SU1305224A1 - Method of producing pulp for chemical processing - Google Patents

Abstract

The invention relates to the field of pulp and paper industry and improves the quality of the target. product and intensify the process. Air-dry pine chips are loaded into the autoclave, water heated before is poured, and clarified hydrolyzate of activated sludge is added in an amount of 0.04-1.00% by weight of water, obtained by treating the activated sludge 0, 5-1.0% sulfuric acid at 120 and clarification. The temperature is raised to 170 ° C in 100 minutes, it is allowed to stand at this temperature for 60-90 minutes, then the hydrolyzate is collected and sent for biochemical processing. Prehydrolyzed cheek is boiled in a sulphate method and then bleached. 2 tab. Q € (L 00 o SL

Description

This invention relates to the pulp and paper industry and relates to a process for the production of pulp for chemical processing using aqueous prehydrolysis of plant raw materials, followed by sulphate pulping and bleaching.

The purpose of the invention is to improve the quality of the target product and intensify the process.

According to the method for producing cellulose for chemical processing by pre-hydrolysis of plant raw materials with water in the presence of activated sludge, sulphate pulping and bleaching of cellulose, before the hydrolysis, activated sludge is treated with 0.5-1.0% sulfuric acid at 120-140 s and clarified, at This consumption of activated sludge is 0.04-1.00% by weight of water ..

Due to this treatment and clarification of sludge, wood hydrolysis is accelerated and, thus, the digester turnover is reduced, which leads to an increase in pulp production on the installed equipment and an improvement in the quality of pulp and prehydrolyzate for biochemical processing.

Chemically bound compounds of amino acids and soluble lignin lose their ability to condense in an acidic medium with the sugars dehydration products in solution (furfural, formaldehyde, etc.). The formation of chemical compounds prevents the formation of dense precipitates of caramel on the process equipment.

The method is carried out as follows.

The treatment of activated sludge, water prehydrolysis of wood and sulphate cooking are carried out in the following modes.

Processing (hydrolysis) of the activated sludge is carried out at 120-140 ° C and concentrated. Sulfuric acid emissions are 0.5–1.0% and the concentration of initial activated sludge is 30 g / l for 2 hours. The residue of non-hydrolyzed active sludge is separated. The centrifuge clarified hydrolyzate of activated sludge is fed into the water supplied to the water: the hydrolysis of wood in an amount of 0.04–1.0% a.s.s. by weight of water.

Aqueous prehydrolysis of pine chips is carried out at

0

five

60-90 min and hydromodule 1: 4 in the presence of 0.04-1.00% clarified hydrolyzate of activated sludge. The duration of the brew is 90-120 minutes.

Sulfate cooking is carried out with the activity of white liquor 115 g / l in units , sulphidity 29%, consumption of active NajO 19% by weight of wood. Cooking temperature is 170 C.

Example 1. To obtain hydrolyzate of activated sludge, initial activated sludge with a concentration of 30 g / l is taken from the biological wastewater treatment facilities of the pulp and paper industry and hydrolyzed with a solution of 0.5-1.0% sulfuric acid at 120-140 0 for 2 h The residue of unhydrolyzed activated sludge is separated by centrifugation or sludge. To conduct water hydrolysis of wood, a clarified hydrolyzate of activated sludge is used to prevent the caramelization of the hydrolyzate. In tab. 1 presents the results of experiments on hydrolysis of activated sludge.

From the data of Table 1 it follows that the best results in hydrolysis of activated sludge are obtained at 140 ° C and concentration

0 sulfuric acid in the solution is 0.5-1.0%, the amino acid content is 340-510 mg / l, and the non-hydrolysable residue is 40-57%, the amino acid content in the solution is 340-510 mg / l, which contributes to the reduction of the caramel formation process on the process equipment in the process of water boiling wood. The most likely mechanism of inhibiting the formation of caramel is that water-soluble lignin binds to the amino acids of the activated sludge hydrolyzate in compounds that, being also soluble in water, lose their ability to

5 to condensation in an acidic environment with sugars dehydration products in solution (furfural, formaldehyde, etc.). That is why the formation of dense sediments deposited on the process equipment is prevented.

Example2. 140 g of air-dry pine 55 chips are loaded into the autoclave, water is poured, heated to

temperature, and the clarified hydrolyzate of activated sludge prepared according to example 1 in an amount of 0.04% abs. dry matter (aa cv)

, 60 min. Rasot mass of water supplied to the hydroli wood. Raise the temperature from 70 to 100 minutes, then stand at 170 ° C for 90-60 minutes, the water ratio 1: 4. Then, the obtained prehydrolyzate is selected and sent for biochemical processing. Prehydrolyzed chips are subjected to sulphate cooking: impregnation with lye at 30 minutes, temperature rise from 135 to 60 min. Stand of 170 ° C for active alkali cooking in NajO units 19%, sulfidity - 29%. Pulp bleaching is then carried out.

In tab. 2 shows the results of experiments obtained in the processes of water prehydrolysis with the use of hydrolyzed activated sludge with a pH of 1.3 as an additive, without hydrolyzed active sludge and known data.

Example 3. Aqueous prehydrogen-LIP, sulphate pulping, bleaching of cellulose is carried out according to the regime described in Example 2. Aqueous prehydrolysis of pine chips is carried out in the presence of 0.15% a.s. hydrolyzate activated sludge lasting 75 min. Indicators obtained cellulose and prehydrolyzate, as well as some process parameters are presented in table. 2

PRI m e R 4. Water prehydro. LIZ, sulphate pulping and bleaching of cellulose are carried out according to the regime presented in Example 2. The aqueous prehydrolysis is carried out in the presence of 0.5-0.8-1% a.s. hydrolyzate activated sludge lasting 70-60 minutes. The indicators of the obtained product, as well as some process parameters are given in table. 2

The results are shown in Table. 2

show that the use of acidic and clarified hydrolyzates of activated sludge as an additive in water, directed to the water prehydrolysis of wood, intensifies the process

hydrolysis and improves the quality indicators of cord cellulose. According to the proposed method, the degree of penetration of cellulose is improved and the content of di-cellulose increases, and the ash content of cellulose is reduced, which leads to a decrease in the cost of chemicals for acidification and bleaching of cellulose.

The content of caramel in the waste prehydrolyzate 0.02-0.07 g / l

(in the known method 0.8-1.0 g / l), which significantly improves the conditions for cooking and bleaching.

Invention Formula

The method of producing cellulose for chemical processing by pre-hydrolysis of vegetable raw materials with water in the presence of active

silt, sulphate pulping and cellulose bleaching, characterized in that, in order to improve the quality of the target product and intensify the process, before hydrolysis, the active sludge

is treated with 0.5-1.0% sulfuric acid at a temperature of 120-140 ° C and clarified, while the consumption of active sludge is 0.04-1.00% by weight of water.

I. Water hydrolysis of pine chips

The content of hydrolyzed activated sludge in the process of water boiling,%

pH of hydrolysis at the beginning

The content of activated sludge in the process of water boiling, g / l

Prehydrolysis temperature, С

Duration of temperature rise, min

The duration of hydrolysis, min

II.Sulfite cooking

The consumption of active alkali for cooking,%

Sulfidity,%

III.Characteristics of pulp produced

Stiffness be

The content of oL-cellulose,%

The ash content in the pulp,%

IV.Characteristics of prehydros

6.3

10.0

170

120

18-23 30

80.0 95.8 0.69

About 0.04 6.2 6.1

100 90

85

19 19 29 29

110 MO 96.2 96.2 0.30 0.32

0.15 0.5 0.8 6.0 5.8 5.5

170 170 170 170 170

120 100 100 95 90

75 70 65

19 19 19 29 29 29

113 113 110

96.3 96.4 96.5

0.32 0.34 0.36

table 2

0.15 0.5 0.8 6.0 5.8 5.5

1.0 5.2

170

90

85

75 70 65

60

19 19 19 29 29 29

19 29

113 110

96.4 96.5

0.34 0.36

110

96.5

0.4

Process indicators by steps

Known method

The proposed method options

, Z I1II-ZE 1-TZ I} I

1 PB after inversion,% 2.10 3.8 3.8 3.8 3.8 3.9 3.9

Suspended substances, g / l

Non-hydrolysable activated sludge,%

6.0 0.5 2.0 1.9 1.9 1.8

60.0 55

50.

48 45 40

The proposed method options

1.5

50.

48 45 40

40

Claims (1)

Claim A method of producing cellulose for chemical processing by preliminary hydrolysis of plant materials with water in the presence of activated sludge, sulphate cooking and bleaching of cellulose, characterized in that, in order to improve the quality of the target product and to intensify the process, activated sludge is treated with 0.5-1.0 before hydrolysis % sulfuric acid at a temperature of 120-140% and clarify, while the flow rate of activated sludge is 0.04-1.00% by weight of water. * - 1 1 1 1 OS 1 1 1 1 m 1 A t— 1 1 1 1 A 1 00 V— 4 © 05 1 03 1 · 1 1 . 1 tn Os Joint venture 1 tf I 1 1 | j s 1 1 1 1 1 1 1 1 in 1 1 1 f 1 0 1 A 0 1 R 1 1 f A 1 00 t— about 1 1 1 1 1 w ABOUT <R 1 YU 1 1 1 1 1 nJ 1 1 1 1 <r 1 1 1 0 1 00 1 A 0 1 H 1 1 1 A 1 0 00 05 W 1 1 1 I- 1 ABOUT 1 <r g- w 1 1 I u -4 g t 1 1 1 cho 1 1 1 1 W 1 A 0 1 1 1 1 A 1 00 <r G. g * 1 1 1 1 ABOUT 1 cn on g ** w 1 1 i 1 1 f I 1 1 1 1 ¹ I ( 1 1 T— w J ¹ 1 1 cn 1 A 00 A 1 1 1 A 1 0 Joint venture 4 © 40 1 ί ω 1 1 ABOUT 1 co Joint venture P- w 1 1 1 1 ί 1 1 .ffi 1 1 1 1 s r 1 1 1 I 1 m 1 1 ¹ S 1 1 m 1 A 00 1 a 1 1 A 1 CHO co Yu 40 1 ¹ 5! £ 1 1 1 1 1 1 <t o> w 1 1 1 ! 1 1 ' 5 1 1 1 CM 1 ¹ s 1 1 0 1 A m t t A 1 40 00 about w 1 i 5 1 1 1 <r 05 w 1 1 " 1 g Ί 1 1 1 " 1 1 1 m 1 1 s 1 1 00 1 A 0 f ! · & I 0 1 A 1 00 YU 00 P* 1 1> B .1 cp 1 ABOUT 1 cn <t g * w 1 1 • 1 1 1 1 1 * 4 1 1 About 1 1 1 <r I 1 o 1·! 1 tn 4 A 0 A 1 1 - 1 1 A 1 tn V— g *. 00 1 1 nJ 1 1 ABOUT 1 cn co g ** in 1 1 C t 1 1 1 s 1 I ) 1 1 1 o 1 1 1 1 1 1 r— . 00 1 ! 1 Ph 1 1 cn 1 A r— ft 1 1 o 1 t A 1 CM 0 w with 1 1 a 1 1 ABOUT 1 cn cn g " w 1 I m 1 1 1 ! 1 s 1- - + - 4 1 1 ft 1 ! 1 I 1 TO 1 1 1 m 1 nJ 1 1 W 1 A 40 1 1 1 1 A 1 CM m Yu t— 1 1 " 1 * - 1 <r with 40 1 I___g 1 1 1 1 1 1 1 1 T-. 1 1 o 1 1 ABOUT 1 A CM Ι 1 ex 1 1 A 1 CM m about about 1 14 1 t 1 00 cho 1 1 s 1 1 1 1 1 ^k 1 r 4 1 1 nJ 1 1 > i a 1 1 1 tn 1 1 >> 1 ABOUT 1 00 1 A 0 g ft- 1 CM 1 A 1 40 CM 1L CM 1 1 rt 1 T— 1 0 1 co g ** 40 1 1 ex 1 1 1 1 1 f 1 i 1 1 I r 1 1 1 1 i X 1 1 W 1 A 1 1 <u 1 1 A 1 V— co about about 1 1 H 1 1 ABOUT 1 m CM G ”* 40 1 1 1 1 1 1 r t 1 1 1 J 1 1 1 1. 1 cn 1 1 A 0 1 1 1 1 1 A 1 co 00 05 1 1 1 1 1 1 t 0 1 CM CM 40 W 1 ί 1 1 eleven t A R 1 1 1 o 1 Φ R 3 f 1 1 ft 1 to + F PH > "* 1 ! * 1 u ABOUT 3 2 Joint venture 1 1 s 1 and 2 R to A S O 1 1 ft 1 f A and Λ F R h 1 1 1 r 3 s r η About nJ 1 t and ol 1  s E- and I n ft and 1 1 " 1 a 0 ABOUT ft about H about 1 1 ft 03 1 ol a to R. f f TO 1 1 and CO 1 Ph υ W ‘ X a ft> a 1 1 o S 1 ft to § Ph - 2h f f 3 1 1 o h 1 0 th · <- 2 AND OUT 2 1 table 2 Process indicators by steps Known Suggested Method, Variants I. Water hydrolysis of pine chips The content of hydrolyzate of activated sludge in the process of water cooking% - 0 0.04 0.15 0.5 0.8 1,0 pH of hydrolysis at the beginning 6.3 6.2 6.1 6.0 5.8 5.5 5.2 Content Active- silt in the process of water cooking, g / l 10.0 - - - - - Prehydrolysis temperature, ° C 170 170 170 170 170 170 170 Duration of temperature rise up to 170 ° С, min 120 120 100 100 95 90 90 The duration of hydrolysis, min 100 90 85 75 70 65 60 II. Sulphite cooking The consumption of active alkali for cooking, % Na ₂ O 18-23 19 19 19 19 19 . 19 Sulfide% thirty 29th 29th 29th 29th 29th 29th III. Characteristics cellulose Hardness, ° Be 80.0 110 110 113 1 13 110 110 Content <3. cellulose,% 95.8 96.2 96.2 96.3 96.4 96.5 96.5 The ash content in cellulose,% 0.69 0.30 0.32 0.32 0.34 0.36 0.4 IV. Prehydrolyzate Characterization Continuation of Table 2 Process indicators by steps Known method The proposed method options 1 _ ± _and eleven eleven eleven 1 4L | eleven 1 < 1-] eleven 1 .g 1 eleven eleven L ‘ PB ’after inversion,% 2, 10 3.8 Suspended substances, g / l 6.0 0.5 Non-hydrolyzable activated sludge,% 60.0 55 3.8 3.8 3.8 3.9 3.9 2.0 1.9 1.9 1.8 1,5 fifty· 48 45 40 40