SU1151629A1 - Liquor for producing sulphite pulp - Google Patents

Abstract

COOKING SOLUTION FOR THE RECEPTION OF SULPHITE PULP, containing an active base, sulfurous anhydride and the aquatic environment, so that, in order to increase the yield of cellulose, it contains as an aqueous medium waste water from the milling of coniferous wood with water-containing content bark substances 2-5Z by weight of absolutely dry wood with the following ratio of components, wt.%; Active base 0.90-1.18 Sulfuric anhydride 4.86-8.20 Discharge water from the conformation of coniferous wood. Wood with a content of water-extracting substances of the bark of 2-5% by weight absolutely hoi; fevesina Else

Description

The invention relates to pulp and paper production, namely to cooking solutions for the production of sulphite unbleached pulp. The aim of the invention is to increase the yield of pulp. As an aqueous medium in the cooking liquor to produce unbleached sulphite pulp, wastewater from pulp and paper enterprises may be used, coming from the nodes of the mechanical debar of softwood pulp and coniferous wood bark extracts. Sewage of debarking knots has the following characteristics: total dry matter content is 0.47–4.0 g / l; biological oxygen consumption of BOD-11502190 mg / l and VPK about 1640-2230 mg / l; reducing substances 0.4-3.34 g / l; bichromate oxidability 230 617 mg / l; permanganate oxidability 94-2410 mg / l. Aqueous solutions with the content of extracts of coniferous wood bark in the amount of 2.05, 0 wt.% Can be obtained either directly on pulp and paper mills by using the water of the debarking nodes and by extracting the debarking waste. The extraction was carried out at 90-100 ° C and atmospheric pressure for 90-150 minutes. At the same time, the aqueous solution has the following composition, wt%: Tannins 25-70 Low Molecular Hydrocarbons 11.5-53.4 Resinous Substances, 5 Use as an aqueous medium wastewater from the debarking of coniferous wood with a content of water-extracting substances of the bark of 2-5 % by weight of absolutely dry wood leads to an increase in the yield of pulp due to the regulated process of condensation of lignin with tannins. With a higher content of bark water-extracting substances in the cooking solution, the cooking process becomes difficult to control, while with a lower content, the effect of increasing the yield of cellulose decreases. Example 1. Spruce chips, when cooked from peeled wood on UShch-34, humidity 8.3% in the amount of 50 g of absolutely dry wood, are loaded into a 0.4 liter aktoklav. In the autoclave pour cooking solution of the following composition, wt.%. Active base 0.96 Sour sulfuric acid 4.86 Sewage water from coniferous barking wood. Remaining The amount of water-extracting substances of wastewater bark in the cooking solution is 2% of the mass of absolutely dry wood. At the same time, they have the following composition, wt%: Tannins 57.5 Low molecular weight carbohydrates32.45 Resinous substances 10.05 Cooking is carried out in the following mode: heating to IOS for 105 minutes; stand at 90 minutes, the temperature rises to 100 minutes. Duration of cooking at 135 ° C 60 min. For comparison, the method of cooking is carried out by a known method with the addition of wet forming to the cooking solution of waste water produced by fiberboard with the following composition: biological oxygen consumption VPK 50 400 mg / l and H1 physical oxygen consumption COD 1200 mg / l Both cookings are carried out in triplicate. Example 2. Spruce chips prepared from barked wood on U1NTS-ZA, humidity 8.3% in the amount of 50 g of absolutely dry wood are loaded into a 0.4 l autoclave. An autoclave is charged with a cooking solution of the following composition, wt%: Active base 0.9 Sulfur dioxide 5.4 Sewage water from conifer softwood debunk Water-extracting substances of the cortex named after the following composition, wt.%: Dubious substances 45.0 Low molecular weight. carbohydrates53,4 Resinous substances 1,6 Sulfite cooking spruce chips

in accordance with the mode described in Example 1.

The comparison is carried out by a known method with a cooking solution containing an aqueous medium based on the waste water produced by the wet-forming fibreboard of the following composition: biological oxygen consumption BOD 600 mg / l, chemical oxygen consumption COD 1900 mg / l.

Both cookings are carried out in triplicate.

Example 3. Spruce chips obtained from debarked wood at the UHZT-ZA 8.3% moisture in the amount of 60 g of absolutely dry wood are loaded into a 0.4 l autoclave. In the autoclave pour the cooking solution of the following composition, wt.%:

Active base 1.0

Sulfurous anhydride 8,2

Water solution ext

the active substances of the cortex

ate the rest

An aqueous solution of the extractives of the spruce bark is obtained at a pilot plant by extracting water from the debarking water at 95 ° C and atmospheric pressure for 150 minutes. As a result of its evaporation, the solution has the following composition: total solids content is 32%, among them tannins are 49%. The content of water-taking substances of spruce bark in the cooking solution is 5.0% by weight of absolutely dry wood.

Sulfite cooking spruce chips is carried out according to the mode described in example I.

I For comparison, the method of cooking is carried out by a known method with a cooking solution containing an aqueous medium on the basis of waste water produced by the production of wood-fiber wet-forming plates of the following composition: biological oxygen consumption of the military industrial complex 1745 mg / l, chemical oxygen consumption of COD 5903 mg / l.

Both cookings are performed in triplicate.

Example 4. Birch wood chips prepared from barked wood on UP-3, with a moisture content of 9.6% in an amount of 50 g of absolutely dry wood are loaded into an aktoklav

0.4 l. An aaric solution of the following composition, wt.%, Is poured into the aktoklav. Active base 1.17. Sulfur dioxide 5.5. min and water ratio 1: 8. The concentration of solids in the solution is 3.5%, with tanning substances being 40%, carbohydrates 32%, and resinous substances 28%.

The content of spruce bark extractives in the cooking solution is 5% by weight of absolutely dry wood.

Sulfite cooking of birch chips is carried out in the following mode: temperature rise to 105 ° C 110 minutes; stand at 60 min, temperature rise up to 132 ° С 100 min, stand at 55 min.

For comparison, the method of cooking is carried out by a known method with the wet molding of the following composition added to the cooking solution of waste water produced by fiberboard: biological consumption of oxygen BJ 500 mg / l and chemical consumption of oxygen ХЖ 1300 mg / l.

Example 5. Birch wood chips prepared from barked wood on UShch-ZA, moisture content of 9.6% in the amount of 60 g of absolute dry wood is loaded into a 0.4 l autoclave. In the autoclave pour the cooking solution of the following composition, wt.%:

Active base 1,8

Sulfurous anhydride 5,5 Stoke water from coniferous stumps Else

The content of waste bark extractives in the cooking solution is 2% by weight of absolutely dry wood, while they have the following composition, wt.%:

Tannins 70

Low molecular weight

carbohydrate 11,5

The resin of substance 18.5 Sulfite cooking of birch chips is carried out according to the regime described in Example 4.

For comparison, the method of cooking is carried out by a known method with the wet forming of the following composition added to the cooking solution of waste water produced by fiberboard: biological oxygen consumption BOD A80 mg / l, chemical oxygen demand COD 1700.mg / l.

Cookings are carried out in triplicate.

The table presents the average data on the yield, degree of delignification and mechanical indicators of the obtained cellulose.

From the data in the table it can be seen that the use as

water environment from debarking coniferous dreeiesin rocks with a content of water-extracting substances of softwood bark in the amount of 2-5% by weight of absolutely dry wood allows to increase the yield of cellulose: while cooking spruce chips by 2.0-2.7%, when cooking birch chips on P, 72, 4%. This reduces the consumption of fresh water for cooking and expands the raw material base to produce cheap and effective additives to sulphite cooking solutions. At the same time, the wastewater disposal problem of the debarking nodes that pollute the environment is solved.

Claims (1)

A COOKING SOLUTION FOR PRODUCING SULPHITE CELLULOSE, containing an active base, sulfur dioxide and an aqueous medium, distinguished by the fact that, in order to increase the yield of cellulose, it contains waste water from the debarking of coniferous wood with a content of water-extracting substances from the bark 2 -5% by weight of absolutely dry wood in the following ratio of components, wt.%; Active base 0.90-1.18 Sulfur Anhydride 4.86-8.20 Wastewater from debarking coniferous wood with a content of water-extractive substances from the bark of 2-5% by weight of absolutely dry wood Else>