JPS6316197B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an agent for controlling fouling in water systems, and particularly to an agent for controlling the growth and adhesion of seawater organisms in channels, plants, etc. that utilize slime and seawater mainly derived from microorganisms in water systems such as cooling water systems. It is something. In recent years, with the development of the chemical industry, petrochemical industry, and other industries, large amounts of industrial water have become necessary. In addition to industrial tap water, seawater, lake water, river water, and groundwater are used as sources of industrial water. Various types of microorganisms are always present in these industrial waters, and depending on the water quality and environment in which they exist, many of these microorganisms can continue to proliferate and cause various problems, such as: When water is used for cooling, microorganisms living in the water proliferate and grow on the walls of water facilities, forming slime, which causes problems such as a decrease in heat exchange efficiency and poor water flow. . In particular, when circulating water is used in an open system using an open cooling tower, the circulating water is forcibly aerated in a part of the system and comes into contact with the air, and is exposed to sunlight. The growth of aerobic microorganisms such as bacteria and algae is encouraged. In order to prevent slime damage caused by microorganisms that have grown and multiplied in these irrigation water systems,
Disinfectants and/or antibacterial agents such as chlorine or chlorine-based organic compounds, chlorine-based inorganic compounds, quaternary ammonium salts, and cyanide compounds have been used, respectively. However, these agents are generally a source of pollution in wastewater pollution, and cannot be put into practical use because they are either unusable, highly toxic to living things such as humans, animals, or fish, or highly corrosive to equipment materials. Many of these are difficult, and the development of non-polluting drugs is desired. Therefore, the present inventors focused on hydrogen peroxide as such a drug. Hydrogen peroxide itself has the advantage of being a completely non-polluting agent that has low toxicity and decomposes into water and oxygen gas. However, hydrogen peroxide can prevent slime adhesion at a low concentration of about 0.5 to 200 ppm as described in JP-A No. 51-94001, but it is easily degradable, so it cannot be used in actual use. However, in order to maintain an effective concentration for a certain period of time, it is necessary to replace the equivalent amount of decomposed hydrogen peroxide, resulting in the disadvantage that a considerably large amount of hydrogen peroxide is required. In addition, in recent years, the industrial use of seawater has increased significantly, and large amounts of seawater are used in temporary quantities, for example, in thermal power plants, steel plants, petrochemical industries, and the like. Additionally, it is used to cool boiler condensers on ships. However, when using seawater in this way, adhesion problems caused by various organisms that live in seawater, such as mussels, barnacles, water bugs, bryozoans, and seaweed such as blue laver, cannot be ignored. Creatures that cause particularly severe damage include mussels and barnacles. When these seawater organisms grow and grow in large numbers in waterways, they narrow the waterways, and when they fall off and flow into condensers and heat exchangers, they reduce the cooling effect.Furthermore, when they clog condenser tubes, seawater This causes turbulent flow and mechanically accelerates metal corrosion. To prevent such damage, a method of injecting drugs is usually used. Typical agents conventionally used include liquid chlorine, effective chlorine generators such as sodium hypochlorite, tri-n-propyltin, tri-n-butyltin, tri-n-phenyltin chlorides, Examples include organic tin compounds such as oxides and hydroxides, but these agents have residual toxicity and cumulative toxicity, and are widely considered to destroy the ecological environment of seawater organisms. In addition, effective chlorine generating agents have problems such as odor, corrosiveness to metal materials, and foaming. Furthermore, in the case of liquid chlorine, there are also problems such as danger during transportation and work stability during injection. In addition, organic tin compounds also have problems, such as having a unique pungent odor, being likely to cause irritation if they come in contact with the skin, and being less effective against soft contaminants that do not have shells, such as water bugs and seaweed. Therefore, instead of using these toxic chemicals, it is often done manually to remove the deposits from flow channels, plants, etc., but this requires a huge amount of money and also increases the risk of deposits from deposits. As the gases die, putrefactive gases are generated and fill dark rooms, which often results in personal injury due to poisoning. Therefore, there is a demand for the development of a new, safe drug to replace conventional drugs, and the present inventors focused on hydrogen peroxide as such a drug. As mentioned above, hydrogen peroxide itself has low toxicity, and since it decomposes into water and oxygen gas, it has the advantage that there is no need to worry about causing environmental problems due to residual or accumulated poisons. However, although hydrogen peroxide itself is effective in preventing the adhesion of marine organisms, it has the disadvantage that a relatively large amount is required to obtain a satisfactory adhesion-controlling effect, and it is too expensive. Therefore, the inventors of the present invention have conducted extensive research into drugs that produce effective and synergistic effects when combined with hydrogen peroxide. As a result, while in many cases additive effects or slight synergistic effects were not observed, combinations with extremely significant synergistic effects were discovered and the present invention was achieved. That is, the present invention provides hydrogen peroxide and the general formula (In the formula, R represents a hydrogen atom or a hydrocarbon group, and
and Y each represents an alkylene group having 3 to 12 carbon atoms. ) or a water-soluble salt thereof as an active ingredient. As the hydrogen peroxide used in the present invention, in addition to aqueous solutions of hydrogen peroxide with various concentrations, substances that generate hydrogen peroxide in the presence of water or seawater can also be used. Such compounds include, for example, carbonates, borates,
respective hydrogen peroxide adducts such as monophosphates, diphosphates, metasilicates and urea; metal peroxides, such as peroxides of alkali metals and peroxides of alkaline earth metals; Peroxides include metal superoxides, such as superoxides of alkali metals, and compositions and mixtures thereof. Moreover, the biguanide polymer used in the present invention has the general formula In the formula, R represents a hydrogen atom or a hydrocarbon group, preferably a hydrogen atom, and X and Y each represent an alkylene group having 3 to 12 carbon atoms,
Preferably it represents a methylene group. These water-soluble salts are not particularly limited as long as they are water-soluble, but neutral salts with acids such as hydrochloric acid and acetic acid are generally preferred. In addition, the molecular weight is 900-1200
Polyhexamethylene biguanide hydrochloride is particularly preferred because it is commercially available and easily available. Although biguanide polymers or their water-soluble salts have been known as harmless industrial disinfectants and disinfectants, their effects on adhesive products living in seawater have not yet been elucidated. First of all, the effects of the combined use of hydrogen peroxide were clarified for the first time by the present inventors. For example, in the case of mussels, trochophore, D
The juvenile shellfish undergoes the larval stage of larval stage and the ambo stage, and then metamorphoses into the adult shellfish, and in the case of barnacles, it passes through the larval stage of nauplius and cypris, and then metamorphoses into the adult body, but in general, attachment occurs during these larval stages. It is said to occur in When hydrogen peroxide and biguanide polymers or their water-soluble salts are combined, the larvae either stop their activity and enter a state of asphyxia at concentrations that would have little effect on each drug alone, or even if they attach to the larvae, they do not survive. will inhibit the growth of In the present invention, hydrogen peroxide and a biguanide polymer or a water-soluble salt thereof are added to the water system in required amounts, but the method of addition may be such that both drugs are mixed and adjusted in advance. , both drugs may be added separately. When adding them separately, there is no particular restriction on the order of addition, etc., but it is preferable that the addition of the next drug is started while the first drug added remains in the water. When using hydrogen peroxide and biguanide polymers or their water-soluble salts for slime control, the amount used varies depending on the type of slime in the water system and the situation in which it occurs, but in general, the concentration of hydrogen peroxide in the water system is 0.05~ The amount is 100 ppm, preferably 0.1 to 50 ppm, and the biguanide polymer or its water-soluble salt is 0.01 to 20 ppm, preferably 0.5 to 10 ppm.
This is the amount. If the amount of the chemical used is lower than the lower limit of the above range, a sufficient slime control effect will not be obtained, and although it can be made higher than the upper limit, the excess amount of the chemical will be wasted. In addition, when using hydrogen peroxide and biguanide polymers or their water-soluble salts to prevent seawater deposits, the amount used varies depending on the degree of contamination of the seawater system, the type of adherent organisms, etc. The concentration of hydrogen peroxide is 0.05~50ppm, preferably
0.1-10ppm, biguanide polymer or its water-soluble salt 0.005-5ppm, preferably 0.01-1ppm
It can be added for 0.5 to 24 hours a day. In addition, hydrogen peroxide is 0.05 to 1 ppm, and biguanide polymer or its water-soluble salt is 0.005 to 0.1 ppm.
Although the combination has almost no effect on stopping the activity of adherent larvae, it significantly stops the growth after attachment, so a substantially sufficient adhesion control effect can be obtained. Although it is preferable to repeat the above treatment, it is not necessarily necessary to perform it every day; for example, in winter when the seawater system is less contaminated, it may be performed once every 2 to 3 days. The entire amount of hydrogen peroxide and biguanide polymer or water-soluble salt thereof may be added to the water at once (hereinafter referred to as impact administration),
Alternatively, an amount to achieve the above-mentioned concentration may be gradually and continuously added (hereinafter referred to as continuous administration). Shock dosing is suitable when the water is used in a cyclical manner, and continuous dosing is suitable for cases where the water is not recirculated but is passed through the water system in a single manner, or for cooling purposes where the residence time in the water system is relatively short even if the water is recirculated. Suitable for low concentration operation of aqueous systems. When water passes through the irrigation system, continuous administration requires that the water is either before being supplied to the irrigation system or while it is passing through the irrigation system. For continuous administration,
There is no particular restriction on the time for adding the drug, but it is generally 0.5 to 24 hours, preferably 6 to 12 hours. The above treatment may be carried out only once, but it is preferably carried out repeatedly. When performing the process repeatedly, the number of repetitions and the interval between each time can be determined as appropriate depending on the type of slime, the situation of occurrence, etc. The interval between each treatment is preferably once every 2 to 5 days in summer, and once every 4 to 10 days in winter. In addition to the adhesion control agent of the present invention, known agents in this field, such as chlorine, effective chlorine generators such as sodium hypochlorite, hydrazine, organotin compounds, quaternary ammonium salts, and sodium dimethyldithiocarbamate, may also be used. It is okay to use organic sulfur compounds such as As described above, the present invention has succeeded in controlling the generation and adhesion of slime in irrigation water systems extremely economically and efficiently, eliminates slime troubles, and is suitable for industrial use without any pollution problems. It is extremely valuable. The present invention will be explained in more detail with reference to Examples. Example 1 Meat juice liquid medium (meat extract 10g/, peptone
Unidentified mixed bacteria of slime origin were cultured overnight in 10ml (10g/, NaCl 5g/, PH7.2), and then transferred to a mono-tube (φ17mm) containing the same medium (10ml) as above at 10 ⁷ cells/ml. The inoculation was carried out to achieve a bacterial concentration of about 100%. Culture was carried out with shaking at 35°C, and changes in growth over time in terms of OD (optical density) were automatically recorded using a biophoto recorder (TN-112D, manufactured by Toyo Kagaku Sangyo). The proliferation initiation time was determined from the obtained chart, and the synergistic effect was demonstrated as follows. Length of the induction period when no drug is given t ₀ Length of the induction period when the drug () is used alone t ₁ Length of the induction period when the drug () is used alone t ₂ Length of the induction period when the drug () is used alone Length of induction period when () is used in combination t Delay time due to single use of _1,2 drug () (means the induction period extended by drug administration, hereinafter referred to as independent delay time) Δt ₁ = t ₁ − _{t 0} Single delay time due to single use of drug ()
Δt ₂ = t ₂ − _{t 0} Delay time due to combined use of drug () and drug () (hereinafter referred to as combination delay time)
Since Δt _1,2 = t _1,2 − t ₀ or more, the sum of individual delay times (Δt ₁ + Δt ₂ )
is the additive delay time, and the difference between this and the combined delay time [Δt _1,2 −(Δt ₁ +Δt ₂ )=Δt*] is the synergistic delay time (hereinafter written as such). Therefore, the synergistic effect is Δt _1,2 - (Δt ₁ + Δt ₂ ) / (Δt ₁ + Δt ₂ ) × 100 = Δt* / (Δt ₁ + Δt ₂ ) × 100 = α (%), and this α (%) is The presence or absence of a synergistic effect and its magnitude were determined by the value of α, which is called efficiency. That is, when α=0, there is an additive effect; when α>0, there is a synergistic effect, and the larger α is, the greater the synergistic effect is. When α<0, it is a negative synergistic effect (offsetting effect), which is lower than the additive effect. In this example, polyhexamethylene biguanide or its water-soluble salt was used with an average molecular weight of 1200.
Polyhexamethylene biguanide hydrochloride was used. The results are shown in Table 1.

【table】

[Table] As is clear from Table 1, a synergistic efficiency of 77 to 314% can be obtained by using the slime control agent of the present invention consisting of hydrogen peroxide and polyhexamethylene biguanide hydrochloride having an average molecular weight of 1200. did it. Example 2 The slime control effect of the agent of the present invention was tested in a model plant with a circulating cooling water system installed in a certain chemical factory in the Tokyo area. The specifications of the model plant are as follows. Amount of water held () 940 Amount of circulating water (/hr) 4100 Amount of make-up water (/hr) 114 Amount of blowdown water (/hr) 49 Amount of scattered water (/hr) 8 Concentration multiple 2 Heat medium temperature (℃) 56 Cooling tower return water temperature ( ℃) 37~38 Cooling tower water supply temperature (℃) 30 Flow velocity in heat exchanger pipes (m/sec) 0.5 Total heat transfer area (m ² ) 0.707 As make-up water, some river water is mixed with Tokyo Johoku industrial water. I used something similar. In addition, in order to promote slime generation and adhesion, 400% of slime containing zooglaia and diatoms as main components was collected from the on-site cooling tower where the same make-up water was used at the start of the test.
ml (sedimentation volume after 30 minutes, equivalent to about 10 g of dry weight) was added. The test was conducted for 20 days in each test area, and the medicinal efficacy was evaluated based on the overall heat transfer coefficient (U) change of the heat exchanger,
After 20 days, the amount of slime adhering to the wall of the heat exchanger tube (SUS304) was measured. In addition, in this test, hydrogen peroxide was 35w/
Using w% aqueous solution, polyhexamethylene biguanide or its water-soluble salt is 20w/w% of polyhexamethylene biguanide hydrochloride having an average molecular weight of 900.
Both drugs were mixed in advance and added using an aqueous solution. The mixing ratio is as follows. 35w/w% hydrogen peroxide 80 parts 20w/w% polyhexamethylene biguanide hydrochloride 20 parts The results are shown in Table 2.

[Table] As can be seen from Table 2, the decrease in U in the untreated area was
350kcal/ ^m2・hr・℃, while that in the test plots was less than 100kcal/ ^m2・hr・℃, and the slime adhesion rate in the test plots was 15 to 23% compared to the untreated plot. %, no slime adhesion was observed in appearance, and good slime control was achieved. Example 3 The effects of the drug of the present invention were tested using D-shaped mussel larvae that were artificially hatched and reared by the temperature stimulation method, and barnacle cypris larvae that were hatched from developed adults and reared. For the test, 20ml of seawater containing D-shaped larvae or cypris larvae (density of approximately 50 larvae/ml) was placed in a φ24mm test tube, and the drug was adjusted to the specified concentration using a stereomicroscope every hour for 24 hours. The activity status of the larvae was observed and the time required to stop 100% activity was determined. In this test, polyhexamethylene biguanide or its water-soluble salt was used with an average molecular weight of 1200.
The hydrochloride of polyhexamethylene biguanide was used. For comparison, the effects of using only hydrogen peroxide or polyhexamethylene biguanide hydrochloride were also tested. The results are shown in Table 3.

【table】

[Table] Shows what happened.
Example 4 A one-month water flow test was conducted in the spring, when the mussels are attached, in a temporary model waterway installed at a steel factory in the coastal area. The model waterway is 5
It consists of rows of waterways, and the seawater flow rate of each waterway is 10m ² /
hr, average flow velocity is 0.3 m/s. In this test, a 35w/w% aqueous solution of hydrogen peroxide was used, and a 20w/w% aqueous solution of polyhexamethylene biguanide hydrochloride with an average molecular weight of 900 was used as polyhexamethylene biguanide or its water-soluble salt. Injected. 4th result
Shown in the table.

[Table] (Note) In test areas No. 3 and 4, hydrogen peroxide and polyhexamethylene biguanide hydrochloride were injected at the same time.
It was injected into the interstitial zone.
Comparative Example 1 In the same manner as in Example 4, the effect of using hydrogen peroxide or polyhexamethylene biguanide hydrochloride alone was tested. The results are shown in Table 5.

[Table] Example 5 A one-month water flow test was conducted in the same model waterway as in Example 4 during the summer season when barnacles are attached. The drugs used were the same as in Example 4, but in this test both drugs were mixed in advance and then added. The mixing ratio was as follows. 35w/w% hydrogen peroxide 90 parts 20w/w% polyhexamethylene biguanide hydrochloride 10 parts The results are shown in Table 6.

[Table] Comparative Example 2 In the same manner as in Example 5, the effect of using hydrogen peroxide or polyhexamethylene biguanide hydrochloride alone was tested. The results are shown in Table 7.

【table】

【table】

Claims (1)

[Claims] 1. Hydrogen peroxide and general formula (In the formula, R represents a hydrogen atom or a hydrocarbon group, and
and Y each represents an alkylene group having 3 to 12 carbon atoms. ), or a water-soluble salt thereof, as an active ingredient.