CS263541B1 - Method of intensification of pulping milling process - Google Patents

Abstract

The solution concerns the intensification of the grinding process by using some amines applied to the fibrous pulp suspension before or during the grinding process. The application achieves a 5 to 50% reduction in grinding time or energy savings. As suitable amines, trimethylol- and/or triethanol-tripanol-amine are used. in an amount of 0.1 to 5% wt. based on the wt., a.a. of the pulp.

Description

The invention describes a method of intensifying the pulp milling process by chemical means, i.e. by using additives which allow the milling process to be accelerated and thus to reduce the energy consumption of the milling process.

It is known that the grinding process is one of the most energy-intensive sections of paper production · There are efforts to reduce this energy intensity · Research can be divided into two directions · The first deals with the modification of the grinding equipment, so it is a machine matter · The second The direction is one that seeks to recognize the internal structure of the pulp and to release the internal bonds of the individual fibers and fibrils by chemical compounds. In cooperation with the mechanical action of the grinding device, the grinding process can be significantly accelerated. There is a Japanese patent Kokai 71, 893/80 for a mixture of chemicals that accelerates grinding and improves paper strength.

The mixture comprises NaOH, Na 2 P 2 O or Na 2 HPO 2, gluconate or sodium citrate and a chelatone reagent. The influence of dyes on the course of the milling process has been addressed by CENTOLA G., and BOBUSO D. (Pundamentals of Papermaking Fibers. Kantley, TS Brit · Pap ·

Board Mak. Assoc. 1958, p. 349). They found a positive effect of acid and direct dyes. LANE, J.N., SLOAN, Y., ALLAN, G.G. (Modification of the Befining Process by Additives «Particularly Congo Bed. Yng. Symp. Pundamental Concepts in Befining,

Sept. 16 ^ 18 (1980, Appleton, WI., USA) report up to 50% acceleration of the grinding process by adding Congo in red.

No (6.5 (7, 1983)) investigate the effect of polyelectrolytes on the milling process. They found a positive effect of polyethyleneimine and polyacrylamide. PULTAVA-GEBASIMOVA, N., DIMITBOVA, S., NEDELCHBVA, N. (CELLULOSE KHABTIYA 15 »No. 2,22-24, 36, 1984) found positive

263 541 Adjusting the B-IO3 (PEG ester type) antifoaming agent to grinding speed · KEDELCHEYA E., DBNCHEVA, S., YALCHBV, V., BOZALINOV, D.

(Cellulose Chem. Technol., 12, 409-414, 1985) discloses an acceleration of grinding due to the addition of hydrolyzed polyacrylonitrile. NEDBLCHEVA, E., IVANOYA, N., MLABENOVA, S. (Cellulose Chem * Technol., 20, 10J 115, 1986) have been following the effects of polyacrylamide, polyethyleneimine, polyamidamine for longer. Acceleration of grinding represented about 30% ·

When using additives, it is necessary to consider their availability and evaluate the economic and ecological side ·

The disadvantages of these methods are the high prices of additives *

In the case of dyes, this is the coloring of the final product and waste water pollution.

These disadvantages can be overcome to some extent by the process of the present invention, which discloses the use of trimethyloL- and / or triethanol- and / or tripropanol-amines as a significantly accelerating milling process. Trimethylolamine, triethanolamine, tripropanolamine or a mixture of these substances is dosed in an amount of 0.1 to 5% by weight, however, usually 1% by weight of the absolutely dry (as) pulp to the pulped pulp before grinding or during the grinding process. said amines or mixtures thereof in the form of an aqueous solution.

The advantage of this method of intensifying the grinding process is the availability of amines, especially trioethylolaain *, prepared by reaction of formaldehyde and ammonia in a weakly acidic environment.

The addition of trimethylol-, triethanol- and tripropanol-amines acts throughout the range of fiber processing (SB) and their action is based on new theoretical ideas about the behavior and influence of so-called hydration forces in hydrated hydrophilic systems, “3”

263,341 such as pulp suspensions. The action of these amines disrupts the attractive hydration forces, releases the internal structure of the hydrated pulp and hence accelerates the milling process, resulting in a proportional reduction in energy consumption. This saving is particularly significant in the preparation of highly ground pulps, i.e. 40 SR and above ·

Example 1

A 7 L two percent bleached kraft pulp suspension was prepared in the pulper. The suspension was transferred to a disk laboratory mill and a grinding experiment was performed.

During the milling experiment, the power input to the milling aggregate was kept constant and the mechanical processing of the pulp was assessed by the Schopper-Riegler method (SRI).

Example 2

In a pulper, 7 L of a 2% bleached kraft pulp suspension was prepared with an addition of 1 wt. triethanolamine per weight a.s. pulp and then run in a laboratory disc mill under the same conditions as in Example 1 · The values obtained are shown in the table · Mechanical properties are comparable to Example 1.

Example 3

A 7 L 2% bleached kraft pulp suspension was prepared in the pulper. After transfer to laboratory

-4 263 541 disc mill was added to the weight of a.i. pulp 0.75% by weight of trimothylolamine prepared by reaction of formaldehyde. with ammonia in the corresponding molar ratio in a weakly acidic medium. Then a milling experiment was carried out under the same conditions as in Examples 1 and 2. For the values found, see the table. Mechanical properties are comparable to Example 1 ·

Example 4

A 7 L 2% bleached kraft pulp suspension was prepared in the pulper. After transfer to a laboratory disk mill, 0.5 wt. tripropanolamine to the weight of a.s. pulp and a grinding experiment carried out under the same conditions as in Examples 1 and 2. Observed values, see Table · Mechanical properties are comparable to Example 1

Example 5

A 7 L 2% bleached kraft pulp suspension was prepared in the pulper with 0.5 wt. % trimothylolamine and 0.2 wt. triethanolamine per weight a.s. pulp. The suspension was transferred to a laboratory disk mill and a grinding experiment was performed under the same conditions as in Examples 1 and 3. For the values found, see Table. The mechanical properties are comparable to Example 1.

Table: Grinding times of bleached kraft pulp with added amines

Stage Grinding time (min) Grinding see Ex.1 See Ex.2 See Ex 3 See Ex 4 See Ex 9 (SK) (water) Tristanol trimethylol tripropa (mixture) Amine Amine Nolamine

20 May 6.5 4.0 3.5 2.8 3.0 30 19.0 7.0 1 1,5 6.5 6.5 40 31.0 12.0 18.0 11.6 12.0 50 44.0 20.0 25,0 ' 19.0 19.0 60 57.0 31.5 35.0 29.0 10.0

263 541

Claims (1)

SUBJECT OF THE INVENTION Method for intensifying the pulp milling process by chemical means, characterized in that before or during the milling process, 0.1 to 5% by weight of the fibrous pulp suspension is added, but generally 1% by weight of trimethylol and / or triethanol and / or tripropanol amine, by weight as pulp.