Class notation for treatment and conditioning of fuel.
Purpose
To ensure satisfactory performance of fuel treatment and fuel conditioning.
Benefits
This class notation represents a total system approach to a fuel oil treatment and conditioning system, offering owners an easy way of achieving a predictable performance for the fuel oil treatment and conditioning system on board.
Features
A notation for an enhanced fuel oil treatment system, with a total system approach addressing the size and efficiency of purifiers, arrangement of fuel oil bunker tanks to enable bunkering without mixing incompatible fuels, arrangement and size of fuel oil settling tanks, capacity of fuel heaters, and requirements relating to temperature and viscosity control requirements.
Fuel (-cSt, _kg/m3, -°C) indicates the maximum viscosity in cSt at 50°C, the maximum density in kg/m3 at 15°C of the fuel oil, and the maximum outside air temperature for which the installation is approved.
The notation from DNV takes care of the following potential problems:
Undersized purifiers resulting in too low removal efficiency of catalytic fines.
Inaccurate temperature control of purifier pre- heaters affecting efficiency of purification
Accumulation of sludge in bottom regions of service tanks and settling tanks may cause carry-over of contaminants under heavy weather conditions (roll/pitch)
Insufficient volume of settling tanks with too short residence time for settling out of impurities
Fuel tank arrangements that do not facilitate handling of two bunker fuel batches without mixing causing sludge precipitation due to incompatibility
Inadequate capacity of fuel oil heaters causing too high viscosity of fuel feed to engines leading to inferior combustion
Inaccurate viscosity control system for fuel feed to engines
Too small heating capacity in fuel tanks
Process
Approval of drawings, confirmation on board by newbuilding surveyor before the notation can be given.