est extraite après être passée par ledit étage d'évaporation spécifique et soumis à un premier processus de séparation (SEP). Au cours dudit processus de séparation, les cristaux (particules) dudit sel sont séparés et au moins une partie des cristaux de sel est recyclée (RFR) directement dans ledit étage d'évaporation spécifique ou dans une position située devant ledit étage. Ceci réduit la formation d'incrustations et réduit la précipitation dans les étages d'évaporation.
PCT/SE2010/050182 2010-02-17 2010-02-17 Procédé et appareil de commande d'incrustations dans un train d'évaporation à étages multiples pour la liqueur noire Ceased WO2011102761A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/SE2010/050182 WO2011102761A1 (fr) 2010-02-17 2010-02-17 Procédé et appareil de commande d'incrustations dans un train d'évaporation à étages multiples pour la liqueur noire

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/SE2010/050182 WO2011102761A1 (fr) 2010-02-17 2010-02-17 Procédé et appareil de commande d'incrustations dans un train d'évaporation à étages multiples pour la liqueur noire

Publications (1)

Publication Number Publication Date
WO2011102761A1 true WO2011102761A1 (fr) 2011-08-25

Family

ID=44483175

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2010/050182 Ceased WO2011102761A1 (fr) 2010-02-17 2010-02-17 Procédé et appareil de commande d'incrustations dans un train d'évaporation à étages multiples pour la liqueur noire

Country Status (1)

Country Link
WO (1) WO2011102761A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103318980A (zh) * 2013-07-03 2013-09-25 金东纸业（江苏）股份有限公司 制浆废水的处理装置和处理方法
WO2014159709A1 (fr) * 2013-03-14 2014-10-02 Veolia Water Solutions & Technologies North America, Inc. Système et procédé pour récupérer la chaleur d'une liqueur noire faible dans un procédé de préparation de pâte de bois
CN113461088A (zh) * 2020-03-31 2021-10-01 国家能源投资集团有限责任公司 浓盐水自然蒸发浓缩结晶系统及方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5647955A (en) * 1994-10-24 1997-07-15 Tampella Power Oy Method of reducing scaling of heat transfer surfaces in an evaporation plant of a sulphate cellulose mill
US6090240A (en) * 1997-02-21 2000-07-18 Ahlstrom Machinery Oy Method of inhibiting scaling in black liquor evaporators
WO2008057031A1 (fr) * 2006-11-07 2008-05-15 Metso Power Ab Procédé et équipement pour l'évaporation de la liqueur noire qui est obtenue en résultat d'un processus de lessivage durant la fabrication de pâte de cellulose

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5647955A (en) * 1994-10-24 1997-07-15 Tampella Power Oy Method of reducing scaling of heat transfer surfaces in an evaporation plant of a sulphate cellulose mill
US6090240A (en) * 1997-02-21 2000-07-18 Ahlstrom Machinery Oy Method of inhibiting scaling in black liquor evaporators
WO2008057031A1 (fr) * 2006-11-07 2008-05-15 Metso Power Ab Procédé et équipement pour l'évaporation de la liqueur noire qui est obtenue en résultat d'un processus de lessivage durant la fabrication de pâte de cellulose

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014159709A1 (fr) * 2013-03-14 2014-10-02 Veolia Water Solutions & Technologies North America, Inc. Système et procédé pour récupérer la chaleur d'une liqueur noire faible dans un procédé de préparation de pâte de bois
CN103318980A (zh) * 2013-07-03 2013-09-25 金东纸业（江苏）股份有限公司 制浆废水的处理装置和处理方法
CN103318980B (zh) * 2013-07-03 2014-08-20 金东纸业（江苏）股份有限公司 制浆废水的处理装置和处理方法
CN113461088A (zh) * 2020-03-31 2021-10-01 国家能源投资集团有限责任公司 浓盐水自然蒸发浓缩结晶系统及方法

Similar Documents

Publication Publication Date Title
US6436233B1 (en) Feeding cellulose material to a treatment vessel
NO178705B (no) Fremgangsmåte for fjerning av fargepartikler og/eller klebrige forurensninger fra resirkulert papir-cellulosemasse
US5403442A (en) Method of deaerating and pumping a fiber suspension prior to washing
EP2427598B1 (fr) Procédé de lixiviation améliorée de cendres de filtre électrostatique en provenance d'une chaudière de récupération
WO2011102761A1 (fr) Procédé et appareil de commande d'incrustations dans un train d'évaporation à étages multiples pour la liqueur noire
NO312471B1 (no) Fremgangsmåte og innretning for behandling av fyllstoff- inneholdende materiale
JP6298813B2 (ja) 強力な白液と残留アルカリレベルの低い石灰泥を得る方法及び装置
US20160040356A1 (en) Method and assembly for processing cellulose pulp of wood processing industry
US10870947B2 (en) Process for isolation of hemicelluloses from biomass pulping process waters or spent liquors
US20030201213A1 (en) Combined sand and liquor separation for chip transport in pulp processing
KR19990067424A (ko) 오염된 펄프 부유물 처리를 위한 방법 및 설비
CN116716753B (zh) 一种制浆系统
FI127615B (en) A method for treating recovery boiler ash
SE530999C2 (sv) Förfarande för behandling av finfördelat fibermaterial vid kokning av pappersmassa
US4963227A (en) System and apparatus for recovery of turpentine from thermomechanical pulping process
WO1995025198A1 (fr) Clarification et/ou filtrage de la liqueur verte et appareil conçu a cet effet
US11993895B2 (en) Method of feeding wood chips to a prehydrolysis reactor
EP3446034B1 (fr) Procédé et agencement pour la production de vapeur de traitement
Perera Application of Ultrasound for Fouling Prevention in Eucalyptus Black Liquor Evaporators
US20030102092A1 (en) Processes and systems for handling knots in a chemical pulping process
WO2006087431A1 (fr) Procede et appareil destines a eliminer les impuretes fines des suspensions fibreuses
Padmanabham et al. Operating Experience of Black Liquor Desilication at APPM-Unit: Coastal

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10846249

Country of ref document: EP

Kind code of ref document: A1

DPE2 Request for preliminary examination filed before expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 10846249

Country of ref document: EP

Kind code of ref document: A1