3.2.2 Another example of improper combustibility at other vessel
Fig. 14 shows the relation between cylinder liner excessive wear and fuel oil suppliers. The excessive wear occurred in the period of using #1 fuel. And in this case, cylinder liner temperature also showed an indication of the improper combustibility of #1 fuel, as shown in Fig. 15. Fig. 16 shows the cylinder liner temperature vs. main engine speed to present the temperature difference caused by #1 fuel. Furthermore, Al+Si of the #1 fuel was 45ppm, and this also promoted the excessive wear.
Fig. 14 Relation between cylinder liner excessive wear and fuels oil supplier
Fig. 15 Trend of cylinder liner temperature
Fig. 16 Cylinder liner temperature vs. main engine speed
3.3 Used Lubricating Oil (ULO)
The contamination of the fuel with ULO deteriorates the efficiency of the purifier severely, especially for the performance of separating the impurities such as catalytic fines, because the additives in lubricants have strong affinity for impurities. The contents of Zinc (Zn), Calcium (Ca), Magnesium (Mg), Iron (Fe), Copper (Cu) and Phosphorus (P) are the indexes of contamination with ULO.
Generally speaking, crude oil does not contain zinc. And the great majority of crude oil has a content of calcium with below 2ppm. And many automotive lubricants contain zinc, calcium and magnesium. In addition, wear particles such as iron, copper, etc. are contained in ULO.
Fig, 17 shows the contents of Calcium and Zinc. Concentration of those in the fuel supplied by #B is in a higher range.
We are of the opinion that ULO must not be added to bunkering fuel in order to keep the safe operation.
Fig. 17 Fuel oil analysis results
3.4 Low sulfur contents
Sulfur contents is also one of the index for the fuel refined by FCC refinery process. Because this refining system is including the desulfurization process.
Fig. 18 shows that the sulfur content of U.S.A. West Coast is usually below 2% mass. Especially, the fuel supplied by #B contains sulfur approximately 1% (minimum 0.4%). On the other hand, #6 vessel which was in service in Far East to Europe bunkered at Europe and Asia, and the sulfur content was 3 〜4%.
Low sulfur content itself has an adverse effect on piston running behavior.
BACK CONTENTS NEXT
