WO2021057159A1

WO2021057159A1 - Processing technology for removing adhesive substances from paper pulp

Info

Publication number: WO2021057159A1
Application number: PCT/CN2020/100237
Authority: WO
Inventors: 陈学萍; 李聪定; 宋杰; 刘召强; 刘媛
Original assignee: 山鹰国际控股股份公司
Priority date: 2019-09-25
Filing date: 2020-07-03
Publication date: 2021-04-01
Also published as: CN110512458B; CN110512458A

Abstract

The present invention relates to the field of paper pulp processing. Disclosed is a processing technology for removing adhesive substances from paper pulp. A preparation method mainly comprises: first performing heat dispersion on a pulp, diluting same, and adding cleaning enzymes, before milling and pulping, and then adding cationic organic polymers to obtain processed pulp. In the method, the combining of biological enzymes and cationic organic polymers is used to effectively control the negative impact that adhesive substances in waste paper pulp have on production, and the obtained product is of quality high. During the preparation process, no pollution is generated, the energy consumption is low, the operation is simple, and the removal effect of adhesive substances is obvious. The processing technology may be applied to industrial production and has good application prospects.

Description

Treatment process for removing stickies in paper pulp

Technical field

The invention belongs to the field of pulp processing, and in particular relates to a treatment process for removing stickies in the pulp.

Background technique

Waste paper is a low-consumption, low-pollution renewable resource. Its recycling is conducive to resource conservation, circular economy, environmental protection and alleviation of insufficient supply of raw materials in the paper industry. With the recycling of a large amount of waste paper and the development of printing technology and the use of a wide range of papermaking additives, the problem of stickies in waste paper pulp has become more and more prominent, and it has become an important solution for the development of the waste paper pulp industry. . Moreover, as the amount of closed circulating water in white water is decreasing, the tiny stickies in the white water will accumulate in the water circulation system, increasing the concentration of stickies in the paper machine. These sticky substances will pollute the papermaking nets and calender rolls. , Drying cylinder, forming holes and small spots on the paper sheet, not only affects the appearance of the paper, but also easily affects the normal operation of the printing press.

At present, the common methods for removing and controlling stickies in the slurry are mechanical control method, chemical control method and biological control method. The mechanical control method is mainly used to remove large stickies in waste paper pulp, including screening, purification, washing, flotation, and thermal dispersion. The chemical control law uses methods such as chemical adsorption, dispersion, modification, and surface passivation to remove fine stickies. The biological control method mainly uses biological enzymes to treat stickies. The mechanism of enzyme treatment is to hydrolyze the chemical bonds in the components of the stickies, making the size of the stickies smaller, thereby reducing the stickiness of the stickies and preventing sticky particles. Of flocculation. These methods are commonly used stickies control methods in the waste paper industry. Although they have a certain removal effect, the removal efficiency is also affected by many factors such as equipment, cost, additives, and temperature.

CN106368035A discloses a method for removing stickies in waste paper pulp by high temperature esterase TTEST, which specifically includes the following steps. First, esterase TTEST strain is added to seed liquid culture medium for shaking inoculation culture, and then to fermentation medium for shaking culture , Obtain the high temperature esterase TTEST crude enzyme solution, purify and prepare the high temperature esterase TTEST; then add esterase to the waste paper pulp, the treatment time is 45-120min, the treatment temperature is 40-80℃, the pH is 6.0-9.0, stirring The speed is 100-150rpm; finally, the slurry is screened, dyed and pressed, and the sticky content in the waste paper pulp is analyzed by scanning software. As a result, the sticky removal rate is measured to reach 54.7-69.5%. The preparation process of this method is relatively complicated and is not suitable for a wide range of industrial applications.

CN101725064B discloses a method for improving the effect of removing stickies in waste paper pulp. The method includes first crushing waste paper with a sticky content of less than or equal to 10% by weight at a temperature of 40-60°C , The crushed pulp is added to the sieving machine, where the sieving water temperature is 40-60 ℃, and then the sieved good pulp is diluted to a pulp weight concentration of 0.8-1.5%, which is relative to the absolute dry mass of the pulp , And then add 0.01-0.5% non-ionic surfactant and 0.0025-0.5% anionic dispersant to the slurry. After stirring, perform flotation at 40-50℃ to remove waste. Stickies in pulp. The preparation process of this method is cumbersome and the preparation conditions are harsh, which is not suitable for large-scale production.

CN109666661A discloses a biological enzyme preparation for removing stickies in pulp. The method specifically transforms the wild-type lipase gene sequence to obtain a lipase mutant with lipase activity, which can survive at a high temperature of 65°C, and The slime removal effect of this high-temperature-resistant lipase mutant was tested, and finally an enzyme preparation containing the high-temperature resistant lipase mutant with the slime removal effect under high temperature conditions was obtained. The genetic sequence modified by this method has great uncertainty, the yield of active lipase is not high, and many impurities are generated during the preparation process.

In order to improve the quality of removing stickies in the pulp, R&D personnel have conducted a lot of research. However, the current removal technology still has problems such as complicated preparation process, high impurity content of the target product, and poor removal effect, which cannot meet the requirements of obtaining high quality. Therefore, there is an urgent need to develop a preparation process with low production cost, low impurity content and high sticky removal quality.

Summary of the invention

In view of the shortcomings of the prior art, the present invention provides a treatment process for removing stickies in pulp, which can effectively remove stickies in pulp, improve the quality of pulp, and meet people's demand for high-quality pulp. The method has low cost, simple process, and is suitable for industrialized production.

In order to achieve the above objectives, the present invention adopts the following technical solutions:

A treatment process for removing stickies in paper pulp includes the following steps:

(1) Thermal dispersion: thermally disperse the waste paper slurry to obtain material 1;

(2) Dilution: Dilute the material 1 obtained in step (1) with papermaking white water to obtain material 2;

(3) Disc grinding and beating: adding clean enzyme to material 2 obtained in step (2) to obtain material 3, and then performing disc grinding and beating to obtain material 4;

(4) Organic matter treatment: The cationic organic polymer is added to the material 4 obtained in step (3) and stirred to obtain a treated slurry.

The slurry after the above treatment can be directly subjected to the subsequent slurry preparation and papermaking processes.

Further, the weight percentage concentration of the waste paper slurry in step (1) is 25-35%, and the waste paper pulp is diluted with papermaking white water to obtain the waste paper slurry.

Further, the thermal dispersion described in step (1) includes but is not limited to the use of a thermal dispersion machine.

Further, the temperature of the thermal dispersion described in step (1) is 90-110°C, preferably 98-103°C.

Further, the thermal dispersion time in step (1) is 10-20 seconds, preferably 12-14 seconds, more preferably 12 seconds.

In step (1), the stickies of the waste paper slurry are dispersed into fine stickies invisible to the naked eye through a thermal disperser at a high temperature.

Further, the dilution with papermaking white water in step (2) refers to adding papermaking white water equivalent to 4-6 times the weight of material 1 for dilution, preferably 5.2-5.5 times, more preferably 5.5 times.

Further, step (3) specifically includes: adding clean enzymes to the material 2 obtained in step (2) and mixing for 10-15 minutes, preferably 12 minutes, to obtain material 3, the weight percentage of waste paper slurry in material 3 The concentration is 3.5-5.5%, preferably 4-5%, more preferably 4.5%.

Then, the material 4 is obtained after disc grinding and beating.

The clean enzyme described in step (3) is added to material 2 and mixed for 10-15 minutes to facilitate the clean enzyme to decompose the lipid bonds in the fine stickies and passivate the fine stickies to avoid re-flocculation of the fine stickies Into big stickies.

Further, the addition amount of the clean enzyme in step (3) is 100-300 g clean enzyme per 1000 kg of absolute dry pulp mass, preferably 150-200 g.

Further, the source of the cleansing enzyme includes but is not limited to:

Clean Enzyme ^TM PC-33xx, purchased from Ruichenxing Company;

Clean Enzyme ^TM SC-36xx, purchased from Ruichenxing Company;

Clean Enzyme ^TM SC-37xx, purchased from Ruichenxing Company;

Clean enzyme ^TM WC-38xx, Chen Xing available from the Swiss company.

Further, the temperature of the disc grinding and pulping in step (3) is 40-60°C, preferably 48°C.

In step (3), when the pulp passes through the disc mill, the disc teeth will have a mechanical effect on the pulp, which has the effect of splitting and shortening the fibers. For fibers that are not too long, they will try to avoid shortening. For fibers that have been fully swollen, the probability of cutting will be greatly reduced.

Further, the cationic organic polymer in step (4) is a petroleum extract, which is called a slime control agent in production.

Further, the source of the cationic organic polymer includes but is not limited to:

A commercial product purchased from Fumiao Technology Co., Ltd., the article number is OPTIEFIXER ^{TM C798}

Purchased from Nanjing Shipei Environmental Protection Technology Co., Ltd., the article number is

Commercial product of Sperse 1306;

Commercial product of Sperse 1307;

A commercially available product purchased from Shanghai Emerson Chemical Co., Ltd., the article number is sticky matter control agent 3511.

Further, the addition amount of the cationic organic polymer in step (4) is 200-400 g cationic organic polymer per 1000 kg of absolute dry pulp mass, preferably 280 g, and the addition equipment used includes but is not limited to a pneumatic pump.

Further, the stirring time in step (4) is 10-15 minutes, and the stirring temperature is 40-65°C, preferably, the stirring temperature is 57°C.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The present invention is different from other single treatment methods. It adopts the method of combining biological enzymes and cationic organic polymers to effectively control the amount of stickies in waste paper pulp and reduce the disadvantages caused by stickies to production. influences;

(2) The stickies in the slurry are kneaded by a thermal dispersion machine at high temperature and high concentration to form small stickies that are invisible to the naked eye. In order to reduce the viscosity of the small stickies, avoid small stickies Re-polymerize into large stickies, reduce the viscosity of stickies and passivate the surface by adding clean enzymes;

(3) When the pulp passes through the disc mill, the disc teeth will have a mechanical effect on the pulp, which has the effect of splitting and shortening the fibers. For fibers that are not too long in length, they will try to avoid shortening them. For fibers that have been fully swollen, the probability of cutting will be greatly reduced.

(4) Adding cationic organic polymer, the sticky in the slurry is bridged to the fiber through the cationic organic polymer tower, and the fiber is copied to take the sticky out of the system, thereby reducing the sticky in the slurry;

(5) The entire treatment process is simple in operation, low in cost, and pollution-free, improves the quality of the slurry, ensures the quality of the paper, and has high efficiency in removing stickies.

detailed description

The following specific examples are used to illustrate the feasibility of the present invention. Those skilled in the art can easily understand the advantages and effects of the present invention from the content described in this specification. The terms used in the examples of the present invention are used to describe specific specific embodiments, not to limit the scope of protection of the present invention. Various details in this specification can be modified or changed without departing from the spirit of the present invention. It can also be applied based on different viewpoints.

The raw materials used in the embodiments of the present invention are all commercially available products, the slurry used in the experiment is obtained by workers in the field using conventional technical methods, and the instruments used are all conventionally used in the field.

Source of raw materials:

The waste paper in the waste paper pulp comes from recycled cardboard paper, including domestic cardboard and foreign cardboard;

Papermaking white water comes from: paper machine clean water is used as the thickening water to dilute the slurry from 3-5% by weight to 0.5-1.5% by weight. The slurry is dehydrated and formed on the forming wire, and under the wire The separated filtrate is white water, and the filtrate contains fine fibers and chemicals;

Hydrochloric acid was purchased from Shandong Zhongkai Biological Technology Co., Ltd., and sodium hydroxide was purchased from Tianjin Dingshengxin Chemical Co., Ltd.;

Basic embodiment

Different values of each parameter in the basic embodiment constitute different specific embodiments, for example: parameters A, B, C, D, E, F, G, H, M, N, I, K, L, as shown in Table 1. .

(1) Thermal dispersion: thermally disperse the waste paper slurry whose weight is A, temperature is B, and weight percentage concentration is parameter C in the previous step, the temperature of thermal dispersion is parameter D, and the time of thermal dispersion is parameter E, to obtain Material 1;

(2) Dilution: add papermaking white water equivalent to the weight of F times the parameter of material 1 into material 1 for dilution, and obtain material 2;

(3) Disc grinding and pulping: Use hydrochloric acid or sodium hydroxide to adjust the pH of the material 2 obtained in step (2) to 7, and add the clean enzyme of parameter G to it, and the mixing time is parameter H to obtain material 3, which is waste paper The weight percent concentration of the slurry is the parameter N; then the disc grinding and beating is performed, and the temperature of the disc grinding and beating is the parameter M, and material 4 is obtained;

(4) Organic matter treatment: The cationic organic polymer of parameter I is added to the material 4 obtained in step (3) for stirring, the stirring time is the parameter K, and the stirring temperature is the parameter L to obtain the processed slurry.

In step (1), the stickies in the slurry are kneaded by a heat disperser at a high temperature to form small stickies that are invisible to the naked eye.

In step (3), the clean enzyme is mixed with the material for a certain period of time, which is convenient for the clean enzyme to decompose the lipid bonds in the fine stickies and passivate the fine stickies to avoid re-flocculation of the fine stickies into large stickies and passivation surface. When the pulp passes through the disc mill, the disc teeth will have a mechanical effect on the pulp, which has the effect of splitting and shortening the fiber. For fibers that are not too long in length, they will try to avoid shortening, and for the fully moistened fiber. For swollen fibers, the chance of cutting will be greatly reduced.

Comparative example 1

The difference from Example 5 is that the mass of clean enzyme added in the preparation process is 90 g.

Comparative example 2

The difference from Example 5 is that the mass of the clean enzyme added in the preparation process is 350 g.

Comparative example 3

The difference from Example 5 is that the mass of the cationic organic polymer added in the preparation process is 150 g.

Comparative example 4

The difference from Example 5 is that the mass of the cationic organic polymer added in the preparation process is 500 g.

Comparative example 5

In Example 3 of Chinese Patent CN106223096B, high temperature esterase is used to remove stickies in waste paper pulp.

Table 1 Values of different parameters in each embodiment

Effect detection test:

1. Stickies removal effect

(1) Testing method: Testing according to the T 277pm standard, the specific testing steps are as follows:

A. Weigh a certain amount of slurry, dilute it to a 1% slurry concentration, and use a standard decomposer to decompose for 15,000 revolutions to determine the moisture content of the slurry;

B. Put black filter paper on the collection plate of the stickies sieving instrument. After the screening process starts, pour the decomposed slurry into the stickies sieving instrument bucket;

C. After the automatic collection is completed, take out the black filter paper, cover it with special coated paper, and then cover with a layer of absorbent paper on top and bottom, and place it in the dry paper sheet. Dry for 10 minutes at 0.08MPa and 900°C to make the glue sticky. The object is cured by heat;

D. Take out the dried black filter paper and remove the special coated paper. The peeled coated paper is easy to stick to the sticky area, making the coating white;

E. Use a specific nozzle to rinse the slurry and other non-sticky substances on the filter paper with water for 20-25 seconds, the nozzle water pressure is 0.1MPa, the water flow rate is 9.6L/min, and the nozzle flushing distance between the filter paper is 180mm;

F. After washing the black filter paper, cover it with silicone-coated release paper, and dry it in a paper sheet former for 5 minutes;

G. Use a black felt pen to dye the non-sticky material on the ginger filter paper black;

H. Use the scanning analysis software IGT Verity IA Image Analysis to scan and analyze the stickies on the filter paper to calculate the content of stickies.

(2) Test objects and test results:

The stickies removal rate of the processed slurries obtained in Examples 1-6 and Comparative Examples 1-4 were measured. Comparative Example 5 was the stickies removal rate obtained in the prior art. The results are shown in Table 2.

Table 2 Stickies removal rate test results

It can be seen from Table 2 that the removal rate of stickies in the waste paper slurry treated with clean enzymes and cationic organic polymers can reach 67.1-72.3%, which is significantly better than the removal effect of the prior art and the comparative example, and the removal rate of the glue The removal rate of stickies can reach up to 72.3%, which meets the requirements of the present invention.

The above-mentioned embodiments only express several embodiments of the present invention, and the descriptions are relatively specific and detailed, but they should not be understood as limiting the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

A treatment process for removing stickies in paper pulp, which is characterized in that it comprises the following steps:

(1) Thermal dispersion: thermally disperse the waste paper slurry to obtain material 1;

(2) Dilution: Dilute the material 1 obtained in step (1) with papermaking white water to obtain material 2;

(3) Disc grinding and beating: adding clean enzyme to material 2 obtained in step (2) to obtain material 3, and then performing disc grinding and beating to obtain material 4;

(4) Organic matter treatment: the cationic organic polymer is added to the material 4 obtained in step (3) and stirred to obtain the treated slurry.
The preparation method according to claim 1, wherein the weight percentage of the waste paper slurry in step (1) is 25-35%, and papermaking white water is used to dilute the waste paper absolute dry pulp to obtain waste paper Slurry.
The preparation method according to claim 1, wherein the temperature of the thermal dispersion in step (1) is 90-110°C, and the time of thermal dispersion is 10-20 seconds.
The preparation method according to claim 1, characterized in that the dilution with white paper-making water in step (2) refers to adding 4-6 times the weight of material 1 with white paper-making water for dilution.
The preparation method according to claim 1, wherein step (3) is specifically: adding clean enzymes to material 2 obtained in step (2), mixing for 10-15 minutes to obtain material 3, and waste in material 3 The weight percent concentration of the paper pulp is 3.5-5.5%, and then the disc grinding and beating are performed to obtain material 4.
The preparation method according to claim 1, wherein the addition amount of the clean enzyme in step (3) is 100-300 g clean enzyme per 1000 kg of absolute dry pulp mass.
The preparation method according to claim 1, wherein the temperature of the disc grinding and beating in step (3) is 40-60°C.
The preparation method according to claim 1, wherein the cationic organic polymer in step (4) is a petroleum extract.
The preparation method according to claim 1, wherein the addition amount of the cationic organic polymer in step (4) is 200-400 g of cationic organic polymer per 1000 kg of absolute dry pulp mass.
The preparation method according to claim 1, wherein the stirring time in step (4) is 10-15 minutes, and the stirring temperature is 40-65°C.