FI119559B - Procedure for treating pulp - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to a process for treating pulp used in the manufacture of paper or board, wherein the pulp is passed from a pulp source to a pulp treatment and further through a short circulation to a headbox of a paper or board machine.

Background of the Invention

Pulp treatment is the part of the process that is located between the pulp mill and the paper or board machine. The task of pulp processing is to produce a pulp of short duration in a paper or board machine, consisting of one or more partial pulps which are mixed together. The pulp treatment consists of a number of mixing tanks in which the partial pulps are mixed together, the consistency of the pulps and the concentration of the pulps are adjusted, and the necessary fillers and other chemicals are added.

20

In current pulp processing systems, pulp • V. the masses from the production are stored in separate storage tanks, • · · 1 from which the mass is passed to the pulp processing process. The masses * · · are led from storage tanks to dosing tanks while diluting : 25 weights in the lower part of the storage tank or in the tube between the tanks or in the i ::: dosing tank. Depending on the pulp, the pulps can be defibrated or m · ♦ "pulverized in the pulping process. From the dispensing tanks, pulps are further fed into a common mixing tank where various pulp components are mixed. In addition to various pulps, fillers and other additives may be mixed.

From the mixing tank, the pulp is fed to the machine tank, where the pulp is diluted to a final consistency and then passed to the paper machine! for a short cycle. In a short rotation of the paper machine, the pulp is diluted to headbox consistency with water recovered from the wire section of the paper machine.

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The present pulp handling systems described above are complex and include a large number of different containers and equipment with a considerable space requirement. One of the reasons for this complexity of the pulping system is that various intermediate containers and dispensing containers 5 are considered essential in pulping to maintain a sufficiently uniform pulp quality and to maintain process conditions as constant as possible.

However, many successive tanks and dilution points cause, for example, process control because the control chain becomes long and complex, thus easily causing problems with process consistency and flow control, which results in varying pulp feed rates and consequent variations in basis weight. One problem is also the consistency disorders, which are caused e.g. the barreling of the tanks, whereby high-mass pulp particles detached from the inner surface of the tanks cause peaks in the consistency. Disruptions in consistency can also result from uneven disassembly or drainage of the tanks.

20

There are solutions where the pulp feed arrangement for the short circulation of the papermaking machine and further to the headbox has been simplified, but the entire pulp handling process from the pulp tower to the short • v of the papermaking machine. simplification and abandonment of all | : 25 of intermediate tanks and metering tanks in bulk handling because tanks: however, are considered necessary to balance the quality of the pulp.

• · · * # * 'Existing solutions mainly focus on simplifying short circuits. In addition, the pulp handling system has been considered as a buffer storage between pulp mill and paper machine in case of disturbances: Vj 30.

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BRIEF DESCRIPTION OF THE INVENTION In the present invention, it has been found that many intermediate tanks, mixing tanks and dispensing tanks in 35 pulp processing processes are not necessary, but uniform and high quality pulp can be dispensed at short batch, paper and board can solve or at least substantially reduce the problems of the prior art. It is therefore an object of the present invention to provide a process for treating pulp which enables the pulp used to make paper or cardboard to be processed and fed from a pulp source to a paper or board machine without interrupting the pulp in storage containers, mixing containers or machine containers. In addition, aggregation of the partial masses and dilution of the masses is carried out without containers.

To accomplish this purpose, the process according to the invention is essentially characterized in that the pulp treatment is carried out in the pulp treatment pipeline so that the pulp flow is continuously advancing at a rate determined by the volume flow.

15

Thus, the process for treating pulp according to the invention does not require conventionally used metering tanks, mixing tanks, machine tanks, and associated pumps and other actuators in the process arrangement. However, the invention is based on the idea that the pulp is fed in a uniform and continuous volume flow, for example from a pulp storage tower, to a closed pulp processing pipeline where the pulp flow continues continuously all the way from the pulp source to the particle mixing point. All actuators required for the pulping process are • · | 1 '25 so that they do not cause a delay in the continuous flow of mass:; · *: in piping. Also, in piping and actuators, the mass does not come into contact with the free air • space, which reduces air mixing: ···: into the mass.

In the process according to the invention, the pulp used in the manufacture of paper or paperboard may be a chemical, mechanical or chemical pulp, a scrap or a recycled fiber. The pulp source is preferably a pulp storage tower or a debris tower, but the pulp source may also be a pulp directly from a pulp mill or pulp from pulping. The pulp is diluted to the desired consistency while pumped from the pulp source to the pulp processing pipeline or diluted, for example, at the bottom of the storage tower. The mass proceeds at this 4,119,559 consistency until the mass is diluted to the required headbox consistency before being fed to the headbox. Thus, the pulp is not diluted at several points, as is the case with current pulping systems. The consistency of the pulp in the mas-5 treatment pipeline is generally greater than 4% until final dilution to the headbox consistency occurs.

Dilution to headbox consistency with water recovered from the wire section of the papermaking machine can occur simultaneously as the partial masses of compound-10 are interconnected in the pulp processing pipeline. In this case, the dilution to the headbox consistency also occurs in the mass flow and the pulp progresses continuously to the headbox feed pump of the paper or board machine.

The task of pulping is to pulping, milling and cleaning of pulps. In the process of the invention, these required pulp treatment steps are performed in the pulp treatment pipeline so that the pulp flow is not stopped but continuously advances to the next process step. The process steps and actuators required for pulp processing depend on the type of paper or board being manufactured and the pulps used, and thus vary from paper machine to particle processing. However, the process for treating pulp according to the invention can be applied to all types of paper and board machines.

• · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · finished paper sheets for improved properties or printability. In the process of the invention, the above-mentioned substances can be mixed with the pulp in the pulp stream.

: V: 30 t ”]: Depending on the type of paper or board being manufactured, the pulp fed to the headbox of the papermaking machine for short circulation will consist of one or more partial pulps. In the method according to the invention, the partial masses are mixed together in a mass flow and mixing can be ensured by using a mixing pump. The mixing pump also allows the fillers, additives and other chemicals added to the mass to be uniformly mixed into the mass.

5,119,559

The process arrangement required by the method according to the invention is simple in hardware and requires fewer actuators and other components than current pulp processing systems. Further, the devices required by the process of the invention are smaller in size because the volumes of the pulps to be treated are smaller than conventional ones. In addition, the need for piping is reduced from the current one. As a result, the process arrangement according to the invention can reduce process acquisition and maintenance costs. The Proses-10 layout also takes up significantly less space. In addition, the energy consumption of the pulp treatment process is reduced because, for example, pulps are not mixed in large tanks and pumped from one tank to another. Water consumption can also be substantially reduced in the process.

In the process of the invention, the pulp is diluted in the step of leading the pulp from the pulp source to the pulp processing tube and the next time the pulp is diluted to the headbox consistency either at the mixing point of the partial masses or before being fed to the headbox. This greatly simplifies the process-control system required for the process, and smooths the mass consistency fluctuations, as well as disturbances due to flow changes: * · *. minimized. Thus, the quality of the paper being produced is uniform. ·! ·. em- brace.

• · * # · · * · ♦ • · | The method according to the invention also accelerates species changes on a paper Γ: machine because the pulp is not stored in a number of containers before a short circulation, and consequently the amount of wreckage is reduced with the changes. Since the process arrangement according to the invention has eliminated all intermediate containers in the pulping process, the mass: Λ; In addition, there is no accumulation which detaches from the edges of the tanks and affects the quality of the pulp.

! BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 to 11,515,559 show a schematic diagram of a prior art papermaking system, Fig. 2 a schematic diagram of a pulp system according to the invention, and Fig. a pulp treatment system according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Before describing the invention in more detail, the applicant would like to define a few terms used in the description of the invention. In this context, "pulp treatment piping" means piping with actuators where the mass flow is progressed and the required pulping steps are performed, including particle mixing and mixing. In a pulping pipeline, the diameter may vary between actuators, for example, but the flow does not stop "Actuators" means, for example, the refiner, pulverizer, strainer, and pumps required to carry out the various pulping processes. "" Flow ", as used herein, refers to the pulp through the pulp processing pipeline.

• · t · · • · ♦

1-3 illustrates the pulping systems shown in Figures 1-3. three partial masses and their treatment as a simplified diagram, j f 25 but for the method according to the invention there may be · “: N pieces, where N is a positive integer £ 1. The pictures do not show: “mm. control systems, dilution water flows, fiber recovery systems, and not all possible actuators associated with the system.

: Y: 30: [[[: Figure 1 is a diagrammatic representation of a conventional prior art paper or board machine pulping system.

• ·

In Figure 1, each particle is fed from its storage tank 10A, 10B, 35 10C by means of pumps 11A, 11B, 11C to the metering tanks 13A, 13B,: ***: 13C and is first diluted in the lower part of the mass tower ··· * 7 119559 with water flow. From the dosing tank 13A, 13B, 13C each portion is again fed by dosing pumps 14A, 14B, 14C to the mixing tank 15 where the partial masses are mixed and the mass from the mixing tank 15 is further fed to the pulp feed pump 16 to the various and the final dispensing consistency is diluted in the machine container 17, from where the thick pulp is further fed to the pulp feed pump 18 for a short cycle. In pulp processing, partial pulps may be pulverized or ground, for example, between storage towers and dispensing tanks 10 with actuators 12A, 12B, 12C, as shown in Figure 1. In addition, the necessary fillers and other additives are mixed in the pulp with the pulp. thus, the composition of the machine pulp is adjusted to fit in the machine container 17 prior to the pulp being fed into a short cycle where the pulp 15 is diluted to the headbox consistency.

Figures 2 and 3 illustrate by way of example the process arrangements of the method according to the invention.

Figure 2 is a schematic diagram of a pulp treatment arrangement of the method of the invention. Partial masses are led from a pulp source, for example from a storage tower 10A, 10B, 10C, to a pulp processing pipeline by means of pumps 11A, 11B, 11C. Dilution of partial masses. the desired consistency is carried out in the lower part of the storage towers 10A, 10B, 10C and / or while the pulp is pumped into the pulp processing piping. Pumps 11A, 11B, 11C provide a smooth and continuous: ** volume flow through the required actuators 12A, 12B, 12C and sorters 19A, 19B, 19C to the pulp feed pump 20 where the partial pulp flows are mixed and the combined flow is conducted in sV: 30 still in a continuous flow for a short cycle of a paper or board machine. The strainer may be located separately in each particle mass flow, as shown in the figure, or alternatively the strainer may be located within the compound! at or after the pulp feed pump 20.

Figure 3 shows an alternative process arrangement of the method according to the invention. The partial masses are dosed at the desired consistency 35 8 119559, for example, from storage tanks 10A, 10B, 10C to a closed pulp treatment pipeline by means of pumps 11A, 11B, 11C, and the flows of partial pulps in the pulping pipeline are immediately connected thereafter. The combined mass flow is conducted as a continuous flow stream 5 through actuators 12 and a screen 19 to a pulp feed pump 20 which further feeds the mass flow into a short circulation.

The actuators 12, 12A, 12B, 12C and the sorters 13A, 13B, 13C, 19 shown in Figures 2 and 3 are not necessary for bulk treatment, but their location 10 may vary and the mass flow of different fractional masses may have different actuators at different points in the bulk piping. . Actuators 12A, 12B, 12C mainly refer to defibrator and / or milling. Their need in the pulping process depends on the pulp. The pump 20 may be so-called. a viscous pulp feed-15 pump which further pumps the pulp for short circulation or the pump 20 may be so-called. a mixing pump with simultaneous dilution.

The pulp source is preferably a pulp storage tower, as shown in the figures. The pulp from the pulp production is generally stored in 20 storage towers before being subjected to the actual pulping process. The purpose of the pulp storage tower is to function as a so-called. as a buffer between the pulp mill and the paper machine. However, the pulp source may also be the pulp directly from the pulp mill, • · ·: v. pulp from pulping or a wreckage tower where the pulverized i: * 25 wreckage is stored, or so-called. the equalization tank between the pulp mill and the pulp treatment. The pulp may thus be a chemical, mechanical or chemical pulp, scrap or recycled fiber.

• · • · · * ·

The supply of pulp from the pulp source to the pulp processing pipeline at a constant and: Y: 30 continuous volume flow is achieved by a pump. The dilution water is mixed with the pulp while the pulp is pumped into the pulp treatment pipeline or the pulp is already diluted, for example! at the bottom of the storage tank. The consistency of the pulp is maintained within a certain constant consistency in the pulp processing pipeline, preferably about 4-6%, but the consistency may vary over a wider consistency range depending on the pulp. The pulp can be diluted with water recovered from the wire section of the papermaking machine to the headbox consistency, while the viscous particles are mixed together by a mixing pump 20, from which the diluted pulp is further passed through the necessary process steps to the headbox. In this case, the so-called. short cycle dilution is already done at this stage and it is no longer necessary to dilute the mass flow before the headbox.

5

One of the prerequisites for achieving a uniform consistency in the pulp treatment pipeline is to mix well in the pulp storage tower, debris tower, or leveling tank so that the consistency is not greatly varied but diluted to the desired consistency at the bottom 10 of the tank. In addition, the tank or storage tower must be dismantled smoothly.

The pump generates sufficient pressure to maintain a sufficient volume flow of the pulp in the pipeline. Continuous flow in the pipeline ensures that the pulp does not build up on the pipe walls, as is the conventional method of standing and mixing the pulp in tanks, which results in clogging and drainage when the tanks are dismantled. Thus, the method according to the invention provides e.g. reduced consistency fluctuations due to stuttering and other impurities.

The bulk treatment pipeline is a closed system, i.e., the mass does not come into contact with the free air • in the pipeline, thus reducing;: Y without mixing with the mass. Pulp processing pipeline; ; * 25 can be vented if necessary. Particularly if the pulp from pulping is used directly as a pulp source. Dehumidification is carried out: * ·· advantageously while the pulp is pumped into the pulp processing pipeline.

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The mass flow proceeds, without stopping, through the process steps required to process the pulp, such as defibration, refining and screening. Needs: * · *: These actuators have been selected and dimensioned. Act- • · · •. the devices also do not cause backflow. In addition, when selecting actuators, it should be noted that they do not cause excessive resonance * in the mass flow.

:! *: 35 • · · ·

Aggregates and other additives are mixed into the mass flow without mass mixing tanks. The above substances are added either to the flow of partial masses or to the newly combined mass flow. The flow rate of the pulp in the pulp processing piping should be dimensioned so that it is sufficient for the above substances to mix uniformly with the pulp as a result of the flow. The mass flow is influenced in particular by the fact that the pulp is fed from the pulp source to the pulp processing pipeline at a sufficient rate. The flow rate of the pulp is influenced by many factors and therefore needs to be adjusted to suit the paper machine.

10 The uniform mixing of fillers and other additives into the pulp is generally ensured by a mixing pump 20 through which the pulp flow is led to a short circulation. Partial masses are also mixed together in the pulp processing pipeline without separate mixing tanks in the mass flow and the mixing is intensified by so-called. pumping mixer 15 or mixing pump 20 as shown in Figures 2 and 3. If necessary, the wet wreck can be brought directly to the particle mixing site without being recycled through the wreck tower and pulp treatment.

In Figure 3, the mass flow purification is performed prior to mixing the mass flow by means of a pulp feed pump 20. Alternatively, each flow of particle masses may be screened separately prior to mixing the partial masses as shown in Figure 2. The slider 19 may also be located * after the pump 20.

i: * 25 • ♦ · :: ·: Figures 2 and 3 show that the mass flow is mixed with a mass feed pump 20 and it is shown above that it is also possible to dilute the mass to a headbox consistency. However, it is possible that the process arrangement does not the mass feed: V: 30 pumps / mixing pump 20 shown in the figures, but the masses proceed in a continuous flow straight up to the headbox feed pump.

• *! It is also possible that the partial flow streams are not mixed with each other, but proceed as their own continuous flows to a short circulation and to 35 headboxes. The pulp treatment for each particle mass follows the same principles as described above.

11 119559

The system for controlling the consistency and mass flow required by the method is simple because the pulp is diluted only at the point from which the pulp is led in a constant volume flow to the pipeline and the next time to the required headbox consistency, either during The consistency of the pulp is adjusted by changing the amount of dilution water to be mixed with the pulp, i.e. the dilution water is added in an appropriate proportion to the amount of pulp and the consistency. Because the consistency is adjusted in the early stages of pulp processing and the next time before the pulp is fed to the headbox, problems caused by consistency disorders, e.g. basis weight variations can be minimized on a paper machine. This is influenced by e.g. the fact that the process process according to the method does not have delayed containers, but the variations in consistency can be quickly corrected.

15

The consistency of the constituent pulps is different and, depending on the paper being produced, the pulps are mixed in different proportions. Thus, the need for dilution of the masses is also particle specific. The consistency is measured in the pulp treatment pipeline prior to mixing the partial pulps 20 and is used to control the dilution water flow.

.y. If necessary, the pulp treatment piping may have dilution fittings that allow the pulp to be diluted in the mass flow, but • · · .I. as a rule, in the process of the invention, the pulp is diluted to the desired consistency while being fed from the pulp source to the pulp processing pipeline.

• · • · * · * «

The above process arrangements of the process according to the invention simplify the pulp handling of the paper and board machine and, in part: V: 30, also the short cycle process arrangement such that various intermediate tanks: 1: and mixing tanks are no longer needed. but the pulp treatment can be carried out in a continuously progressive pulp | flow. The pulp flow from the pulp source to the pulp treatment proceeds rapidly through the necessary processing steps all the way to the headbox of the paper and board machine, and sometimes the pulp does not stand: 1: in intermediate containers.

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The embodiments described above illustrate by way of example the solution of the invention and one skilled in the art will recognize that the process arrangement of the invention may include different process steps depending on the type of paper or board being manufactured and will vary from one paper or board machine. Accordingly, the invention is not intended to be limited to the exemplary embodiments and devices described above, but is intended to be extensively applied within the scope of the inventive concept defined in the claims defined below.

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Claims (12)

119559 A process for treating pulp used in the manufacture of paper or board, wherein the pulp is led from a pulp source (10A, 10B, 10C) to a pulp treatment and further to a short circulation and headbox of a paper or board machine, characterized in that pulping is carried out that the mass flow proceeds continuously at a rate determined by the volume flow. 10 2. Förfarande enligt patentkrav 1, pivoting tape, att pulping mass, mechanical pulp, chemimechanical pulp, utskott eller returfiber. 15 3. Förfarande enligt patentkrav 1 eller 2, tiltecknat av, att mass (10A, 10B, 10C) to lagringstorn for mass, to utskottstorn in eller for direct frän massatillverkning. Method according to Claim 1, characterized in that the pulp is a chemical pulp, a mechanical pulp, a chemimechanical pulp, a scrap or a recycled fiber. Method according to claim 1 or 2, characterized in that the pulp source (10A, 10B, 10C) is a pulp storage tower, a wreck tower or a tube pulp directly from pulping. 4. Förfarande enligt face av de föregäende patentkraven, bend-20 tecknat av, att massan leds frän massskel (10A, 10B, 10C) som et likformigt och kontinuerligt volymflöd account massabehandlingsrörsystemet. • · • · · * A method according to any one of the preceding claims, characterized in that the pulp is led from the pulp source (10A, 10B, 10C) in a uniform and continuous volume flow to the pulp processing pipeline. • · ti · • * · 5. Förfarande enligt face av de föregäende patentkraven, canter y tecknat av, att massan späds ut account en såsdistant samtidigt när • · · • 25 massan leds frän massakällan (10A, 10B, 10C) account massabehandlings-j-i rörsystemet. • · • ·· • A method according to any one of the preceding claims, characterized by a · · ·. It is ensured that the pulp is diluted to the desired consistency while ··· 25 pulp is led from the pulp source (10A, 10B, 10C) to the pulp • · ·: piping system. A method according to any one of the preceding claims, characterized in that the pulp is diluted to the desired consistency at the bottom of the storage tower: V: 30 or of the wreckage atom (10A, 10B, 10C). ··· • · • ♦ »·· 6. Förfarande enligt face av de föregäende patentkraven, kännetecknat av, att massan späds ut account en omskad consistency i den nedre: V: 30 delen av lagringstomet eller utskottstornet (10A, 10B, 10C). · «· • * 7. Förfarande enligt patentkrav 5 eller 6, kännetecknat av, att massan] späds ut account en consistency u ca. 4-6%. • i • 35 8. Förfarande enligt nägot av de föregäende patentkraven, translation- ··· ·. ***. tecknat av, att i massabehandlingsrörsystemet massaflödet gär genom · ** 119559 massabehandlingssteg (12, 12A, 12B, 12C, 19, 19A, 19B, 19C), worm till exempel malning, defibrering och / eller silning av mass. Method according to claim 5 or 6, characterized in that! dilute the mass to about 4-6% consistency. m A method according to any one of the preceding claims, characterized in that the pulp flow in the pulp processing pipeline passes through the pulping processes (12, 12A, 12B, 12C, 19, 19A, 19B, 19C), such as pulping defibration and / or targeting. 9. Förfarande enligt face av de föregäende patentkraven, anvil-5 tecknat av, att i massabehandlingsrörsystemet i massan blandas fyllandsämnena, chemikalierna och de andra tillsatsämnena i massflödet. 9. A method as claimed in any one of the preceding claims, characterized in that fillers, chemicals and other additives are mixed with the pulp in the pulp stream. 10. Förfarande enligt face av de föregäende patentkraven, bending tecknat av, att tle eller flera delmasflöden sammanfogas i massabehand i massabehandlingsrörsystemet. Method according to one of the preceding claims, characterized in that two or more partial mass streams are combined with one another in a mass flow in a pulp processing pipeline. 11. Förfarande enligt avgot av de föregäende patentkraven, tecknat av, att massan späds ut med vatien som harterter frän virapartiet samtidigt neer eler flera delmassaflöden sammanfogas. 15 A method according to any one of the preceding claims, characterized in that the pulp is diluted with water recovered from the wire section while two or more partial mass flows are combined. Method according to claims 9-11, characterized in that the mixing is performed by a mixing pump (20). * · • * · • · · »· · · · · · · · · · · · · · · · · · · · · ··· * * · · · · · · · · · · · · · · · · · · · · · · · · · ··· ¥ ¥ 99 119559. 1. Förfarande för behandling av mass som används vid tillverkning av papper eller carton, i glitter förfarande mass leds frän en mass-5 calla (10A, 10B, 10C) till massabehandling och vidare account den cir-kuleringen och inloppslädan av en pappers- eller board mask, kän-netecknat av, att massabehandlingen utförs i et massabehandlings-rörsystem, att massaflödet rör sig kontinuerligt framät med en has-tighet som bestäms av volymflödet. 10 12. Förfarande enligt patent krav 9-11, kännetecknat av, att bland-ningen utförs med en blandningspump (20). · • · · «· · · · · · · · · · · · · · · 9 · 9 9 9 9 9 9 9 9 9 9 9. 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 • 9 9 999 9 999 9 9 • 9 999