WO2022208944A1

WO2022208944A1 - Method for preventing adherence of marine organisms etc.

Info

Publication number: WO2022208944A1
Application number: PCT/JP2021/036139
Authority: WO
Inventors: 洸太藤戸; 弘宜錦織
Original assignee: 株式会社片山化学工業研究所
Priority date: 2021-04-02
Filing date: 2021-09-30
Publication date: 2022-10-06

Abstract

The purpose of the present invention is to provide a method for preventing adherence of marine organisms etc. that exhibits an excellent effect of preventing the adherence of marine organisms and slime to seawater-using equipment through which seawater flows, without the use of a halogenic agent. The present invention relates to a method for preventing adherence of marine organisms etc. that prevents marine organisms and slime from adhering to seawater-using equipment through which seawater flows, said method being characterized by comprising: a peracetic acid addition step for adding an agent containing peracetic acid to the seawater; and a hydrogen peroxide addition step for adding hydrogen peroxide to the seawater, wherein in the peracetic acid addition step, the agent is added to the seawater such that the concentration of peracetic acid in the seawater is 0.1-10 mg/L, and the time during which the agent is added in the peracetic acid addition step is 0.5-12 hours per day.

Description

Method for preventing adherence of marine organisms, etc.

The present invention relates to a method for preventing adhesion of marine organisms and the like.

For example, many power plants, ironworks, petrochemical plants, etc. that use seawater as cooling water are built in places facing inland seas and bays in order to avoid waves. When seawater is taken in inland seas and bays, marine organisms such as mussels, barnacles, bryozoans, and hydroids living in the seawater, as well as slimes, etc. It adheres to water passages and causes various obstacles. For example, adhering marine organisms grow to clog water conduits such as heat exchanger tubes, impeding the flow of seawater and causing turbulence, causing problems such as erosion corrosion. In addition, if attached marine organisms are stripped off due to water pressure, flow velocity, etc., the tubes and strainers of the heat exchanger will be clogged, inhibiting the passage of seawater, and reducing the original function of the heat exchanger. cause.
In addition, in various factories, seawater is used not only as cooling water but also, for example, as dilution water and washing water. There is a problem that the flow of seawater is obstructed by the adhesion of slime or the like.
The normal attached breeding season for the above marine organisms is said to be from April to October. cause.

The marine organisms that inhabit the seawater described above coexist in the natural world while competing for attachment substrates, and mussels and barnacles have a strong reproductive power and are prone to the above attachment problems. Then, when the attachment of mussels and barnacles is suppressed, other marine organisms reproduce in their place. The representative marine organisms are hydrozoans, and among them, attachment failures of the Hydra and Obelia species have become a problem.

Conventionally, sodium hypochlorite, chlorine generating agents such as electrolytic chlorine or chlorine gas (also referred to as "chlorine agents"), hydrogen peroxide or peroxides have been used to prevent the formation (adherence) of the above marine species. A hydrogen generating agent (also referred to as a “hydrogen peroxide agent”) has been added (Patent Documents 1 and 2).

For example, Patent Document 2 discloses a method for suppressing adhesion of seawater animals, which is characterized by using hydrogen peroxide or a hydrogen peroxide generating agent, which is easily decomposable and has residual toxicity and accumulated toxicity. As a result of research into a safer method for suppressing adhesion of seawater animals without causing problems, it is disclosed that hydrogen peroxide is extremely effective. Further, organic peracids such as peracetic acid and salts thereof are disclosed as hydrogen peroxide generators.

Further, for example, Patent Literature 3 discloses a technique relating to an aquatic pest adhesion inhibitor characterized by containing peracetic acid. It is known that peracetic acid exerts a bactericidal action in a small amount in a short period of time, is excellent in biodegradability, and is excellent in safety ([Claim 1] etc., [0014] paragraph etc.). Also, for example, U.S. Pat. No. 6,200,000 discloses the use of peracetic acid as a microbial inhibitor in the white water circulation system of the pulp and paper industry, particularly Flavobacterium, Alkaligenes, Serratia, Paecilomyces, Geotrichum, Cephalosporium, Rhodotorula and Candida. It is disclosed that a strong bactericidal effect is observed against bacteria that constitute slime such as.
On the other hand, from the description of Patent Document 5, it is disclosed that the acetic acid contained in the peracetic acid-containing drug is used by microorganisms in the water system ([0010] etc.). It is known that increasing the amount increases the microbial load.

JP-A-11-037666 Japanese Patent Publication No. 61-002439 JP-A-06-227907 JP-A-63-122604 JP 2007-198869 A

In order to prevent the adhesion of marine organisms, there is a movement to avoid using halogen-based agents such as chlorine agents and bromine agents in consideration of the environmental impact of the generation of trihalomethanes and organic chlorine compounds, and the use of halogen-based agents. There is a demand for the development of a method for preventing adhesion of marine organisms and the like, which can exhibit an excellent effect of preventing adhesion of marine organisms and slime, without the need for cleaning.

As such a method, for example, as described in the above-mentioned Patent Document 2, there is a method for suppressing adherence of marine animals using hydrogen peroxide, which is easily decomposed into water and oxygen in water. However, since the antifouling effect of hydrogen peroxide and hydrogen peroxide generators on marine organisms is selective for the type of marine organisms, the normal use of hydrogen peroxide is limited to hydrozoans. It is difficult to prevent adhesion of marine organisms, which are not easily affected by strong oxidants and disinfectants.
On the other hand, as a chemical for effectively preventing adhesion of hydrozoans, a halogen-based chemical has conventionally been used, but as described above, it is not preferable from an environmental point of view.

In addition, in the method for suppressing adhesion of marine animals described in Patent Document 2 above, an organic peracid such as peracetic acid or a salt thereof is disclosed as a hydrogen peroxide generator. However, as described in Non-Patent Document 1, low-concentration peracetic acid easily decomposes into acetic acid and hydrogen peroxide. Adding acetic acid was considered equivalent to adding hydrogen peroxide, so it was considered unnecessary to add low-concentration peracetic acid.

In addition, peracetic acid is widely known as a disinfectant, for example, peracetic acid is used as in the water pest adhesion inhibitor and adhesion prevention method using peracetic acid as described in the above-mentioned Patent Document 3. A method for preventing adhesion of marine organisms and the like can be mentioned. However, in the method described in Patent Document 3, a high concentration peracetic acid solution of 0.16% or more (i.e., 1600 ppm or more) is immersed in or sprayed on seaweed nets and marine structures to produce algae and shellfish. However, the effect of adding low-concentration peracetic acid (for example, 10 ppm or less) has not been shown for preventing the adhesion of marine organisms and slime in a system in which seawater flows.

It is an object of the present invention to provide a method for preventing adherence of marine organisms and the like, which is capable of exhibiting an excellent effect of preventing adherence of marine organisms and slime to seawater utilization facilities through which seawater flows, without using a halogen-based chemical. Make it an issue.
In addition, the present invention provides a method for preventing adhesion of marine organisms, etc., capable of exhibiting an excellent effect of preventing adhesion of barnacles, hydrozoa, and slime to seawater utilization facilities through which seawater flows, without using a halogen-based chemical. The task is to provide

The inventors of the present invention have found that by adding a combination of a chemical agent (A) containing hydrogen peroxide and a chemical agent (B) containing peracetic acid to seawater, seawater such as barnacles and hydrozoa The inventors have found that it is possible to effectively prevent living organisms and slime from adhering to seawater utilization facilities through which seawater flows, and have completed the present invention.

That is, the present invention provides a method for preventing adhesion of marine organisms and slime to seawater utilization equipment through which seawater flows, comprising a peracetic acid addition step of adding a chemical containing peracetic acid to the seawater, and hydrogen peroxide. and a step of adding hydrogen peroxide to the seawater, and in the step of adding peracetic acid, the chemical is added to the seawater so that the concentration of peracetic acid in the seawater is 0.1 to 10 mg/L, and the peracetic acid is added to the seawater. The method for preventing adhesion of marine organisms is characterized in that the chemical addition time in the addition step is 0.5 to 12 hours per day.
The peracetic acid addition step and the hydrogen peroxide addition step are preferably performed alternately and/or overlapped.
It is preferable that the agent containing peracetic acid contains acetic acid, and in the peracetic acid addition step, the agent is added to the seawater so that the concentration of acetic acid in the seawater is less than 10 mg/L.
In the hydrogen peroxide addition step, hydrogen peroxide is preferably added to the seawater so that the concentration of hydrogen peroxide in the seawater is 0.1 mg/L or more.
The chemical addition time in the hydrogen peroxide addition step is preferably 12 to 24 hours per day.

According to the method for preventing adhesion of marine organisms and the like of the present invention, adhesion of a wide range of marine species (for example, marine organisms such as barnacles and hydrozoa) and slime to seawater utilization facilities in which seawater flows is prevented. can be prevented.
Furthermore, according to the method for preventing adhesion of marine organisms and the like of the present invention, a wide range of marine organism species (e.g., marine organisms such as barnacles and hydrozoa) and slime can be prevented.

The present invention is a method for preventing adhesion of marine organisms and slime to seawater utilization equipment through which seawater flows, comprising a peracetic acid addition step of adding a chemical containing peracetic acid to the seawater, and adding hydrogen peroxide to the seawater. In the peracetic acid addition step, the chemical is added to the seawater so that the peracetic acid concentration of the seawater is 0.1 to 10 mg / L, and the peracetic acid addition step A method for preventing adhesion of marine organisms, etc., characterized in that the chemical addition time is 0.5 to 12 hours per day.
In consideration of the impact on the environment, the inventors of the present invention have found that marine organisms such as barnacles and hydrozoa, and slime can be used in seawater utilization facilities in which seawater is circulated, without using halogen-based chemicals. In order to examine the method of preventing adhesion, experiments were repeated using model channels. As a result, the present inventors have found that by adding a combination of a peracetic acid-containing agent and hydrogen peroxide to seawater, it is possible to utilize seawater in which marine organisms such as barnacles, hydrozoa, and slimes circulate. It was found that adhesion to equipment can be effectively prevented. As described above, the bactericidal action of high-concentration peracetic acid is known. For example, in Patent Document 3, a high-concentration peracetic acid solution of 1600 ppm or more is used to prevent adhesion of algae and shellfish. However, it was only known that peracetic acid at low concentrations, eg, 10 ppm or less, could be used as a source of hydrogen peroxide. In addition, according to Non-Patent Document 1, it has been said that there is no necessity to use peracetic acid at a low concentration as a source of generation of hydrogen peroxide. Therefore, low-concentration peracetic acid has not actually been used for the purpose of preventing adhesion of marine organisms.
Under such circumstances, the present inventors have found that low-concentration peracetic acid (0.1-10 mg/L) has an excellent anti-adhesion effect on hydrozoans, and have completed the present invention.
In the method for preventing adhesion of marine organisms and the like of the present invention, a chemical containing peracetic acid is particularly effective in preventing adhesion of hydrozoa, and hydrogen peroxide is particularly effective in preventing adhesion of barnacles. be. Also, both peracetic acid-containing chemicals and hydrogen peroxide are effective in preventing slime from sticking. Since the method of the present invention includes a peracetic acid addition step of adding a chemical containing peracetic acid to seawater and a hydrogen peroxide addition step of adding hydrogen peroxide to seawater, it can be widely applied to seawater utilization facilities in which seawater flows. Adhesion of marine organisms and slime can be effectively prevented.

In the present invention, the seawater utilization facility through which seawater flows may be a seawater cooling water system in factories such as power plants, steelworks, and petrochemical plants that use seawater as cooling water. , the system may be a system in which seawater flows when using seawater as dilution water, washing water, or the like, and is not particularly limited. The seawater utilization equipment is not particularly limited as long as it forms a flow path through which seawater flows, and examples thereof include seawater intake channels, pipes, water conduits, heat exchangers, condensers, and drainage channels. .

In the method of the present invention, the peracetic acid addition step and the hydrogen peroxide addition step are preferably performed alternately and/or overlapped. In the method of the present invention, alternately performing the peracetic acid addition step and the hydrogen peroxide addition step means that the peracetic acid addition step and the hydrogen peroxide addition step are alternately performed with a time interval between them. Alternating without gaps, alternating with overlapping times, and combinations thereof. In addition, in the method of the present invention, the peracetic acid addition step and the hydrogen peroxide addition step are performed in duplicate, which means that the peracetic acid addition step and the hydrogen peroxide addition step are performed at the same time. It includes performing the other step intermittently or continuously while the other step is being performed.
That is, in the method of the present invention, when the peracetic acid addition step and the hydrogen peroxide addition step include a period in which both steps are performed alone, the peracetic acid addition step and the hydrogen peroxide addition step are performed alternately. In other words, when the peracetic acid addition step and the hydrogen peroxide addition step do not include a period in which both steps are performed independently, the peracetic acid addition step and the hydrogen peroxide addition step are performed in duplicate.
In addition, when the peracetic acid addition step and the hydrogen peroxide addition step are performed alternately with an interval, it is preferable that the interval is less than 6 hours. Moreover, when the peracetic acid addition step and the hydrogen peroxide addition step are performed alternately with an overlap time, it is preferable to provide an overlap time of less than 6 hours.
In addition, the order in which the peracetic acid addition step and the hydrogen peroxide addition step are performed in the method of the present invention does not matter.

In the method of the present invention, the peracetic acid addition step and the hydrogen peroxide addition step are preferably performed alternately. Since the chemical containing peracetic acid also contains hydrogen peroxide, overlapping the peracetic acid addition step and the hydrogen peroxide addition step means that the amount of hydrogen peroxide added to seawater is This is because the amount of hydrogen peroxide added is excessive, and the effect of preventing adhesion of marine organisms and slime cannot be expected in accordance with the amount of hydrogen peroxide added, which is not preferable from an economic standpoint.

[Drug containing peracetic acid]
In the method of the present invention, the agent containing peracetic acid may contain peracetic acid. A synthesized peracetic acid solution can be used, and is not particularly limited. For example, the agent containing peracetic acid may have been produced by the equilibrium reaction of hydrogen peroxide and acetic acid in an aqueous solution, and the peracetic acid solution produced by such equilibrium reaction is converted to It is preferable to use it as a drug to The peracetic acid solution produced by the equilibrium reaction contains hydrogen peroxide, peracetic acid and acetic acid. The peracetic acid concentration in the peracetic acid solution (that is, the peracetic acid concentration in the drug containing peracetic acid) can be measured by a known measuring method (eg, titration method).
The acetic acid used in the on-site synthesis of a drug containing peracetic acid may be acetic acid or a salt thereof, and an acetic acid solution commercially available for industrial use may be used.

Moreover, the peracetic acid-containing chemical used in the method of the present invention is preferably produced by the equilibrium reaction of hydrogen peroxide and acetic acid in an aqueous solution as described above.
The drug containing peracetic acid used in the method of the present invention preferably has a peracetic acid content of 1% by mass or more, more preferably 3% by mass or more, based on 100% by mass of the drug. It is more preferably at least 10% by mass, and even more preferably at least 10% by mass. Moreover, the content of peracetic acid is preferably 40% by mass or less with respect to 100% by mass of the drug.

When the drug containing peracetic acid used in the method of the present invention is produced by the equilibrium reaction of hydrogen peroxide and acetic acid in an aqueous solution, the concentration of acetic acid in the drug is 0.00% of the peracetic acid concentration. It is preferably 5 times or more and 25 times or less. This is because acetic acid is consumed by microorganisms and causes an increase in slime in seawater utilization facilities in which seawater flows.
The concentration of acetic acid in the agent is more preferably 0.5 to 20 times the peracetic acid concentration, further preferably 0.5 to 10 times, and 0.5 to 5 times. It is more preferably 0.5 times or more and 2 times or less is particularly preferable.

When the chemical containing peracetic acid used in the method of the present invention is produced by the equilibrium reaction of hydrogen peroxide and acetic acid in an aqueous solution, the concentration of hydrogen peroxide in the chemical is the concentration of peracetic acid. It is preferably 1-fold to 5-fold, more preferably 1-fold to 3-fold, and even more preferably 1-fold to 2-fold. When the peracetic acid-containing drug is produced by an equilibrium reaction between hydrogen peroxide and acetic acid in an aqueous solution, the peracetic acid-containing drug contains hydrogen peroxide, but the addition of the drug applies only to the peracetic acid addition step in the method of the present invention, and does not apply when the peracetic acid addition step and the hydrogen peroxide addition step are performed in duplicate. In the peracetic acid-adding step of the present invention, the peracetic acid-containing chemical may contain hydrogen peroxide, but peracetic acid is not added in the hydrogen peroxide-adding step of the present invention. Therefore, the case where the peracetic acid addition step and the hydrogen peroxide addition step are performed alternately with an overlap time means that hydrogen peroxide different from the chemical containing peracetic acid is separately added to the seawater.

In the method of the present invention, the method of adding the drug containing peracetic acid is not particularly limited, but in one or more embodiments, it may be carried out by sending the liquid from a pipe connected to the pipe with a pump or the like. In addition, the drug may be appropriately diluted with seawater or fresh water.

In the peracetic acid addition step, a chemical containing peracetic acid is added to seawater so that the peracetic acid concentration in seawater is 0.1 to 10 mg/L. By adding a peracetic acid-containing agent to seawater so that the concentration of peracetic acid in seawater falls within the above range, it is possible to effectively prevent adhesion of hydrozoans to seawater utilization facilities through which seawater flows. .
In the method of the present invention, it is preferable to add an agent containing peracetic acid to seawater so that the concentration of peracetic acid in seawater is 0.15 mg/L or more, and the agent is added so that the concentration of peracetic acid in seawater is 0.2 mg/L or more. Adding to seawater is more preferable. In the method of the present invention, it is preferable to add a peracetic acid-containing agent to seawater so that the peracetic acid concentration in seawater is 6 mg/L or less, and peracetic acid is added to seawater so that the peracetic acid concentration is 4 mg/L or less. It is more preferable to add the chemical to seawater, and it is even more preferable to add the chemical to seawater so that the concentration becomes 2 mg/L or less.
Further, in the method of the present invention, the upper and lower limits of the peracetic acid concentration in seawater can be appropriately combined to determine the numerical range.
In the method of the present invention, the concentration of the agent containing peracetic acid is preferably adjusted appropriately so that the concentration of peracetic acid in seawater falls within the above range.

In the method of the present invention, the peracetic acid-containing agent used in the peracetic acid addition step contains acetic acid as described above, and in the peracetic acid addition step, the concentration of acetic acid in seawater is less than 10 mg / L. Addition of the above agents is preferred. Acetic acid is a kind of organic acid and is a water-soluble low-molecular-weight compound that can be used by microorganisms. Therefore, when the acetic acid concentration of seawater is 10 mg/L or more, microorganisms in the seawater may consume acetic acid and increase it.
In the method of the present invention, in the peracetic acid addition step, it is more preferable to add a chemical containing peracetic acid to the seawater so that the acetic acid concentration of the seawater is 6 mg/L or less, and the acetic acid concentration of the seawater is 5 mg/L or less. It is more preferable to add the above-mentioned chemical to seawater so that the concentration becomes 2 mg/L or less.

[hydrogen peroxide]
The hydrogen peroxide added in the hydrogen peroxide addition step of the method of the present invention may be at least one of hydrogen peroxide and a hydrogen peroxide generator. Hydrogen peroxide, in one or more non-limiting embodiments, may be in the form of an aqueous hydrogen peroxide solution. Examples of hydrogen peroxide generating agents include those that generate hydrogen peroxide in liquids such as water. In one or more embodiments, soluble percarbonates such as sodium percarbonate and potassium percarbonate, perboric acid Examples include various soluble peroxyacid salts such as soluble perborate salts such as sodium and potassium perborate, urea/hydrogen peroxide adducts, metasilicate/hydrogen peroxide adducts, and sodium peroxide. However, in the method of the present invention, the hydrogen peroxide generating source does not contain peracetic acid.

In the hydrogen peroxide addition step, the method of adding hydrogen peroxide to seawater is not particularly limited, but in one or more embodiments, it may be carried out by sending the liquid from a pipe connected to the pipe with a pump or the like. . In addition, hydrogen peroxide may be appropriately diluted with seawater or fresh water.

In the hydrogen peroxide addition step, hydrogen peroxide is preferably added to the seawater so that the concentration of hydrogen peroxide in the seawater is 0.1 mg/L or more. As described above, hydrogen peroxide has an excellent effect of preventing adhesion of barnacles to seawater utilization equipment in which seawater flows, and it is more preferable that the hydrogen peroxide concentration in seawater is 0.1 mg / L or more. is 0.15 mg/L or more, by adding hydrogen peroxide to seawater, it is possible to sufficiently effectively prevent barnacles from adhering to seawater utilization facilities through which seawater flows. On the other hand, when the concentration of hydrogen peroxide in seawater exceeds 2.0 mg / L, the amount of hydrogen peroxide added increases, and the seawater in which marine organisms and slime seawater according to the amount of hydrogen peroxide circulates. It is not preferable from an economical point of view because the effect of preventing adhesion to the equipment used cannot be expected.
In the method of the present invention, it is preferable that the concentration of hydrogen peroxide to be added is appropriately adjusted so that the concentration of hydrogen peroxide in seawater falls within the above range.

In the method for preventing adhesion of marine organisms of the present invention, the chemical addition time in the peracetic acid addition step is 0.5 to 12 hours per day. If the peracetic acid-containing drug is produced by the equilibrium reaction of hydrogen peroxide and acetic acid in an aqueous solution, the addition time of the drug in the peracetic acid addition step is within 12 hours per day. This is because the addition time to seawater is also within 12 hours, and by limiting the addition time of acetic acid consumed by microorganisms, it is possible to prevent the increase of slime and the like. Further, in the method for preventing adhesion of marine organisms and the like of the present invention, it is preferable that the chemical addition time in the hydrogen peroxide addition step is 12 to 24 hours per day. Addition in each addition step may be continuous addition or intermittent addition, and is not particularly limited.
Further, in the method for preventing adhesion of marine organisms of the present invention, the addition time may be adjusted according to the peracetic acid concentration of the peracetic acid-containing agent in seawater. The peracetic acid concentration of the peracetic acid-containing agent relative to seawater may be adjusted. For example, when a chemical containing peracetic acid is added to seawater so that the peracetic acid concentration in seawater is 0.1 mg/L or more and less than 2 mg/L, the addition time of the chemical is 0.5 to 12 hours. Preferably. Further, when a chemical containing peracetic acid is added to seawater so that the peracetic acid concentration in seawater is 2 mg/L or more, the addition time of the chemical is preferably 0.5 to 6 hours.

Marine organisms and the like for which the method of the present invention is used include marine organisms including barnacles, hydrozoa (sea hydra, obelia) and slime. It is preferably used for prevention.

The agent (agent containing peracetic acid, hydrogen peroxide) in the present invention is added to the intake channel, the heat exchanger or the piping attached to the condenser, the water conduit, the inlet of the heat exchanger or the condenser. It can be either entrance. Moreover, the peracetic acid addition step and the hydrogen peroxide addition step may be performed at the same position in the seawater utilization facility through which seawater flows, or may be performed at different positions. Both the peracetic acid addition process and the hydrogen peroxide addition process should be located at least one of the intake channel, the entrance of the heat exchanger, and the entrance of the condenser in terms of the effect of preventing damage due to adhesion of marine organisms. is preferred.

In the adhesion prevention method of the present invention, the measurement location of the peracetic acid concentration, the acetic acid concentration and/or the hydrogen peroxide concentration in the seawater flowing through the seawater utilization facility is not particularly limited. Any place where the water quality is measured is acceptable, and it is preferable to carry out at least one of the drainage channel, the outlet of the heat exchanger, and the outlet of the condenser.

In the method for preventing adhesion of marine organisms of the present invention, other additives known in the art may be used in combination as long as the effects of the present invention are not impaired.
For example, low concentrations of halogen-based chemicals that do not affect the environment (e.g., hypochlorous acid, hypobromous acid, seawater electrolyte, combined chlorine and combined bromine such as monochloramine, N-chlorosulfamate (e.g., stabilized chlorine, stabilized bromine, chlorine dioxide, etc.), dialkyldithiocarbamates, marine biofouling inhibitors such as cationic surfactants, iron-based metal corrosion inhibitors, antifoaming agents, and the like.

In the method of the present invention, the concentration of each component in seawater (peracetic acid concentration, acetic acid concentration, hydrogen peroxide concentration, residual chlorine concentration, etc.) can be measured by a known method.

The present disclosure will be further described below using examples. However, the present disclosure should not be construed as being limited to the following examples.

[Evaluation test using model channel]
A hydrographic test equipment was installed at a certain place on the coast of Wakayama Prefecture facing the Pacific Ocean, and tests were conducted. Unfiltered seawater (pH 8) pumped using a submersible pump was pumped into a water channel (test area) branched into 8 systems at a flow rate of 1 m ³ /h for 78 days (August 2020 to October 2020). , and the chemicals listed in Table 1 were added to each channel so that the concentration in seawater and the addition time per day were shown in Table 1 (Reference Examples 1 and 2, Comparative Examples 1 to 4 and Examples 1 and 2).
In addition, unfiltered seawater (pH 8) pumped using a submersible pump was sent to a water channel (test area) branched into 7 systems at a flow rate of 1 m ³ /h for 76 days (April 2021 to June 2021). Water was passed through the system, and the chemical shown in Table 1 was added to each channel so that the concentration in seawater and the addition time per day shown in Table 1 were obtained (Comparative Example 5 and Examples 3 to 8). .

In each waterway (inside each test area) of the waterway test apparatus, an acrylic column (inner diameter 64 mm × length 300 mm × thickness 2 mm, surface area: 602.88 cm ² , divided into half in a semicircular shape) is used for the investigation of attached organisms. A vinylon net with a mesh size of 5 mm and a thread diameter of 1 mm was attached to the inner surface of one of the perillas and made into a column again). ) was measured to evaluate the effect of preventing adhesion of marine organisms.
In addition, a test tube made of titanium (inner diameter: 23.4 mm, length: 1000 mm, wall thickness: 1.0 mm) was installed in each water channel to check the effect of preventing slime stains. The amount of dirt mainly composed of formed slime was measured to evaluate the slime adhesion prevention effect. In addition, as a blank, the test was also performed without the addition of the drug.
The obtained results are shown in Table 1 together with peracetic acid concentration, acetic acid concentration and hydrogen peroxide concentration in seawater, and addition time per day.

(Drug containing peracetic acid (peracetic acid solution A))
Peracetic acid solution A was prepared by mixing 35% hydrogen peroxide 60%, acetic acid 38%, sulfuric acid 1%, and 60% HEDP (1-hydroxyethylidene-1,1-diphosphonic acid) aqueous solution 1%. It was prepared by leaving it for days. The hydrogen peroxide and total peroxide concentrations of the prepared peracetic acid solution A were measured by a conventionally known titration method, and the composition was calculated from the obtained results. 4% and 26.7% acetic acid.

(Drug containing peracetic acid (peracetic acid solution B))
Peracetic acid solution B is a mixture of 35% hydrogen peroxide 60%, acetic acid 32%, water 6%, sulfuric acid 1%, and 60% HEDP (1-hydroxyethylidene-1,1-diphosphonic acid) aqueous solution 1%. , was prepared by standing at room temperature for 2 days. The hydrogen peroxide and total peroxide concentrations of the prepared peracetic acid solution B were measured by a conventionally known titration method, and the composition was calculated from the obtained results. 0% and 32.0% acetic acid.

The prepared peracetic acid solution A or peracetic acid solution B was placed in front of the acrylic column for checking the anti-adhesion effect, using a metering pump, so that the concentration in seawater and the addition time per day shown in Table 1 were obtained. added. Specifically, in Comparative Examples 3 and 4 and Examples 1 to 4 and 8, peracetic acid solution A or peracetic acid solution B was added between 12:00 and 18:00 (6 hours) in one day. In Examples 5 and 7, the peracetic acid solution A was added between 14:00 and 16:00 (2 hours) in one day. Further, in Example 6, the peracetic acid solution A was added between 14:00 and 24:00 (10 hours) in one day. In Comparative Example 5, the peracetic acid solution A was added between 14:00 and 4:00 the next day (14 hours).

(hydrogen peroxide)
Hydrogen peroxide was adjusted to the chemical concentration to be added to seawater by appropriately diluting a commercially available 35% hydrogen peroxide solution with pure water. It was added so that the concentration in seawater and the addition time per day shown in Table 1 were obtained. Specifically, in Reference Example 2, from 6:00 p.m. 18 hours), the hydrogen peroxide solution was added. In Example 6, hydrogen peroxide was added during the period from 00:00 to 14:00 (14 hours) in one day. In Comparative Example 5, hydrogen peroxide was added during the period from 4:00 to 14:00 (10 hours) in one day.

(chlorine)
Sodium hypochlorite is adjusted to the chemical concentration to be added to filtered seawater by appropriately diluting a commercially available sodium hypochlorite aqueous solution with an effective chlorine concentration of 12% with pure water. A metering pump was used before the production column, and added so that the concentration in seawater and the addition time per day shown in Table 1 were obtained. Specifically, in Reference Example 2, the sodium hypochlorite solution was added between 15:00 and 17:00 (2 hours) in one day.

(Aliphatic quaternary ammonium salt)
Hexadecyltrimethylammonium chloride, which is an aliphatic quaternary ammonium salt, was placed in front of an acrylic column for checking the anti-adhesion effect in the same way as hydrogen peroxide, using a metering pump. It was added so as to meet the addition time per day. Specifically, in Example 8, the aliphatic quaternary ammonium salt was added between 18:00 and 12:00 the next day (18 hours).

When adding two or more types of chemicals to each channel, separate chemical addition points were provided in front of the acrylic column for checking the anti-adhesion effect.

[evaluation]
(Measurement of number of attached barnacles and coverage of hydrozoa)
Deposition of barnacles and coverage of hydrozoa (%) were measured from the recovered column. As for the attachment of barnacles, the presence or absence of attachment of barnacles with a diameter of 2 mm or more was confirmed by visual observation of each column. The hydrozoan coverage (%) is obtained by pressing a net with a mesh size of 5 mm against the column after the completion of water passage, counting the number of meshes on the coated surface and the uncoated surface, and dividing the surface area of 602.88 cm ² of the column into 100%. The coverage was calculated as Based on the calculation results, evaluation was made as follows.

(Barnacles)
When no barnacles with a diameter of 2 mm or more adhered, it was evaluated as "O", and when adhesion was observed, it was evaluated as "X". If the evaluation is "O", it can be judged that there is an effect of preventing adhesion of barnacles. The results obtained are listed in Table 1.
(hydrozoans)
It was evaluated as “◯” when the coverage was 5% or less, “Δ” when the coverage was 5 to 10%, and “×” when the coverage exceeded 10%. If the evaluation is "Δ", it can be judged that there is an effect of preventing adhesion of hydrozoa, and if the evaluation is "◯", it can be judged that the effect of preventing adhesion of hydrozoa is sufficient. The results obtained are listed in Table 1.

(Slime measurement)
After the test, the dirt mainly composed of slime formed on the inner surface of the test tube removed from the water channel was scraped off, collected in a 100 mL graduated cylinder, and the wet volume after standing still for 4 hours was measured.
The slime scraped off in the blank originated mainly from microorganisms adhering to the test tube. Similar to the confirmation of the adhesion prevention effect in the column, the slime adhering to the inner surface of the test tube also contains detritus, but the titanium tube diameter of the test tube is about 1/3 of the column diameter, and the inside of the tube is distributed. The seawater flows at high speed, and it has been confirmed that there is no attachment of mussels such as mussels, barnacles, bryozoans, and other marine organisms.
From the state of slime adhesion on the blank, in this test example, "○" when the wet volume is 5 mL or less, "△" when the wet volume is more than 5 mL and 10 mL or less, and "×" when the wet volume exceeds 10 mL ” was evaluated. If the evaluation is ".DELTA.", it can be judged that there is an effect of preventing adhesion of slime, and if the evaluation is "O", it can be judged that the effect of preventing adhesion of slime is sufficient. The results obtained are listed in Table 1.

As shown in Table 1, peracetic acid solution A or peracetic acid solution B (both of which contain peracetic acid) was added as chemical 1 to seawater so that the concentration of peracetic acid in seawater was 0.1 mg/L or more. In Examples 1 to 8, in which the agent was added for 1 hour or less and hydrogen peroxide was added to the seawater as chemical agent 2, adhesion of barnacles, hydrozoa and slime could be effectively reduced.
In particular, barnacles and hydrozoa marine organisms can be reduced to the same level as Reference Example 2 in which chlorine is added to seawater as agent 1 and hydrogen peroxide is added to seawater as agent 2. It was confirmed that it is effective in preventing adhesion of marine organisms.
On the other hand, in Comparative Examples 1 and 2, in which only hydrogen peroxide was added, the effect of preventing adhesion of hydrozoa was not sufficient, and in Comparative Example 3, in which only peracetic acid solution A was added, the adhesion of barnacles was prevented. The effect was not sufficient. In addition, in Comparative Example 4, in which peracetic acid solution A was added to seawater so that the peracetic acid concentration in seawater was 0.05 mg/L as chemical agent 1, even when used in combination with hydrogen peroxide, adhesion of hydrozoans The preventive effect was not sufficient.
Further, when confirming Comparative Example 5, peracetic acid solution A was added to seawater so that the peracetic acid concentration in seawater was 0.1 mg/L or more as chemical agent 1, and hydrogen peroxide was added to seawater as chemical agent 2. However, since the addition time of the peracetic acid solution A was 14 hours and exceeded 12 hours, slime adhered. Comparing Comparative Example 5 and Example 6, the peracetic acid concentration in peracetic acid solution A is the same at 2.5 mg/L, but the addition time of peracetic acid solution A is different. That is, it was confirmed that slime increased due to the influence of acetic acid in the peracetic acid solution A when the addition time of the peracetic acid solution exceeded 12 hours.

Claims

A method for preventing adhesion of marine organisms and slime to seawater utilization equipment through which seawater flows,
a peracetic acid addition step of adding a chemical containing peracetic acid to the seawater;
A hydrogen peroxide addition step of adding hydrogen peroxide to the seawater,
In the peracetic acid addition step, the chemical is added to the seawater so that the peracetic acid concentration in the seawater is 0.1 to 10 mg/L,
A method for preventing adhesion of marine organisms, etc., characterized in that the chemical addition time in the peracetic acid addition step is 0.5 to 12 hours per day.
The method for preventing adhesion of marine organisms, etc. according to claim 1, wherein the peracetic acid addition step and the hydrogen peroxide addition step are performed alternately and/or overlappingly.
3. The marine organism according to claim 1, wherein the agent containing peracetic acid contains acetic acid, and in the peracetic acid addition step, the agent is added to the seawater so that the concentration of acetic acid in the seawater is less than 10 mg/L. and other adhesion prevention methods.
4. The prevention of adhesion of marine organisms etc. according to claim 1, 2 or 3, wherein in the hydrogen peroxide addition step, hydrogen peroxide is added to the seawater so that the hydrogen peroxide concentration of the seawater is 0.1 mg / L or more. Method.
The method for preventing adhesion of marine organisms etc. according to claim 1, 2, 3 or 4, wherein the chemical addition time in the hydrogen peroxide addition step is 12 to 24 hours per day.