SU1327943A1 - Suspension for cooking cellulose - Google Patents

Abstract

This invention relates to chemical technology and can be used in the pulp and paper industry for pulping. It provides with the use of increased efficiency of the process. The pulping pulp contains anthraquinone particles and black liquor. The particles of anthraquinone are in suspension with the following granulometric and quantitative composition, wt.%; particles with a size of 0.04-0.06 mm 12-20; 0.06-0.10 mm 30-38; 0.10-0.20 mm the rest. The ratio of components in the suspension is, wt%: anthraquinone particles 17-51, black liquor 49-83. 6 ill., 2 tab. 00 X) 4 SB

Description

This invention relates to chemical technology and can be used in the pulp and paper industry for pulping.

The purpose of the invention is to increase efficiency.

FIG. Figure 1 shows the dependence of the concentration of the anthraquinone suspension and the circulation time required to prepare a suspension with the required particle size distribution; in fig. 2 - the dependence of the initial shear stress, then on the average particle diameter dcp; in fig. 3 shows the sedimentation curves for suspensions with anthraquinone particles of different diameters dcp; in fig. 4 shows the dependence of the circulation time required to obtain a suspension with particles, where dcp is 0.08; 0.11 and 0.15 mm; in fig. 5 shows the dependence of the initial shear stress To on the average diameter of the anthraquinone particles dcp; in fig. 6 shows the sedimentation curves.

Example. The mixer is pre-filled with black liquor. The circulation of the liquor from the mixer and then back through the circulation pipeline is then started. Next in the mixer serves anthraquinone in the required amount.

The suspension is transported via the circulation line from the mixer and back. The suspension thus prepared is pumped into production. A centrifugal pump of the AH-6 type can be used as a pump, and a variable speed mixer can be used as a mixer. The ratio of components in the suspension is wt.%: Particles of anthraquinone 17-51, black liquor 49-83.

Freshly prepared suspension of anthraquinone prepared by a known method, has the following particle size distribution, wt.%:

0.06-0.1 mm20

0.10-0.2 mm55

0.2-0.35 mm20

0.35-0.85 mm5

The particle size slurry prepared by circulation contains, in m.%:

0.06 0.10 0.2

12-20

30-38

Rest

From FIG. 1 it follows that at an anthraquinone concentration of 4 wt.%, A longer time is required for preparing a suspension containing particles with the required particle size distribution, which means that the energy required for preparing a suspension in this case will be significantly higher than at concentrations of anthraquinone in the range of 10-51 wt.%

At a concentration of more than 51% anthraquinone, time increases again.

preparing a suspension with the required particle size.

Dramatically increases the energy cost of preparing a suspension of concentration

anthraquinone more than 51%. This is due to the additional energy costs for the destruction of the solid structure of the suspension of high concentration (more than 51%).

Transporting a freshly prepared suspension of anthraquinone of particle size is difficult to form blockages in pipes and transport equipment. Determination of the optimal particle size distribution of anthraquinone particles, which is the most economical

5, the process of transporting the slurry and eliminating equipment obstructions is done empirically. The particles of anthraquinone are dispersed using sieves into the following fractions: 0.02-0.04; 0.04-0.06; 0.06-0.10; 0.10-0.20; 0.2-0.5.

0 By mixing, the suspensions of the compositions shown in Table 2 are prepared and examined. one

Table 1

0.04-0.06 0.06-0.10 0.10-0.20

12-20 30-38

Rest

Oh 1 1

55 Thus, suspension 1 is prepared with the proposed particle size distribution (Table 1), suspension 2 with a composition that includes particles of a smaller fraction, i.e. 0.02-0.04 mm (Table 1) and suspension 3 with a composition that differs from that offered by the presence of anthraquinone particles of a larger fraction, i.e. 0.2-0.5 mm. The study of the mobility of the prepared suspensions of anthraquinone is carried out on a rotational viscometer. FIG. Figure 2 shows the dependence of the initial shear stress on the average diameter of the particles of anthraquinone in suspension.

Analysis of the graph shown in FIG. 2 shows that the presence of particles of the fine fraction in the suspension, and therefore a small dcp, leads to a significant increase in the initial shear stress (a very strong structure), and therefore a large expenditure of energy on the supply of the suspension. So at dcp 0.11 mm TO 4 N / m, and at dcp 0.08 mm it is 15 N / m.

FIG. Figure 3 shows the deposition curves of the suspensions under study with a particle size distribution presented in Table. one.

The deposition curves show that the presence of large particles of anthraquinone in suspension (0.2-0.5 mm) with dcp 0.15 mm causes a very rapid precipitation of the suspension, which is due to the formation of obstructions of the transport equipment. So for a suspension with a dcp of 0.08 mm, the deposition time is 40 ms for a suspension with a dcp of 0.11 mm. 20 min, and for a suspension with dcp 0.15 mm 10 min.

From the graph in FIG. 4 it follows that for preparing a suspension with dcp particles of 0.08 mm (suspension 2 of table 1), the energy required for circulating the suspension is twice as high as for preparing a suspension containing particles with dcp 0.11 mm, i.e. . the formation of a fine fraction (0.02-0.04 mm) in a suspension requires much higher energy consumption than for the preparation of a suspension that does not contain these particles. As a result of the research we can draw the following conclusions.

The presence in the suspension of a fraction of anthraquinone particles of a large size (0.2-0.5 mm) as compared with the proposed particle size distribution leads to the formation of obstructions of transport equipment and pipes, because in suspension containing anthraquinone particles of 0.2-0.5 mm in size, the fastest sedimentation of the solid phase occurs (Fig. 3).

In addition, the presence in the suspension of particles of anthraquinone smaller compared with the proposed particle size distribution of the size (0.04-0.06 mm) leads to a significant strengthening of the structure (Fig. 2), and therefore to additional energy costs during transportation of the suspension. In addition, the preparation of a suspension containing a fraction of 0.04-0.06 mm requires a significantly longer time and, therefore, more energy than the preparation of a suspension with the proposed particle size distribution.

Finally, the most acceptable from the point

From the standpoint of the economics of the process and the elimination of transport equipment obstructions, suspension 1 (Table 1), containing particles with a particle size distribution in the range of 0.04-0.2 mm.

The determination of the required percentage composition of anthraquinone particles in the range of 0.04-0.2 mm is carried out empirically. Using sieves, anthraquinone particles are scattered into the following fractions, mm: 0.04-0.06; 0.06-0.1; 0.1-0.2. Then suspensions are made with a percentage of the fractions presented in Table. 2

table 2

25

0

0.04-0.06

0.06-0.1

0.10-0.2

0.04-0.06

5 2 0.06-0.10 0.10-0.20

12-20

30-38 0.108

Rest

5-10 30-38 0,117

Rest

0.04-0.06 0.06-0.10 0.10-0.20

0.04-0.06 0.06-0.10 0.10-0.20

20-30 30-38

Rest

12-18 18-20 60-70

0.7

0.124

Thus prepared suspensions

different in quantitative composition

anthraquinone particles from suspension 1 (Table 2).

Suspension 2 with a particle size distribution shown in table. 2, different from

the proposed smaller percentage of particles of the fine fraction (0.04-0.06 mm), suspension 3 is distinguished by a large percentage of particles of the small fraction (0.04-0.06 mm), and suspension 4 contains a larger percentage of particles of the coarse fraction (0.10– 0.20 mm).

The suspension with the quantitative composition of the particles of anthraquinone, presented in Table. 2, are examined on a rotational viscometer and the deposition curves are taken. The results of the experiments are presented in FIG. 5 and 6.

Analysis of the graphs shown in FIG. 5 and 6 shows that an increase in the percentage ratio of the fraction 0.04-0.06 mm (suspension 3 in Table 2) leads to a significant hardening of the structure of the suspension (Fig. 5, point 3 on the graph), and therefore to additional energy loss m during transportation; a decrease in the percentage of particles with sizes of 0.04-0.06 mm leads to the formation of a weak structure (point 2 in Fig. 5), but this significantly increases the sedimentation rate of the suspension (curve 2 in Fig. 6), and therefore transport equipment is blocked; with an increase in the percentage of particles of the coarse fraction (0.10-0.20 mm, suspension 1 in Table 2) in suspension

0

five

There is no structure suspension (point 4 in Fig. 5), but then in this suspension the fastest sedimentation of the solid phase occurs (Fig. 6, curve 4) and as a result of rapid sedimentation the transport equipment and pipes are blocked; The most acceptable from the point of view of the process economy and the elimination of transport equipment obstructions is suspension 1 with the percentage of particles presented in Table. 2

Claims (1)

Invention Formula Cellulose pulping suspension, including particles of anthraquinone and black liquor, characterized in that, in order to increase efficiency, it contains particles of anthraquinone with the following grain-size and quantitative composition, wt.%: Particle size 0.04-0.06 mm12-13 0.06-0.10 mm38-39 0.1-0.2 mmEverything else and the ratio of components in the suspension is, wt.%: Anthraquinone particles17-51 Black liquor49-83 10 P 20 W W 50 60 Mae. 7o 1 astic af mpaxuHona s1 / sleney 9us.1 0.06 Od BJ5 OM wed Afm 20 thirty Fig. no50 in Time t, Mun oW 008 „ojo 7g“ T- “7 Average asr particle api, mm Pus.f G5 Yu 0.0 e0,090,100.110.12 Average particle diameter dfp mm FIG. five 100 ten (Reg. 6 5060 Wren t, min Compiled by T. Kruglova Editor A. VorovichTechred I. Vereye Corrector A. Zimokosov Order 3422/7 Circulation 565 Subscription VNIIPI USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, ul. Project, 4