SU1100316A1 - Method for preparing bark for making tanning extracts - Google Patents

Abstract

1. METHOD OF PREPARATION OF THE COCK FOR THE PRODUCTION OF BROWNED ECI; TRACTS by separating the bark from the wood, grinding it, dividing it into fractions and drying it, so that, in order to increase the productivity of the process and improve the quality crust by preserving the content of the tannides, the crust is crushed to a particle size of 20-40 mm, while drying is carried out in an aerodynamic flow of the drying agent in two stages, the first of which is carried out at a speed of movement of the drying agent 20-30 m / s with an initial temperature of 400 -600 C and final 200-300s in for 2-3.5 s, the second - at a drying agent speed of 2-3 m / s and a final temperature of 80-100 ° C for 3-5 minutes, and the separation into fractions is carried out after drying. . , 2. The method according to p. 1.0 t whether h a yusch and also with the fact that a large fraction (L is pressed into briquettes at 900-1000 kg / cm and holding time under pressure of 2530 s.

Description

35

The invention relates to the timber, pulp and paper and woodworking industries and can be used in the preparation of wood bark for the production of tanning extracts.

A known method of preparing bark is that the bark, separated from the wood and crushed, is divided into large and small fractions. Particles with sizes of 80–100 mM along the fibers and 20–200 mm across the fibers are taken, placed in a container and dried under natural conditions for 5–15 days to a moisture content of 16–28% lj.

The disadvantage of this method is low labor productivity, because drying in natural conditions is not efficient and can be done only in summer. In addition to THAT, during long-term drying, as well as during storage and transportation, the content of tannides in the bark decreases, i.e., the raw material loses its dubbing properties.

The aim of the invention is to increase the productivity of the method and improve the quality of the bark by maintaining the content of tannides.

The goal is achieved in that according to the method of preparing the bark for the production of tanning extracts by separating the bark from the wood,% grinding it, dividing it into fractions and drying, the bark is crushed to a particle size of 20-40 mm, while drying is carried out in an aerodynamic flow of drying agent two stages, the first of which is carried out at a speed of movement of the drying agent of 20-30 m / s with an initial temperature of AOO-600 C and a final 200-300s for 2 3, 5 s, the second - at a speed of the drying agent of 2-3 m / C and the final temperature of 80-100 C for 3-5 minutes, and p The fractions are made after drying.

In this case, a large fraction is pressed into briquettes at 900-1000 kg / cm and a holding time under pressure of 2530 s.

According to the invention, the temperature of the crust does not rise higher, thus avoiding the decomposition of the tannides.

The bark particles are suspended in the drying process. This is due to the fact that

the bark particles are crushed to 20-40 mm, and the speed of the drying agent is 20-30 m / s. Drying in two stages, with a gradual decrease in temperature, ensures such evaporation of bound moisture, which does not overheat part of the bark, thereby preserving the tannides. The bark is dried to a final moisture content of 10-15%, however, during prolonged storage, its humidity rises, resulting in the formation of mold and the destruction of tannin-containing compounds,

 Pressing into briquettes eliminates this drawback, while the chosen parameters of pressing density ensure that the moisture is kept at the level of 10-15% and the required strength of the briquettes.

The method is carried out as follows.

The bark is separated from the wood, crushed to particle size of 20–40 mm and subjected to high-temperature, high-speed drying in aerodynamic | Chesky flow of the drying agent with temperature parameters at the inlet

the raw material of the AOO-BOO with and at the output of 80–100 ° C, the bark undergoes two stages of drying: the first — at a speed of movement of the drying agent of 20–30 m / s for 2–3.5 h;

the temperature of the drying agent is reduced to 200-300 ° C, and the second - at the speed of the drying agent. that 2-3 m / s for 3-5 minutes, while the gas temperature is reduced to

80-100 ° C, and the temperature of the particles of the dried bark does not exceed 100 ° C over the entire period of drying with a decrease in the moisture content of the bark from 60 to 10%, which does not have a practical effect on the

Keeping tandidov in the bark. After weeding the dried bark mass, the fine fraction with a particle size of less than 20 mm is sent for incineration to produce a drying agent.

as. it is not suitable for the production of extracts under industrial conditions due to clogging of filters of diffusers. The coarse fraction is pressed into briquettes at a specific pressure of 900–1000 kg / cm, time taken to release briquettes under pressure for 25–30 s, followed by a gradual decrease of the specific pressure to zero for 5 -10 min. And the heating temperature of the press dies no more than the AIA. Ready for the production of tanning ext-graktov raw materials in the form of briquettes loaded vehicles.

Example. Used for spruce bark moisture 54%. The content of tants in the original bark in terms of 16% humidity is 7-8%. The bark separated from wood is ground to an average particle size of 25 mm and dried in an aerodynamic flow of flue gases in two stages. The first stage of drying is carried out for 2 s, with the velocity of the particles of the bark and the flow of gases 30 m / s. During this time the temperature of the flue gases decreases from 600 to 250 s, and the humidity of the bark from 54 to 29%. The second drying stage is performed sequentially from the first one in the flue gas stream for 4 minutes at a gas velocity of 2.5 m / s. In the second stage, the temperature of the gases decreases from 250 to, and the humidity of the bark from 29 to 10%. The dried bark is sorted into two fractions: the first - with a particle size of up to 20 mm. the second - with a particle size of more than 20 mm. The content of the fine fraction is 46% of the total mass of the bark. The shallow bark is used as fuel to produce a drying agent (flue gases), it was enough to produce the required volume of gases, with a temperature of 600 ° C. A large fraction of the sorted bark is pressed into briquettes at a specific pressure of 1000 kg / cm with briquettes under pressure for 25 seconds and then relieving the pressure for 7 minutes and the heating temperature of the press dies is 70 C. The content of the tannins in the briquettes remains equal to that of the Kopfe, i.e. 7-8% in terms of 1b% of the humidity. This condition is ensured by the fact that in the process of high-speed, high-temperature drying, particles of the bark do not reach thermal decomposition, tannides.

The use of the proposed method of preparing raw materials for the production of tannery extracts provides, in comparison with the known, full effective use of bark, increasing labor productivity by reducing drying time, the possibility of year-round raw material harvesting, improving production culture, protecting the environment from vehicle load and reducing the cost of transportation of raw materials.

Claims (2)

1. METHOD FOR PREPARING THE BARK FOR PRODUCING BUBLE EXTRACTS by separating the bark from wood, chopping it, fractionating and drying it, which consists in that, in order to increase the productivity of the method and improve the quality of the bark by preserving the content of tanides, the bark is crushed to a particle size of 20 to 40 mm, while drying is carried out in the aerodynamic flow of the drying agent in two stages, the first of which is carried out at a speed of movement of the drying agent of 20-30 m / s with an initial temperature of 400-600 ° C and a final 200-300 ° C for 2 -3.5 s, the second - at a speed of a drying agent of 2-3 m / s and a final temperature of 80-100 ° C for 3-5 minutes, and fractionation is carried out after drying. :. _β 2. The method according to p. 1, with only one <g n and with the fact that a large fraction is pressed into briquettes at 900-1000 kg / cm ^; and exposure time under pressure 2530 s. SU „„ 1100316