SU1675451A1 - Method for preparation of fibrous half-product for paper belt formation in manufacture of paper - Google Patents

Abstract

The invention relates to the technology of preparing the semi-finished fiber to the ebb of a paper web in the manufacture of paper and reduces the energy intensity of the process while maintaining the quality of the prepared mass. The fibrous material is prepared by sorting in three stages with feeding the first stage waste to the second stage of sorting, followed by cleaning the sorted mass, returning it to the first stage and grinding the second stage waste, feeding the ground waste to the third stage, discharging the sorted mass after the third stage to mixing with sorted mass from the second stage and removal of third stage waste for mixing with waste from the first stage of sorting and feeding the mixture obtained together with the waste E grading after the first stage to the second stage grading sortirovz- audio, Table 1., 3-yl. sl C

Description

The invention relates to methods for preparing a semi-finished fiber product and may find application in the pulp and paper industry in the manufacture of various types of paper.

The aim of the invention is to reduce the energy intensity of the process while maintaining the quality of the prepared mass.

The method of preparing the fibrous semi-finished product for the paper web in the manufacture of paper involves sorting the mass in three stages, separating the sorted mass and waste after each stage, in which after the first stage the sorted mass is fed for recycling, and the waste is fed to the second sorting stage, followed by cleaning the sorted mass , returning it to the first sorting stage and grinding the waste, feeding the ground waste to the third sorting level, removing the sorted mass from it stage for mixing with sorted mass from the second stage, removal of waste from the third stage of sorting for mixing with waste from the first stage of sorting and feeding the resulting mixture together with waste from the first stage of sorting to the second stage of sorting.

FIG. 1 shows a diagram of the preparation of the fibrous mass of the proposed method; in fig. 2 and 3 flow diagrams for the consumption of absolutely dry fiber.

The method includes the following operations. Fibrous semi-finished product (cellulose or wood pulp), with

about cl

If necessary, it was rinsed; through pipeline 1, before pump 2, it was diluted to south to the concentration required by the sorting conditions. By pump 2, the suspension is fed to a coarse screen for sorting or jammers (chips) 3 to remove litter, large particles of bark and mineral impurities. The waste from sorting 3 through line 3 a is discharged or fed to hammer mills 4, after which it goes to waste milling section 5.

The sorted mass 3 after coarse sorting enters through pipeline 6 to the first stage 7 of sorting. The first sorting stage 7 is a separate sorting or two sorts connected in series to provide the necessary sorting efficiency of the first stage, which works with a waste fraction of 25-35%. The first stage waste goes to the second sorting stage 8 with sorts having larger screen openings. than sorting in the first stage 7. The second stage of sorting works with a waste fraction of 40-50%. The sorted mass from this stage is cleaned in a centricliner installation 9 according to the cascade principle. The cleaned mass from unit 9 is returned to line 1 in front of pump 2, and the waste from unit 9 is either dumped or fed to compartment 5 for grinding waste. The waste from the second stage of waste sorting is fed to the waste grinding section 5, where it is milled in one or two stages, and then pump 10 is fed to the third sorting stage 11, where the sorting works with a waste fraction of 20-30% and has the size of screen openings as in stage 8. The waste from the third stage of sorting is mixed with waste from the first stage 7 in front of the pump 12 and re-sorted in the second stage 8 of sorting. The sorted mass from the third stage is mixed with the sorted mass from the second stage of sorting in front of the pump 13 and the mixed mass is cleaned in a centricliner installation 9. The sorted mass from the sorts 7 is dehydrated in a thickener 14, and the filtered water is collected in a filtrate collection 15 used as a constant tank head pressure. In order to ensure the functioning of the pumps in the circuit with a constant suction pressure, the pipeline from the pool 15 is connected to the suction pipe to all pumps.

In the production of groundwood pulp for newsprint, the invention is illustrated by the following examples.

Example 1 Fibrous semi-finished product — wood pulp that has passed through a chipping machine, with a grinding degree of 60 ° SHR is sorted according to a double sorting scheme with a waste fraction of 25-35% and sorted weight with a grinding degree of 70-75 ° ShR is fed to UVK-700-02 for cleaning , waste from

0 of the first stage is fed to the second stage of sorting, operating with a waste fraction of 40-50%. Subsequent purification is carried out on the centricliner unit UVK-300-01 and the cleaned mass is returned

5 to the first stage of sorting. Waste of the second stage is ground in two stages: on USR-03 at high concentration, and then on MDS-33 at low concentration. Ground waste sorted at third

The grading stage 0 with a waste fraction of 20-30%, the graded mass of this stage is mixed with the second stage graded mass, and the waste is mixed with waste from the first stage grading.

5 The flow distribution by flow rate of absolutely dry (a.s.) fiber in t / s is shown in FIG. 2 with an input flow rate of 500 t / s.

Example 2 (known). Woody

0, the mass is sorted according to the double screening scheme with a share of waste of 25-35% and the sorted mass is fed to the purification unit at UVK-700-02. Waste of the first stage is fed to the second stage of sorting, which works with a share of waste of 30-50%. The waste of sorting the second stage is ground in two steps: at USR-03 at high concentration, and then at MDS-33 at low concentration. Ground waste sorted into

0 of the third stage of sorting with a fraction of waste of 20-40%, the waste of which is returned to grinding. The third stage sorted mass is mixed with the first stage waste and is fed to the second stage. Distribution of flows according to consumption The fibers for this method are shown in FIG. 3 with an input flow rate of 500 tons / s. From the flow diagrams shown in FIG. 2 and 3, it is clear that the proposed

0 method of preparing the fibrous semi-finished product for reflux reduces the consumption of the ground mass from 173 tons / s a.s. fibers up to 90 t / s, i.e. almost doubled.

In addition, the proposed method gives

5 it is possible to reduce the total mass consumption in the sorting process from 1733 t / s to 1534 t / s. those. load on consumption fiber reduced by 12%.

Indicators of the overall efficiency of the removal of fires (e.k.) preparation processes

wood pulp to paper tide are given in the table. They are evaluated by the method of mathematical modeling. The effect of the degree of costliness of the prepared mass “and the indicator of breaking length is described by the expression

BL 4221.7- 12.96 {CSF) + 170.98 In (SC), where CSF is the sagas of the prepared mass, Canadian standard;

SC is the content of fires according to Sommerville,%.

The morbidity of the mass after defibers usually varies within 3-5%, and the discontinuous length of the prepared pulp for newsprint is at the level of 3200 m. Considering the above data, the relative difference of the breaking length in preparing the mass for the paper ebb is known and proposed. does not exceed 5%. those. is within the relative error of measurement of the breaking length.

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Thus, the proposed method allows to reduce the energy intensity of the process while maintaining the quality of the prepared mass.

Formula and Gaining Method for preparing a fibrous semi-finished product to ebb a paper web in the manufacture of paper, including sorting the mass in three stages, separating the sorted mass and waste after each stage, in which after the first stage the sorted mass is fed for processing, and the waste is fed to the second stage sorting followed by cleaning the sorted mass, returning it to the first step of sorting and grinding the waste, feeding the ground waste to the third step of sorting, rejecting the sorting mass from this stage for mixing and removal of waste from the third stage of sorting, characterized in that, in order to reduce the energy intensity of the process while maintaining the quality of the prepared mass, the sorted mass after the third stage is diverted to mixing with the sorted mass from the second stage, and waste from the third stage of sorting is diverted to mix with waste from the first stage of sorting, the resulting mixture is fed together with the waste sorting after the first stage to the second stage of sorting.

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Claims (1)

Claim A method of preparing a fibrous prefabricated product for casting a paper web during paper production, including sorting the pulp in three steps with the separation of the sorted pulp and waste after each step, in which the sorted pulp is fed to the second stage after the first step, and the waste is fed to the second sorting stage with subsequent cleaning sorted mass, returning it to the first stage of sorting and grinding the waste, feeding the ground waste to the third stage of sorting, removing the sorted mass from this rely on mixing and removal of waste from the third stage of sorting, characterized in that, in order to reduce the energy intensity of the process while maintaining the quality of the prepared mass, the sorted mass after the third stage is taken to mix with the sorted mass from the second stage, and the waste from the third sorting stage is taken to mixing with the waste from the first sorting stage, the resulting mixture is fed together with the sorting waste after the first stage to the second sorting stage. . - Experience The proportion of waste,% with EAA Total AAU,% by method I stage II stage III stage famous proposed 1 35 fifty ' 20 91.7 90.0 75.0 90.0 50,0 2 35 thirty 20 91.0 89.0 75.0 70.0 50,0 3 25 fifty 20 88.4 86.2 65.0 90.0 50,0 4 35 fifty thirty 91.7 89.7 75.0 90.0 65.0 5 25 fifty thirty 88.4 • 85 _; 7 65.0 90.0 65.0 6 thirty 70.0 50 90,0 25 65.0 90.0 88.0 thirty fifty 20 90.0 89.0 7 70.0 90.0 50,0 Fig.Z