1. Håkon B. Thoresen 24 September 2009 Fuel changeover considerations HFO-MGO INTERTANKO Bunker Sub-committee, Nafplia, Greece

2. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 2 Fuel Change-over challenges (HFO MGO)? Fuel Pumps  Thermal damages due to inadequate engine cool-down.  Damages due to insufficient lubricity of the fuel  Damages due to gasing of MGO Fuel Preheaters  MGO should by-pass the fuel preheaters during operation Fuel Tank  Fuel in the return/recirculation pipes returned to correct fuel tank?  MGO tank capacity/availability?

3. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 3 Fuel Change-over challenges (HFO MGO)? B urners (Boilers)  Fuel pumps should be changed or modified to accommodate the lower viscosity fuel.  Post-purge of the furnace after MGO use is recommended. Pressure jet burner  A lower viscosity may cause an increase in the fuel input through the nozzle (increase risk of smoke emission) Rotary cup burner  The fuel amount (pressure) should be checked/adjusted in order to obtain a reasonably smokefree combustion  Gassing of MGO if a suitable heat shield is not fitted Steam atomising burner  MGO may cause overfiring if the pressure alone controls the oil amount of the burner.

4. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 4 Change-over from HFO to MGO/MDO When switching from residual to distillate fuel, changing the fuel temperature too quickly or uneven temerature changes may cause thermal shock causing uncontrolled clearance adaptation which can result in sticking/scuffing of the fuel valves, fuel pump plungers, and suction valves. The temperature increase/decrease rate should be less than 2°C/min* to protect the fuel equipment from thermal shock Courtesy Man B&W * Wartsila allow up to 15°C/min temperature increase/decrease according to service letter RT-82

5. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 5 Change-over from HFO to MGO/MDO  There is a possible risk of incompatibility when the two fuels are mixed together. In particular, the addition of a paraffinic-type distillate fuel to a thermally cracked heavy fuel often correlates with poor solubility of asphaltenes  The mixed fuel could result in some of the asphaltenes coming out of solution and forming sludge. This may cause clogging of filters and separators, sticking of fuel injection pumps (deposits on plunger and barrel), and plugged fuel nozzels.  The mixture is not expected to be homogeneous immediately and some temperature/viscosity fluctuations are to be expected. The process therefore needs careful monitoring of temperature and viscosity.

6. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 6 Change-over from HFO to MGO/MDO  Man Diesel recommend that the compatibility of the two fuels is checked – preferably at the bunkering stage.  ASTM D 4740 - This test method covers the determination of the compatibility between a residual fuel and a blend stock (MDO or MGO).  This procedure is used to identify fuels that, if mixed, could result in excessive centrifuge loading, strainer plugging, tank sludge formation, or similar operating problems. Compatible Incompatible

7. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 7 Change-over from HFO to MGO/MDO NOT compatible Compatible Mixing HFO with MGO/MDO from the same port

8. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 8 MGO Quality  Lubricity may be poor in ultra low sulphur fuels (<0.05%)  The use of MGO/MDO with a sulphur content close to zero and, at the same time, a low viscosity might cause fuel pump and fuel valve wear and, consequently, the risk of sticking.  During service on low viscosity fuel, internal leakages in the fuel equipment will increase and there might be a risk of starting difficulties  ISO 8217 DMA (MGO) spec has a minimum viscosity @ 40°C of 1.40 mm2/s MAN Diesel limits the viscosity at the engine inlet to min. 2 cSt.

9. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 9 MGO/MDO 2009 – Sulphur ≤0.10 ***Viscosity at 40˚C (mm²/s)*** ***Percentage of MGO/MDO samples tested: Jan – June 2009***

10. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 10 MGO/MDO 2009 – Sulphur ≤0.05 ***Viscosity at 40˚C (mm²/s)*** ***Percentage of MGO/MDO samples tested: Jan – June 2009***

11. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 11 MGO/MDO 2009 – Sulphur ≤0.10 and Flash Point

12. © Det Norske Veritas AS. All rights reserved. Fuel changeover considerations HFO-MGO 24 September 2009 12 Safeguarding life, property and the environment www.dnv.com