SU1217960A1 - Method of producing sulphate pulp - Google Patents

Description

This invention relates to the pulp and paper industry, in particular to a method for producing sulphate pulp from hardwood.

The purpose of the invention is to increase the efficiency of the delignification process and reduce the resin content of the target product.

Along with this, resinous substances found in the hydrolytic lignin extract are utilized, which allows increasing the yield of tall products by 2-2.5 times, increasing the density of black liquor, which ensures a reduction in steam consumption for the liquor evaporation.

The essence of the invention is that according to the method for producing sulphate cellulose by cooking wood chips from hardwood wood with an alkaline extract of hydrolytic lignin and white sulphate liquor, cooking is carried out at a ratio of alkaline extract and white liquor from lil to 1: 3 substances in the mixture of these reagents 11-20% by weight of absolutely dry wood.

The alkaline extract of hydrolytic lignin pr the proposed method contains 88.4 - 210 g / l of dry substances including 8.83 - 21.55 g / l of NaiO and 62.72 - 149.47 g / l of organic substances. Organic matter consists of 15% resinous matter, 20% carbohydrate degradation products, and 65% alkaline soluble colloidal lignin. The low molecular weight decomposition products of carbohydrates and coniferous lignin formed during its hydrolysis are catalysts for the delignification process. Coniferous resinous substances. extracted from hydrolyzed lignin by alkaline extraction, act as solubilizing components for extracting hardwood (resin) substances, therefore, by using hydrolyzed lignin extract in sulphate cooking of hardwood mixed with white liquor, it provides better impregnation and increases efficiency of the delignification process.

01

Example I. Hydrolytic lignin alkaline extract is prepared according to. The following technology: 260 g of hydrolytic lignin, which is a waste product, humidity 54%, is treated with 580 ml of a solution of caustic soda with a concentration of 124.6 g / l at a temperature of 85-90 from 60 minutes at a water ratio of 1: 6. The extract is separated.

and the resulting solid residue is washed with 200 ml of hot water (75 ° C). Washing was carried out 6 times. After that, a strong extract and 1.2 and 3 washes are combined. Solution

contains 16.3 g / l of 58 g / l of dry matter. Further, this solution is used to process the next sample of hydrolytic lignin under similar conditions with the addition of 35 g,

NaOH to increase the content of organic substances in the solution. Ext., Ract are separated, and the solid residue. . washed with water (4th, 5th and 6th), obtained by the first treatment.

The strong extract is combined with the washings, the resulting solution contains 8.83 g / l Naij, 0, 116 g / l dry matter, including 104.9 g / l organic matter, of which.

15.74 g / l resin. Birch chips with a moisture content of 31%, aged for 3 weeks, in the amount of 70 g of absolutely dry wood are loaded into a 0.4 liter autoclave and pour cooking

a solution containing 98 ml of white liquor with a concentration of 109.4 g / l and a sulfidity of 30%, 110 ml of water and 75.0 ml of the obtained alkaline extract of hydrolytic ligiin containing 11.02% of organic matter, including 1.69% of resin from masses of absolutely dry wood. The consumption of active alkali of cooking liquor is 14.5% by weight absolutely dry

wood and organic substances of hydrolytic lignin extract. Cooking is carried out at 90 minutes, heating to 165 ° C for 120 minutes. Hydronic module cooking 1: 4.5. In parallel

The same regime is used for cooking of freshly cut birch wood with a moisture content of 43.2%. Cooking leads in triplicate.

The table shows the average

data indicators obtained cellulose and the composition of black liquor.

At the same time, for comparison, sulphate cooking of birch trees is carried out.

springs with an alkaline extract of hydrolytic lignin and white sulphate liquor with a ratio of white liquor and alkaline extract 1: 3 - 3.7 and the total content of or-; Ganic substances 9% by weight of absolute; lute dry wood (according to the prototype) and with one poor lye ((base object). Average data on yield, degree of delignification, content of substances in the cellulose, extruded by alcohol benzene, as well as on the composition of black liquor in the table.

Example 2. In the autoclave capacity of 0.4 l load birch wood chips, aged for three weeks, moisture 31% in the amount of 70 g of absolutely dry wood and pour 00 ml of white liquor concentration of 109.4 g / l and 30% sulfidity. 84 ml of water ri YuO ml of alkaline extract of hydrolytic lignin obtained according to example 1 and of the same composition, containing 15% of organic substances, including 2.25% CMOJUI from absolutely dry wood. The cooking mode and alkali consumption are similar to Example I. In parallel, freshly cut birch wood with a moisture content of 43.2% is cooked in the same way. Average indicators of cellulose and black liquor are presented in the Polish.

by

Organic content;

, Sustained by others 11,02 / 1,69

Freshly cut wood

11.03 / 1.7

Vzderzhanna wood15, 0 / 2.25

, Freshly cut wood 15.0 / 2.25

604

Example 3. A 0.4 liter autoclave is loaded with birch wood chips, held for three weeks, humidity 10.3%, in an amount of 70 g of absolutely dry wood and filled with P2 ml of white liquor with a concentration of 97.65 g / l and sulphite 25%, 54 ml of water and 134 mi alkaline extract of hydrolytic lignin obtained in example 1 and the same composition containing 20% of organic matter, including 3% resin from absolutely dry wood. The mode of cooking and the consumption of alkali are similar to example I. In parallel, according to the same mode, Jlvod t cooking freshly cut birch wood with a moisture content of 43.2%. The average data for cellulose and black liquor are presented in the table.

From the analysis of the table, it follows that the proposed method for producing sulphate pulp makes it possible to increase the efficiency of the delignification process, as evidenced by a decrease in the delignification degree. by 21-22% compared with the base object and 15% compared with the prototype. The method also makes it possible to reduce the resinous content in cellulose by 35% compared with the prototype and by 45% compared with the base object and to increase the yield of tall oil products by 216-250%.

Delignification degree

resin content,%

52.6 51.5

16.2 18.3

; st, 6

51.1

16.2 18.3

by

Organic content;

Weathered wood 20, 0 / 3.0

Freshly cut wood20, 0 / 3.0

i Known method (prototype)

Vvderzhanna wood

Vae object (cooking with white liquor)

(windbreak 1 (spring)

0.54 1.08 172.4 95.7

.0.96 1,081 171.55 95.8

0.54 1.084 180.7 100.3

0.92 1,084 179.4 99.2

Weathered wood

0.551.104 205.8P4,20140.8

Table continuation ..

Stile

DYGNIFICATION

1 sodder.zhiie; resin.

51.8 51.2

16.5 18.85

52,8

18.0

53.2

23.9

M8iO 127.9

123.7 132.5

Freshly cut spring

Known prototype method

Vzherzhenna

wood

Vase object

(cooking with white

lye)

Freshly chopped

wood

Editor L.Avramenko

Compiled by A. Moiosov

Tehred S. Migunova Proofreader S. Shekmar

Order 1088/35 Circulation 355 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Filial ShSh Patent, g, Uzhgorod, st. Project, 4

1,089 183.17 101.7

135.7

1,0805 162.04 90.04

127,84

1,052 136.1 74.9

100

Claims (1)

METHOD FOR PRODUCING SULPHATE CELLULOSE by cooking wood chips from hardwood with an alkaline extract of hydrolytic lignin and white sulfate liquor, characterized in that, in order to increase the efficiency of the delignification process and reduce the tar content of the target product, the cooking is carried out with a ratio of alkaline extract and white liquor from 1: 1 to 1: 3 and the total content of organic substances in the mixture of these reagents is 1 1-20Z by weight of absolutely dry wood. >