World Bunkering > News > Autumn 2011 > Coriolis: the new black?

Sir,

Interesting to see from Dr. Weinstein’s response (Spring 2011, page 33) to my article in the Winter 2011 issue just how much agreement there is; effectively it appears he agrees there is no reason why Coriolis should be the only available choice for bunkering.

So when he says (and I agree): “What we found curious was the idea that the primary motivation to use Coriolis meters in bunkering is immunity to entrained gas,” it isn’t me saying it. While no one may have actually claimed this, it has been a fair inference from the various articles and it was important enough in the BP trials in Singapore that air had to be deliberately introduced and allowance made for 0.5% accuracy and not the 0.15% achievable with air free fluids.

Dr. Weinstein’s statements that this capability is not a major factor, that an absence of air is beneficial (including to Coriolis meters), and also “many barges are designed to completely avoid aeration”; showing that entrained air is not an insuperable problem, there is no reason to make Coriolis the only approved technology. Bunkering problems are not just about quantity. To the extent that it is about “value for money”, it is about both quantity and quality, and quality is also a factor in environmental legislation. Is quality a serious problem? Of course it is.

While no one seems to have measured just how frequently “cappuccino effect” fuels are encountered; DNVPS has just released results of a survey on bunkering problems that demonstrates the surprising extent of quality problems and a frequency with which quality is more often an issue than quantity.

Hence, during bunkering, any solution needs to address both quality and quantity as the fuel is being transferred; once the fuel is on board, it is “use it” or “debunker” (14% of operators had to de-bunker according to the survey). That said, it is important to detect (easily done) and reject and fuel showing evidence of the “cappuccino effect” because air corrupts several of the affordable online and offline quality tests. An ability to meter fuels with entrained air might thus be at the expense of quality assurance.

“Coriolis meters eliminate several sources of uncertainty currently present in bunkering”

The growing number of articles promoting the use of Coriolis meters, is such that many believe this is now a “done deal”, and while Coriolis is certainly a valuable technology, does it really show the superiority that would make it the exclusive choice for bunkering?

In these articles Coriolis is rightly promoted as a tremendous advance in bunker quantity accounting. But the comparison is with tank dipping – exclude entrained air capability and substitute a different meter technology and these articles could pretty much describe the advantages of any meter technology over tank dipping. The important comparison is of Coriolis metering with other possible technologies.

The article didn’t argue that Coriolis meters shouldn’t be used, just that they should not be an only choice; that the marine industry is just as capable of managing a choice of technologies as is the oil industry.

Jon Watson