SU1397580A1 - Method of producing pulp - Google Patents

Abstract

The invention relates to the pulp and paper industry and makes it possible to increase the strength of the pulp, to increase its yield and the yield of processed garment liquids. In pulsation autoclave load chips and pour aqueous ammonia solution in the amount of 10-25% of its total consumption. The pressure in the apparatus due to the transfer of oxygen is maintained at 2.0 MPa. Oxygen consumption is 80-95% of the total consumption. After 2 hours of cooking, the spent cooking liquor is removed from the autoclave and the welded cellulose fibers are removed. At the stage of returning it to the cooking appliance, the remaining amount of aqueous ammonia and oxygen is fed into the spent cooking liquid. After the end of continuous cooking, the contents of the autoclave are cooled, the pressure is reduced to atmospheric, the pulp is discharged and washed. 1 hp f-ly, 1 ill., 1 tab. and SS CO

Description

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The invention relates to methods for producing pulp and is intended for use in pulp and paper industry in the manufacture of pulp semi-finished products for the manufacture of various types of paper and cardboard.

The goal of the invention is to increase the strength of cellulose, to increase its output and yield of processed products of cooking liquid.

The drawing shows the scheme for the production of pulp according to the proposed method,

Part of the cooking agents (aqueous solution of ammonia and oxygen) is not fed to the cooking apparatus 1 ,, but to the used cooking liquid after the unloader 2 at the stage of its return to the cooking apparatus 1.

The supply of oxygen to the spent cooking liquor contributes to an improvement in the quality of cellulose and a decrease in the yield of by-products of the cooking liquid. The supply of an aqueous solution of ammonia into the spent cooking liquid slows down the subsequent dissociation, contributes to

clav (with a capacity of 7 l) is charged with 400 g of birch chips, water ammonia is poured, they are continuously boiled for 2 hours at and A h at 140 C. Pressure in the apparatus by supplying all the oxygen and processing its flow through the apparatus l / min support equal to 2.0 MPa. The pH of the cooking solution is maintained at a level of 8.8-9.0 by feeding the entire amount of an aqueous solution of ammonia into the apparatus. Two hours after the start of cooking, the spent circulating cooking liquor is removed from the autoclave and the welded cellulose fibers are separated. Spent circulating cooking liquor is returned to the cooker. After the end of continuous cooking, the contents of the autoclave are cooled to 80 ° C, the pressure is reduced to atmospheric, the pulp is discharged, washed and analyzed.

The indicators characterizing the cooking process, the quality of cellulose and the glass are presented in the table (experiments 1, 3, 5 and 7).

Example 2.B cooking apparatus (pulsation autoclave with a capacity of 7 liters)

pulp yield, processing products, load 400 g of birch wood chips, 35

ki cooking liquid and reduces the strength characteristics of cellulose.

The supply to the used cooking liquid at the stage of its heating to the oxygen cooking apparatus in the amount of 5–20% of its total consumption and water ammonia in the amount of 75–90% of the total consumption changes the delignifying properties of the cooking liquid. cooking Q provides an increase in the yield of cel- diseases, products of processing of cooking liquids and an improvement in the strength characteristics of cellulose. Such treatment of the cooking liquid is effective if the combination of the parameters of the used cooking liquid is achieved at the following values: chemical oxygen consumption (COD) of 15,000–59,000 mg O2 / l and nitrogen content in

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water solution of ammonia is added, cooking is carried out continuously for 2 hours, at 150 ° C and 4 hours at 140 ° C. 0 MPa. The pH of the cooking solution is maintained at 8.8-9.0. After 2 hours of cooking, the spent circulating cooking liquid is withdrawn from the autoclave and the welded cellulose fibers are collected.

At the stage of returning it to the cooking appliance, oxygen and an aqueous solution of ammonia are continuously supplied to the spent circulating cooking liquid (the amount of reagents is given in the table). After the end of the continuous cooking, the contents of the autoclave are cooled to. pressure is reduced

Absolutely dry matter (A.v.v.) va-to atmospheric, cellulose is unloaded.

dry liquid 15.1-19.9%. When the limit values for one of these parameters are exceeded, the selectivity of the delignifying effect of the cooking liquid on the wood components changes.

Example 1 (known). Used cooker (pulsation auto

water solution of ammonia is added, cooking is carried out continuously for 2 hours, at 150 ° C and 4 hours at 140 ° C. The pressure in the device due to the supply of oxygen to the cooking device and the organization of the flow through the device 1.2 l / min is equal to 2, 0 MPa. The pH of the cooking solution is maintained at 8.8-9.0. After 2 hours of cooking, the spent circulating cooking liquid is withdrawn from the autoclave and the welded cellulose fibers are collected.

At the stage of returning it to the cooking appliance, oxygen and an aqueous solution of ammonia are continuously supplied to the spent circulating cooking liquid (the amount of reagents is given in the table). After the end of the continuous cooking, the contents of the autoclave are cooled to. pressure is reduced

before atmospheric, the pulp is discharged.

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washed and analyzed.

The indicators characterizing the cooking process, the quality of cellulose and lye, are presented in the table (experiments 2, 4.6 and 8).

As can be seen from the table, the proposed method helps to increase the strength of cellulose, increase its

output, as well as the release of products of processing waste cooking liquor (organomogneralnyh fertilizers).

Formula inventions

A method for producing cellulose, which includes feeding cellulose-containing raw materials, ammonia and oxygen in aqueous solution, continuous cooking at elevated temperature and pressure, withdrawing circulating cooking liquid and welded cellulose fibers from the cooking apparatus,

fiber division and subsequent return

Intense spine of pulsation.

spent circulating cooking liquid for cooking, characterized in that, in order to increase the strength of cellulose, increase its yield and yield of processed waste cooking liquid, water ammonia is fed into the cooking device in the amount of 10-25% of its total consumption, oxygen 80-95% of its total consumption is supplied, and the rest of the aqueous solution of ammonia and oxygen is introduced into the recycled circulating fluid at the stage of returning it to the cooking apparatus.

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Krechkam kch mowed with whole / goodies. By fibers.

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Claims (1)

Claim A method for producing cellulose, including feeding to the cooking apparatus cellulose-containing raw materials, aqueous pacT-jQ thief of ammonia and oxygen, continuous cooking at elevated temperature and pressure, removing circulating cooking liquid and welded cellulose fibers from the cooking apparatus, separating the fibers and then returning the waste circulating cooking liquid for cooking, characterized in that, with a chain of increasing the strength of the pulp, increasing its output and the output of the processed products of the spent cooking liquid, water OR ammonia is fed into the cooking apparatus in an amount of 10-25% of its total consumption, oxygen is supplied in an amount of 80-95% of its total consumption, and the remaining amount of an aqueous solution of ammonia and oxygen is introduced into the spent circulating liquid at the stage of its return to the cooking apparatus . Specifications Indicators for. experience 1 (famous) 2 (proposed) 3 (famous) 4 (proposed) 5 (famous) 6 (proposed) 7 (Lives) 8 (proposed) The intensity of the ripple, mm-min 2500 2500 1500 1500 3500 3500 3500 3500 Consumption 0] supplied to the country. botanical cooking fluid, X of the total 0 5.1 0 19.9 . 0 10 0 7.9 Worker ΝΗ ₃ supplied to the spent cooking liquid, X of the total 0 75 0 82 0 90 0 75 Sulphite number 0.29 0.18 0,07 0.08 1.6 1.7 2.6 2.6 Sorted pulp yield, X 8.6 52,4 5,6 53.5 52.0 54.8 52.7 58.6 Lack of penetration, X 52,5 • 8.4 51.1 Bj 6.0 3,1 *, 2 2.3 Bursting length of cellulose, m 7500 9100 6700 8700 8000 9600 6800 8200 COD of spent cooking liquid, mg 0, / l 14800 32000 39,000 69000 13000 15,000 80,000 40900 Nitrogen content in a.s. waste cooking liquid. X 14.2 16.7 20.3 19.9 14.8 fifteen, 15.9 17.1 The output of by-products of the processing of waste cooking liquid, kg / t of pulp 210 280 250 270 205 265,250 270 I I I _t Shchts _t ("-25%) 4 f _x (75-90%) J (ucoopod (5-2O%)