Connect with us

Buoy Seawater Batteries , how do buoys get power ? magnesium at the anode

Discussion in 'General Electronics' started by Br Dan Izzo, Sep 9, 2004.

Scroll to continue with content
  1. Br Dan Izzo

    Br Dan Izzo Guest

    Seawater Battery

    magnesium at the anode

    The power for all the NEREID system is supplied by the SWB system,
    which consists of three SWB1200 (Kongsberg Simrad, Norway) cells
    (Hasvold et al., 1997), a DC/DC converter, and an accumulator. The
    cell is a magnesium/oxygen battery based on a magnesium anode
    (negative electrode) that uses seawater as the electrolyte and oxygen
    dissolved in the seawater as the oxidant.

    The chemistry of the cell is the dissolution of magnesium at the
    anode, given as

    2Mg = 2Mg+ + 4e-, (1)
    and consumption of oxygen at the cathode,

    O2 + 2H2O + 4e- = 4OH-, (2)
    which is written in a simplified form

    2Mg + O2 + 2H2O = 2Mg(OH)2. (3)
    The formation of an alkaline at the cathode surface may lead to the
    formation of a calcareous deposit as follows:

    4Ca2+ + 4HCO3- + 4OH- = 4CaCO3 + 4H2O. (4)
    The alkaline reaction products need to be removed from the cathode
    surface by sea current because the calcareous formation disturbs the
    reaction (Equation 2) at the cathode.

    The anodes are AZ61 magnesium alloy rods with a diameter of 184 mm and
    a length of 2200 mm, including the anode connector device. The anode
    can be replaced by ROV and is surrounded by the cathodes suspended
    from the titanium frame (Fig. F19). The weight (in air) of each anode
    is 110 kg and that of the titanium cathode frame is 62 kg. The cathode
    element consists of a titanium wire core with carbon fibers oriented
    radially (Fig. F20). The carbon fibers allow rapid material transport
    and high current density. The cathode collector lead is connected to
    the titanium frame, which is also part of the cathode. The titanium
    frame allows seawater to pass easily through the cells so that
    oxygen-rich seawater is supplied to the cathode and the products of
    the cell reactions are removed.

    The obtainable cell voltage is ~1.6 V, although this depends largely
    on the conductivity of the seawater, which may vary with temperature
    and salinity. The catalytic effect of bacteria colonizing on the
    cathode surface, which was observed on all seawater cells in previous
    deployments of the system, is another of the many factors affecting
    the cell voltage. The maximum cell power is limited by the rate of the
    supply of oxygen to the cathode. The oxygen supply rate is
    proportional to the oxygen concentration in the seawater and the speed
    of circulation. To produce the designed output of 6 W for each cell, a
    minimum circulation of 20 mm/s, oxygen concentration of 3 ppm, and
    minimum salinity of 20 is required. At Sites 1150 and 1151, where the
    water depth is ~2500 m, an oxygen concentration of ~2.7-3.6 ppm is
    expected based on previous study near these sites (M. Kawabe, pers.
    comm., 1998).

    Because the cells have an open structure, the isolation between them
    is low, which leads to large leakage currents in serially connected
    cells. The cells are consequently connected in parallel. The DC/DC
    converter changes the low cell voltage (1.6 V) into the output voltage
    (42.0 V). The output of the DC/DC converter is fed to the accumulator
    that averages the power demand on the DC/DC converter and the seawater
    cells. After deployment of the cells, the DC/DC converter is inactive
    until the cell voltage becomes >1.54 V. After the cells are activated,
    the DC/DC converter takes power from the cells and charges the
    accumulator as long as a sufficient cell voltage (>1.28 V) is
    available. If the cell voltage becomes lower than that threshold, the
    DC/DC becomes inactive until the cell voltage is restored to 1.54 V.
    The low threshold depends on the status of the accumulator cell
    charge. The lower the cell charge is, the lower the threshold becomes.
    The lowest threshold is ~1.28 V. The accumulator consists of multiple
    2-V Cyclon (Hawker Energy) lead acid cells that form a 5-Ah 36-V cell
    in total. The accumulator cell is float charged by the DC/DC output.
    The voltage of the accumulator output is 42.0 V when the accumulator
    cell is fully charged and has no charging voltage applied by the DC/DC
    converter. The cell is stored in a 6500-m depth-rated pressure housing
    that has four-pin GISMA series-10 underwater connectors for the load
    output and the DC/DC converter. The DC/DC converter is also stored in
    a similar pressure housing but has two Subconn one-way underwater
    power connectors for the SWB cells and the GISMA connector for the

    Battery Frame
    The SWB system is mounted on the PAT, as shown in Figures F21 and F22.
    The three SWB cells are stored in concentric positions. The PAT is
    made of ordinary angle steel that is zinc coated; the base is coated
    with tar epoxy paint to protect it from corrosion. The titanium frame
    of the SWB cell and the stainless-steel pressure housings for the
    DC/DC converter and the accumulator are mounted on the PAT with
    polyvinyl chloride insulators. The top of the PAT is a white, flat
    panel made of fiber-reinforced plastic (FRP) drainboard that has
    access holes for the SWB anodes. The flat panel, which viewed from
    above is circular, serves as the ROV platform and is supported by a
    metal frame. The diameter of the top plate is 3200 mm. The bottom
    structure of the PAT is also circular, and the diameter is 3658 mm,
    which corresponds to the diameter of the reentry cone. The bottom leg
    is 240 mm in height. The battery cells are elevated above the reentry
    cone to improve seawater circulation through the cells. The center
    bottom part of the PAT contains coaxial rings placed to guide it
    smoothly over the riser assembly on its installation. The hole in the
    top center part of the PAT provides space for the MEG frame. The total
    height of the PAT is 2640 mm to accommodate the SWB cells. The
    vertical position of MEG on the riser is set to allow ROV service.

    The PAT also holds the SAM recorder frame beneath the PAT top panel.
    The top part of the SAM recorder protrudes from the panel. The SAM
    recorder can be lowered into the hole of the frame panel so that the
    UMC at the bottom of the SAM bulkhead is mated by gravity force to a
    UMC receptacle on the stab-plate placed in the SAM frame. In the
    lowering operation the hole keeps the SAM canister upright; a key on
    the bottom bulkhead of the SAM canister aligns with the keyway in the
    hole to provide correct orientation for mating the UMC. The cable from
    the UMC receptacle has a T-junction: one branch is connected to the
    SWB system and the other goes to a receptacle mounted on the FRP
    panel. An installed cable on the panel is used by the ROV to connect
    the UMC receptacle to the MEG canister. Initially, the ROV cable is
    fastened to the top panel by fastening mechanisms and a parking
    connector for the ROV plug. In September 1999, the ROV removed the
    fasteners and connected the ROV's UMC plug to the MEG canister. The
    SAM recorder can be ejected with help from an ROV-operated lever
    mechanism in the SAM frame (Fig. F23). The lever can be locked at two
    positions: one at the mated position of the SAM and the other at the
    released position. By using the locking positions, the ROV can easily
    replace the SAM recorders.

    This is the html version of the file
    G o o g l e automatically generates html versions of documents as we
    crawl the web.
    To link to or bookmark this page, use the following url:

    Google is not affiliated with the authors of this page nor responsible
    for its content.
    These search terms have been highlighted: seawater magnesium

    Page 1
    De-P002Room: PosterTime: June 8 17:30-19:30Evaluation of Kongsberg
    Simrad magnesium seawater battery SWB 600 aimed to verylong term ocean
    bottom observation# Tomoki Watanabe [1], Masashi Mochizuki [2], Hajime
    Shiobara [3], Toshihiko Kanazawa [4][1] Earthquake Res. Inst., Univ.
    Tokyo, [2] ERI, Univ. of Tokyo, [3] Dep. Earth Sci., Fac. Sci., Toyama
    Univ., [4] ERI, TokyoUnivFor very long term ocean bottom observation
    more than several years, we made evaluation of Kongsberg Simrad
    ASseawater battery SWB 600(anode: magnesium, cathode: fibre glass
    carbon) around Japanese Sea in December, 1998. Inpresent experiment,
    we measured voltage of seawater battery directly using a digital
    recorder and cement resistors. Seawaterbattery began to produce
    electric power just after touch with seawater. Maximum power output of
    3W(1.83V) was observed atthe beginning of deployment, and most of this
    value indicated 2W(1.5V). In this experiment, we found that output
    voltagefrom seawater battery was strongly influenced by
    electrochemical circumstances in seawater.


    Data buoy operations safety


    Following explosion in august 2001 of a moored data buoy during
    maintenance onboard a ship in the Bay of Bengal which resulted in the
    death of a crew member, the Indian National Institute for Ocean
    Technology (NIOT) who operated the buoy consituted an expert committee
    to examine the incident. The committe included distinguished
    scientists in mechanical and electrical engineering, battery
    development and manufacture, forensic science and pressure vessels.
    This committee had concluded that the explosion was due to the
    emission of hydrogen and oxygen from overcharged batteries, ignited by
    an electrical spark. The recommendations of the expert committee were
    then placed before the Data Buoy Cooperation Panel and the issue was
    discussed further with the buoy operator represented by Dr. Premkumar
    (), Panel Members, and manufacturers at its 17th
    session in Perth, 22-26 OCtober 2001.

    Report from manufacturer also suggested that likely causes of the
    explosion were:

    The release of hydrogen gas from the batteries inside the instrument
    cylinder, resulting from their overcharging;
    A temperature rise of the batteries resulting from the buoy being kept
    on deck for 1.5 hours, leading to the generation of hydrogen beyond an
    acceptable limit;
    A spark generated in the electrical circuit.
    After discussion, the panel recommended that manufacturers should
    enhance buoy safety through improved design in the following areas

    Batteries are to be placed in a vented compartment, eliminating voids
    as far as possible, with a double venting arrangement;
    Incorporation of an overcharge controller and temperature controlled
    switch, to disconnect the batteries from the solar panels when
    Incorporation of an explosive gas sensor and temperature sensor inside
    the battery compartment and instrument cylinder, with the data to be
    transmitted once a day, to allow corrective action, or suitable
    explosive gas testing procedures, to be undertaken on buoy retrieval
    or servicing;
    Incorporation of continuous monitoring of battery charge current and
    voltage, to be transmitted with the buoy data;
    Incorporation of a suitable purging system and procedures.
    The panel requested both manufacturers and buoy operators to keep it
    informed of the improvements being carried out towards buoy safety, so
    that it in turn can inform all other operators of these as a part of
    its technical information exchange function, in the interests of the
    whole community. Information on current manufacture and maintenance
    recommendations will be placed in this web page.

    Buoy operators and manufactuers are urged to take above information
    into account.


    Annex: Other accidents which already happened
    UK Met. Office (information provided by Wynn Jones):

    Some years ago UK Met. Office had a buoy invert because the foot had
    been removed by fishermen or other unauthorised persons. When the buoy
    was eventually retrieved after it had drifted ashore there was some
    evidence that some of the batteries had come loose and had shorted
    against the steel lid of the container pod they are housed in, causing
    an explosion. However, the explosion was contained within the buoy
    hull which remained water tight. There was no injury to anyone and the
    buoy, and most of its electronics were reused. After that, UKMO
    modified the brackets that hold the batteries in place such that they
    will not move even if inverted. UKMO practise of housing them in their
    own stainless steel container which is itself inside the steel hull of
    the buoy probably minimises the consequences such an explosion can

    NDBC (information provided by Eric Meindl, ):

    A short summary of findings and activities at NDBC with respect to
    dealing with explosive gases in moored buoys is given below. NDBC
    efforts began in 1988 when an aluminium buoy (6-m NOMAD type),
    returned from the field and just opened up within NDBC industrial
    facility, exploded. As a result, NDBC now uses meters to sample the
    interior of all buoys. NDBC have experienced one or two other
    explosions at sea with no injuries, and many incidents when
    technicians have taken air samples, found the situation dangerous, and
    implemented special procedures to vent the buoy. Information below
    addresses specifically the NDBC buoys, which are vented systems, not
    sealed as other systems might be. Nevertheless, there may be some
    information others can use to make their procedures safer. NDBC also
    has specific, detailed reports of their experiences and what they
    know. These can be made available upon request.

    Summary of NDBC Buoy Power System Flammable Gas

    Problems and Solutions

    1. Hydrogen gas generation in buoys:

    Hydrogen gas mixtures in air are flammable between 4% and 75% by
    Accumulation rates increase with poor buoy ventilation (water
    intrusion blocks the lower center compartment vent)
    Electrolysis (the conductive path is from the positive terminal,
    through seawater moisture on the exterior of batteries to the buoy
    Reduction of battery electrolyte (potassium hydroxide and zinc),
    aluminum and seawater. The primary batteries are located near the
    bottom of the buoy center compartment.
    Normal charging of secondary batteries and discharging of primary
    Microbial induced corrosion
    2. Hydrogen Gas Generation Past Incidents:

    SSC/6N03 1988 Explosion resulted in one death & one injury (a)
    44013/3D22 12 Sep. 97 Buoy returned to SSC with 100% LEL
    46027/3D24 14 Oct. 97 Caustic residues in bottom of compartment (b)
    46013/3D21 30 Oct. 97 Caustic residues; 100% LEL in 4 voids (b)
    43D34/3D34 11 Nov. 97 Caustic residues; 100% LEL in void #2 (b)
    46030/3DV07 21 Sep. 99 Buoy exploded prior to a service visit
    46014/3D59 3 Oct. 99 Buoy Exploded during service visit (b)
    42035/3D24 3 Nov. 99 100% LEL due to plugged vents (b)
    42039/3D56 6 Nov. 00 100% LEL in a compartment; stuck vent valves

    (a) The generation of hydrogen was caused by impurities in the primary
    batteries received from the manufacturer.

    (b) The generation of hydrogen was caused by seawater intrusion into
    the battery compartment.

    3. Hydrogen Gas Mitigation:

    Obtained expert Marine Chemist Consultants
    Improved tests of buoy hatch and cable penetrations
    Installed a third battery compartment vent tube (if the buoy leaks,
    the lower vent ) is blocked by water
    Improved watertight integrity of hatch gaskets and multiplug
    Increased buoy freeboard
    Improved equipment compartment ventilation
    Installed a seal fence to reduce excessive loading on hatch covers
    Provided sufficient clearance between the hatch cover lip and the
    dog-bolt tabs
    Improved hatch gasket deficiencies (insufficient gasket stiffness,
    gaps in the hatch gasket joint, and the position of the gasket joint
    relative to the bow of the buoy)
    Filled voids with inert gas
    Maintain safe entry procedures and training
    Installed explosive gas sensors (FAA)
    Deduced the use of primary batteries.The future goal is to discontinue
    the use of primary batteries.
    Bilge pumps (not yet implemented)


    Back to DBCP Home Page
    Points of contact


    M a g P o w e r S y s t e m s I n c.

    Technology for a New Age of Power.
    News Release Home | About Us | Contact Us | Legal

    About Us
    Fuel Cell
    Hydrogen Inhibitors
    R & D Team
    Investor Relations
    What's New
    IP Flow Chart
    News Release

    Download Executive Summary in PDF

    "We have developed an environmentally friendly power generating system
    that combines the technology of a Power Cell with that of a battery.
    The MagGen Power Cell system is an alternative and emergency
    self-generating power source that is in a class by itself."
    Shawn McGroarty, Chairman/C.E.O.

    MagPower Systems Inc.
    at the leading edge of New Power Technology.

    News Release

    News Release - January 22, 2003

    MagPower completes testing of Magnesium-Air Fuel Cell on Ultra Guard's
    portable water purification system.

    VANCOUVER, BC, Canada – MagPower Systems Inc. announces the successful
    testing of its Magnesium-Air Fuel Cell as a power source for Ultra
    Guard's portable water purification system.

    Having supplied to MagPower the portable water purification system,
    testing was conducted at MagPower's lab facilities by Joey Jung at BC
    Research Inc. with Mr. Ken Fielding, President of Ultra Guard present
    for this momentous occasion.

    Bruce W. Downing, President of MagPower Systems Inc. "This was the
    first direct use of our fuel cell on a specific application and we are
    extremely pleased with the results".

    Ultra Guard has offices in Langley BC and will be making available
    their system worldwide using MagPower's Magnesium-Air Fuel Cell.
    MagPower's fuel cell operates with a salt-water electrolyte combined
    with the companies patent pending Hydrogen Inhibitors. With its
    indefinite shelf life, the Magnesium-Air Fuel Cell has distinct
    advantages over heavy lead acid batteries that are currently used.

    MagPower Systems Inc. is an energy systems company that is focused on
    the development of innovative energy solutions based on its patent
    pending hydrogen Inhibitors. Through the application of its Hydrogen
    Inhibitors, MagPower has developed a Magnesium-Air Fuel Cell and the
    ability to reduce production costs in the electrowinning process
    (zinc, copper, nickel), coolants, hydrogen embrittlement, anodizing,
    zinc alkaline batteries, electroplating, waste water recycling and
    metal-air power sources (zinc, aluminum).

    News Release - January 14, 2003

    MagPower completes testing of Hydrogen Inhibitors for Mitsui
    Corporation's zinc electrowinning process.

    VANCOUVER, BC, Canada – MagPower Systems Inc. announces the successful
    testing of its Hydrogen Inhibitors in Mitsui Corporation's zinc
    electrowinning process. MagPower's Hydrogen Inhibitors increase the
    current efficiency in the electrowinning process, thus reducing
    production costs.

    Having supplied to MagPower the electrolyte used in their
    electrowinning process, testing of MagPower's Hydrogen Inhibitors was
    conducted by Dr. David Dreisinger, University of British Columbia.
    Calculated results on the first run of tests indicate annual savings
    of $2.5 Million in the production of Mitsui's zinc.

    Bruce W. Downing, President of MagPower Systems Inc. "We are very
    pleased to be working with Mitsui and with the results of the test".

    Mitsui has offices in Tokyo and Osaka with their electrowinning
    facilities located in Kamioka and Hikoshima, Japan.

    MagPower Systems Inc. is an energy systems company that is focused on
    the development of innovative energy solutions based on its patent
    pending hydrogen Inhibitors. Through the application of its Hydrogen
    Inhibitors, MagPower has developed a Magnesium-Air Fuel Cell and the
    ability to reduce production costs in the electrowinning process
    (zinc, copper, nickel), coolants, hydrogen embrittlement, anodizing,
    zinc alkaline batteries, electroplating, waste water recycling and
    metal-air power sources (zinc, aluminum).

    Introducing a Cleaner, Safer, Cheaper and More Versatile Fuel Cell

    VANCOUVER, BC, March 29, 2002 – MagPower Systems is introducing a
    proprietary Magnesium-Air Power Cell (MAPC) as a primary, alternative
    and emergency power generator. MAPC's greater safety and cost savings
    are significant advantages over the better-known hydrogen fuel cell

    Bruce Downing, President of MagPower Systems Inc, says: "The
    Magnesium-Air Power Cell supports the global push for a sustainable
    environment. MAPC is more easily recycled. It is clean, green and
    consumes no fossil fuels. No toxic emissions are produced, thus
    reducing harmful greenhouse effects. To recharge the cell, you
    basically replace the magnesium core and the salt or sea-water
    electrolyte. "

    The simple magnesium anode and natural electrolyte make this cell less
    combustible than a hydrogen fuel cell. It does not require a
    safety-sealed fuel storage like HFC. The fuel can either be magnesium
    or a magnesium-alloy, while the fuel for HFC must be pure hydrogen.
    This makes MAPC easily transported by plane with no special safety
    permits. It is safe around children since magnesium is non-toxic. All
    of these features make MAPC better for consumer products.

    MAPC has an indefinite shelf life because the electrolyte can be
    removed before storage. When power is needed, the electrolyte is
    poured back into the cell. No other electrolyte in a non-magnesium
    fuel cell, power generator nor battery can be removed, stored and
    reused by the consumer. This sustainability provides a reliable source
    of power for emergency situations.

    In addition to the inexpensive saline solution, the cell has fewer
    parts so production is less costly and faster than with HFC. This also
    makes the MAPC less expensive than HFC per 12-volt system. Downing
    explains the technical findings of a 12-volt unit: "There is more
    electric yield per cell, 80% v. 45% to 60%. The voltage is higher per
    cell, 1.6 v. 0.8. Operating temperatures are lower, 55o C instead of
    70o to 100o C. And it can operate at temperatures as low as –10o C,
    whereas HFC cannot operate well at low temperatures."

    More Versatile
    The cleaner, safer, cheaper qualities mean greater adaptability of the
    technology. Four different MAPCs are being developed with strong
    support from the federal and provincial governments, and industry
    alliances. These include a portable unit (12 volt / 300 watt), an
    industrial unit (125 volts) with BC Hydro, an automobile unit with
    interest from Volvo Car Corporation, and a marine unit in
    collaboration with the National Research Council of Canada. As a
    member of Team Canada in the fuel cell sector, MagPower demonstrated
    its expertise in Japan.

    Active Ingredient
    The secret to the superior qualities of MAPC over HFC is the company's
    unique R&D approach to energy. Research in this magnesium-air
    technology began in the sixties, but no one was able to produce a
    viable product, as most of the energy loss was due to hydrogen
    formation. MagPower has successfully controlled the formation of
    hydrogen, which is the key to commercialization.

    The company's R&D team at UBC and BC Research developed a breakthrough
    hydrogen inhibitor (HIT) as the controlling agent. Independent testing
    verified that instead of the usual rapidly decreasing power discharge
    curve, adding a hydrogen inhibitor produces a flat line power
    discharge. Downing says: "We're the only ones in the world so far who
    have figured out how to control hydrogen. By adding a hydrogen
    inhibitor to the electrolyte, energy outputs are now commercially

    No Reverse Engineering
    Most importantly, reverse engineering of the hydrogen inhibitor (HIT)
    process is not possible. MagPower can develop unique and customized
    HIT for various applications. This gives the company a significant
    position in the marketplace. With this advantage, MagPower filed two
    Intellectual Property patents in the USA for the specialized process
    of controlling hydrogen for MAPC and zinc electrowinning. The company
    also filed a patent with the World Patent Co-operation Treaty (PCT),
    covering 84 countries.

    Besides hydrogen reduction, HIT can be transferred to other
    electrochemical processes such as batteries and electrowinning (the
    plating out of metals from electrolytic solution in refining and
    waste-water treatment). For example, independent tests for zinc
    electrowinning confirmed that MagPower's inhibitor increased the
    current efficiency from 89% to 97%. The primary benefits include
    substantial power consumption savings with secondary savings from
    increased productivity, and reduction of health and safety hazards.

    MagPower licenses its MAPC technology for specific applications
    (including manufacturing) and the use of HIT to mineral producers, but
    retains production of the hydrogen inhibitors. The abundant market
    utilizations for MAPC and HIT are significant and continuous revenues
    for MagPower. The licensing structure provides long-term growth for
    the company. McGroarty, a seasoned entrepreneur explains, "We're not
    here today, gone tomorrow. We're here for the future of BC. In order
    to develop more market niches with future applications, we're inviting
    all interested investors to examine our unique business model."

    The Company
    MagPower Systems Inc., established 1999, is a private company whose
    purpose is to license the versatile Magnesium-Air Power Cell and
    patent-pending hydrogen inhibitor process. The President, Bruce W.
    Downing (M.Sc., P.Geo., FGAC), has over 25 years of technical
    experience and the CEO, Shawn A. McGroarty, has over 20 years of
    senior management experience in the corporate sector in Canada and the

    The Board of Directors is planning to list MagPower on a public
    exchange in 2004.


    President: Bruce Downing

    CEO: Shawn McGroarty

    Phone: 604.940.3232
    Fax: 604.940.3233
    Address: 340 - 6165 Highway 17 Delta, BC

    Web address:


    This news release contains forward-looking statements relating to
    future results of the company as defined in the Private Securities
    Litigation Reform Act of 1995. Actual results may differ materially as
    a result of certain risks and uncertainties. These risks and
    uncertainties include, but are not limited to: the successful
    commercialization of its alternative fuel cell technology; its ability
    to acquire and develop both new and existing forms of alternative
    energy technology; market acceptance and demand; pricing pressures and
    other competitive factors; as well as other risks and uncertainties,
    including but not limited to those detailed from time to time in the
    company's Securities and Exchange Commission filings. These
    forward-looking statements are made only as of the date hereof, and
    the company undertakes no obligation to update or revise the
    forward-looking statements, whether as a result of new information,
    future events or otherwise.


    Copyright 2002 MagPower Systems Inc.
  2. Noozer

    Noozer Guest

    So...What's your point?
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day