RU2343241C1 - Method of production of pulp - Google Patents

Abstract

FIELD: textiles; paper.

SUBSTANCE: method refers to production of pulp from flax raw material and can be used in the paper-pulp industry for producing of pulp for chemical processing as well as for example of cotton wool, paper and cardboad. The method is realised by means of consequent simultaneous tillage and purification of flax-cuke or flax straw, washing and cutting of the material. Then it is soaked, processed in a thermochemical way, washed through and bleached. Then it is washed again, wrung and dried. Following thermomechanic processing of the pulp containing material it is possible to perform maturation in the alkaline solution.

EFFECT: efficiency increase of method of producing of pulp from flax raw material with high degree of chaff.

2 cl, 1 tbl, 12 ex

Description

The invention relates to the pulp industry, in particular to the production of cellulose from vegetable cellulose-containing material, and can be used for the production of cellulose from flaxseed raw materials intended for chemical processing, production of cotton wool, in the paper industry, etc.

A known method of producing cellulose from cereal plants, which consists in the fact that plant cellulose-containing raw materials are cut into pieces 3-4 cm long. The cross-section is uniformly sprayed with a 15-40% NaOH or KOH solution with a 2: 5 hydromodule and mixed thoroughly. The mass is loaded into a closed container and treated with compressed air (pO ₂ <1 atm). Washed with water, dried. The cellulose yield is 46.2% (Accepted Japanese Application No. 52-6362, CL 39 A4, 1977).

However, in a known manner it is impossible to obtain high-quality cellulose from flaxseed raw materials with a high yield of the target product.

A known method of producing cellulose by loosening plant materials, alkaline cooking using NaOH, surfactant, T = 120-130 ° C for 1 hour, washing with 1-5 times the amount of clarified water, hydrocyclone treatment with clarified water, grinding, fine hydrocyclone treatment with clarified water, 2-fold bleaching with NaOCl at pH = 9-11.5, T = 90 ° C for 1 hour, washing with 2-fold softened water, acidification with H ₂ SO ₄ at 15-40 ° C for 1 hour, washing with softened water, extraction, drying with air (continuous process s regulations №4-2 «Production of simple and cellulose esters", approved January 18, 1995 Gene. Director Engels JSC "Khimvolokno").

A known method of producing cellulose, including the mechanical treatment of cellulose-containing material by simultaneously loosening and cleaning it, cooking in an alkaline solution at a temperature of 130-140 ° C under a pressure of 3-4 atm for 180-210 minutes, washing, bleaching in an acidic solution with sodium hypochlorite, wringing, loosening and drying (RU 2078163, class D04H 1/02, publ. 1997).

The disadvantages of the above methods are: the alkaline cooking process in harsh conditions - at a temperature of T = 120-140 ° C, pressure P = 2-4 atm, the use of sodium carcinogen for bleaching.

The closest analogue is the method of producing cellulose by simultaneously loosening and cleaning the cellulose-containing material, grinding, hardening in a NaOH solution and cleaning, alkaline cooking for 1.5-3 hours with a hydraulic module 1: (5-20), containing additional surfactants, washing, bleaching in a solution of H ₂ O ₂ , washing, spinning and drying (RF Patent for Application No. 2005127650 with a decision on the grant of a patent dated 02.27.07).

The disadvantage of this method is the inability to obtain cellulose from flaxseed raw materials with a high degree of pointedness, in particular from flax straw and green flax.

The basis of the present invention is the task of creating an effective economical method of producing cellulose from flax raw materials with a high degree of pointedness and green flax, suitable for chemical processing, cotton production, in the paper industry, etc.

The problem is solved in such a way that in the method of producing cellulose by sequentially loosening and cleaning the cellulose-containing material, locks, thermochemical processing, washing, bleaching, washing, spinning and drying, before locking the material is additionally washed and cut, the processing is carried out thermo-mechanochemical, moreover, as cellulose-containing material take flax green or flax straw.

In an embodiment of the method according to claim 1, additionally after thermomechanochemical processing of the material, it is left to ripen in an alkaline solution.

Flax raw materials are used as a cellulose-containing material: flax-greens — stems selected between flowering and early yellow ripeness of the flax plant (for 40-50 days) before the intensive accumulation of lignin (Zhivetin V.V., Ginzburg L., Olshanskaya O .M. Flax and its complex use. - M .: Inform-Knowledge, 2002, - 400 p.) And / or oilseed straw (flax-curly, flax-mezhumok) after separation of seeds.

The process according to the claims is carried out using the apparatuses and chemicals described below as follows.

Loosening and cleaning of flaxseed raw materials is carried out simultaneously with the help of bale feeders of types SRTSK, GRP to remove mechanical impurities, weeds, flowers, seeds.

The loosened raw materials through pneumatic transport enter the washer, where dust and dirt are removed with technical water containing 0.5% surfactant.

As surfactants, syntanol-ALM-10, a monoalkyl ether of polyethylene glycol based on higher synthetic fatty alcohols according to TU 6-14-864-88 or Neonol AF _9-12 , monoalkylphenol based on propylene trimers according to TU 2483-077-05766801-98, is used.

Then flax raw materials are cut using a multi-disc mill type MMDR-379 to a cut length of 10-15 mm.

The lock is carried out in a screw apparatus with reverse zones of the type ASH-200 in an alkaline solution prepared in circulating water with a NaOH content of 10-60 g / l and a surfactant of 0.5 g / l for 15-60 minutes at a temperature of 95- 100 ° C. The hydraulic module is 1: (10-20).

Cooked pulp with a concentration of flax raw materials of 5-10% is subjected to thermo-mechanochemical processing in a screw apparatus with cam zones of the type ASh-200 at a temperature of 95-100 ° C for 15-30 minutes.

The spent alkaline solution, together with the non-cellulose components of flaxseed raw materials dissolved in it, is separated from flaxseed by decantation for possible reuse.

The semi-cellulosic pulp is washed in softened water to remove alkali residues from the semi-cellulose. The operation is carried out in 2 stages by aging in containers with water at a temperature of 80-90 ° C for 20-30 minutes in the first stage and 40-50 ° C for 20-30 minutes in the second stage. The hydraulic module during flushing is 1: (10 ÷ 20) at each stage.

Flax pulp bleaching is carried out in a solution of hydrogen peroxide with a concentration of 5-10 g / l at a temperature of 85-95 ° C for 90 minutes. Hydraulic module - 1: (10 ÷ 20).

Rinsing from a bleaching solution is carried out with softened water as well as during washing after an alkaline cooking operation.

The spin operation is carried out on centrifuges such as AG or AOG to a moisture content of 40-50%.

Cellulose is dried by flue gases at a temperature of 140-160 ° C on a vibratory dryer.

The dried cellulose is fed into a cyclone to separate it from the air and then onto the packaging.

According to claim 1 after thermomechanochemical treatment, if it is necessary to improve the physicochemical parameters of cellulose, the ripening in the same alkaline solution is carried out, strengthened to a NaOH concentration of 10-60 g / l at a temperature of 95-100 ° C for 30-60 minutes and served in 2 steps for washing with softened water as described above.

To prove the conformity of the claimed method to the criterion of "industrial applicability" we give specific examples of the method.

Example 1

100 kg of unpacked flax-greens is fed into a bale opener with a capacity of 22 kW and a capacity of 800 kg / h, where it is subjected to shredding and removal of random mechanical impurities, weeds, roots, etc. Loosened raw materials are washed in a cylindrical container of 3 m ^{3 of} industrial water containing 5 g / l of syntanol ALM-10.

The peeled flax raw materials are cut in a multi-disc mill MMDR-379 (power 10 kW, capacity 25 tons / day) to a fiber length of 10-15 mm.

Then chopped flax-greens and 2 m ^{3 of an} alkaline solution with a concentration of NaOH of 10 g / l in circulating water and 0.5 g / l of syntanol ALM-10 are fed into the ASH-200 screw machine with reverse zones (capacity 1000 kg / h), heated to a temperature of 100 ° C, and hold the lock for 60 minutes. After that, the pulp prepared by the mass pump (productivity - 470 m ³ / h) is transported to the ASh-200 screw machine containing cams, and thermomechanical treatment is carried out for 30 minutes at a temperature of 100 ° C.

At the end of the thermomechanochemical treatment and separation of the spent solution, flaxseed pulp is washed twice in a container of 10 m ³ with softened water for 30 minutes at a temperature of 85 ± 5 ° C and for 30 minutes at a temperature of 35 ± 5 ° C. The hydraulic module is 1:20 .

Next, washed flaxseed pulp is placed in a container of 10 m ³ with a solution of hydrogen peroxide concentration of 10 g / l for bleaching at a temperature of 90 ° C for 1.5 hours. The hydraulic module during bleaching is 1:20.

Bleached cellulose is washed with softened water in a container of 10 m ³ volume, first for 30 minutes at a temperature of 85 ± 5 ° C, then for 30 minutes at a temperature of 35 ± 5 ° C. The hydraulic module at both stages of this flushing operation is 1:20.

The flax pulp suspension is fed by a mass pump to a horizontal centrifuge (capacity 900 kg / h). Cellulose is squeezed to a moisture content of 40%.

Cellulose is dried by feeding flax pulp to a vibrating dryer. The temperature of the flue gas is 140-160 ° C. Cellulose is obtained in a yield of 60%, with a mass fraction of α-cellulose - 94%, a dynamic viscosity of 16 MPa · s.

Example 2-3 is carried out analogously to example 1, changing the process conditions. The examples are presented in table 1.

Example 4

The conditions are the same as in example 1, but to increase the mass fraction of α-cellulose, a ripening operation is introduced after thermomechanical processing. The pulp enters the ASH-200 auger apparatus with reverse zones (productivity 1000 kg / h), where the working alkaline solution is further strengthened to an alkali concentration of 10 g / l. Ripening is carried out for 60 minutes at a temperature of 100 ° C. After washing with softened water in two stages and bleaching (concentration of Н ₂ О ₂ - 5 g / l, temperature - 95 ° С), the rest is carried out according to the conditions of Example 1. Cellulose is obtained in a yield 57% and an ash content of 0.2%.

Example 5-6. Cellulose obtained analogously to example 4, changing the process conditions (see table 1).

Example 7-12 The method is carried out similarly to examples 1-6, only as a source of raw materials use straw flax curly (table 1).

Physico-chemical parameters of the target product are determined according to GOST 595-79 "Cotton cellulose" (see table 2).

Analysis of the data in tables 1 and 2 shows that the proposed method is effective, since it allows you to get cellulose used for chemical processing, cotton wool, paper, cardboard, etc. And the use of oilseed straw (waste products of linseed oil) or flax greens (stalks selected between flowering and early yellow ripeness of the flax plant (for 40-50 days) as a raw material, significantly reduces the cost of cellulose.

Table 1 Technological parameters of the method Units Examples and meaning of parameters one 2 3 four 5 6 7 8 9 10 eleven 12 Raw materials Green flax Curly Flax Straw 1.Lock using
- caustic soda g / l one four 6 one four 6 2 3 5 2 3 5 - syntanol ALM-10 g / l 0.5 0.5 - 0.5 0.5 - 0.5 0.5 - 0.5 - 0.5 - neonol AF _9-12 g / l - - 0.5 - - 0.5 - - 0.5 - 0.5 - Temperature ° C one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred Duration min 60 60 thirty 60 thirty fifteen 60 60 60 thirty thirty fifteen Hydraulic module 1:20 1:20 1:20 1:20 1:20 1:10 1:20 1:20 1:20 1:20 1:20 1:10 2. Thermomechanochemical treatment Temperature ° C one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred Duration min thirty thirty thirty thirty thirty thirty fifteen fifteen fifteen fifteen fifteen fifteen 3. Ripening
Temperature
° C - - - one hundred one hundred one hundred - - - one hundred one hundred one hundred Duration min - - - 60 thirty thirty - - - 45 fifteen fifteen

Continuation of table 1 4. Bleaching in a solution of hydrogen peroxide g / l 10 10 10 5 5 5 10 10 10 5 5 5 Temperature ° C 90 90 90 95 95 95 90 90 90 95 95 95 Duration min 90 90 90 90 90 90 90 90 90 90 90 90 Hydraulic module 1:20 1:20 1:20 1:20 1:20 1:10 1:20 1:20 1:20 1:20 1:20 1:10

table 2 Name of quality indicator of flax pulp Units Examples and parameter values one 2 3 four 5 6 7 8 9 10 eleven 12 1. Mass fraction of α-cellulose % 94.0 94.7 95 95.8 96 95.6 91 90 91.3 92.8 93 92.5 2. Dynamic viscosity MPa · s 26 43 75 60 101 86 eighteen 34 57 21 43 26 3. Mass fraction of ash % 0.3 0.28 1.17 0.2 0.21 0.20 0.41 0.39 0.33 0.21 0.3 0.26 4. White % 70 75 80 73 75 72 60 70 63 65 61 60

Claims (2)

1. The method of producing cellulose by sequentially simultaneously loosening and cleaning the cellulose-containing material, locks, thermochemical processing, washing, bleaching, washing, spinning and drying, characterized in that before the lock, additional washing and cutting of the material is carried out, the processing is carried out thermo-mechanochemical, and as a cellulose-containing material take flax green or flax straw. 2. The method according to claim 1, characterized in that in addition, after thermo-mechanochemical processing of the material, it is left to ripen in an alkaline solution.