With all due respect ECA’s have been in place for a good number of years now necessitating the use of lower TBN cylinder oils. When I was involved building ships 10 years ago there were discussions on splitting the cylinder oil day tank to hold different TBN oils.
The new ship I’m on now has two CLO daytanks (and a CLO heater which is a first for me). Since we have a scrubber and SCRs, I’m assuming we’ll just be running 3% HFO with the 100 TBN stuff only.
A Danish instructor I had in a MAN class who sailed 2nd on the Triple E class said they would blend their own CLO onboard based on analysis of the scrapedown sample.
So yeah, it’s definitely down to a science at this point.
Putting Low Sulfur fuel in tanks that previously had High Sulfur fuel without cleaning first is very problematic as those tanks would be contaminated. It would take numerous refills before the fuel burned would actually be considered Low Sulfur in said tanks.
That depends on the residue fraction. How much is that in a big tank? Surely not much more than a percent… you should be good on the second fill-up, so long as the stuff you buy doesn’t teeter right on the edge of the spec. This begs the question: does the price difference of an extra load of ultra low outweigh the cost incurred by manually transferring the residue to the settling tank? I’m guessing yes by quite a bit, so there’s a fun item on the to-do list for the last run in December.
(Disclaimer: I’ve never had the actual pleasure of looking inside an hfo tank, so there’s a fair amount of guesswork in the above.)
Yes. At least myself and my Chief Engineer are, but that won’t change how a Port State official treats us when the inevitable inspection takes place.
For us at least, the transition has been discussed for over a year and with input from the fleet to the office. It wasn’t perfect, but a plan was set in place and we will be in compliance by the beginning of December. I think a lot of companies would have jumped to the new fuel sooner, but the fuel has not been available in large enough quantities until pretty much this week.
I will say that I haven’t seen the trending prices for HFO so low since the mid 90’s.
It is not only in port that you can be checked. Even in the middle of the Pacific Ocean use of too high sulphur fuel can be detected. At least if this article in Splash 24/7 today is to be believed:
When I was involved with Shell’s Arctic Drilling venture they were required to use ULSD per the EPA permits. We found that just filling “empty” tanks with ULSD before sailing the GOM and again in Port Hueneme, CA on their way to Seattle was not sufficient. Going forward many of the ships involved cleaned their tanks before their first loading of ULSD.
Obviously it doesn’t take much to contaminate ULSD’s threshold of 15ppm (sulfur) as compared to Low Sulfur Fuel percentages.
I will add that most of the guys on the ships didn’t fully understand the programs requirements. I think they could have mitigated the situation by designating tanks clean versus dirty to transfer and flush tanks to get them progressively cleaner.
Got any idea why that is? I was assuming perfect mixing, 1% residue fraction in the tank, 2.7% sulfur in the HFO, gives 0.01 x 0.01 x 0.027 = 2.7 ppm sulfur contribution from the tank residue. Maybe the sludge has a higher sulfur concentration than the fuel?
…and my little equation works out to 0.00027%, which only goes to show that it ain’t that easy. This is interesting a propos the amateurs vs pros thread. When it comes to fuel quality transitions in regulatory compliance, I’m very much an amateur. Thus, my inclination is to say “Hold my beer, I’ve got this on the back of an envelope.” Then the pro comes along and says “That’s not how it worked last time I did it”.
I’ve been trying to read up on HFO sludge composition, but it’s tricky. No matter what search terms I use, Google seems to think I want my tank cleaned in time for 2020, which pollutes the results. Anyone got a paper?
Only 1% unpumpable? That seems low. A 500 ton tank only will have 5 tons when MT? I’d guess more like 30 tons but the chief would have a better idea.
Also the LSFO supplied usually does have very close to the minimum required.
Ah ok. The only large-ish tanks I ever cared for were mixed mode fuel / ballast; I guess those are designed with a bit more care in that regard. Given your 6% figure, the hfo sulfur contribution would be 1620, 97, 5.8, 0.35 ppm after successive fill-ups, without accounting for the sludge. The more I read about that, the more I realize that it’s not very nice stuff, and certainly not something you’d want anywhere near your nice, clean ultra low.
In short, there’s nothing to contradict @chief_seadog’s assertion that having the tanks cleaned is in order.