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US firm Emerson Process Management says its Micro Motion® Certified Marine Bunker Measurement Solution is the first traceable, transparent, mass-based measurement system with third-party certification for heavy fuel oil (HFO) bunkering.

Installed on a vessel, barge, or at a terminal, the Certified Marine Bunker Measurement Solution monitors the bunker delivery, reports final totals, and provides a ticket that can be used for custody transfer.

This bunker custody transfer system is said to meet international standards and provide accurate, transparent bunker fuel deliveries that will aim to minimize the number of disputes between barge operators and ship operators, while enabling operators to accurately monitor fuel and improve operational efficiencies.

While bunker transfers are billed based on mass, measurements are calculated using volumetric-based methods. Traditional bunker measurement relies on look-up tables and manual dips, as well as laboratory tests to determine density measurements. Emerson points out that the practices are labor intensive, and can result in legal disputes and potential reputation damage. With bunker fuel costs amounting to 50-70% of the total ship operating expense, even small inaccuracies can have a major effect on operating costs.

Emerson worked with industry leaders in shipping, supply, and barge operations to develop its certified bunker measurement system. The solution includes a Micro Motion ELITE® Coriolis Meter, Series 3000 transmitter with Marine Bunker Transfer Package, and bunker delivery ticket printer.

The solution is capable of handling the density and viscosity variation inherent in HFO and was certified by Nederlands Meetinstituut (NMi), the notified body for testing to the guidelines of the European Instruments Directive (MID) and Issuing Authority for OIML (International Organization for Legal Metrology). The Micro Motion meter meets the OIML standard R117-1 and the overall solution meets MID standard 2004/22/EC Annex MI-005.

Highlighting the difficulties in calculating measurements, Emerson said: "The process of marine bunkering presents challenges to any measurement device. Unlike gasoline or diesel fuel, the density and viscosity of HFO varies enormously and can even vary across a single bunkering as the fuel may stratify in the storage tank. This means that measurement systems based on volume need a correction factor applied to determine the mass of the fuel that has been delivered. In addition, the fuel being delivered can become aerated, which will affect the volume measurement."

Emerson says its Micro Motion Coriolis meters deliver consistent, accurate mass measurement. The Certified Marine Bunker Measurement System has been specifically designed to handle high-viscosity, aerated liquids and is said to offer an overall accuracy within 0.5% of mass. The transmitter post alerts when the level of entrained air reaches a pre-set limit, allowing the operator to take steps to reduce aeration and ensure accurate delivery. A printed bunker transfer receipt includes the time, date and the total quantity transferred, and can be used as a legal (Weights & Measures) document.

The Certified Marine Bunker Measurement System can be installed on either barges or the vessel itself. It has been independently verified by NMI (a participating member of OIML) for aerated HFO.

According to Emerson, Micro Motion Coriolis meters, with no moving parts to break, wear or risk performance drift, deliver 'the highest accuracy and performance possible', adding: "ELITE High Capacity meters are capable of handling flow rates over 1,500 ton/h and delivers reliable performance and the highest flow rates of any Coriolis meter available today."

ELITE High Capacity Coriolis meters have been tested with crude oil and other liquid and gas hydrocarbons in accordance with American Petroleum Institute (API) and American Gas Association (AGA) guidelines.

Image: The Certified Marine Bunker Measurement Solution includes a Micro Motion ELITE® Coriolis meter, Series 3000 transmitter with Marine Bunker Transfer Package, and bunker delivery ticket printer.