It's good to find folks willing to read still about these days.
Long haul trucking and railroads use diesel instead of gasoline engines for a reason - the higher density of diesel contains more energy per unit volume.
Marine diesel is not typically the same as highway diesel for this reason; the push for higher cetane ratings and lower sulfur in highway diesel reduces the aromatics content and therefore the density, but also decreases the resistance to ignition.
Marine fuel oil (and heavy fuel oil in general) has higher density - you can see some of the heaviest grades are "heavier than water" - if they were liquids at 15°C, and even the heaviest grade has a maximum pour point of 30°C / 86°F so it's still not really "tar / asphalt". There is a lot of energy per unit volume available in heavy fuel oils for propulsion across the oceans (or generating electricity in a fuel oil powered generator as another example).
FWIW, the term "bunker fuel" is a holdover from when oceangoing vessels had actual coal bunkers with men shoveling coal into the furnaces.
Used Oil - Large Ship Air Pollution
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It's good to find folks willing to read still about these days.
Long haul trucking and railroads use diesel instead of gasoline engines for a reason - the higher density of diesel contains more energy per unit volume.
Marine diesel is not typically the same as highway diesel for this reason; the push for higher cetane ratings and lower sulfur in highway diesel reduces the aromatics content and therefore the density, but also decreases the resistance to ignition.
Marine fuel oil (and heavy fuel oil in general) has higher density - you can see some of the heaviest grades are "heavier than water" - if they were liquids at 15°C, and even the heaviest grade has a maximum pour point of 30°C / 86°F so it's still not really "tar / asphalt". There is a lot of energy per unit volume available in heavy fuel oils for propulsion across the oceans (or generating electricity in a fuel oil powered generator as another example).
FWIW, the term "bunker fuel" is a holdover from when oceangoing vessels had actual coal bunkers with men shoveling coal into the furnaces.
Some other recent findings just FYI:
- Refined diesel is about twice the cost of bunker.
- Worlwide consumption of bunker is around 3M bpd.
First item is an estimate and anecdotal. Second is from eia.gov which should be a weekly must read for bitog'ers.
Why use anecdotal pricing in the Information Age? You can see some grades relative to others here for free. 
Bunker Fuel Price Link
Note the MDO (Marine Diesel Oil) prices vs. IFO (Intermediate Fuel Oil) prices vs. MGO (Marine Gas Oil) prices - you can then compare to highway diesel prices if you like.
If you click on a price, the link will take you to additional information - note the prices are in $US per metric ton here for bunker fuels, making comparisons easy for us in USA - no currency conversion needed.
ULSD diesel here has a specific gravity of about 0.8, so a metric ton of highway diesel at the average US pump price today of $2.50 per US Gallon is about $830, including pump taxes of course.
So comparing MDO to ULSD, the ULSD price is about (not quite) double. Comparing IFO to ULSD, ULSD is about (not quite) quadruple.
Bunker Fuel Price Link
Note the MDO (Marine Diesel Oil) prices vs. IFO (Intermediate Fuel Oil) prices vs. MGO (Marine Gas Oil) prices - you can then compare to highway diesel prices if you like.
If you click on a price, the link will take you to additional information - note the prices are in $US per metric ton here for bunker fuels, making comparisons easy for us in USA - no currency conversion needed.
ULSD diesel here has a specific gravity of about 0.8, so a metric ton of highway diesel at the average US pump price today of $2.50 per US Gallon is about $830, including pump taxes of course.
So comparing MDO to ULSD, the ULSD price is about (not quite) double. Comparing IFO to ULSD, ULSD is about (not quite) quadruple.
MolaKule
Staff member
Originally Posted By: Nyogtha
It's good to find folks willing to read still about these days.
Marine fuel oil (and heavy fuel oil in general) has higher density - you can see some of the heaviest grades are "heavier than water" - if they were liquids at 15°C, and even the heaviest grade has a maximum pour point of 30°C / 86°F so it's still not really "tar / asphalt".
There is a lot of energy per unit volume available in heavy fuel oils for propulsion across the oceans (or generating electricity in a fuel oil powered generator as another example).
FWIW, the term "bunker fuel" is a holdover from when oceangoing vessels had actual coal bunkers with men shoveling coal into the furnaces. 
Using the word "tar" in the original article was totally senseless and irresponsible.
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Originally Posted By: MolaKule
Using the word "tar" in the original article was totally senseless and irresponsible.
nuclear powered freighter prototype:
What would the cost per year be like now for a nuclear powered freighter and a similar sized bunker fuel ship?
Quote:
As a result of her design handicaps, training requirements, and additional crew members, Savannah cost approximately US$2 million a year more in operating subsidies than a similarly sized Mariner-class ship with a conventional oil-fired steam plant. The Maritime Administration placed her out of service in 1971 to save costs, a decision that made sense when fuel oil cost US$20 per ton. In 1974, however, when fuel oil cost $80 per ton, Savannah's operating costs would have been no greater than a conventional cargo ship. (Maintenance and eventual disposal of its nuclear power plant are other issues, of course.) In a note of historical parallel, the ship's namesake, SS Savannah, which in 1819 became the first steam powered ship to cross the Atlantic Ocean, was also a commercial failure despite the innovation in marine propulsion technology.
And if you can find the specs. You will find jet engines and the turbines used on many military boats, pollute way more than these very efficient large engines do. Nuke is not safe or clean. Go visit fukushima.
We were on a cruise just after Christmas, and the cruise ship was powered by 2x LM2500s.
When in harbour, they were clearly running something like diesel or heating oil...at sea, they were clearly running re-used oil of some description.
Originally Posted By: DeepFriar
Originally Posted By: Shannow
Media grabs it, because they can beat it.
Did you look at the sulfur limits in the link I posted for various grades of marine fuel oils?
BTW, those are undergoing reduction just like gasoline and highway diesel have been.
No, but NOX formation is far more complex than SOX formation, due to nitrogen in the air being present along with nitrogen in the feedstock. Hotter combustion temperatures which are desireable for thermodynamic efficiency create more thermal NOX from nitrogen in the air. So thermal NOX formation is greatly influenced by combustion apparatus design. Only way to completely avoid around thermal NOX generation from combustion is to use pure O2 for combustion which is not feasible from safety, logistics, or air seperation (or water cracking) energy efficiency to generate the pure O2. Having said that, refining processes which reduce sulfur in fuel also reduce nitrogen in fuel.
For CO2 emissions, I don't believe that would significantly change, but have never studied it per se on less refined vs. more highly refined petroleum derived fuels nor know of any such studies. Most combustion control, coupled with environmenal conttol, of industtial combustion processes target a certain max threshold of CO for fuel efficiency, safety, and pollution control, thus maximizing the CO2 produced from the fuel. This is up to including precious metal combustion promoters containing platinum and / or palladium to drive combustion completion in some cases.
The number that continues to trouble me is that bunker consumption is about 8 million barrels per day. Total US consumption is 18-20 million barrels per day of all types most of which is subject to fairly strict EPA emissions limits. If the emissions of 15 large tankers (circa 2009) out of say, 1200 such ships, equal the pollutants of the entire planet's auto population what then must be the total bunker input to harmful emissions worldwide? Even allowing for a vast error budget in the data the numbers are gripping. Squeezing this corner of the envelope alone could allow us to free other economic activity from diminishing returns actions. Note that I am not some environmentalist wonk, it's just that the inputs from marine, if true, are jaw dropping.
And nothing new, especially with globalization.
I understand ARCO developed a tanker to burn petcoke instead of bunker back in the 70's or early 80's. I heard that within a few years after it was built, there weren't many places on earth it could dock due to emissions legislation.
Liquid marine fuels still offer considerable advantages over prior, and more modern, solid fuel alternatives that have the energy content to make a transoceanic voyage without refueling. One disadvantage is a crafty captain & chief engineer can siphon off heavy crude from cargo to burn as fuel and pocket the fuel savings. I put myself through college being in a part of the industry that watched for such things.
Yet we generate gigawatts of electrical energy from solid fuel combustion.
I understand that it's not new data. Or a new situation. For me at least it is discouraging that there is so much continuing sturm und drang about auto emissions when clearly improvements there are into the diminishing returns arena. And at quite high cost to the car buying public for relatively little additional gain compared to that available from marine, power generation, et al. Yet it is not discussed as openly, often and vigorously as it deserves. The proverbial man in the street knows nothing of this and, as I have now belabored too long, I suspect the powers that be would rather he did not. Because if he did he just might see the game he is paying for only gets more expensive without a corresponding benefit. Somebody is gaining something when it only "looks" like progress is being made. That "somebody" is the whole carbon free cult and those associated with it.
Excuse me, there is a black helicopter on my lawn, I'll be right b.......
Resurrecting this old thread with new updates instead of starting a new thread.
The 2020 global sulphur limit and the Scrubber exercise.
https://www.linkedin.com/pulse/2020-global-sulphur-limit-scrubber-exercise-john-yallouridis
Note the sulfur limit in marine fuel oil is decreasing to 0.5 wt% (5000 wppm) by 2020 for ships without scrubbets. However also note that the Open Loop scrubber technology simply dumps the acidic SOX & NOX directly into seawater for ocean acidification bypassing the emissions to atmosphere and acid rain step. Also note the teport pointing out increased industrial emissions yo refine the fuel oil to this level, incredibly well-balanced factual reporting on this issue.
Here is a good article on the reported economic impact of these new regulations.
https://mobile-reuters-com.cdn.ampproject.org/c/s/mobile.reuters.com/article/amp/idUSKBN1HI1AT
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Right now there's no system for ships to take on new fuel supplies on the open ocean, only in coastal areas. From my marine transport custody transfer inspection days, we would routinely do bunker surveys, pulling samples of the fuel oil in the ship's fuel tanks and taking measurements for quantity, especially ships hauling heavy crude oil or residual oil. It wasn't too hard to catch a vessel skimming cargo to put in its fuel tanks, and the captain and chief engineer were typically the ringleaders pocketing the difference in fuel budget monies vs. fuel purchased. Sometimes they would be plain stupid, saw Federal Marshals immediately impound a ship carrying residual oil from the Middle East to South Texas with no stops in between arrive with chock full fuel tanks. Anyway, you could require a bunker survey on every vessel when it arrives in port each time to catch those dealing with potential fuel pirates who may pencil-whip a CofA for a fee. The issue is keeping your independent inspectors & labs etc. truly independent on a global basis.
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