SU866021A1 - Pulp production method - Google Patents

Description

This invention relates to a process for the production of pulp which can be used in pulp and paper industry in the production of pulp intended for the manufacture of various types of paper and for chemical processing. A known method for producing cellulose is by two-stage pulping of raw materials in the reactor at elevated temperature and pressure with an alkali solution in the presence of oxygen-containing gas, aeration of the cooking solution in the process until the sulfite number reaches 1.5-3.0 and semi-mass grinding between steps fll. The disadvantage of this method is that with an increase in the capacity of the pulp mill, it is not possible to achieve large mass transfer coefficients, therefore, the quality indicators of the target product decrease and the second stage of cooking is complicated. The purpose of the invention is to improve the quality of the target product and simplify the process. The delivered chain is achieved by aerating the ground pulp and leading it to a gas content of an 18-20% 6 reactor with a self-priming turbine agitator. The second stage of cooking is carried out with the continuous circulation of the fibrous mass with a mezdua aerator and a cooking reactor. The chips are fed to the cooker for the first cooking stage, then semi-steamed chips are subjected to semi-mass grinding in a disk refiner and fed to the reactor for the second cooking stage, from which the ground mass is continuously fed to the aerator with a turbine mixer to saturate the oxygen to IS-ZOZ- The horo gas content and re-fed to the reactor for the second stage 3 cooking. The mass circulation in the reactor-aerating system is continued for the time necessary to obtain a product of the required quality. Example. Conducted cooking chips from pine wood. At the first stage, the processing of chips with a solution of caustic soda with an A% concentration was carried out at a liquid modulus of 5: 1. The temperature rise to 2 hours. The duration of cooking at this temperature is 30 minutes. After treatment, the solution was poured, the chips were washed and subjected to semi-mass grinding in a disk refiner. The resulting mass was loaded into a 50-liter electrically heated reactor equipped with a three-liter aerator with a turbine agitator. 1 Next, the caustic soda solution was poured. The consumption of caustic soda was 8% by weight of absolutely dry fiber obtained after the first stage. Mass concentration is maintained at 5%. Oxygen for aeration of the ground mass was fed continuously to the aerating device, its flow rate was controlled by a flow meter. The idle gas content is 18.5%. The mass was pumped by a pump in the reactor-aerator system. The mass circulation ratio is 10 volumes of mass contained in a fifty liter reactor per hour. The remaining conditions for the implementation of the proposed method, a known method, as well as the results obtained are shown in the table.

a, c and mime

Oh

all,% a, C, min running, cellulose%

four

four

170

170 80 5: G. 30 5: 1

58.3

58.3 13.1 15.1

8.0

8.0 „

20: 1

20: 1

180

130

90

70

20

ten

kgf

10.0

10.0

ol

0.7

1.5

l h 7,6 7,6

48.3

53,

From the data given in the table, it follows that the implementation of cooking by the proposed method in comparison with the known method provides an improvement in the quality of cellulose. The yield of sorted pulp is respectively 53.1 and 48.3%, the content of sorting waste is 1.5. and 9.1%.

The implementation of the proposed method provides intensive oxygen exchange in the reactor, regardless of its performance, and thus allows to obtain cellulose with higher quality indicators. This method can be implemented in a high unit power unit, which will reduce the equipment metal consumption and improve technical and economic indicators. process.

 The economic effect from the implementation of the proposed invention with a production volume of 100 thousand tons. cellulose per year will be 130 thousand rubles.

8660216

Table continuation

Claims (2)

Claim 1: A method for producing cellulose by two-stage pulping of raw materials in a reactor at elevated temperature and pressure with an alkali solution in the presence of kilo-containing gas, aerating during the cooking process and semi-mass grinding between steps, in order to improve the quality of the target product and simplifying the process, aerating is expanded by mass and saturated with oxygen up to 18–20% gas content in an aerator with a spin-suction turbine agitator. 2. The method according to claim 1, wherein the second stage of the cookA is carried out during continuous circulation of the ground mass between the aerator and the reactor Sources of information taken into account when ev spertiz I. USSR Copyright Certificate No. 598991, cl. About 21 3/02, 1976.