[go: up one dir, main page]

GB2207912A - Marine biofouling reduction - Google Patents

Marine biofouling reduction Download PDF

Info

Publication number
GB2207912A
GB2207912A GB08811713A GB8811713A GB2207912A GB 2207912 A GB2207912 A GB 2207912A GB 08811713 A GB08811713 A GB 08811713A GB 8811713 A GB8811713 A GB 8811713A GB 2207912 A GB2207912 A GB 2207912A
Authority
GB
United Kingdom
Prior art keywords
copper
ions
release
sea water
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
GB08811713A
Other versions
GB8811713D0 (en
Inventor
Michael Frederick Diprose
Edward Emyr Williams
Brent Knox-Holmes
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Unisheff Ventures Ltd
Original Assignee
Unisheff Ventures Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Unisheff Ventures Ltd filed Critical Unisheff Ventures Ltd
Publication of GB8811713D0 publication Critical patent/GB8811713D0/en
Publication of GB2207912A publication Critical patent/GB2207912A/en
Pending legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B63SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63BSHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B59/00Hull protection specially adapted for vessels; Cleaning devices specially adapted for vessels
    • B63B59/04Preventing hull fouling

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Agricultural Chemicals And Associated Chemicals (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)

Abstract

Marine biofouling of structures in contact with seawater is prevented by the simultaneous release into the seawater of copper and chlorine ions and which cooperate in a synergistic manner to provide an unexpected and unpredictable enhancement of the biocidal effect on marine organisms over and above the effect that could be predicted from the separate use of copper ions and chlorine ions.

Description

MARINE BIOFOULING REDUCTION This invention relates to marine biofouling reduction.
There are a number of on-shore and off-shore installations, that utilise sea water either as a substance to be processed e.g. in desalination plants and in the production of sea water magnesia, or in cooling systems in, e.g. power stations or the like. In such usages, large volumes of sea water are drawn through the system. One effect of the intake of large volumes of sea water is an inevitable fouling of the system, in one or both of two forms. Thus, there is marine biofouling caused by the attachment of macroorganisms and microorganisms to the walls of the pipework of the system. If left unattended the build-up of such biofouling organisms can obstruct or even block the system, and to close down the system and clean the affected pipework is expensive and timeconsuming.In addition to this there is socalled corrosion fouling where the surface of the material of the pipework or the like itself reacts with substances in the sea water producing either a deposit on or the direct degradation of the surface. Both types of fouling are closely interrelated as microbial biofouling almost invariably leads to corrosion fouling, a phenomenon generally known as microbially induced corrosion.
Similar considerations apply to sea water systems on board ships and to ships hulls and off-shore structures such as oilrigs in permanent contact with sea water.
Fouling as is mentioned above constitutes a major economic problem it being currently estimated that the cost to the world's petrochemical industry alone exceeds 1.4 billion, caused by such items as energy losses due to increased frictional resistance to the passage of water, increased heat transfer resistance, the provision of excess surface areas in heat transfer equipment to compensate for losses, premature replacement due to fouling, loss of power and production due to down time, and the provision for and rectification of safety hazards caused by corrosion failure in such items as heat exchange and associated equipment.
In an attempt to reduce the degree of marine biofouling, it is known to provide a copper electrode at the sea water intake of an installation or e.g., the intake of a cooling system of a ship, or on the surface of a structure sited in sea water, to which a DC current is applied. This causes the release of copper ions into the sea water to poison the marine biofouling organisms. However, micro-biofouling organisms are able to produce an outer skin to provide a degree of immunity to poisoning, and there is the progressive loss of electrode material.
It is the object of the present invention to provide a more effective method of reducing marine biofouling and associated corrosion fouling of sea water systems and on the hulls of ships and exteriors of oil rigs or other offshore installations.
According to the present invention a method of preventing marine biofouling of structures in contact with sea water comprises simultaneously releasing copper ions and chlorine ions into the seawater to produce an environment actively hostile to potential marine biofouling organisms.
The effect of releasing copper ions and chlorine ions simultaneously is that they cooperate in an unexpected synergistic manner to provide a biocidal effect on marine organisms that is considerably greater than the effect that could have been predicted from the separate use of copper ions and chlorine ions.
Preferably, the generation of copper and chlorine ions is achieved by strategically positioning on the structure appropriate electrodes, e.g., at the inlet to a sea water system, or spaced along the surface of a structure, and applying an appropriate current to the electrodes.
According to a second aspect of the present invention, a method of preventing marine biofouling and associated corrosion fouling of structures in contact with sea water comprises generating across the structure a combination of alternating and direct currents between two strategically located electrodes whereby to release into the sea water around or within the structure controlled amounts of chlorine ions and copper ions to produce an environment actively hostile to potential marine biofouling organisms.
In addition it is preferred to provide a third electrode for the simultaneous release of aluminium ions and which elevates considerably the alkalinity of- the sea water to a level that further enhances the biocidal action of the copper and chlorine ions.
Micro-organisms are able to produce a skin to resist any acidity in the sea water, or to resist any pollutants such as copper. But such organisms are highly sensitive to any alkalinity, and by ensuring that it is relatively high within a system or around a structure, the effectiveness in the combined effect of chlorine and copper ions is greatly increased.
The electric field generated by the AC current is adjusted so as to disrupt the settling behaviour but not be at a sufficient high level to cause the death of organisms.
At this general level there is believed to be a sufficient disruption of the action potentials at the nerve/muscle interfaces to assist in preventing the organisms from adhering to the walls of the system and to make them even more sensitive to the biocidal effect of the simultaneous presence of copper and chlorine ions.
The electrodes for an appropriate current generating means for the invention can be selected from a number of usable materials e.g. copper or arsenical copper for the release of copper ions, platinised titanium for the release of chlorine ions and when present aluminium for the release of aluminium ions. In a DC only system DC current is applied to each electrode in controlled manner and whereby to provide a required level of copper ions and chlorine ions with minimum erosion of the electrodes. In a combined AC/DC system the AC and DC current is applied to the copper electrode and the DC current applied to the platinised titanium and aluminium electrodes.Thus, a relatively high AC current can be applied to the copper electrode for its electric shocking effect, and a lower DC current applied to the copper electrode for the release of copper ions, and when there is the maximising of the disturbance of the marine biofouling organisms, with a predictable erosion of the electrodes, at a lower level than when a DC system alone is employed which consequently have a considerable useful life, and by careful control of current there are only small amounts of hydrogen and chlorine gas generated which can be dangerous if they are allowed to build up to any appreciable extent in, e.g. the ducting of a sea water system.
The generation of an electric field between the electrodes produces a current of a density dependent on the electrode type, form, and value of the impressed current, and by the resistance dictated by the salinity of the sea water and the distance between electrodes.
The effect on marine biofouling organisms is believed to be the sensitising of them, making them more sensitive to the combined action of the copper and chlorine ions released into the sea water, thereby enhancing their biocidal effect. Although difficult to quantify it is also believed that there is a disruption of the action potentials at the nerve/muscle interfaces of the organisms that reduces their capability of adhering to the walls of the system.
In a series of experiments to test the effectiveness of the invention, sea water was caused to flow across steelwork at a rate of 1 metre per second and at a volume of 2 to 3 cubic metres per hour and the degree of fouling checked after periods of two months and four months. That degree of fouling was used as a control factor.Simultaneously, sea water was caused to flow across steelwork at the same rates, in one instance with an arsenical copper electrode and a one amp AC generating system, in another instance with a platinised titanium electrode and a one amp DC generating system, in a third instance with an arsenical copper and an aluminium electrode with a 5mA DC system for the copper electrode and a 5mA DC system for the aluminium electrode, and in a fourth instance with an arsenical copper electrode with a 5mA amp DC system, a platinised titanium electrode wiht a .5A DC system and an aluminium electrode with a 25mA DC system.
After two and four months the degrees of fouling were measured and compared, with the following results, the control representing l% fouling 2 months 4 months Control 188 188 Cu 32.62 88.2 CI 24.28 62.1 Cu+Al 28.52 68.5 Cu+Cl+Al 8.14 25.5 Thus, after two months, the copper/AC system with its electrical shocking reduced fouling to approximately 32% of the fouling in the control system, with substantially no loss of electrode material. After four months, fouling had still been reduced by a significant 22% in comparison with the control.
With the invention, fouling after two months had been reduced to approximately 8% of that of the control, and to approximately 25% of that of the control after four months.
Those other electrodes tested for comparison, whilst showing reductions in fouling in comparison with the control, have significantly higher degrees of fouling in comparison with the second aspect of the invention, and which displayed degrees of fouling reduction at both two months and four months that could not be predicted from the effect of each type of electrode when considered alone.

Claims (7)

1. A method of preventing marine biofouling of structures in contact with sea water comprising simultaneously releasing copper ions and chlorine ions into the seawater to produce an environment actively hostile to potential marine biofouling organi sns.
2. A method as in Claim 1, wherein the release of copper ions and chlorine ions is by the application of a direct current to strategically positioned electrodes of a suitable character, e.g., at the inlet to a sea water system, or spaced along the surface of a structure.
3. A method of preventing marine biofouling and associated corrosion fouling of structures in contact with sea water comprising generating across the structure a combination of alternating and direct currents between strategically located electrodes whereby to release into the sea water around or within the structure controlled amounts of chlorine ions and copper ions to produce an environment actively hostile to potential marine biofouling organisms.
4. A method as in Claim 3, wherein a third electrode is provided for the simultaneous release of aluminium ions and which elevates considerably the alkalinity of the sea water to a level that further enhances the biocidal action of the copper and chlorine ions.
5. A method as in any of Claims 1 to 4, wherein the electrode materials for the release of copper ions and chlorine ions are of copper or arsenical copper and platinised titanium respectively.
6. A method as in Claim 3 wherein, the electrode masterials are of copper or arsenical copper to which an AC and a DC current is applied for the release of copper ions and platinised titanium to which a DC current is applied for the release of chlorine ions.
7. A method as in Claim 3, wherein the electrode material is aluminium to which a DC current is applied for the release of aluminium ions.
GB08811713A 1987-05-29 1988-05-18 Marine biofouling reduction Pending GB2207912A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB878712707A GB8712707D0 (en) 1987-05-29 1987-05-29 Marine biofouling reduction

Publications (2)

Publication Number Publication Date
GB8811713D0 GB8811713D0 (en) 1988-06-22
GB2207912A true GB2207912A (en) 1989-02-15

Family

ID=10618148

Family Applications (2)

Application Number Title Priority Date Filing Date
GB878712707A Pending GB8712707D0 (en) 1987-05-29 1987-05-29 Marine biofouling reduction
GB08811713A Pending GB2207912A (en) 1987-05-29 1988-05-18 Marine biofouling reduction

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB878712707A Pending GB8712707D0 (en) 1987-05-29 1987-05-29 Marine biofouling reduction

Country Status (1)

Country Link
GB (2) GB8712707D0 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996013425A1 (en) * 1994-11-01 1996-05-09 Synton Oy Method for inhibition of growth of organisms on faces of constructions submerged in a liquid
GB2303316A (en) * 1995-07-19 1997-02-19 Baker Hughes Ltd Biofouling reduction

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3241512A (en) * 1964-02-12 1966-03-22 William G Green Anti-fouling, barnacles, algae, eliminator

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3241512A (en) * 1964-02-12 1966-03-22 William G Green Anti-fouling, barnacles, algae, eliminator

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WO 87/03261 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996013425A1 (en) * 1994-11-01 1996-05-09 Synton Oy Method for inhibition of growth of organisms on faces of constructions submerged in a liquid
US5868920A (en) * 1994-11-01 1999-02-09 Synton Oy Method for inhibition of growth of organisms on faces of constructions submerged in a liquid
GB2303316A (en) * 1995-07-19 1997-02-19 Baker Hughes Ltd Biofouling reduction
GB2303316B (en) * 1995-07-19 1999-06-16 Baker Hughes Ltd Biofouling reduction
US6183646B1 (en) 1995-07-19 2001-02-06 Baker Hughes Incorporated Biofouling reduction

Also Published As

Publication number Publication date
GB8712707D0 (en) 1987-07-01
GB8811713D0 (en) 1988-06-22

Similar Documents

Publication Publication Date Title
US4869016A (en) Marine biofouling reduction
US5346598A (en) Method for the prevention of fouling and/or corrosion of structures in seawater, brackish water and/or fresh water
AU649246B2 (en) Method and apparatus for the prevention of fouling and/or corrosion of structures in seawater, brackish water and/or fresh water
US5868920A (en) Method for inhibition of growth of organisms on faces of constructions submerged in a liquid
Ali Inhibition of mild steel corrosion in cooling systems by low-and non-toxic corrosion inhibitors
GB2207912A (en) Marine biofouling reduction
WO1991018130A1 (en) Method and apparatus for the prevention of fouling and/or corrosion of structures in seawater, brackish water and/or fresh water
Rajendran et al. Synergistic effect of Zn exp 2+ and phenyl phosphonic acid in corrosion inhibition of mild steel in neutral environment
Cleland Corrosion risks in ships' ballast tanks and the IMO pathogen guidelines
NO169950B (en) PROCEDURE FOR AA HIDDEN MARINE BIOGROING OF CONSTRUCTIONS THAT ARE IN CONTACT WITH SEAWATER
CN87104491A (en) Method for reducing marine organism adhesion scale
Castle et al. Interaction of marine biofouling and corrosion on copper based alloys
CN101905913A (en) Seawater antifouling system and method based on propeller shore-based electrolysis
Wagner et al. An investigation of microbiologically mediated corrosion of copper-nickel piping systems selectively treated with ferrous sulfate
Morse Analysis of factors inducing dislodgement of zebra mussels (Dreissena polymorpha) from steel surfaces exposed to cathodic potentials
JPH01180289A (en) Sewage treating apparatus on sea surface
CN206970281U (en) A kind of current type anticorrosion and antifouling electrode assemblies
Spears et al. Electrolysis of copper screening: a technique for the prevention of marine fouling
Bour-Beucler Seawater fouling and biofouling
Williams et al. Marine biofouling solutions for closed seawater systems.
Upsher A review of microbially induced corrosion (MIC) of steel and a preliminary investigation to determine its occurrence in naval vessels
Zhongdao Protection of steel piles in harbours by using DZ tape and cathodic polarization
Lyublinskii Physico-Chemical Antifouling Protection
Glover et al. Corrosion and fouling resistance of cupro-nickel in marine environments
Visser Minimum-Cost Platform Designs—Cook Inlet, Alaska