SU887666A1 - Pulp semi-finished material production method - Google Patents

Description

The invention relates to the pulp and paper industry, namely to the field of pulping semi-finished product by oxygen-alkaline method.

The iavesten method of producing a fibrous semi-finished product by oxygen-alkaline cooking is ligoNO TS € of the Lulose material in the presence of manganese compounds, introduced into the alkaline solution before the oxygen-alkaline cooking and during its 1. U

However, this method is not sufficiently effective, since the introduction of manganese compounds during cooking or throughout the cooking leads to the fact that a part of manganese, ca, acts on the cooking site, where its addition has a negative effect.

The closest to the invention is a method for producing cellulosic semi-finished product, which includes feeding lignocellulosic raw material and alkaline cooking solution to a cooking apparatus, raising the temperature of the reaction mixture in the cooking apparatus, introducing manganese compounds into the 25th cooking liquor and cooking at the final temperature in the presence of oxygen-containing gas 2.

In this method, manganese compounds are introduced into the initial cooking solution before 20

temperature increase or during cooking at the final temperature.

This method is not sufficiently characterized by the HIGH yield and strength of the target product.

The purpose of the invention is to increase the yield and strength of the target product.

This is achieved by the fact that according to the proposed method of producing a fibrous semi-finished product, including supplying cellulose raw material and alkaline boiling solution to a va, cooking apparatus, raising the temperature of the reaction mixture in the cooking apparatus, introducing manganese compounds into the cooking solution and cooking at the final temperature; in the presence of oxygen-containing gas, manganese compounds are introduced in the process of raising the temperature when the output value of the lignocellulosic residue is 70-85% of the mass of the initial absolutely dry lignocese llyuloznogo feedstock.

The proposed method is based on the use of manganese only at that delignification stage, where it exerts an exclusively positive effect — at the welding stage, by the time of development of which the mass loss of the delignified lignocellulosic material (wood) is 15-30%, i.e., yield 85- 70% off

mass of absolutely dry (a. s.) lignocellulosic material.

The proposed method for the production of cellulosic semi-bricate is carried out as follows.

Lignocellulosic material (for example, wood chips, shavings or sawdust) is loaded into the batch cooking apparatus, the cooking liquor is poured and, heating the contents of the cooking apparatus, start cooking in the presence of oxygen or oxygen-containing gas, which can be supplied to the cooking apparatus by various known in ways. It is preferable to use air as the oxygen-containing gas. Upon reaching a yield of 70-85% by weight of the starting lignocellulosic material in the cooking apparatus, once with a dosing pump, the whole martian is added to the batch and the cooking is continued in the usual way until the cellulose lolufate is obtained.

In case of continuous operation, the addition of manganese compounds is introduced into the circulation system of that zone of the cooking apparatus through which the partially delignified linne cellulose passes. 3; the output of which is 70-85% and 1 va. continue on in the usual way.

The implementation of the proposed method involves an elementary preliminary study of the change in the yield of lignocellulosic material during cooking under accepted conditions and the oxygen-alkali cooking mode to determine the cooking time or zone (in a continuous cooking apparatus) when the output of the lignocellulosic residue is in the required range of 70- 85%.

The proposed method can be used for pulping the semi-finished product in the Sch | Iroko.m range. The final degree of delignification and output.

In the examples given, the proposed method is carried out under the conditions of oxygen soda cooking, which is one of the most common types of oxygen-alkali cooking.

The known and proposed methods are carried out under strictly saline conditions; and have in all (The examples given, the following are the same factors: the initial cooking solution is 10.0 g / l NagCOs with pH 11.3-11.5 ; hydronic module — 15: 1; initial pressure of oxygen — 1.47 MPa (15 at.i); degree of the autoclave being filled with oxygen — 50% (during cooking, no more oxygen is supplied); manganese compound additive — 0.05% of mass. absolutely dry wood (in units of Mn) in

as a freshly prepared suspension, which is obtained and that the manganese compounds are dissolved in part of the cooking liquor.

Various manganese salts, such as manganese chloride, manganese sulfate, manganese nitrate, manganese silicate, can be used as manganese compounds.

Although in the examples presented, experiments on the implementation of the proposed method using manganese chloride are carried out, any of these compounds 1 manganese is in this case a technical equivalent and leads to the achievement of similar results.

All cooking was carried out in a battery unit with 1 liter autoclaves each, equipped with shirts and electrically heated. The brewing mode for all brewings: temperature from 20 to 140 ° C - 30 min, from 140 to 170 ° C - 120 MI | N, cooking time at the final temperature of 170 ° C - varies, depending on the required degree of delignification ( Ca. p1p) or yield of the resulting pulp semi-finished product.

Example I. Cooking is subjected to cutting chips of a thickness of 0.5-0.8 mm. According to a known method, two cooking were carried out (X ° 1 and 2). In one of these cookings (No. 1), the vegetable-prepared dispersion of manganese chloride is introduced into the initial solution before the soil; in another cooking (No. 2) - at the beginning of the cooking stage at the final temperature, orienting this, at the moment of introduction of the additive, the yield of wood residue is 62.7%, that is, below the lower limit (70%) specified in the proposed method.

According to the proposed method (cooking No. 3), manganese chloride is added at the welding stage (after 80 min from the beginning of the temperature rise from 20 ° C) after reaching a yield of 84.5% by weight of absolutely dry wood, i.e. specified IB proposed method.

From the results presented in table. 1, it can be seen that, practically with the same degree of delignification of the proposed method, cellulose is obtained with a yield of 0.8-4.1% by weight of absolutely dry wood, exceeding the yield of pulp by a known method {2. The strength characteristics of cellulose, obtained by the proposed method, are also higher in terms of breaking length by 11%, resistance to squeezing - on, resistance to tearing - by 10%.

Example 2. By a known method held cooking No. 4 and 5.

The basic conditions of cooking, the results of which are presented in this example (see Table 2), are similar to the cooking conditions of Example 1 and are described when describing the conditions of laboratory testing of the proposed method.

The method of oxygen-alkaline cooking

Table 1

Indicators

The degree of delpgnification of cellulose, Kapp number

The yield of pulp,% by weight of absolutely dry wood

Nenrovar,% by weight of absolutely dry wood

Content of active NaOH in liquor, g / l

pHa liquor

Physical Mechanical

strength indicators:

bursting length, m tear resistance, mN pushing resistance, kPa i

The difference is only at the point of introducing db№ and manganese chloride in cooking

the proposed method (cooking number 6); The additive is also introduced "at the stage of the brewing process", but already achieved: and an output of 71.4% by weight of absolutely dry wood.

Table 2 As can be seen from Table. 2, the implementation of the proposed (Oposhoba in the production of pulp of almost the same degree of delignification in such a case leads to an increase in the yield by 1.7% by weight of ac. Of wood while reducing the lack of penetration by 1.7-1.8% and the increase in bending resistance more than 2 times, and the tearing resistance is 3.5 times. Example 3. The differences between the cooking conditions of Example 3 (see Table 3) and the cooking conditions of the two previous examples are as follows:

As see from table. 3, under these cooking conditions, somewhat different from the conditions of the previous two examples, when cooking using the proposed method, the yield of pulp practically does not change. However, the strength of cellulose p: ri considerably increases. So, the bending resistance is increased from 14 to 230%, the tear resistance by 8-37%, the burst resistance by 18-22%.

From the results of the cooking given in examples 1-3, it can be seen that the proposed method in most cases achieves a significant increase in both cellulose yield (on average by 2.2% by weight of absolute-dry wood) and its strength (example, ry 1 and 2). In some cases, while maintaining the output unchanged, it is possible

a significant increase in the strength of cellulose (see example 3).

Judging by the content of active alkali in the spent liquor and its pH2o value, and also taking into account that comparisons in each of the examples were carried out with a practically constant degree of delignification of the obtained cellulose, it can be seen that the advantages obtained by the proposed method take place at a constant cooking speeds and are not accompanied by an increase in the consumption of active

NaOH cooking.

Claims (2)

Invention Formula The method of obtaining the pulp briquette, which includes feeding the lignocell to the following: for cooking, thinner spruce chips (thickness 0.3-0.5 mm) are used; the point of addition of manganese in one of the variants of the known method, (cooking No. 8) - after 5 minutes of cooking, at a final temperature of 170 ° C (upon reaching a yield of 60% of the mass of A. of wood); The point of introduction of manganese according to the proposed method is at the Stage of welding upon reaching a yield of 84.0% by weight of a.s. wood ;, the duration of cooking at the final temperature for all cooking (No. 7-9) -15 min. Table 3 of the lulosis SVdr and alkaline cooking solution in the cooking apparatus, the temperature rise of the reaction mixture in the cooking apparatus, the introduction of co, single manganese into the cooking solution and the heat of the final temperature In the presence of oxygen or oxygen-containing gas, In order to increase the yield and strength of the Target Product, the compound margarica is introduced in the process of raising the temperature of the specie at a value of (the yield of ligna-cellulose residue is 70-85% of the mass of the initial absolutely dry lignocellulose Sources of information taken into account in the examination: 1. French Patent No. 2264125, class D 21 C 3/02, published 1975. 2. USSR author's certificate number 344054, cl. D 21 C 3/02, 1970 (prototype).