SU889764A1 - Pulp production method - Google Patents

Description

(54) METHOD FOR OBTAINING CELLULOSE

one

The invention relates to a method of pulping and can be used in the pulp and paper industry for the production of pulp for the manufacture of various types of paper and cardboard, as well as for chemical processing.

A known method of sulfur-free gzvlochnoy pulping, in which the additives of polycyclic quinones, in particular anthraquinone and its derivatives 11, are used to increase the yield of cellulose from wood and intensify the cooking.

However, the effectiveness of anthraquinone depends on the amount specified for cooking. However, anthraquinone is toxic, and toxicity also depends on its consumption.

The aim of the invention is to increase the efficiency of the process.

The goal is achieved by the fact that according to the method of producing cellulose by boiling the raw cellulose-containing raw material with soda melting liquor in the presence of anthraquinone or its derivative at elevated temperature and pressure, before cooking the cellulose-containing

Sorbic acid or alkali metal sorbate in an amount of 0.05-0.15% by weight of dry raw material is additionally introduced into the cooking liquor.

Moreover, after cooking the cellulose-containing raw material in soda varAUsAl lye, it is possible to conduct additional oxygen-alkali cooking. The method can be carried out in the following embodiments.

During alkaline cooking, the chips are loaded into an autoclave equipped with a heating device, 4% is poured

15 caustic soda solution. The wood: solution ratio is created equal to 1: 5, additives of the anthraquinone derivative are introduced, for which methylanthraquinone is used, and sorbi20 new acid or its salt — potassium sorbate in quantities of 0.05–0.15% by weight of dry wood. Raise the temperature to 170 ° C for 2 hours. The duration of cooking at this temperature when using hardwood chips is 70-80 minutes. After this time, the autoclave with its contents is cooled, the liquor is removed, the cellulose is discharged, washed, sorted and analyzed. .

In oxygen-alkaline cooking, the alkaline cooking level is carried out at the same alkali concentration, temperature, and liquid module as soda-scale cooking with the introduction of methyl anthraquinone and sorbic acid or potassium sorbate in an amount of 0.05-0.15 to wood. However, its duration is shorter and is 40 minutes. After this time, the pressure in the reactor is reduced, the solution from the first cooking stage is removed, the chips (partially boiled) are washed or unloaded, and discharged into the reactor for oxygen cooking. Then pour 0.5% alkali solution. The ratio of solid: liquid (T: W) is equal to 1:10. Oxygen is heated to a pressure of 0.6 MPa, after which the temperature is raised to 115 ° C. The duration of cooking at this temperature is 2.5 hours. The required value of the interfacial surface is achieved by swinging the autoclave. It is monitored by sulfite M numbers. The value of the sulfite number, which is provided by the accepted conditions of mixing, is 0.3 mol / l 0.1 MPa Oi h.

At the end of cooking, the pressure of oxygen is released and the mass is cooled. The welded pulp is discharged, washed, sorted and analyzed.

Example 1. Conducted cooking pulp from aspen chips of normal size in autoclaves with a capacity of 0.5 l, placed in a glycerin bath

Liquid cooking module - 1: 5, concentration in solution - 4%. As an additive, a mixture of sorbic acid and 2-methylanthraquinone is used, as well as a mixture of potassium sorbate and 2-methylanthraquinone.

Table 1 shows the main parameters of cooking and quality indicators of cellulose, as well as the results of cooking, with the addition of only 2-methylanthra | quinone (by a known method) and without additives. Table 1

Amount to - 0,1 (SK) 0,13 (SK) of a mavka,% to wood0, 1 (MA) 0,1 (MA) 0,2 (MA)

The continuation of the table.1 shows the total effect of sorbic acid and methylanthraquinone and potassium sorbate with methylanthraquinone.

Example 2. Conducted two-stage oxygen-alkaline pulping of aspen wood chips without semi-mass grinding using

1st stage cooking as an additive of sorbic acid and potassium sorbate mixed with methylanthraquinone; - :.

The first - natron cooking stage was carried out under the same conditions as in Example 1, from the point of view of temperature, the magnitude of the liquid modulus.

boiling and concentration of NaOH in solution. Duration of cooking is reduced by 40 minutes. The mass yield after the 1st cooking stage is 65%.

The second cooking stage was carried out at an alkali concentration (NaOH) of 0.5%, a T: W ratio of 1:10, a cooking temperature of 115 ° C and an initial oxygen pressure of 0.6 MPa. Gross duration

Value added - 0.1 (SC) ki,% to wood

Duration of cooking at the 1st stage, h - min

Duration of cooking at 2-P steps, h-min

The yield of pulp from wood (as seen from Table 2, the addition at the 1st stage of cooking a mixture of sorbic acid and methylanthraquinone or potassium sorbate and methanthraquinone is more effective than the addition of an equivalent amount of methylanthraquinone alone.

With a volume of cellulose production of 250 thousand tons per year, the economic effect from the use of this invention, both in the process of single-stage alkaline treatment and in the process of two-stage treatment using oxygen-containing

cooking in the 2nd stage 2 h 30 min. Between the 1st and 2nd cooking steps after the separation of the liquor, the chips are washed.

Table 2 shows the main results and indicators of cellulose, as well as data on cooking in a known manner, i.e. with the addition of 2-methylanthrachikoHa, and without additive.

Table 2

0.1 (CK)

0.1 (MA)

0.1 (MA) 0.2 (MA)

0-40

0-40

0-40

0-40

2-30

2-30

2-30

gas at the second stage, is 425 thousand rubles. in year.

1. Method for producing cellulose by boiling the raw cellulose-containing raw material in: a soda-tree in the presence of anthraquinone or its derivative at elevated temperature and pressure, characterized in that, in order to increase the efficiency of the process, before cooking the cellulose-containing raw material sorbic acid or alkali metal sorbate in the amount of 0.050, 15% by weight of absolutely dry raw materials.

78897648

2. Method POP.1, distinguish-Sources of information

u and with the fact that, after cooking, in the examination of cellulose-containing raw materials in soda cooking liquor, an additional 1. PuEp and Paper Internatlonat are carried out,

relatively oxygen-alkaline cooking. 1978, 20, No. 9, pp.49-52.

Claims (2)

Claim 1. The method of producing cellulose by cooking the original cellulose-containing raw material55 in soda liquor in the presence of anthraquinone or its derivative at elevated temperature and pressure, characterized in that, in order to increase the efficiency of the process, sorbic acid is additionally added to the cooking liquor before cooking cellulose-containing raw materials or alkali metal sorbate in an amount of 0.05I5 0.15% by weight of absolutely dry raw materials 2. The method according to claim 1, characterized in that after cooking the cellulose-containing raw materials in soda liquor, an additional oxygen-alkaline cooking is carried out.