JPH05155719A - Release of slime - Google Patents

Abstract

PURPOSE:To readily and efficiently release slime adhering to an aqueous system with industrial advantage. CONSTITUTION:Slime adhering to an aqueous system is released by intermittently adding an isothiazolone-based compound to the slime-adhering aqueous system. The isothiazolone-based compound exhibits a denaturation and decoloration effect on the slime and the viscosity of the polysaccharide can be removed. The already adhered, slime, therefore, can efficiently be released by intermittently adding the isothiazolone-based compound to the aqueous system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slime stripping method, and more particularly to a method for stripping slime adhering to a cooling water system easily, efficiently and industrially advantageously.

[0002]

2. Description of the Related Art In cooling water systems of various factory plants, slime composed of bacteria, filamentous fungi, algae, etc. is generated in the system, resulting in reduced thermal efficiency, clogging of water passage pipes, corrosion of pipe metal materials, etc. There is an obstacle. In addition, slime damage causes serious problems also in paper pulp process water systems, wastewater treatment water systems, and the like.

Conventionally, as a measure against slime in a cooling water system, a method using a chemical agent has been taken. As the chemical agent, a slime removing agent for removing or cleaning the adhered slime, a cleaning agent, or preventing adhesion of slime is used. There are slime control agents and bactericides.

Among these agents, slime control agents and bactericides are used for the purpose of reducing the adhesion potential of slime by keeping the concentration of microorganisms in water low. Generally, slime control agents are said to sterilize and suppress the enzymatic reaction of bacteria and the denaturing action of cell membranes. On the other hand, the slime stripping agent disperses aggregates of bacteria and removes them from the adhered surface by eliminating the viscosity of the adhesive substance (generally polysaccharides) outside the cells.

Conventionally, as a slime remover and a cleaning agent,
Hydrogen peroxide and hydrazine are used. Also, isothiazolone compounds are used as slime control agents.

[0006]

Hydrogen peroxide and hydrazine, which have hitherto been used as slime removers and detergents, both show excellent effects, but have problems in terms of skin irritation, wastewater treatment, etc. However, in all cases, the emergence of alternative products is desired from the viewpoint of safety.

On the other hand, the use concentration of the slime control agent and the bactericide is in a range until the bactericidal effect is realized when the growth control limit is exceeded. I can't, and I haven't confirmed it. Incidentally, the isothiazolone compounds conventionally used as slime control agents are highly safe but have strong skin irritation.
In the actual system, it is used in a concentration range of about 0.1 to 0.5 ppm. However, even with this isothiazolone compound, the slime-stripping effect by eliminating the viscosity of the polysaccharide was not expected at all.

The present invention has been made in view of the above-mentioned conventional circumstances, and the slime adhering to the cooling water system is easily and efficiently exfoliated industrially advantageously by using a highly safe chemical agent. The purpose is to provide a method.

[0009]

The slime stripping method of the present invention is characterized in that the adhered slime is stripped by intermittently adding an isothiazolone compound to an aqueous system to which the slime is deposited.

That is, the inventors of the present invention have conducted extensive studies to provide a highly safe slime release agent, and as a result,
Although it was used as a slime control agent, it has not been used as a slime remover at all, and the isothiazolone compound, which was not even expected, has the action of eliminating the viscosity of polysaccharides, and it is used as a slime remover. It was found that the effect was exhibited, and the slime peeling method of the present invention using this isothiazolone compound was completed.

The present invention will be described in detail below.

The isothiazolone compound used as the slime release agent in the present invention is preferably
The compounds represented by the following general formula or are included.

[0013]

[Chemical 1]

Specifically, 5-chloro-2-methyl-3
-Isothiazolone, 2-methyl-3-isothiazolone,
2-ethyl-3-isothiazolone, 4,5-dichloro-
2-octyl-3-isothiazolone, 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-3
-Isothiazolone magnesium nitrate, 2-methyl-3-isothiazolone magnesium nitrate, 2
-Ethyl-3-isothiazolone calcium chloride,
Examples include 4,5-dichloro-2-octyl-3-isothiazolone magnesium nitrate.

Such an isothiazolone compound may be used as an inclusion compound with a host compound which can be stably included as a guest compound.

In this case, as the host compound, for example, one kind or two or more kinds of multimolecular host compounds selected from the following (1) to (24) can be used.

(1) 1,1,6,6-Tetraphenyl-2,4-hexadiyne-1,6-diol (2) 1,6-bis (2-chlorophenyl) -1,6
-Diphenylhexa-2,4-diyne-1,6-diol (3) 1,1-bis (2,4-dimethylphenyl)-
2-propyn-1-ol (4) 2,5-bis (2,4-dimethylphenyl) hydroquinone (5) 1,1,4,4-tetraphenyl-2-butyne-1,4-diol (6) 1,1,2,2-tetraphenylethane-1,
2-diol (7) 1,1-bi-2-naphthol (8) 9,10-diphenyl-9,10-dihydroanthracene-9,10-diol (9) 1,1,6,6-tetrakis (2 , 4-Dimethylphenyl) -2,4-hexadiyne-1,6-diol (10) 9,10-bis (4-methylphenyl)-
9,10-Dihydroanthracene-9,10-diol (11) 4,4'-Cyclohexylidenebisphenol (12) N, N, N ', N'-tetrakis (cyclohexyl)-(1,1'-biphenyl) -2,2'-dicarboxamide (13) 1,4-diazabicyclo- (2,2,2)-
Octane (14) 4,4'-sulfonylbisphenol (15) 4,4'-butylidene bis (3-methyl-6)
-Tert-butylphenol) (16) 2,2'-methylenebis (4-methyl-6-)
tert-butylphenol) (17) 4,4'-thiobis (3-methyl-6-te
rt-butylphenol) (18) 2,2′-methylenebis (4-chlorophenol) (19) deoxycholic acid (20) t-butylhydroquinone (21) 2,5-di-tert-butylhydroquinone (22) cholic acid (23) Granular corn starch (porous Y-20) (24) α, α, α ′, α′-tetraphenyl-
1 ', 1'-Biphenyl-2,2'-dimethanol Among these host compounds, those which release about 90% or more of the isothiazolone compound included in the aqueous system within 1 hour after addition are preferable.

When the isothiazolone compound represented by the general formula is converted into the inclusion compound by the host compound, the complex structure is unfolded during the inclusion, and thus the inclusion compound is represented by the general formula. It becomes an isothiazolone compound.

In the present invention, the preferred concentration and mode of addition of the isothiazolone compound varies depending on the target water system. For example, in the case of a closed circulation cooling water system, the isothiazolone compound itself represented by the above general formula is 1 ppm or more, Especially 3-10ppm, especially 5-6p
pm addition, and if it is an open circulating cooling water system, the inclusion compound of the isothiazolone compound is 1 ppm or more, especially 3
It is preferable to add 10 to 10 ppm, especially 5 to 7 ppm. In addition, the addition cycle in the case of intermittently adding the isothiazolone compound is appropriately set within a range of about once a week to two months depending on the slime adhesion state of the cooling water system.

Examples of the water system to be treated by the method of the present invention include various water systems such as a cooling water system, a paper pulp process water system and a waste water treatment water system.

[0021]

FUNCTION The isothiazolone compound has slime modification and decolorization effects and can eliminate the viscosity of the polysaccharide. Therefore, by intermittently adding the isothiazolone-based compound to the water system, the slime that has already adhered can be effectively removed.

In particular, by using the isothiazolone compound in the form of an inclusion compound obtained by inclusion with an appropriate host compound, the skin irritation can be reduced and the handling property can be improved.

[0023]

EXAMPLES The present invention will be described more specifically with reference to the following experimental examples and examples.

Experimental Example 1 To 1 liter of dechlorinated water obtained by bubbling water from Atsugi City, soil components (bacteria) collected from an actual factory cooling water system were added so as to be 1% by weight. 5-chloro-
An inclusion compound containing 2-methyl-3-isothiazolone (hereinafter abbreviated as "CMI") and 2,2'-methylenebis (4-chlorophenol) in a ratio of 3: 7 (weight ratio) was 6 mg as CMI. / L, and then add 2
The mixture was stirred and dispersed at 00 rpm for 5 minutes, and left at room temperature for 4 days.

After 4 days, the precipitate was taken out and observed by an electron microscope. As a result, a large number of angular projections and filamentous substances were found on the surface of the sediment when no drug was added, but when a drug was added, The filamentous material disappeared, and the protrusions on the surface had also changed to a rounded state. From this result, it can be seen that the drug has a remarkable slime peeling effect and a surface modifying effect.

Example 1 An application test of the present invention was carried out on two open circulating cooling water systems of an actual factory having a scale of 100 refrigeration tons and 40 refrigeration tons. The clathrate compound used in Experimental Example 1 was charged into both water systems at a rate of 6 mg / l, and the normal cooling water system was operated for 2 weeks.

Two weeks later, the treatment effect was visually confirmed for the cooling tower filler in the cooling water system of 100 refrigeration tons, and for the draining board muffling mat in the cooling water system of 40 refrigeration tons.

As a result, regarding the cooling tower filler, dark green to brownish slime was initially adhered to the entire surface of the filler with a thickness of about 3 mm, but after two weeks most of the slime was peeled off, or It was found that even if they were attached, they were peeled off to the extent that the thickness was not felt. The adhered slime turned green.

On the other hand, in the draining board sound deadening mat, nori-like slime adhered to the entire surface of the mat before the treatment.
It was found that the slime had almost disappeared after the treatment.

In any case, no skin irritation peculiar to CMI was felt during the treatment.

[0031]

As described in detail above, according to the slime stripping method of the present invention, the isothiazolone compound is used to easily and efficiently remove slime already attached to the water system.
It is possible to peel off industrially advantageously.

Claims (1)

[Claims] 1. A slime stripping method, wherein the deposited slime is stripped by intermittently adding an isothiazolone compound to an aqueous system to which slime is deposited.