The method of preparation of the fibrous mass

 

The invention is intended for use in the pulp and paper industry. The method consists in fractionation of the original fibrous mass on the short and long fibre fractions and the grinding of long fibre fraction, which milled long-grain fraction addition fractionary emitting short and long fibre fractions and selected long-fibre fraction additionally grind. The grinding of long fibre fraction obtained after fractionation of the original fibrous mass, conduct, in particular, mixed with long fiber fraction obtained after further fractionation. Possible additional fractionation long fiber fraction in the mixture with the original fibrous mass, as well as carrying out grinding of long fibre fractions in the mixture with the original fibrous mass. Provides better quality paper pulp by reducing its polydispersity. 3 C.p. f-crystals, 1 tab., 3 Il.

The invention can be used in the pulp and paper industry, namely in the preparation of paper pulp from waste paper or wood pulp. Most afasa fine cleaning in the vortex conical cleaners.

Certain varieties of waste paper used in the production of paper and cardboard, sharply differ in their quality and contain fibers of different lengths from shortest to longest, reaching lengths of 5 mm to Ensure uniform quality of the paper is already in its collection impossible. Therefore, the regulation of quality (screening) is carried out in the process of recycling waste paper.

Pulp and waste paper, contains fibers of different lengths, from very short to reaching lengths of 3 mm, i.e., is a polydisperse fibrous material.

From the point of view of physical and chemical properties and morphological structure of the fibrous material from waste paper (recycled fiber) compared to the primary (pulp) is characterized, in addition to increased arnosti, and even the dead state of the surface of the fibers caused by the drying of paper or paperboard in the process of their production. Secondary fibers undergo significant changes to their physical and chemical properties, they are dead and hard and again made of these paper products are characterized by significantly lower values of strength properties than the primary.

Fibrous material of thickness, obtained from various species of wood sulfite and sulfate ways, bleached and unbleached, and various types of wood pulp. Short-fiber fraction it represents very Horny snatches fragile fibers and is characterized by low length, the higher value of the degree of grinding, bad boyhoodparadise properties and increased susceptibility to grinding in the grinding process. Long fiber fraction is less prone to the phenomenon of keratinization, made from the highest quality fibers and is characterized by great length and thickness of the fiber, low degree of grinding and potentially high strength characteristics.

The presence of short-fiber fraction causes not only an increase in the degree of grinding and the deterioration of dehydration on the grid paper-making machine, but also prevents proper processing of the fibrous material in the refining process in order to restore his boomgaarden properties. In addition, the fibers of this faction have a weakened ability to intermolecular chemical interaction in the formation of a sheet of paper and thereby reduce its mechanical strength. Joint grinding of short - and long fibre fractions leads ACCA is characterized by poor processing properties and a reduced ability to dehydration.

To improve boomgaarden properties and maintain within the limits of water-holding capacity of the fiber from recycled fibres are divided into short - and long-fibre fraction and subjected to grinding only long-fibre fraction to achieve the required strength characteristics, and then either mixed with short or use each fraction by individual appointment.

The separation of the fibrous mass fraction is carried out in an apparatus called fractionation. The ratio of long fiber and short fractions in fractionator with sieve fractionation elements regulate by changing the diameter of the holes of the sieve of fractionator and pressure drop of the suspension on both sides of the sieve cavities for short and long fibre fractions. In fractionation plants for screening fibrous materials, working on the principle of hydrodynamic separation of the fiber short and long-fibre fraction, proportion between them adjust by changing the distance between the containers to collect fractions and the disc-shaped hydrodynamic sorting element.

The known method of prigotovit (Szwarcztajn E. , Przbysz K. Einige Aspekte der Fraktionirung von Zellstoff und Altpapier// Das Papier. - 1975. - 7. - S. 295-300).

This method involves the use of each of the obtained fractions by individual appointment.

Known method of preparing paper pulp, secure and.with. The USSR 444848, class D 21 D 1/00, publ. 14.11.74, including the refining of fibrous material and composed of short and long fibre fractions. When this short-fiber fraction obtained by fractionation of the fibrous material before grinding.

This method is taken as a prototype as the closest to the technical essence: This way, when the available short-fiber fraction is not subjected to additional grinding, practically excludes the possibility of negatively affecting the quality of the finished product of the degradation of these fibers. In addition, the power consumption for grinding is reduced, since the grinding is subjected not all used in the production of pulp, and only long-fibre fraction. However, in ground, long fibre fraction even after multi-stage grinding contains a significant amount of unground long fibers, which together with the conditional fibers get into the setup DL is fine cleaning paper pulp from crushed in the grinding process to spot sizes of polluting inclusions with a specific gravity greater than the fibers used conical vortex cleaners (centricleaner).

All types of conical vortex cleaners are fundamentally the same design and are tapered body with located inside of the conical chamber. At the base of the conical casing tangentially built a tangential nozzle for feeding a fibrous suspension into the chamber. In the centre of the base of the conical housing has a pipe for withdrawal of the suspension of the cleaned fiber material. At the apex of the conical body is a pipe for the removal of waste cleanup from the camera.

In the tangential inflow mass supplied under pressure, creates a rotational movement of the mass, with heavier and larger particles to move towards the periphery, then the wall of the cone down. In the center of the cleaner flow rate increases so that there is a flow of the opposite direction. Under the pressure of the particles from one rotating layer is transferred to another up until the increasing centrifugal force would balance the static pressure. While large particles move with the flow of mass and, reaching the sides of the case, down and shock the flow, and with it lifted up and removed through the exhaust pipe. When the three step purification scheme of the original fibrous mass is fed to the first step of purification, after which the treated fibrous mass enters the process stream, and the waste arrives at the second purification stage. Together with the waste treatment stage enjoys a significant amount of good fiber, which is extracted in the cleaners of the second stage. Waste a second level heading third level and after extraction of the fiber removed. The extracted fiber third stage enters the stream of the second stage and then to the first cleaning stage.

In the process, conical vortex cleaners inside them are hydrodynamic flows, which are characterized by high gradients of velocity and large values of the shear stresses. The presence in a moving stream of fibrous suspensions of these two hydrodynamic characteristics leads to the phenomenon of fractionation, i.e. the phenomenon of separation of fibers on the working areas of each purifier depending on their length with increasing length of the fibers in the direction from the center of the cleaner to its conical peripheral wall. This distribution of fibers within each purifier makes the output more costie to waste, located at the top of the cone cleaner. The above phenomenon causes a lower value of mass fraction of fibers in the suspension of the cleaned fiber material than the same indicator in suspension at the entrance to the conical vortex cleaner, the same value of mass fraction of fibers in the slurry waste cleanup higher than at the inlet in the cleaner.

In addition, the cleaning process in the vortex conical cleaners accompanied by an increase in the values of the average length of the fibers as the pure material and fibrous material in the waste cleanup from level to level in the direction from the first to the last. And in waste cleanup increasing values of the average length of the fibers more rapidly than in the purified material. This phenomenon leads to the fact that the extracted second or subsequent treatment stages, long fibre material, going back to the previous inputs of each of the purification steps, is in the circuit between the phases of treatment and is not output from the system. In turn the source of fibrous material applied to the first cleaning stage, also brings its portion of long fibers, thus in this system, the accumulation of det clogging of the outlet openings for waste treatment in conical vortex cleaners tubes from long fibers. The process of cleaning fibrous material in stoppered conical vortex cleaners stops and untreated fibrous material is directed into the exit port of the pure material. As a result, the cleaning efficiency of fibrous material is reduced. To restore normal operation conical vortex cleaners with clogged holes fibrous tube destroy (manually) and remove. After a certain period of time, this phenomenon is repeated. The period of time between scopariinae cleaners depends on the number of long fibers to be cleaned fibrous material. More so than their more frequent plugging cleaners.

The objective of the invention is to reduce polydispersity fibrous mass by reducing the number of long fibers by separating the long-fibre fraction, its cyclic grinding, additional fractionation and thus better quality paper pulp coming on fine polishing.

The problem is solved in that in the method of preparation of the fibrous mass, including fractionation of the original fibrous mass on the short and long ends and grinding dlinnoyu irout emitting short and long fibre fractions and selected long-fibre fraction additionally grind.

The problem is solved also by the fact that the grinding of long fibre fraction obtained after fractionation of the original fibrous mass, exercise mixed with long fiber fraction obtained after further fractionation.

The solution also carried out at the expense of additional fractionation long fiber fraction in the mixture with the original fibrous mass.

The problem is solved also by the fact that the grinding of long fibre fraction is carried out in a mixture with the original fibrous mass.

The invention is illustrated by the diagrams shown in Fig.1-3.

In Fig. 1 shows a scheme for preparing fibrous mass using a two-stage fractionation emitting short and long fibre fractions and circular grinding, long fibre fraction.

In Fig. 2 - scheme-preparation of pulp using the fractionation of a mixture of the original fibrous mass and milled, long fibre fraction.

In Fig.3 - scheme of the preparation of pulp using fractionation on short and long fibre fractions milled mixture of the original fibrous mass and dlinnovolnovoi and thin clearing of contaminant inclusions larger than 2.0 mm, and chemical-mechanical wood pulp - after coarse and fine purification from heavy inclusions, fires and bends larger than 2,0 mm

The invention is illustrated by the following examples.

Example 1. Schematic diagram of a process for making fibrous mass is shown in Fig.1.

The fiber from recycled fiber with a degree of grinding of the 30oSHR, average fiber length 1.98 mm and a mass fraction of fibers in the suspension of 3.0% is served by pipeline 1 in fractionator 2 to divide it into short and long fibre fractions. Short-fiber fraction from fractionator served by line 3 into the container 4, and the long fiber - pipeline 5 into the container 6. From the tank 6 long fiber fraction of the pump 7 is sent for grinding in the mill 8. From the mill 8 milled long-grain fraction in the pipe 9 serves in fractionator 10 to divide it into short and long fibre fractions. Short-fiber fraction from fractionator 10 directed by pipeline 11 into the container 4, and the long fiber fraction of the pipeline 12 in the tank 6 where it is mixed with long fiber fraction, separated from the original fibrous mass in fractionator 2. Next, the floor is composed of a container 6 for mixing, long fibre fractions, pump 7 for supplying the mixture in the mill 8, 8 mill for grinding a mixture of long fibre fractions, pipe 9 for supplying milled mixture of long fibre fractions in fractionator 10, fractionator 10 for separation of the milled mixture of long fibre fractions of short-fiber fraction, which is sent through the pipeline 11 into the container 4, and the long fiber fraction, which is sent through the pipeline 12 into the container 6 for processing a mixture received in the next cycle.

Short-fiber fraction with a degree of grinding of the 36oSHR and an average fiber length of 1.62 mm, highlighted in fractionator 2 and 10, are mixed in the vessel 4, is diluted to a mass fraction of fibers in the suspension of 0.8% and the pump 13 through the pipe 14 serves under the pressure of 280 kPa (2,8 kgf/cm2on the first cleaning step three-install the conical vortex cleaners 15 for removal of contaminating impurities. Supply waste treatment with the first and second cleaning stages respectively in the second and third cleaning step is carried out at the mass fraction of fibers in the suspension of 0.8% under the pressure of 280 kPa (2,8 kgf/cm2). The outlet pressure treated fibrous slurries and waste cleanup at all levels set equal to 20 kPa (0.2 to the production of paper products.

Determine the degree of grinding and the average fiber length of the original fibrous masses coming through the pipeline 1 and the short-fiber fraction (selection of pipe 14).

From the mass arriving at the clearing in the installation of conical vortex cleaners, as well as from purified mass produced castings. The mass of the casting area 1 m260,

Determine the dirtiness according to GOST 14363.3-84. Cellulose and wood pulp. The method of determining arnosti.

The cleaning efficiency is determined by the following formula: e=100%- Co/si100%, where e is the cleaning efficiency,%; - the number of impurities ranging from 0.1 to 2.0 mm21 m2castings made from purified material; C is the number of impurities ranging in size from 0.1 to 2.0 mm21 m2castings made from the original fibrous material.

Determine the number of sukupolvi conical vortex cleaners for 5 hours.

The results of the determinations are summarized in table.

Example 2. Schematic diagram of a process for making fibrous mass is shown in Fig.2.

The fibrous mass of the secondary fibrous material with a mass fraction of fibers in the suspension of 3.0% is served by pipeline 1 into the container 2 and then Nistru fraction is sent through the pipeline 5 into the container 6, and long-fibre - to line 7 into the container 8. From the tank 8 long fiber fraction of the pump 9 is fed to the grinding mill 10. From the mill 10 milled long-grain fraction is sent through the pipeline 11 into the container 2, where it is mixed with the original fibrous mass. The resulting mixture was fed by the pump 3 through the pipe 5 into fractionator 4 for the separation of short and long fibre fractions. Short-fiber fraction is sent through the pipeline 5 into the container 6, and the long fiber - to line 7 in the capacity of 8, then the pump 9 into the mill 10 for grinding. From the mill 10 milled fibrous mass is fed through the pipeline 11 into the container 2 and mixed with the original fibrous mass perform the next processing cycle in a closed loop continuous selection in fractionator 4 short and long fibre fractions.

Short-fiber fraction with a degree of grinding of the 35oSR and average fiber length of 1.61 mm dilute to the values of the mass fraction of fibers in the suspension of 0.8% and the pump 12 serves under the pressure of 280 kPa (2,8 kgf/cm2on the first cleaning step three-install the conical vortex cleaners 15 for the final fine cleaning it from polluting the stump cleaning is carried out at the mass fraction of fibers in the suspension of 0.8% under the pressure of 280 kPa (2,8 kgf/cm2). The outlet pressure treated fibrous slurries and waste purification all purification steps is set to 20 kPa (0.2 kgf/cm2).

Purified conditioned fibrous mass of installation direct on line 14 in the manufacture of paper products.

Example 3 (prototype). The fibrous mass of the secondary fibrous material share in fractionator on short-fiber fraction with a degree of grinding of the 35oSR and average fiber length of 1.61 mm long fiber fraction with a degree of grinding of the 28oSR and average fiber length of 2.09 mm After grinding, long fibre fraction to the degree of grinding of the 35oSHR and the values of the average fiber length of 1.94 mm mix it with short-fiber fraction and receive fibrous mass with the degree of grinding of the 35oSHR and an average fiber length of 1.84 mm

Prepared fibrous mass serves for the final fine cleaning in the three-setting conical vortex cleaners with the same values of technological parameters, as in examples 1 and 2.

Example 4. Schematic diagram of a process for making fibrous mass is shown in Fig.3.

Chemical-mechanical wood pulp with stept pipeline 1 into the tank 2 and the pump 3 into the mill 4 for grinding. Ground wood pulp is served by pipeline 5 in fractionator 6 for separation of short and long fibre fractions. Short-fiber fraction is directed through the pipe 7 into the container 8, and long-fibre - pipe 9 into the container 2, where it is mixed with the original wood mass and the resulting mixture is sent by the pump 3 into the mill 4 for grinding. Ground mixture of fibrous materials by pipeline 5 is sent into fractionator 6 for separation of short and long fibre fractions. Short-fiber fraction is directed through the pipe 7 into the container 8, and long-fibre - pipe 9 into the container 2 and after mixing with the original fibrous mass perform the next processing cycle resulting mixture in a closed circuit with continuous grinding it in a mill 4 and the selection of milled fibrous mass of short and long fibre fractions.

Short-fiber fraction of pulp with a beating degree of the 75oSHR and an average fiber length of 0.71 mm after dilution to the mass fraction of fibers in the suspension of 0.8% from the tank 8 by the pump 10 serves on the pipe 11 under the pressure of 280 kPa (2,8 kgf/cm2on the first cleaning stage of the three-step is installing the same as in examples 1 and 2.

Purified conditioned fibrous mass from the installation guide on the pipeline 13 in the manufacture of paper products.

Example 5 (prototype). As fibrous masses take chemical-mechanical wood pulp with a beating degree of 57oSR and average fiber length of 1.2 mm Wood pulp share in fractionator on short-fiber fraction with a degree of grinding 74oSHR and an average fiber length 0,73 mm long fiber with a degree of grinding 49oSHR and an average fiber length of 1.59 mm Milled long-grain fraction to the degree of grinding 74oSHR and the average length of the fibers 0,97 mm After mixing short-fiber fraction with milled long-fibre fraction is obtained fibrous mass with the degree of grinding 74oSHR and an average fiber length of 0.87 mm

The table shows that for the same values of the degree of grinding (30oSR) and the average length of the fibers (1.98 mm) source of pulp from recycled fiber receive fibrous mass with the same value of the degree of grinding (35oSHR) how the proposed method (examples 1 and 2), and a known method (example 3). However, a comparative analysis of the average length of the fiber of fibrous masazines of examples 1 and 2 in comparison with the value of the same indicator for example less than 3 respectively by 0.22 mm and 0.23 mm

The table also shows that for the same value of the degree of grinding (57oSHR) and the same average fiber length (1.2 mm) of the original fibrous mass of the chemical mechanical wood pulp used to prepare the pulp for the final fine cleaning in the installation of conical vortex cleaners for the proposed method (example 4) and by a known method (example 5) receive fibrous mass with the same value of the degree of grinding, equal to 74oSHR. However, a comparative analysis of the average fiber length of the fibrous masses coming to treatment in the installation of conical vortex cleaners, you can see that the value of this indicator is for example 4 (the proposed method) in comparison with the value of the same indicator in example 5 (prototype) is less than 0.14 mm

The analysis shows that as a result of implementation of the process of preparing fibrous mass of the proposed method are the fibrous mass with a lower polydispersity fibers. Reduction of polydispersity fibrous mass, in turn, reduces the effect of fractionation of fibrous material in the process of cleaning in conical cleaners, which prevents a phenomenon Zack is Italy. The preparation of the same fibrous mass in a known manner (examples 3 and 5) leads to the clogging vortex conical cleaners and the stability of the cleaning process.

Thus, the known method of preparing a fibrous mass, designed for fine purification from contaminating impurities in multistage installation conical vortex cleaners provides cleaning efficiency fibrous mass 55-58%, while the proposed method ensures the stability of the treatment process and increases the efficiency of cleaning up to 80-82%.

Claims

1. The method of preparation of the fibrous mass, including fractionation of the original fibrous mass on the short and long fibre fractions and the grinding of long fibre fraction, characterized in that the milled long-grain fraction addition fractionary emitting short and long fibre fractions, with the selected long-fibre fraction additionally grind.

2. The method according to p. 1, characterized in that the grinding of long fibre fraction obtained after fractionation of the original fibrous mass is carried out in a mixture with dlinnovolosie milled long-grain fraction addition fractionary mixed with the original fibrous mass.

4. The method according to p. 1, characterized in that the grinding of long fibre fraction is carried out in a mixture with the original fibrous mass.

 

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SUBSTANCE: method involves first subjecting secondary filament-waste paper to breaking-up procedure in hydraulic breaker at temperature of 37-390C and pulp concentration of 2-4%, followed by processing in thermal dispersion apparatus at temperature of 38-550C and pulp concentration of 10-12%.

EFFECT: improved physico-mechanical properties of fibrous materials produced and reduced power consumption.

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