World Bunkering > News > Spring 2011 > Gaining acceptance

Last October’s Singapore International Bunkering Conference and Exhibition (Sibcon) provided a good idea of how work on using flow meters in the bunkering industry has gone.

At the event, the Maritime and Port Authority of Singapore (MPA) announced that it will set aside S$1million (US$0.8 million) from the country’s Maritime Innovation & Technology Fund to support research into mass flow metering. That reflected the reports on field trials carried out in Singapore that the delegates heard from Seah Khen Hee, convenor of the country’s Working Group on Mass Flow Metering.

Among the results of the trials so far were: proper sizing and positioning of meter with respect to bunker tanker is important; a good stern trim of the bunker tanker (1.5 to 2.0 metres) helps to reduce the duration of stripping; there should be no stripping of a cargo tank while another cargo tank is being pumped; a metering system also allows the flexibility to deliver the nominated quantity without stripping; good flow rates were experienced in meter deliveries to VLCCs and large containerships; and crew on board found the metering system easy to operate.

It was clear from discussions on the margins of Sibcon that there was a significant amount of scepticism about flow meters, both locally and more widely. Moreover, an article carried in the winter issue of World Bunkering highlighted the fact that opinion is divided in the industry (see Letter to Editor, opposite).

At Sibcon, the issues associated with stripping cropped up frequently in conversations with suppliers. Asked what developments there had been at Endress & Hauser over the past few months regarding flow meters, a spokesman told World Bunkering: “We are still fine-tuning our system for handling stripping phases.” He also agreed that further testing is still necessary but was relaxed about potential problems concerning calibration, saying: “Once the industry is convinced about the benefits of flow meters, we see this as a relatively simple problem to deal with.”

So how confident is Endress and Hauser that the bunker industry will accept flow meters? “For now we concentrate on providing the best systems for the application. When this is done, time and results will convince.”

Sir,
We read Jon Watson’s article in World Bunkering [Winter 2010; “Coriolis: The New Black”] with great interest this month. As a supplier of Coriolis meters, we want to join in the discussion. Mr Watson makes a number of excellent points in his article, especially the comment that the success of flow metering would be assured if air were prevented from entering the fluid. We have found that many barges are designed to completely avoid aeration, which allows Coriolis meters to achieve a very high measurement accuracy in the neighbourhood of 0.1%. We also agree that proper sizing of flow meters is critical to ensure good accuracy without adversely affecting pumping capacity.

What we found curious was the idea that the primary motivation to use Coriolis meters in bunkering is immunity to entrained gas. In truth, we consider Coriolis meters a good fit for bunkering because of the direct mass measurement, which is unaffected by temperature, pressure, and composition. This eliminates several sources of uncertainty currently present in the bunkering process. And while immunity to entrained gas certainly plays a supporting role, equally important is the lack of required maintenance (no moving parts), relative immunity to drastically changing Reynolds numbers (no calibration required on bunker fuel), and high accuracy.

Over the last few years, Emerson has explored the technical and logistical challenges of bunker quantity measurement. We have found that our Coriolis mass flow meters are well-suited to bunkering; however, like in any application, proper installation and operation practices are critical. This is an area we continue to investigate and test in the field to ensure optimal performance and benefit.

Best Regards,
Joel Weinstein,
Applications Engineer,
Emerson Process Management