SU1493706A1 - Method of producing pulp - Google Patents

Abstract

This invention relates to pulping technology for various types of paper and paperboard and allows for improved yields and improved pulp quality. Cellulose-containing raw materials are subjected to alkaline cooking in the presence of a lignin-containing additive, which uses the product of oxidative-alkaline destruction of lignosulfonates at 120-160 ° С with a content of phenolic groups of 6-8%. The specified additive is taken in the amount of 1-4% by weight of absolutely dry cellulose-containing raw materials. 1 hp ff, 5 tab.

Description

The invention relates to the pulp and paper industry and relates to the method of alkaline pulping of cellulose-containing raw materials with the production of fibrous semi-finished products used for the production of paper and cardboard for various purposes.

The purpose of the invention is to increase the yield and improve the quality indicators of cellulose.

The essence of the invention is that when producing cellulose by alkaline pulping, the process is carried out in the presence of a lignin-containing additive, which uses the product of oxidative-alkaline destruction of lignosulfonates at 120-160 with a phenol rpyini content of 6-8%:

 The product of oxidation-alkaline degradation is taken in the amount of 1-4% by weight of absolutely dry celchx-containing raw material.

The product of oxidative-alkaline destruction of lignosulfonates is obtained by oxidation of sulfite-alcohol stillage with oxygen in an alkaline medium at 120-160 C.

The resulting product is treated with a dilute hydrochloric acid solution to exclude mineral compounds. After washing up to. neutral and air drying the product of oxidation-alkaline destruction of lignosulfonates has the appearance of a brown sludge.

As a result of oxidation, vanillin and related substances are formed.

WITH

with

such as vanillic acid and acetovayillon, and a number of lignin degradation products, some of which are phenolic in nature and are 6-8%. Such substances of a phenolic nature are para-hydroxybenzoic acid, acetoquin con, acetovanilone and others.

Before using the product of oxidative-alkaline destruction of lignosulfonates as an additive for alkaline cooking, it is economically expedient to extract vanillin from it.

In tab. 1 shows the functional composition of the product of oxidative-alkaline degradation of lignosulfonates.

From tab. 1, it follows that in the process of oxidative-alkaline destruction of lignosulfonates, they are partially depolymerized with the elimination of sulfo groups, the formation of carboxyl groups and new phenolic groups upon cleavage of -0-4 lignin bonds.

The products of oxidative-alkaline degradation of lignosulfonates, having a phenolic character, possess nucleophilic properties, such as sulfhydrate ions in sulphate cooking. The interaction of these substances with lignin proceeds according to the condensation scheme, accompanied by fragmentation. At the same time, the process of decommissioning is accelerated, while at the same time the selectivity of the process with respect to the carbohydrate part of the wood increases. The additives used in the prototype method act as anthraquinone. Since in the process of demethylation of lignin, upon receipt of additives according to the method of the prototype, pyrocatechol structures are formed, passing into quinone structures.

The method is carried out as follows.

Example 1. Soda cooking of aspen wood chips without additives (basic version). The active alkalinity of the soda lye is 46.3 g / l in units of NaOH. Alkali consumption - 16% in units of the mass of absolutely dry wood.

Cooking mode: t 168-170 ° C; hydronic module 4.5: 1; rise t ° to the final 15 minutes; stand at final temperature 60 min.

The results of cooking are presented in table. 2

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PRI mme R 2. Spend natron cooking aspen wood chips by the method prototype. For this, 1.5% by weight of absolutely dry chips of demethylated lignin are added to white liquor with alkalinity of 46.3 g / l in terms of NaOH and cooking is carried out with the same consumption of active alkali and according to the mode given in Example 1.

Indicators of the quality of cellulose after cooking are presented in table. 2

PRI me R 3. Conduct boiling aspen chips in the proposed method with the addition of soda lye with active alkali 46.3 g / l in units of NaOH product oxidative-alkaline destruction of lignosulfonates obtained at t ° 120 ° C with phenolic content groups of 6.0% in the amount of:

1.0.5% by weight of absolutely dry chips (control).

2.1.0% by weight of absolutely dry chips;

3.1.5% by weight of absolutely dry chips;

4.2.0% by weight of absolutely dry chips;

5.3.0% by weight of absolute dry chips;

6.4.0% by weight of absolutely dry chips;

7..4.5% by weight of absolutely dry chips (control).

The cooking mode and the consumption of active alkali is similar to the cooking mode shown in example 1.

The quality indicators of cel-choles after boiling are shown in Table 2.

PRI me R 4. Cooking aspen chips in the proposed method Z with an additive to soda alkali with active alkalinity of 46.3 g / l in units of NaOH of the product of oxidation-alkaline destruction of lignosulfonates with a content of phenolic groups 8 % obtained at t 160 ° C in the amount of:

1.0.5% by weight of absolutely dry chips (control);

2.1.0% by weight of absolutely dry chips;

3.1.5% by weight of absolutely dry chips;

4.2.0% by weight of absolutely dry chips;

5.3.0% by weight of absolutely dry chips;

6.4.0% by weight of absolutely dry chips;

7. 4.5% by weight of absolute dry chips (control).

The cooking mode and the consumption of active alkali is similar to the cooking mode shown in example 1.

Indicators of the quality of cellulose after cooking are presented in table 3.

II p and me R 5. Conducted soda boiling of aspen chips using the proposed method with an addition to soda liquor with active alkalinity of 46.3 g / l in units of NaOH of the product of oxidative-alkaline destruction of lignosulfonates after extracting vanillin from it in the amount of:

1.0.5% by weight of absolutely dry chips (control);

2.1.0% by weight of absolutely dry whispers;

3.1.5% by weight of absolutely dry chips;

4.2.0% by weight of absolutely dry chips;

5.3.0% by weight of absolutely dry chips;

6.4.0% by weight of absolutely dry chips;

7.4.5% by weight of absolutely dry chips (control).

The cooking mode and the consumption of active alkali is similar to the cooking mode shown in Example 1.

Indicators of the quality of the pulp after cooking are presented in table. four.

From the data presented in Tables 3 and 5, it can be seen that the addition of products of oxidative-alkaline destruction of lignosulfonates obtained in the range of 120-160 C, increases the yield and improves the strength properties of cellulose, with the maximum increase in yield of 2.2 % compared with conventional soda cooking and 1.4% compared with the method of the prototype, reduce the amount of lack of penetration by 7 times compared with the usual soda cooking and 3.5 times compared with the method of the prototype. The breaking length is increased by 9 and 4.5%, respectively, tearing by 9% compared with conventional soda cooking.

and by 6% compared with the pro- gram method and the fracture resistance increases, respectively, by 50 and 35%.

Example Spend cooking base chips for the proposed method analogously to example 1 with the addition of the products of oxidative-alkaline destruction of sulfate with a content of

0 of these phenol groups 2,4,6,8,10 and 12%, respectively. The consumption of the additive in all experiments is 1.5% by weight of absolutely dry chips.

For comparison, boiling is carried out according to

5 mode of example 1: normal soda with an alkalinity of 46.3 g / l in: units of NaOH without additives and cooking by the method of the prototype with the addition of soda lye with active alkali

0 46.3 g / l in terms of NaOH 1.5% of demeti- gated lignin by weight of absolutely dry chips.

Indicators of the quality of the pulp after cooking are presented in table. five.

5 From table. 5, it follows that the best results are obtained with the addition of products of oxidative degradation of lignosulfonates with a phenolic content of 6–8%.

0 Using the proposed method allows to increase the yield of pulp and improve its quality indicators.

Claims (2)

1. A method of producing cellulose by alkaline pulping of a cellulose containing raw material in the presence of a lignin-containing additive, characterized in that, in order to increase the yield and improve the quality indicators of cellulose, the product of oxidative-alkaline destruction of lignosulfonates is used as a lignin-containing additive at 120-160 C with the content of phenolic groups of 6-8%. 2. The method according to claim 1, of which is of an i-h and y and the fact that the product of oxidative-alkaline destruction of ligninsulfonate takes in the amount of 1-4% by weight of absolutely dry cellulose containing cf. Product OK-alkaline destruction of lignosulphonates at 120 ° C The products of oxidative-alkaline destruction of ligposulphonates at 160 ° C after extraction of vanillin Indicators The output is sorted- B (ty cheshpoloi,% HeiipoBap, X Delignifikaini degree, Kapp unit Duration per m Resistance to fracture, h. Dv. n. Resistance to tearing, ME; Resistance to crushing 52.7 2.1 33.5 1.0 53.9 0.8 54.2 0.6 Table 1 10.9 0.95 5.70 10.20 1.32 3.10 t a b l and c a 3 Table 54.9 0.3 54.5 0.4 54.0 0.8 51.8 and 53.3 1.8 Continuation of table 4 Table3