If they go unchecked, the effect that hard abrasive particles of aluminium silicate - otherwise known as catalytic fines - have on marine diesel engines could be 'cataclysmic'. But now, following more than twenty years experience of working with fuel and fuel systems a performance standard for fuel oil treatment onboard ships could be just around the corner
The main challenge was to find suitable and reliable performance criteria for a fuel oil separators' ability to remove abrasive particles from marine residual fuels, which is the most important aspect in the fuel oil treatment process.
Up till now, it has been nigh impossible to verify that the separators chosen according to the Maximum Recommended Capacity tables provided by manufacturers actually guaranteed the safe removal of harmful solid particles. From an engine wear perspective the need for a standardised method to determine separation performance was obvious, but there are also ship safety issues.
Last year DNV introduced the voluntary class notation Fuel, and a type approval standard for fuel oil separators was developed as part of it. This will have the following benefits when this voluntary additional DNV notation is selected by owners:
- Sizing and efficiency of fuel oil separators are specified with requirement to type approved separators. DNV type approval program for separators' certified flow rate is the basis for size
- Arrangement of fuel oil bunker tanks such that bunkering can be done without risk of mixing incompatible fuels
- Arrangement and size of fuel oil settling tanks to ensure good separation of water and sludge
- Capacity of fuel oil heaters
- Requirements for performance of temperature and viscosity controls.
Following some six months of testing different models, DNV in June 2004 issued a Type Approval Certificate for one maker of fuel oil separators. The testing was carried out based on the DNV Type Approval programme for separators.
It was considered a natural step to develop this standard into an international standard, and DNV, together with enginebuilder MAN B&W, separator manufacturer Alfa Laval, and oil major BP Marine, decided to develop a formal reference document specifying such a method. To meet the demand at the earliest opportunity, the parties agreed that the document should be published as a CEN Workshop Agreement (CWA) rather than as a conventional standard. The Swedish Standards Institute (SIS) was willing to provide the secretariat for the CEN Workshop.
The CEN Workshop Agreement (CWA) has the benefit that it is a public process, open to all interested parties, and is relatively quick, as results are scheduled after one year, available in print through CEN.
The first CWA meeting took place in June in Brussels, where other organisations decided to join the group to continue the separator performance standard work.
DNV was selected to hold the CEN Workshop chairman position. It should be noted that also other interested parties are encouraged to join the working group before December 2004, when the process will be closed for already enrolled parties.
The name of the workshop, 'Method for Testing Separation Performance of Centrifugal Separators for Marine Residual Fuels', is aimed at reducing uncertainties with respect to increased demand for efficient cleaning of marine residual fuels.