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Mardi Gras Sea Trials


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10 hours ago, ronrythm said:

Any ideas on how they will be testing the LNG fuel system? Is there anywhere there for them to load fuel?

 Thanks 

Ron

Yes, Europe has many LNG bunkering facilities, whether terminals or barge/tankers.  The testing will be to load fuel, checking the bunkering systems, to burn some in the engines, testing the fuel supply systems, and to test the re-liquifaction system that takes excess boil off gas, cools it back to -260*F, compresses it and returns it to the tank.  The inerting system that replaces the atmosphere in the fuel tanks with nitrogen will be tested.  All alarms and sensors will be tested, including the leakage sensors in the vacuum space surrounding the fuel tanks.

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3 minutes ago, RWolver672 said:

 

There has to be or it wouldn't have fuel for the sea trials or the trip to the US.

The ship does not depend entirely on LNG for fuel.  The engines are "dual-fuel", meaning they can run on any mixture of liquid (diesel or residual) fuel and gaseous fuel (LNG), from 100% liquid to 95% LNG.  The ship cannot operate on LNG alone, as LNG will not auto-ignite in a diesel engine, so about 5% liquid fuel is used at all times to get combustion going in the cylinders.  Also, the ship is required to have a secondary fuel source (liquid fuel) to get the ship back to port if there is a problem with the LNG fuel system.  I haven't seen the specs on tank capacity, but I would be surprised if the ship could make a transatlantic on one load of LNG.

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Cheng-

 

Always appreciate reading your words, I learn something every time. I’m a complete empty box of knowledge with ships, so apologies if this is widely known... but is LNG a common fuel in the shipping industry? I would imagine there’s obviously a fair bit of data and knowledge, or else how would Carnival get the equipment and such to run a ship off LNG... but for the uninitiated like myself, it seems a bit “Oh, that’s new technology” with all of the usual worries that come with anything new. We are sailing on her in May, and I’m well convinced of her safety. I’m just curious about how common it is not just in the cruise industry, but in shipping as a whole. 

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20 minutes ago, DubNHub said:

Cheng-

 

Always appreciate reading your words, I learn something every time. I’m a complete empty box of knowledge with ships, so apologies if this is widely known... but is LNG a common fuel in the shipping industry? I would imagine there’s obviously a fair bit of data and knowledge, or else how would Carnival get the equipment and such to run a ship off LNG... but for the uninitiated like myself, it seems a bit “Oh, that’s new technology” with all of the usual worries that come with anything new. We are sailing on her in May, and I’m well convinced of her safety. I’m just curious about how common it is not just in the cruise industry, but in shipping as a whole. 

I'm not the Chief, but I believe in the past he has mentioned that LNG has been used in the commercial shipping industry for quite some time, and there is infrastructure for it in many places, just not typically where cruise ships port (right now).

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39 minutes ago, DubNHub said:

Cheng-

 

Always appreciate reading your words, I learn something every time. I’m a complete empty box of knowledge with ships, so apologies if this is widely known... but is LNG a common fuel in the shipping industry? I would imagine there’s obviously a fair bit of data and knowledge, or else how would Carnival get the equipment and such to run a ship off LNG... but for the uninitiated like myself, it seems a bit “Oh, that’s new technology” with all of the usual worries that come with anything new. We are sailing on her in May, and I’m well convinced of her safety. I’m just curious about how common it is not just in the cruise industry, but in shipping as a whole. 

LNG tankers have been carrying tens of thousands of tons of LNG for about 40-50 years now.  There has never been an accident or incident involving the transport of LNG or the use of it as a fuel.  These were steam ships, and they benefited by using the "boil off" gas to fuel the boilers.  The cargo tanks, just like the bunker tanks on the Mardi Gras, are large thermos flasks, with a vacuum sealed area surrounding the fuel tank.  However, just like a Yeti, the insulation is not perfect, so the LNG cannot be held to exactly -260*F all the time, so some of the LNG boils off, and to keep the pressure down (these cryogenic tanks are only at about 3psi (unlike the tanks you see at Walmart to fill up propane tanks), the boil off is used for fuel.  Gaseous fueled diesel engines have been around for quite a while as well, look at the propane buses, etc, that you see on the road.  Dual fuel marine diesels are somewhat new (probably 10-20 years), but because there was no cost savings in buying the fuel, and major cost involved in building a ship to use the fuel, it just was ignored.

18 minutes ago, ProgRockCruiser said:

I'm not the Chief, but I believe in the past he has mentioned that LNG has been used in the commercial shipping industry for quite some time, and there is infrastructure for it in many places, just not typically where cruise ships port (right now).

While Europe has many more LNG bunkering facilities than the US (probably only half a dozen LNG export facilities, those that reliquify natural gas, and only a couple of tankers/barges capable of bunkering a ship in the US at present), I would not say it is wide spread.  Also, the cost differential between liquid fuel and LNG is much greater in the US than everywhere else in the world, being about half the difference in Europe, and almost no difference in cost in Asia, so use of LNG as a marine fuel is still not widespread.

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I recall back in the 70s there was a scare article in one of the radical or enviro mags that said LNG tankers shouldn't be allowed in US harbors because they could explode and blow up half the East Coast. 😲

 

So thank Chief for reminding us this never happened.

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3 minutes ago, DubNHub said:

Thanks a bunch for the reply. Is the transition purely for environmental reasons? Or is LNG or some combo of fuels considered more fuel efficient over traditionally fueled vessels? Or all of the above? Haha

No, LNG is not more efficient, as you need to carry around 3 times the volume of LNG as diesel or residual fuel to get the same amount of energy.  Because of the North American ECA (Emissions Control Area) that mandates fuel with less than 0.1% sulfur, ships have had to either burn diesel fuel (twice as expensive as residual fuel) or invest in scrubbers (and there are problems with scrubbers as well).  LNG solves two problems, it is cleaner than liquid fuel, and in the US it is cheaper per BTU.  There are problems with LNG, it is not the panacea that environmentalists claim, as there is some significant "methane slip" or loss of natural gas during production, transportation, and consumption, and methane has 84 times the global warming effect as CO2.

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4 hours ago, chengkp75 said:

There has never been an accident or incident involving the transport of LNG or the use of it as a fuel. 

 

 

Yep, but boy howdy does that have a possibility for a big bang. I can't help but think terrorists have considered.

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53 minutes ago, BlerkOne said:

 

Yep, but boy howdy does that have a possibility for a big bang. I can't help but think terrorists have considered.

Lots of people think that Hollywood explosions are real.  Combustible substances like LNG have to have sufficient oxygen to combust.  LNG tanks are "inerted" by replacing the atmosphere above the fuel in the tank with an inert (won't combust) gas like Nitrogen, so even if there is a spark or a flame in the tank, it will not have enough oxygen to combust.  Second, combustibles will have a LEL (lower explosive limit) and UEL (upper explosive limit) where if the concentration of LNG is above 14% (IIRC) of the atmosphere, it is too rich, and will not combust, and if it is below 4%, it is too lean and won't combust.  Finally, LNG on ships is kept at cryogenic temperatures (-260*F for LNG), so even if you have a plume of LNG vaporizing near a flame, that LNG is using an incredible amount of thermal energy just vaporizing, so the heat necessary for combustion is removed as well.

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3 hours ago, chengkp75 said:

Lots of people think that Hollywood explosions are real.  Combustible substances like LNG have to have sufficient oxygen to combust.  LNG tanks are "inerted" by replacing the atmosphere above the fuel in the tank with an inert (won't combust) gas like Nitrogen, so even if there is a spark or a flame in the tank, it will not have enough oxygen to combust.  Second, combustibles will have a LEL (lower explosive limit) and UEL (upper explosive limit) where if the concentration of LNG is above 14% (IIRC) of the atmosphere, it is too rich, and will not combust, and if it is below 4%, it is too lean and won't combust.  Finally, LNG on ships is kept at cryogenic temperatures (-260*F for LNG), so even if you have a plume of LNG vaporizing near a flame, that LNG is using an incredible amount of thermal energy just vaporizing, so the heat necessary for combustion is removed as well.

 

Never say never. It may not easily explode, but can result in spectacular fires.

 

 

 

I realize that Fox News has zero credibility, but here you go...

 

https://www.foxnews.com/story/ap-lng-tanker-attack-would-be-devastating

 

 

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Sorry, our internet onboard does not support youtube.  The Fox article said that a terrorist attack "probably" would start a fire, but not definitely.

 

Anyway, the fuel tanks on an LNG fueled ship are different than the cargo tanks on an LNG tanker.  The cargo tanks are up above deck and visible.  The fuel tanks on ships are restricted in the locations they can be in.  They cannot be within 1/4 of the beam of the vessel from the side (so, unlike liquid fuel tanks that are a part of the side of the ship, these have to be away from the side), and since down the middle of the ship is prime real estate in engine rooms, this moves the fuel tanks to one place, the inner bottom.  This is the space, about 2 meters tall, between the bottom hull and the lowest deck of the engine room.  So, the only way to get near these tanks is from below.  Next, the tanks are not integral with the hull, they have a void space around the tank (in addition to the vacuum space around the fuel) that is required so that any potential leaks can be monitored.  So, explosion on the hull bottom would possibly carry through and crack the fuel tank, but then there would be cryogenic LNG mixing with inrushing sea water, not a likely scenario for fire.  

 

No, there is never a zero probability of anything in life, but some things are so small a probability that they can be considered to be negligable.

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5 hours ago, chengkp75 said:

No, there is never a zero probability of anything in life, but some things are so small a probability that they can be considered to be negligable.

 

They said the same thing about SL-1, Three Mile Island, Chernobyl, Fukushima Daiichi...

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On 10/1/2020 at 7:13 AM, chengkp75 said:

Sorry, our internet onboard does not support youtube.  The Fox article said that a terrorist attack "probably" would start a fire, but not definitely.

 

Anyway, the fuel tanks on an LNG fueled ship are different than the cargo tanks on an LNG tanker.  The cargo tanks are up above deck and visible.  The fuel tanks on ships are restricted in the locations they can be in.  They cannot be within 1/4 of the beam of the vessel from the side (so, unlike liquid fuel tanks that are a part of the side of the ship, these have to be away from the side), and since down the middle of the ship is prime real estate in engine rooms, this moves the fuel tanks to one place, the inner bottom.  This is the space, about 2 meters tall, between the bottom hull and the lowest deck of the engine room.  So, the only way to get near these tanks is from below.  Next, the tanks are not integral with the hull, they have a void space around the tank (in addition to the vacuum space around the fuel) that is required so that any potential leaks can be monitored.  So, explosion on the hull bottom would possibly carry through and crack the fuel tank, but then there would be cryogenic LNG mixing with inrushing sea water, not a likely scenario for fire.  

 

No, there is never a zero probability of anything in life, but some things are so small a probability that they can be considered to be negligable.

Lots of problems with diesel fuel causing pollution either when burned or when it is spilled into the sea. What if any problems does LNG cause to the environment verses other types of fuel? As for efficiency I have heard both ways. Better efficiency or not? Cost verses efficiency? Will they burn more or less fuel for a given distance? I would think cruise lines would not switch if it did not give them a financial advantage.

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29 minutes ago, ALWAYS CRUZIN said:

Lots of problems with diesel fuel causing pollution either when burned or when it is spilled into the sea. What if any problems does LNG cause to the environment verses other types of fuel? As for efficiency I have heard both ways. Better efficiency or not? Cost verses efficiency? Will they burn more or less fuel for a given distance? I would think cruise lines would not switch if it did not give them a financial advantage.

LNG is less efficient and better for the environment plus the US has a ginormous supply of natural gas.

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1 hour ago, ALWAYS CRUZIN said:

Lots of problems with diesel fuel causing pollution either when burned or when it is spilled into the sea. What if any problems does LNG cause to the environment verses other types of fuel? As for efficiency I have heard both ways. Better efficiency or not? Cost verses efficiency? Will they burn more or less fuel for a given distance? I would think cruise lines would not switch if it did not give them a financial advantage.

While LNG produces less CO2 (less carbon atoms) than diesel,   there is "methane slip" that I have mentioned previously, which is leakage of methane gas from the production (the well), through transportation, and finally combustion (incomplete combustion), and methane has 84 times the greenhouse gas effect as CO2, over a 10 year period, and 40+ times over a hundred year period.  (This is the "cow fart" argument used by vegans)  Efficiency does not depend on the type of fuel, but the machine it is being combusted in.  An engine only cares how much thermal energy it needs to run, and will take in as much fuel as needed to get that energy.  LNG has less energy per gallon than diesel (about 1/3), so the engine has to burn more gallons to get the same energy, and that means you have to tote around 3 times as much fuel, which takes fuel to move it.  Again, with a diesel electric propulsion plant, the energy required to travel a distance is a factor of hull design, ship weight, and propeller design, not fuel.  The diesels are merely electrical generators, providing energy to the propulsion motors.  So, since LNG has less energy per gallon, you will burn more per mile than diesel.  As I've said, in the US there is a significant cost advantage to using LNG over diesel, especially since the low sulfur diesel is required within the North American ECA.  However, in other places, like Europe, while still having an ECA in place, the cost differential between LNG and diesel is much less, and in Asia LNG is more costly than diesel, and they do not have ECA's mandating low sulfur fuels.

 

If LNG is spilled at sea, there is the possibility of the resulting gas cloud to be toxic to birds or any air breathing life within the area, and there is the possibility of the natural gas being absorbed into the sea water and causing pollution that way.

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21 minutes ago, chengkp75 said:

... and in Asia LNG is more costly than diesel, and they do not have ECA's mandating low sulfur fuels.

 

...

 

I didn't know that, but it does not come as a surprise.

 

GREAT info, BTW.

 

Tom

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23 hours ago, chengkp75 said:

While LNG produces less CO2 (less carbon atoms) than diesel,   there is "methane slip" that I have mentioned previously, which is leakage of methane gas from the production (the well), through transportation, and finally combustion (incomplete combustion), and methane has 84 times the greenhouse gas effect as CO2, over a 10 year period, and 40+ times over a hundred year period.  (This is the "cow fart" argument used by vegans)  Efficiency does not depend on the type of fuel, but the machine it is being combusted in.  An engine only cares how much thermal energy it needs to run, and will take in as much fuel as needed to get that energy.  LNG has less energy per gallon than diesel (about 1/3), so the engine has to burn more gallons to get the same energy, and that means you have to tote around 3 times as much fuel, which takes fuel to move it.  Again, with a diesel electric propulsion plant, the energy required to travel a distance is a factor of hull design, ship weight, and propeller design, not fuel.  The diesels are merely electrical generators, providing energy to the propulsion motors.  So, since LNG has less energy per gallon, you will burn more per mile than diesel.  As I've said, in the US there is a significant cost advantage to using LNG over diesel, especially since the low sulfur diesel is required within the North American ECA.  However, in other places, like Europe, while still having an ECA in place, the cost differential between LNG and diesel is much less, and in Asia LNG is more costly than diesel, and they do not have ECA's mandating low sulfur fuels.

 

If LNG is spilled at sea, there is the possibility of the resulting gas cloud to be toxic to birds or any air breathing life within the area, and there is the possibility of the natural gas being absorbed into the sea water and causing pollution that way.

So now I ask. Why are they switching? Just because of the abundance?

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20 minutes ago, ALWAYS CRUZIN said:

So now I ask. Why are they switching? Just because of the abundance?

Because, as I've said, there is a cost benefit in the US, not only in $/gal, but in $/BTU.  Most of those new LNG fueled ships, for all the lines (Aida is an exception), are bound for the US market.  Outside the North American ECA, or the North Sea/Baltic ECA's, higher sulfur limits are allowed, and the fuel that meets those limits is cheaper or same price as LNG.  It is also good PR to go to a "cleaner" fuel, and the market forecast is that low sulfur diesel will only rise in price as the demand continues to increase as more ECA's are defined, and that with the surplus of LNG the US has, more export/liquifaction facilities will be built and so the supply of LNG for bunkers will increase, driving price down.

 

Many people think of LNG fuel as a panacea over other fossil fuels for ships, but while it does have it's advantages ecologically, it also has it's drawbacks.

Edited by chengkp75
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A new ship using LNG when it first starts its engines produces the usual black smoke out out the stacks. Take the Mardi Gras as an example. After the shake down. Does the black smoke exhaust cease to exist? Is their any visible exhaust. I think there would not be, but you say some diesel is needed also.

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