SU587191A1 - Method of obtaining sulfate cellulose - Google Patents

Description

(54) METHOD FOR OBTAINING SULPHATE PULP

an electrochemical cell without a diaphragm is arranged with an anode to cathode 6.5: 1 ratio, the anode material is stainless steel (CNT). The circulation rate of the solution in the proposed examples was constant and equaled 3.8, boiling was loaded 110 g (in terms of absolutely dry), the boiling range was 4: 1.

Example 1. Pine chips in the form of matches (3x3x20 mm) are poured into the autoclave cooking liquor concentration of active alkali 35 g / l in units. with temperature. The circulation of liquor is turned on, and a voltage is applied to the electrochemical cell electrodes, so that the current density at the anode is 0.025 A / cm. Electrochemical oxidation of the circulating liquor continues for 60 minutes, after which the temperature rises to 170 s over 60 minutes and the cooking at the final temperature continues for 60 min The result is cellulose, the properties of which are given in table 1.

For comparison, sulphate cellulose was obtained in the same mode, but without electrochemical oxidation of the cooking solution. Its properties, as well as the properties of cellulose obtained by the method of the prototype are given in table 1.

Table 1

51, 1

35.4

49,8

40.1 46.8 39.5

Example 2. Matching birch chips in the same conditions as in Example 1, except for the active alkali concentration of the cooking liquor, which was 33 g / l in a.a2O-Duration unitB at the final temperature of 165

55,8

10600

1000

6.0

1150

7,8

1150 6.2

30 min. The properties of cellulose obtained by the proposed and conventional sulfate method in comparison with the properties of cellulose obtained by the method with pre-oxidation

cooking solution are given in table.2.

Table

15.5

9300

3700

6.7

As can be seen from the data given in the examples, the proposed method produces significantly more delignified cellulose and with a greater yield than by the method with pretreatment of lye with oxygen With equal alkali costs for cooking (14% and 13.2% in units) by the proposed method cooking time and cooking temperature are reduced, compared to the prototype method,

Thus, the application of the proposed method for the production of sulfonate cellulose will allow it to be obtained in a high yield, with lower costs of chemicals and energy due to a more intensive process, ..

The proposed method does not require large additional costs for its implementation, since the electrochemical cell can be installed in the circulation systems of cooking solutions in boilers of both periodic and continuous operation.

Electricity consumption in terms of 1 ton of cellulose at such current densities will be 100-200 kWh and almost will not increase. Continuation of the table. 2

the cost of semi-finished products, while increasing the yield of pulp by 3-4% will save up to 10% of wood consumed for cooking.

Invention Formula

A method for producing sulphate pulp, by oxidizing a starting sulphate cooking solution, impregnating a cellulose-containing raw material with a saline solution and then boiling at elevated temperature and pressure, such as ITO, to increase the efficiency of the process by increasing the concentration of polysulfides in the cooking solution, oxidizing sulphate cooking solution electrochemically, directly at the impregnation stage in the liquor circulation system at a current density of 0.001-0.3 a / cm.

Sources of information taken into account in the examination:

1. US patent number 3723242, cl. 162-89, 1973,

2. USSR author's certificate number 325286, cl. -D 21 C, 3/02, 1970.