JP2003306893A - Slime controlling method for papermaking - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for using sodium hypochlorite in a paper-making white water system without causing troubles such as the decoloration of dyes and the peeling of slime. <P>SOLUTION: The slime controlling method for papermaking comprises the addition of an aqueous solution of sodium hypochlorite to the paper-making white water system after diluting the solution. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a slime control method for papermaking. Especially in papermaking white water system,
The present invention relates to a slime control method for papermaking, which effectively suppresses the generation of slime and does not adversely affect the operation such as product quality.

[0002]

2. Description of the Related Art Conventionally, slimes originating from microorganisms such as bacteria and fungi are generated in the papermaking process in the paper manufacturing industry and in cooling water systems in various industries, which causes obstacles such as reduction in production efficiency and quality of products. Is known to occur.

Particularly in the paper manufacturing industry, white water in the papermaking process contains various substances that serve as nutrient sources for microorganisms, and the temperature and pH are often suitable for the growth of microorganisms. It is known that a so-called slime is formed while a sticky substance is taken out of a bacterial cell in the process of growing a microorganism in white water and the pulp, various fillers, chemicals and the like in the process are taken in. Slime that has grown to a certain size may peel off due to the flow rate of process water, etc., which mixes into the paper stock and stains the product, or even paper breaks,
Alternatively, it has a great influence on the operation, such as causing obstacles in the process such as clogging of wires and blankets.

Many slime control agents have been used for the purpose of preventing such slime disorders. In the old days, organic mercury compounds, chlorinated phenol compounds, and formalin were used, but they are highly toxic to humans and seafood, and their use is regulated because they cause environmental pollution.

Recently, methylenebisthiocyanate, 1,2-benzisothiazolin-3-one, and 5-chloro-2-methyl-4-isothiazolin-3, which have relatively low toxicity, are used.
-One, 2,2-dibromo-3-nitrilopropionamide, 1,2-bisbromoacetoxyethane, 1,4-
Bisbromoacetoxy-2-butene, 2,2-dibromo-2-nitroethanol, 5-chloro-2,4,6-trifluoroisophthalonitrile, and 4,5-dichloro-1,2-dithiol-3- Treatment with a synthetic organic compound such as on is generally performed.

If these slime control agents are continuously added at a high concentration to prevent the detection of bacteria and fungi in the system, it is considered that slime troubles caused by the above-mentioned microorganisms will hardly occur. . However, from the viewpoints of environment, safety, and reduction of processing cost, it is desired to reduce the usage amount as much as possible.

[0007] In fact, in a paper mill, the maintenance of the paper machine is regularly performed (such as replacement of wires and blankets) during operation.
Is performed, and at that time, it is usual to wash the dirt in the system together. Therefore, from the above-mentioned viewpoint, the general method for adding a slime control agent is to control the growth of slime within a period from regular cleaning to the next regular cleaning within a range that does not hinder the operation, and the time is 30 minutes / cycle. Four
The intermittent addition method such as times / day is predominant. In other words, in some cases (especially immediately before cleaning, etc.), there is a period between regular cleaning and the next regular cleaning, and in many cases the system is operating with slime occurring in the system to some extent.

Under such circumstances, conventional slime control agents have attempted to achieve the object by improving the efficacy by combining a plurality of the synthetic organic compounds described above from the viewpoint of reducing the usage amount and by synergistic effects thereof. , At present, it is not always satisfactory.

On the other hand, sodium hypochlorite has a strong oxidizing action and is an excellent germicide. Further, it is known that the price is far lower than that of the above-mentioned synthetic organic compound. Further, in terms of safety, it can be said that the safety, including handling, is higher than that of the above-mentioned synthetic organic compounds based on the track record of being used in the field of food and disinfection of pools. Therefore, in this field, it can be said that using sodium hypochlorite as a slime control agent is a very effective method from the viewpoints of consideration for the environment, improvement of safety, and reduction of treatment cost.

However, sodium hypochlorite causes a deterioration in product quality (decolorization of dyes, etc.) and promotes exfoliation of slime generated in the system due to its strong oxidizing action in the papermaking white water system. However, since problems such as slime troubles and stains of the product occur on the contrary, the use in this field was limited to only a part.

[0011]

SUMMARY OF THE INVENTION The present invention has been made under such circumstances, and in a papermaking white water system, hypochlorous acid can be obtained without causing troubles such as decolorization of dyes and peeling of slime. It is intended to provide a method of using sodium acidate.

[0012]

As a result of intensive studies to solve the above problems, the inventors of the present invention have maintained a high slime control effect by examining the addition method of sodium hypochlorite. As a result, the surprising finding that the amount of slime control agents used by conventional synthetic organic compounds can be reduced without causing deterioration of product quality and exfoliation of generated slime was found. The present invention has been completed based on this finding.

That is, the present invention is a slime control method for papermaking in which sodium hypochlorite is diluted in advance to an arbitrary concentration and added to a papermaking white water system.

As a result of pursuing the causes of troubles (decolorization of dyes, peeling of slime, etc.) caused by sodium hypochlorite, the present inventors often derive it from the method of adding sodium hypochlorite. Confirmed to do. That is, the addition amount of sodium hypochlorite required for slime control is predetermined with respect to the actual papermaking white water system,
It is thrown in so as to become that amount. However, it takes some time for the charged sodium hypochlorite to diffuse throughout the system, that is, immediately after charging,
Because the concentration of sodium hypochlorite is temporarily and locally high, the concentration of sodium hypochlorite, which is higher than necessary, reacts with the dye or the slime that has already been generated in the system. It is peeled off.

Based on such knowledge, the present inventors have
It was confirmed that the above-mentioned troubles can be avoided by diluting sodium hypochlorite in advance to a predetermined concentration, and the present invention has been completed.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Sodium hypochlorite used in the present invention has various effective chlorine concentrations, but any of them can be used.

Regarding the dilution ratio of sodium hypochlorite of the present invention, the present inventors have found the following findings as a result of examining various dilution ratios. That is, depending on the type of papermaking white water, when the dilution rate of sodium hypochlorite is higher than 0.3% as the effective chlorine concentration, it is impossible to avoid troubles such as decolorization of the dye and peeling of slime, 0.005%
If it is lower, the amount of the diluted sodium hypochlorite added to the papermaking white water system becomes large, which is not practical.

Therefore, the effective chlorine concentration is 0.005 to
It is desirable to dilute it to 0.3% before adding it to the papermaking white water system, and more desirably 0.01 to 0.1%. Also, water is used for dilution, pure water, tap water,
Both groundwater and industrial water can be used.

The method for adding the sodium hypochlorite of the present invention to the paper white water system after diluting sodium hypochlorite can be effected by either intermittent addition or continuous addition.
Further, it is desirable that the addition concentration is such that 0.1 to 1 mg / L of residual chlorine is detected in the target system at the time of addition. Further, a stabilizer within a range that does not impair the effects of the present invention,
A surfactant, a cleaning agent, a corrosion inhibitor, etc. may be added.

In the present invention, the slime control agent based on the aforementioned synthetic organic compound may be added to the papermaking white water system simultaneously with the diluted sodium hypochlorite or separately. Therefore, the present invention also provides a method for slime control by adding diluted sodium hypochlorite and a slime control agent by a synthetic organic compound to a papermaking white water system at the same time or separately.

[0021]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Test Method) The test method of the examples is described below. Example 1 The slime control method of the present invention was applied to a papermaking white water system of an actual paper mill. A sodium hypochlorite aqueous solution (an aqueous solution containing about 12% of available chlorine) diluted beforehand to an effective chlorine concentration of 0.04% is continuously added to a white water system so that the residual chlorine concentration becomes 0.3 mg / L. did.

Example 2 The slime control method of the present invention was carried out on a papermaking white water system of an actual paper mill. A sodium hypochlorite aqueous solution (an aqueous solution containing about 12% of available chlorine) diluted beforehand to an effective chlorine concentration of 0.04% is continuously added to a white water system so that the residual chlorine concentration becomes 0.3 mg / L. did. Further, a slime control agent (10% methylenebisthiocyanate product) made of a synthetic organic compound was added 4 times a day for 60 minutes at 7 ppm.

The test method of the comparative example is described below. Comparative Example 1 An aqueous solution of sodium hypochlorite (a product containing about 12% of available chlorine) was undiluted into a white paper system of an actual paper mill, and the residual chlorine concentration in the white water system was 0.3 mg.
/ L was continuously added so that it would be.

Comparative Example 2 An aqueous sodium hypochlorite solution (about 1% of available chlorine was added to a white water system of an actual papermaking factory.
The product containing 2%) was continuously added to the white water system as a stock solution so that the residual chlorine concentration was 0.3 mg / L. further,
A slime control agent (10% methylenebisthiocyanate product) of a synthetic organic compound was added 4 times a day for 60 minutes at 7 ppm.

Comparative Example 3 Without adding an aqueous solution of sodium hypochlorite to a white papermaking system of an actual papermaking factory,
A slime control agent (10% methylenebisthiocyanate product) of a synthetic organic compound was added four times a day for 60 minutes at 10 ppm.

The test results are summarized in Table 1. The effect is determined by the number of spots on the product due to slime (average number of occurrences per day), influence on product quality (decolorization of dye), number of bacteria,
It was done by the number of molds.

[0028]

[Table 1]

From the results of Table 1, in Example 1, the number of product spots was smaller than in Comparative Example 1, a stable operation state was realized without decolorization of the dye, and sodium hypochlorite was used in this field. Is possible.

Compared to Example 2 and Comparative Example 2, even in the system in which the organic slime control agent was used in combination, the number of product spots was small and stable operation was possible. Furthermore, compared with Comparative Example 3, the number of bacteria and mold in the papermaking white water system can be reduced, and a more stable operation state is possible.
Furthermore, it is possible to reduce the amount of the organic slime control agent used.

[0031]

From the results shown above, according to the present invention, sodium hypochlorite can be used without causing operational troubles such as slime peeling and decolorization. Furthermore, it is possible to reduce the amount of the conventional organic slime control agent used, reduce the load on the environment, improve the safety, and reduce the treatment cost.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) A01N 37/34 101 A01N 37/34 101 104 104 104 37/48 37/48 37/52 37/52 43/26 43/26 43/80 102 43/80 102 47/48 47/48 59/08 59/08 A C02F 1/50 510 C02F 1/50 510C 520 520B 531 531P 532 532C 532D 532H 532J 540 540B 550 550L

Claims (5)

[Claims] 1. A method for controlling slime for papermaking, which comprises diluting an aqueous solution of sodium hypochlorite in advance and adding it to a papermaking white water system. 2. The method for controlling slime for papermaking according to claim 1, wherein the dilution rate of the aqueous solution of sodium hypochlorite is 0.005 to 0.3% as an effective chlorine concentration. 3. The effective chlorine concentration of the aqueous solution of sodium hypochlorite is 0.01 to 0.1%.
The described slime control method for papermaking. 4. The method for controlling slime for papermaking according to claim 1, wherein an organic slime control agent is added together. 5. The component of the organic slime control agent is methylenebisthiocyanate, 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2,2-dibromo-. 3-nitrilopropionamide, 1,2-bisbromoacetoxyethane, 1,4-bisbromoacetoxy-2-butene,
2,2-dibromo-2-nitroethanol, 2-bromo-2-nitropropane-1,3-diol, dichloroglyoxime, α-chloro-benzaldoxime, 1,2
-Dibromo-2,4-dicyanobutane, glutaraldehyde, 5-chloro-2,4,6-trifluoroisophthalonitrile, quaternary ammonium salts, and 4,5-dichloro-1,2-dithiol-3. -ON, and these components are used alone or in combination.
The described slime control method for papermaking.