JPH0748795A - Prevention of biologically caused trouble of papermaking white water - Google Patents

Abstract

PURPOSE:To effectively prevent occurrence of a biologically caused trouble of papermaking white water and a white water tank in a papermaking process in a papermaking factory without using chemicals or without developing the secondary pollution. CONSTITUTION:This method for preventing occurrence of a biologically caused trouble of papermaking white water is characteristically carried out by blowing and mixing ozonized air and/or ozonized oxygen into papermaking white water in a head tank for white water, applying an ozone oxidation treatment to the papermaking white water and continuously applying an sterilizing and algaecidal treatment to the papermaking white water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing the occurrence of biological damage to papermaking white water in a paper mill.

[0002]

[Problems to be solved by the prior art / invention] Microorganisms and algae are easily proliferated in papermaking white water and white water tanks of paper mills, and the proliferation of these causes paper system breakage, deposits and other biological disorders. . As a measure to prevent these biological system disorders that occur in papermaking white water and white water tanks,
Methods such as cleaning or administration of chemicals such as bactericides and algaecides have been used.

However, in the conventional prevention method, there is a possibility that the effect is not sufficient, or even if the bactericidal and algaecidal effects are obtained, the surplus chemicals are mixed in the waste water and discharged to cause secondary pollution. , Not a satisfactory method. Accordingly, an object of the present invention is to provide a method for effectively preventing the occurrence of paper white water in a paper mill and biological system damage in a white water tank without using chemicals and without causing secondary pollution.

[0004]

In view of the above situation, the present inventors diligently studied a method for effectively preventing the occurrence of paper system white water and biological system damage in a white water tank without secondary pollution. As a result, using ozonized air or ozonized oxygen obtained by ozonizing air or oxygen as a raw material,
By blowing and mixing in papermaking white water, and treating the papermaking whitewater with the obtained ozonized air and / or dissolved water of ozonized oxygen, sterilization of the papermaking whitewater by using a small amount of ozonized air, ozonized oxygen, The present inventors have completed the present invention by finding that algae can be killed and white papermaking paper can be purified.

That is, the gist of the present invention is to blow and mix ozonated air and / or ozonized oxygen into papermaking whitewater in a whitewater head tank to subject the papermaking whitewater to ozonolysis to sterilize papermaking whitewater and to kill algae. The present invention relates to a method for preventing occurrence of biological system disorders in papermaking white water, which is characterized by being carried out continuously.

Normally, ozone is obtained by using air as a raw material and by a method such as silent discharge or ultraviolet irradiation. In this case, the ozone concentration obtained is a maximum of about 3000 ppm, and this can be obtained by using an air diffuser, an ejector or the like in water. When mixed by blowing into water, the ozone concentration in water is 0.
It is about 6 ppm. On the other hand, the ozone concentration in the ozonized oxygen obtained by ozonizing 90% oxygen as a raw material reaches 10,000 to 50,000 ppm, and when the ozonized oxygen is blown into the water by a diffusing pipe, an ejector or the like to mix it in water. Ozone concentration is 1-3pp
Since the concentration is as high as m, it is possible to efficiently sterilize papermaking white water and algae treatment with ozone.

As the air used as a raw material for ozonized air used in the present invention, air in an air cylinder or air depressurized by a dehumidifier or the like by using an air compressor or the like is used. In the present invention, the ozone concentration is usually 2000 to 5000 ppm
Of ozonized air is used. Further, in the present invention, as the high-concentration oxygen used as a raw material for ozonized oxygen, oxygen in an oxygen cylinder or oxygen obtained by a PSA oxygen generator is used. As the PSA oxygen generator, an apparatus using an ordinary zeolite molecular sieve or carbon molecular sieve as an adsorbent can be applied. The P
The oxygen concentration obtained by the SA device is 30 to 99%, and if this is used as the raw material for ozonation, it is 4000 to 50,000.
Ozonated oxygen having an ozone concentration of ppm can be easily obtained at low cost. In the present invention, 50 to 99%,
Oxygen having a concentration of 80 to 99% is preferably used. In the present invention, the ozone concentration is usually 5000 to 5000.
0 ppm of ozonated oxygen is used. In the present invention,
Either ozonized air or ozonized oxygen may be used,
Also, both may be used in combination.

In the present invention, for mixing ozonized air and / or ozonized oxygen with papermaking white water, any device can be used as long as it is a device capable of blowing ozone and mixing to dissolve it by ordinary gas-liquid contact. Specific examples include an air diffuser, an ejector, a static mixer, a gas-liquid mixing pump, and a rotary atomizer.

Ozoned air and / or ozonized oxygen is blown into and mixed with papermaking white water using the above-mentioned gas-liquid contact device, and the obtained ozone is dissolved in ozonized air and / or dissolved water of ozonized oxygen. By treating the papermaking white water and supplying it to the whitewater tank, it becomes possible to sterilize and kill algae in the papermaking whitewater and the whitewater tank, and it is possible to prevent the occurrence of biological system disorders in the papermaking whitewater and the white water tank. According to the present invention, the excess ozone easily self-decomposes.
There is no risk of secondary contamination.

An example of an apparatus used for preventing the occurrence of paper system white water and biological system failure in a white water tank according to the present invention will be described below with reference to FIG.
Will be used to explain in more detail. In the figure, 1 is a device for receiving papermaking raw materials (seed) and adjusting white water concentration (seed box), 2 and 3 are devices for removing contaminants contained in white water (2 is a screen, 3 is a primary cleaner box) 4) a pump for supplying white water, 5 a device for finally separating foreign substances in the white water, 6 a device for uniformly supplying the white water to the white water tank 7 (white water head tank), 8 a paper in the white water A device for making and making paper into a net, a device for receiving overflow white water, a device for circulating overflow white water to a seed box, a device for generating ozonized air and / or ozonized oxygen (ozone). Reference numeral 12 denotes a device for blowing and mixing ozonated air and / or ozonized oxygen.

In the method for preventing occurrence of biological system damage in papermaking white water and white water tanks using the apparatus of the present invention, an ozone generator for generating ozonized air and / or ozonized oxygen
11 is not particularly limited, and a known method using silent discharge or ultraviolet irradiation is used. An ozone generator using a device 12 for blowing and mixing ozonized air and / or ozonized oxygen into the white water head tank 6.
Ozonized air and / or ozonized oxygen generated from 11 is blown and mixed to obtain ozonized air and / or dissolved water of ozonized oxygen. As the device 12 for blowing and mixing ozonized air and / or ozonized oxygen, the gas-liquid contact device as described above is used. Here, the residual ozone concentration in the water when ozonized air and / or ozonized oxygen is blown and mixed is appropriately 0.02 to 1.0 ppm, and the amount of papermaking white water and ozonized air and / or
Alternatively, the blowing amount of ozonized oxygen may be adjusted. If the ozone concentration is less than 0.02 ppm, it is not sufficient to prevent the occurrence of biological damage, and even if the ozone concentration is more than 1.0 ppm, the corresponding effect cannot be obtained and it is not a good idea.

Dissolved water of ozonized air and / or ozonized oxygen obtained by blow-mixing ozonized air and / or ozonized oxygen is subjected to ozone oxidation treatment of papermaking white water in white water head tank 6 and white water tank 7. Used for. The oxidation treatment time is usually 0.5 minutes to 3 hours.

In the present invention, by carrying out these operations continuously, it is possible to effectively prevent the occurrence of biological system damage in the white water in the papermaking process at the paper manufacturing plant.
Therefore, it is possible to reduce the number of paper breaks, reduce the number of deposits, and extend the cleaning interval of the white water tank.

[0014]

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

Example 1 Ozoned air containing 3000 ppm of ozone generated by an ozone generator (a raw material was supplied from an air compressor) was used in a white water head tank having a circulating water amount of 2500 m ³ / day in a papermaking process. The mixture was blown and mixed at 8 m ³ / hour using an air diffusing tube. The residual ozone concentration at the outlet of the white water head tank after blowing ozone was 0.03 ppm. The ozonized air-dissolved water was sent to a white water tank for ozone oxidation treatment. By repeating this series of operations, it was possible to prevent the occurrence of paper system white water in the paper making process and biological system damage in the white water tank. Before the above operation, the white water head tank and white water tank were cleaned 1-3 times a week.
Even so, paper-cutting, deposits, etc. occurred during the second half of the week. After the implementation, the damage to the biological system such as running out of paper and deposit was suppressed, and the cleaning time was often extended to once a week.

Example 2 Instead of blowing ozonized air in Example 1, P
The same operation was performed except that ozonated oxygen containing 20,000 ppm of ozone supplied from the SA oxygen generator was blown and mixed at 0.3 m ³ / hour. The residual ozone concentration at the outlet of the white water head tank after ozone injection is 0.05 pp
It was m. Send this ozonized oxygen-dissolved water to the white water tank,
Ozone oxidation treatment was performed. By repeating this series of operations, it was possible to prevent the occurrence of paper system white water in the paper making process and biological system damage in the white water tank. Prior to the above operation, the white water head tank and the white water tank were cleaned once to three times a week, but nonetheless, paper breaks and deposits occurred during the second half of the week. After the implementation, the damage to the biological system such as running out of paper and deposit was suppressed, and the cleaning time was often extended to once a week.

[0017]

EFFECTS OF THE INVENTION According to the present invention, it is possible to effectively prevent the occurrence of papermaking white water in the papermaking process at a papermaking factory and biological system damage in the whitewater tank without using chemicals and without causing secondary pollution. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing one example of a papermaking white water used in the present invention and a biological system failure occurrence prevention device for a white water tank.

[Explanation of symbols]

1 Device for receiving papermaking / raw materials (seed) and adjusting white water concentration (seed box) 2 Screen 3 Primary cleaner box 4 Pump for supplying white water 5 Separation device for foreign substances in white water 6 White water is uniformly supplied to the white water tank Equipment (white water head tank) 7 White water tank 8 Equipment for making stock from white water into a net and making paper 9 Equipment for receiving overflow white water 10 Pump for circulating overflow white water to seed box 11 Ozonized air and / or ozone Device for generating oxygenated oxygen (ozone generator) 12 Device for blowing and mixing ozonated air and / or ozonized oxygen

Claims (1)

[Claims] 1. A method for continuously sterilizing and algae-killing papermaking white water by ozone-oxidizing the papermaking whitewater by blowing ozonized air and / or ozonized oxygen into the papermaking whitewater in the whitewater head tank and mixing them. A method for preventing the occurrence of biological system disorders in papermaking white water.