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New Mærsk Triple-E ships world’s largest and most efficient; waste heat recovery and ultra long stroke engines contribute to up to 50% reduction in CO2/container moved

Triplee
Rendering of the Triple-E. Click to enlarge.

Mærsk Line has signed a contract with Korea’s Daewoo Shipbuilding & Marine Engineering Co., Ltd. to build 10 of the world’s largest and most efficient vessels—the Triple E (Economy of scale, Energy efficient and Environmentally improved)—with an option for an additional 20 vessels. The newbuilds are scheduled for delivery between 2013 and 2015.

Four-hundred metres long, 59 meters wide and 73 meters high, the Triple-E is the largest vessel of any type on the water today, according to Mærsk. Its 18,000 TEU (twenty-foot container) capacity is 16% greater (2,500 containers) than today’s largest container vessel, Emma Mærsk. The Triple-E will produce 20% less CO2 per container moved compared to Emma Mærsk and 50% less than the industry average on the Asia-Europe trade lane.

In addition, it will consume approximately 35% less fuel per container than the 13,100 TEU vessels being delivered to other container shipping lines in the next few years, also for Asia-Europe service.

Each vessel will cost US$190 million. Besides its size, which provides superior economies of scale compared to other vessels (more cargo means less CO2 per container moved), the efficiency of Triple-E comes from its innovative design.

The Triple-E vessels have a 26% slot cost advantage compared to the 13,100 TEU vessels sailing on today’s oceans considering a full roundtrip from Asia to Europe (based on a bunker price of US$600 per metric tonnes). Slot cost is a consolidated figure from several costs; bunker fuel, vessel costs (operational and capital) plus port and canal fees.

Two ‘ultra-long stroke’ engines turn two propellers, and specially optimized hull and bow forms guide the vessel through the water at the speeds typical in the industry today. An advanced waste heat recovery system captures and reuses energy from the engines’ exhaust gas for extra propulsion with less fuel consumption.

To reduce the environmental impact of the vessels beyond their lifecycle, Mærsk Line is setting a new standard for the way vessels are recycled. All the materials used to build the Triple-E class will be documented and mapped in the vessel’s ‘cradle-to-cradle passport’. This means that when the vessel is retired from service, this document will ensure that all materials can be reused, recycled or disposed of in the safest, most efficient manner.

Propulsion system. The top speed of the Triple-E was capped at 23 knots, two knots lower than Emma Mærsk’s top speed. This meant a power requirement of 65-70 megawatts compared to Emma’s 80 megawatts—about a 19% reduction. A slower max speed also enabled Mærsk Line to consider engines that could operate at slower revolutions—‘ultra-long stroke’— which provides the greatest fuel efficiency.

To retain the efficiency created by the slower revolutions of an ultra-long stroke engine requires a larger propeller diameter. However, the size of the propeller is limited by the dimensions of the vessel and the available space beneath the keel.

To mitigate these restrictions and achieve the desired efficiency, Mærsk Line research determined that a two engine/two propeller ‘twin skeg’ system was superior to the one engine/propeller setup. The Triple-E’s two propellers are 9.8 metres in diameter with 4 blades each, compared to Emma’s single propeller, which is 9.6 metres in diameter with 6 blades. The combined diameter of the propellers provides greater pushing power in the water and the fewer number of blades creates less resistance.

All together, the Triple-E’s twin-skeg propulsion system consumes approximately 4% less energy than Emma Mærsk’s single engine/single propeller propulsion system.

The MAN diesel engines weigh 910 metric tonnes each, and deliver output of 43,000 hp (32,065 kW). Fuel consumption is 168 grams bunker oil per kWh produced.

Waste heat recovery. The Triple-E is the latest in a succession of Mærsk Line vessels (20 vessels, including the 8 Emma Mærsk class vessels) to be equipped with an energy saving advanced waste heat recovery system. For the Triple-E, the effect of the waste heat recovery system is a reduction in the engine’s fuel consumption and CO2 emissions by approximately 9%.

When exhaust gas leaves the engine, it has a very high heat potential. Utilizing this potential in an exhaust gas boiler, it is possible to generate steam. The waste heat recovery system then supplies the steam into a turbine connected to a generator which then recovers electrical energy.

Comments

Thomas Pedersen

ejj. The process you have described, is not an energy source for the ships, but an energy sink :(

Actually, I think seawater is better suited for hydrolysis than fresh water (which takes a lot of energy to make), but even so, hydrolysis requires much more energy in the form of electricity than you could ever get from its use in a fuel cell. I'm afraid what you have described is a 'perpetuum mobile', and they do not work.

It seems you forgot about the source of electricity for the hydrolysis.

And even if you should find some other process that makes hydrogen without electricity, you can be absolutely certain that it takes more energy in some other form than you can get from burning the hydrogen.

This is not a statement of personal opinion but a fundamental law of nature. Try reading about the first and second laws of thermodynamics. They outline why there is no such thing as a 'free lunch' and why perpetuum mobiles are impossible.

Spoiler: The first law of thermodynamics state that energy is constant in a system with interaction with its surroundings. In other words, if you transfer energy (mechanical, electrical, chemical, heat, etc.) to a system from its surrounding, the system's internal energy will increase by the exact same amount. And vice versa. For an engine this means that the chemical energy released by combustion from the fuel is exactly equal to the power output from the shaft plus the heat in the exhaust and the heat from the cooling water (and the increase in temperature of the engine, if it has not yet reached its steady stage operating temperature).

The second law of thermodynamics states that in any *real* process, there is a loss of useful energy. The most clear example is when you brake in your car. All that wonderful momentum in the car, which has taken a lot of chemical energy to achieve, is transferred into heat energy in the brakes. This heat is then released in to the atmosphere, where it is rendered useless. Now, if you could use the momentum to drive an electric generator and charge a battery, or drive a piston to compress air in a cylinder, you could recover a good fraction of you initial energy. But you would never, with any real processes, be able to use that energy to accelerate your car back to the speed it had before.

Essentially, every time you convert energy, you loose some of it! But unfortunately your idea was trying to such energy out the blue sky, and that is not possible with science as it stands today.

ejj

Thanks Thomas...I'm just brainstorming based on the claims of the Purdue researchers...maybe you should contact them & tell them it won't work? http://www.purdue.edu/newsroom/research/2010/101007WoodallBoats.html

CelsoS

ejj,

    ...maybe you should contact them & tell them it won't work?

I hope you're not trying to make fun out of Thomas. He took his time to explain to you basic energy conservation every teenager should learn in school.

The article you linked shows a group of people trying to use Aluminum and Aluminum Hydroxides as a way to convey energy. This is similar to the Aluminum battery chemistry (http://en.wikipedia.org/wiki/Aluminium_battery).

    The aluminum splits water by reacting with the oxygen atoms in water molecules, liberating hydrogen in the process. The waste product, aluminum hydroxide, can be recycled back to aluminum using existing commercial processes.

Their proposition is to "charge" aluminum hydroxide injecting energy and transforming it into pure aluminum (Al) liberating Oxigen (O2) and water (H2O), somewhere else, possibly with a decent performing process.

Energy is stored as the potential of pure aluminum to be reacted liberating it. The same way as coal, wood, hydrocarbons, etc., are oxidized.

Then, when energy is needed, one can "discharge" (extract energy) from the pure Al reacting it with water (H2O) forming aluminum hydroxide while releasing hydrogen (H2). This H2 can then be reacted to O2 to complete the cycle, producing only vapor (H2O+heat).

This H2 still holds a lot of energy and can be easily combusted (reacted with O2, oxidized) in an ICE including those huge diesel/bunker oil engines that move those ships.

They claim that storing energy as "potential chemical reaction energy" in the pure Al has a good energy density, while burning the H2 instead of bunker oil lowers emissions.

Al fuel cells have been used by NASA and USAF since the 60's. It's use is not widespread cause it was not cheap.
(hint: Google NASA + "fuel cell"+ aluminum).

There are no contradictions (Thomas x Purdue), you just have to understand what they told you.

ejj

I apologize if it sounded like I was making fun...but I seriously think that if these Purdue researchers are destined for failure, especially with the hydrogen powered boat concept (even caption of photo says "Purdue doctoral student Go Choi watches hydrogen being generated in a new process to extract the gas from seawater. The hydrogen could then be used to run engines in boats and ships, representing a potential replacement for gasoline and diesel fuel in marine applications.") then people smarter than me need to confront them now so they stop wasting their time & money. You guys seem to have a better grasp of what could cause them to fail than I do...to me, the article is pretty convincing that the researchers are convinced they're onto something.

Engineer-Poet

Debunked 5 years ago: From bad to worse.

Producing hydrogen from metal-water reactions is far worse than just making hydrogen directly. Ammonia borane is probably a much better choice (though uranium is probably the best way to power a big ship).

Alain

Why not simply wash the exhaust gasses ?
Water enough in the ocean.
Soot, NOx and SOx very easily react with seawater.
the soot is a little bit toxic, but can easily be handled by the bacteria. the NOx and SOx form ocean fertilizers.

ejj

Engineer-Poet - correct me if I'm wrong, but your debunking was of straight aluminum, whereas the Purdue team is using a 90% aluminum 10% alloy mix formulation...

(from the Purdue article)

The material is made of tiny grains of aluminum surrounded by an alloy containing gallium, indium and tin, which is liquid at room temperature. The liquid alloy dissolves the aluminum, causing it to react with seawater and release hydrogen, Woodall said.

Unlike other techniques for generating hydrogen using aluminum, the Purdue team uses bulk metal, not powdered aluminum.

"This is important because being able to generate hydrogen with bulk aluminum makes the method practical, whereas using powder is too expensive and cumbersome," Woodall said. "We believe the process is economically competitive with conventional fuels for transportation and power generation."

A key to developing the technology is controlling the microscopic structure of the solid aluminum and the gallium-indium-tin alloy mixture.

"This only works because there is liquid gallium between the grains of aluminum, which dissolves the aluminum bit by bit," he said. "The dissolved aluminum then reacts with water to release hydrogen."

The formulation contains 90 percent aluminum and 10 percent of the liquid alloy. The reaction also produces heat, which could be harnessed to generate electricity.

Engineer-Poet

The energetics of the reaction don't change if a catalyst is used to process bulk metal. The fact that the reaction produces heat also makes me question the purpose; if it gets hot enough to melt aluminum (which I'll bet the aluminum-water reaction does), and you're going to be running the system for a voyage lasting a couple weeks, why bother using an expensive additive to start the reaction at room temperature?

ejj

I think I'm starting to understand the Purdue concept.... "bulk" special formula aluminum would be loadad on a ship as a fuel to create the fuel (hydrogen). They say the hydrogen could be produced "on demand" but only as long as there is "bulk" special formula aluminum remaining. After the chemical reaction to create hydrogen I'm assuming it turns into some kind of precipitate / particulate mixture...which has to be reprocessed (via smelter) back into into the bulk special formula aluminum in order to make more hydrogen. You really can't have a smelter on a ship, which consumes massive amounts of energy in and of itself --- more energy than could ever be supplied by the hydrogen produced....which is why the students talk about co-locating a smelter near utilities powered by solar / wind. But a completely self contained system on a ship is pretty much out of the question. However, if the bulk aluminum lasted a really long time and produced massive amounts of hydrogen (and refueling a ship only had to be done annually or even 6 months) it still might be a promising concept.

ejj

Good video you can rewind but on the link below I have it on the part where they say the energy produced in their reaction is 50 percent what it takes to recycle the aluminum (I'm assuming back into bulk 90/10 form) http://www.youtube.com/watch_popup?v=dhroR7oELwA&vq=small#t=170 Would be nice if it was the other way around...energy needed to recycle only 50 percent of what is produced.

ejj

More good info...
http://nanohub.org/topics/SplittingWaterUsingAluminum

Engineer-Poet

If you use aluminum to react with water to get hydrogen, the hydrogen only contains about half the energy in the aluminum. You'll also wind up carrying the oxygen (and possibly extra water, as hydroxide) with you for an average of half the trip.

Do the math. I did part of it for you already.

ejj

Engineer-Poet: Please see Dr. Woodall's presentation on bulk aluminum alloys...it's very interesting. Of particular interest is slide 40, in which Dr. Woodall describes a scenario for trains, but scaled up & using seawater it could be applied to a container ship.

http://nanohub.org/resources/6568/play?resid=6569&no_html=1

He talks of a 50 car loaded train being able to run using the system for over 600 days. If configured for a container ship it could run for 365+ days? The aluminum can be impure ...the only thing that needs to be recycled is the expensive gallium alloy part, but that can be used over and over and over again.

Engineer-Poet

There is absolutely zero justification for running a train on oxidation of aluminum metal when the electricity which reduced the aluminum could run the train directly at close to three times the efficiency.

Ships have somewhat better justification, as shipping lanes can't be wired into the grid. Still, if the system is geared to producing hydrogen to use in a FC, it makes more sense to use something like ammonia as the storage medium than aluminum. Ammonia can be produced directly from electricity in an electrolytic cell, and doesn't have the systemic losses of oxidation of Al with H2O.

ejj

I think Woodall's presentation is intriguing...it's just a matter of engineering. Your argument for trains works as long as all rail lines in the country can be electrified --- I'm sorry but it'll never happen (in the U.S.). For ships, Maersk is already recycling waste heat, so they could engineer a system to capture it from an aluminum alloy hydrogen system as well. In the presentation, he talks about 60,000 gal (two tank cars) being able to power a 50 car train for 660 days. It seems to me massive numbers of tank cars with the aluminum alloy fuel could be loaded onto a container ship, fed into a hydrogen fuel cell propulsion system...depending on the size and scale of the system refueling may not need to occur but once a year or even less.

Engineer-Poet

Woodall's presentation admits that the electricity-H2 efficiency is only 34% (slide 5).

He also talks about the physical density of energy in aluminum, but fails to note that recycling that aluminum requires carrying the Al(OH)3 which is far bulkier. The aluminum would have to be recycled (contra his assertion in slide 6 that the scrap isn't of interest to recyclers) because the world inventory is only about 12% of the USA's annual energy consumption.

Woodall is also assuming rather high (fuel cell) efficiencies in the use of H2; slide 7 posits 100 km/kg (60+ miles per gge).

I think the idea has possibilities, but more in the recycling of aluminum scrap.

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