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Special Feature: SeaClean Diesel Particulate Filter System

Discussion in 'Special Features & Live Show Coverage' started by YachtForums, Jun 16, 2014.

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  1. SeaClean Diesel Particulate Filter
    Reducing Yachting's Carbon Footprint

    Like sunlight and weather, electrical power is such a normal part of our lives that little thought
    is given to where it comes from. Yacht owners and crews have a far greater awareness than most of
    the population ashore but guests might be surprised when they discover the local power station is located
    literally underfoot. They might also be reminded every time the wind blows or they swim around the boat.

    Diesel generators are a bit like the human body, they convert chemical energy in fuel (food) into thermal, electrical, and mechanical energy. And like the rest of us, they occasionally produce some unsavory byproducts. In the case of diesel generators those byproducts stain the hull paint, foul the air with bad smells, and surround the yacht with a colorful but embarrassing and illegal sheen of unburned oil speckled with rafts of soot. Dry stack exhausts avoid a few of those issues but make up for it by liberally sprinkling Mrs. Owner and her guests with oily black snowflakes while coloring the mast and antennae with a non-glare shade of charcoal gray.

    Even the latest computer controlled 500kW Tier IV diesel generators that appear to exhaust only clear hot air may discharge over a pound of soot and other particulates each week. Those “other particulates” are a big part of the problem for yacht owners, crew, and guests. They are composed of unburned hydrocarbon molecules that attach to the carbon core of a soot particle and may exist separately as nano sized droplets of hydrated sulphates that create the eye-watering, stomach turning odor that many people find so offensive.
  2. Fort Lauderdale based DeAngelo Marine Exhaust has teamed with Richard Boggs’ new firm EnerYacht to develop, fabricate, and install the SeaClean® diesel particulate filter system. Diesel particulate filters (DPFs) have been used on terrestrial and subterranean vehicles since the 1980s but are a relative newcomer to the yachting industry. Early marine installations were characterized by high cost, large size and weight, complicated and unreliable operation, and short interval before removal and cleaning was required. During his tenure as technical superintendent for yacht management firm Camper & Nicholsons in Fort Lauderdale, Boggs was challenged to reduce the negative impact of generator emissions on large charter yachts. After several years of research and observation, Boggs developed SeaClean® a modular solution that could be installed as a complete system or as components to retrofit existing but underperforming exhaust filtration systems.
  3. DeAngelo Marine Exhaust applied its long history of commercial and yacht exhaust expertise to develop, fabricate, and install the hardware required to achieve a long lasting, yacht quality, exhaust treatment system engineered specifically for the customer vessel. DeAngelo’s experience and expertise in designing exhaust components allows the inclusion of SeaClean® components with the lowest back pressure penalty possible.
  4. Diesel particulate filters supplied for yacht installations are dominated by “passive regeneration” type systems. These incorporate a “wall filter” made of porous ceramic with a grid of open channels on the inlet side with an opposite arrangement on the outlet. Exhaust gas enters the open end of a channel that is blocked at the outlet end. The thin wall of the channel traps soot but allows clean exhaust to travel into the adjoining outlet channel which is blocked at the exhaust inlet side and open to the outlet of the filter. The most commonly used filter element is a cylindrical extrusion of synthetic cordierite, a ceramic composed of magnesium, iron, aluminum, and silicon that has been “washed” with a catalyst containing the precious metals platinum, palladium, and rhodium. The catalyst initiates combustion of Soot trapped on the walls of the channel at a much lower temperature than would normally occur. This process of soot removal by combustion is called regeneration. Passively regenerated DPFs require extended periods of high exhaust temperature to initiate the regeneration process.
  5. Unfortunately, and as almost every engineer will admit, yacht generators don’t operate at high loads often or long. Most generators operate with chronic underloading that leads to poor combustion, rapid wear, and excessive emissions. The object of using precious metal catalysts to achieve low temperature regeneration is intended to accommodate this situation but that approach creates its own equally serious problems. Precious metal catalysts are “poisoned” by the sulfur in diesel fuel. They are either masked or chemically neutralized so that regeneration is no longer possible and the filter clogs, often within very few hours. When DPF technology moved from mines and highways to yachts, the filters that performed well on the ultra low sulfur diesel fuel (ULSD) burned in those applications is not always available where yachts are fueled. Early adapters are seeing their filters meeting an early and costly demise. Boggs recognized the reasons many yacht installations failed to live up to expectations and set out to develop a better soot trap.
  6. Exhaust temperature is both the primary indicator of diesel engine loading, particulate production, and DPF function. Frequently, the first option many engineers and captains look to as a solution to generator underloading is a load bank. With the correct type of filter element, a load bank equipped generator/DPF combination can provide some relief but it also adds considerably to maintenance and operating costs.
  7. Load banks increase generator load, they may raise exhaust temperature to the level desired but they also add a great deal of complexity due to the pumps, plumbing, and electrical controls required. The additional fuel consumption is costly and burning more fuel increases the amount of emissions that brought attention to the problem in the first place. Load bank maintenance costs along with increased fuel consumption make this an expensive yet only partial solution.
  8. SeaClean® was developed to address each of the issues that make generator exhaust such a major and expensive problem to many yachts. Every installation is unique and that is one of DeAngelo SeaClean’s strongest attributes, each system is custom engineered, fabricated, and fitted to each generator on a yacht. When it comes to marine exhaust systems, one size does not fit all. Just as a yacht must meet its owner’s requirements, a generator exhaust treatment system must meet the requirements of the yacht itself.
  9. The heart of SeaClean® is the filter element itself, it is sized to impose the least possible restriction to exhaust gas flow while capturing the greatest weight of the noncombustible inorganic components of exhaust which eventually require mechanical removal. The more of this material a filter can hold, the longer the periods between routine cleaning. Overall filter life is extended as well due to less frequent cleaning and a higher catalyst loading. The catalyst used to coat SeaClean® filters resists “poisoning” by high sulfur content in fuel oil. Because high sulfur fuel oil produces more particulates, this enhances the removal of captured particulates through regeneration.
  10. SeaClean® uses a variable output electrical resistance heater to ensure near continuous regeneration by adding heat to the exhaust gases when generator loads are low. Heater power consumption is proportional to generator load and exhaust temperature entering the filter. As generator loads increase so does exhaust temperature. This relationship, the degree which is unique to each vessel and its style of operation, is programmed into the SeaClean® controls so that full rated generator output load is available when it is most needed. The SeaClean® control panel displays actual exhaust temperature and a target temperature which may be adjusted by the engineer. The controller normally operates in automatic mode and requires no engineer input. Manual control is instantly available should the engineer desire to operate the unit as an exhaust cooled loadbank with infinitely variable power input.
  11. SeaClean® incorporates a datalogger to record up to 8000 hours of generator operation. Parameters recorded are exhaust temperature at the filter inlet, backpressure, and heater power consumption. The weight and volume required for a SeaClean® system is extremely low compared to the few other active regeneration systems available and in most cases the system can be fitted within the footprint of the generator sound shield and in the open space above the generator. To join a discussion in progress on the SeaClean system, follow this link...

    For more information contact:

    DeAngelo Marine Exhaust
    3330 SW 2nd Avenue
    Ft. Lauderdale, FL 33315
    DeAngelo Marine Exhaust

  12. SEACLEAN Frequently Asked Questions:

    1) Is the system approved by class?

    Lloyds approves each installation independently and separately. Since each installation is unique to the boat it is on, there is no practical way to obtain a type approval. We have the SeaClean on 3 Lloyds classed yachts to date and all have been surveyed with the system installed. We submit drawings and plans to class before installation.

    2) What sort of Back pressure do you get using this system?

    We typically develop back pressure in the mid teens of water column or just under 4 kPa at 60 to 80 percent loads. This depends a great deal on the rest of the exhaust system. The ideal situation is when we can design and fabricate the system from turbo outlet to overboard. We try to obtain the greatest margin possible in order to extend filter life before cleaning is required.

    3) Do you have a European supplier and installer or a recommendation in Europe for installation?

    We will send a technician to perform or oversee the fitting in whatever location the boat is in, this may in some cases actually save costs compared to using local labor. We also send a technician to commission and fine tune the system after installation is complete.

    4) Can the system be made modular if there are issue fitting it into the engine room?

    The system is modular by design. We build the control panels to fit the size and location you desire and most installations fit within the envelope of the generator sound shield with the water lift separator fit into the space between the shield and the hull. We configure the components to fit the yacht. Both sides may be piped differently if that is what is needed to make it fit and provide for ease of maintenance of the generator.

    5) Are the heaters singular or multiple elements?

    The heater is a single unit comprised of multiple "hairpin" elements. The number of elements depends on the wattage calculated to be required to obtain the correct exhaust temperature. The heater is mounted to the inlet side of the DPF.

    6) Roughly what size unit will we need and what would be the power consumption for it?

    Power consumption varies with generator output and exhaust temperature. We typically install a heater with a maximum output of 20kW on a 170kW generator. The full capacity may or may not be connected, depending on how the yacht operates and how power is managed by the engineers. The rest of the answer is included in the next question.

    7) With the heater controller, if there are multiple elements can it be set to bring the elements on in stages, or do you have a soft start idea?

    We use a zero crossing power controller that modulates power cycle by cycle i.e. 10kw from a 20kW heater would have the controller on for 3 cycles and off for 3 cycles with the switching occurring at the 0 voltage point of the sine wave to prevent noise spikes and harmonic generation that comes from soft starts and contactor type controls. On system startup we have a ramping up period to prevent a sudden large load being imposed. Also, the heaters are isolated unless the generator is online and has been running for at least a minute to allow the power management system to stabilize after bringing a generator online. The power (and thus exhaust gas temperature) is regulated proportionally to the temperature of exhaust gases leaving the turbocharger. This temperature is, of course, proportional to the load on the generator. By using this method, the SeaClean system will not place a load on shorepower when the generator is running offline such as when cooling down after switching to shore power. It does not present a parasitic load on the switchboard when the generator is heavily loaded by large hotel loads. When hotel loads are at maximum, no power is used by the heater so that all power is available to the switchboard.

    8) Do you have a manual regeneration mode on the controller, and do you know if it would be possible to integrate the controller with our alarm and monitoring system?

    Manual operation is available at the front of the control panel at any time the system is online. Normal, automatic, operation provides constant and continuous regeneration across the widest possible generator load range. A high backpressure alarm output is available for integration with a yacht’s alarm and monitoring system. Other outputs are available as options.

    9) Is it possible to set the system up to run as a possible load bank as without guests on we are running at 50% load on the engines and I would rather run them at 80% load?

    By using the manual control feature, the full capacity of the heater is available to serve as an "exhaust cooled" loadbank. If greater loadbank capacity is required or desired beyond what is installed to achieve consistent filter operation, we can install larger capacity heaters in the same "envelope" so there is no space or size penalty. We will design and install a system that provides what you need. It will be economical, and it will work. So far, the only people who have been more impressed than the engineers are the deck gang and guests. The hull stays clean and there is no diesel smell or smoke to offend even the most sensitive nose.
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