Since the beginning of the year in the SECA emission control areas of Europe, only residual fuels with a maximum sulfur content of one per cent is permitted. On the West Coast of the United States a similar ban has been in force since July 1, 2009. The application of the new regulations is not without hazards. A higher number of propulsion failures directly associated with switching over from one fuel to another have been reported. Due to fuel temperature considerations, the changeover from one fuel to the other is not immediate but must be a gradually spread out over a period that can easily last from 30 to 60 minutes. Failure to do this gradually, could lead to seizure of the fuel pump due to low viscosity of the diesel fuel and thermal shock. This delay needs to be taken into account in the ship’s navigational planning of arrival or departure to ensure an orderly fuel change-over prior to entering the ECA. During changeover there is a danger of sludge formation, clogged fuel filters and separators, sticking fuel injection pumps and plugged fuel nozzles. Longer term effects if using a lubrication oil that is not matched to the fuel in use, can lead to cylinder liner lacquering on four-stroke engines with prolonged operation on low sulfur (mainly distillate) fuels causing expensive repair bills! Let’s hope that lessons are learned from the experience of others and these problems are avoided.
Since the beginning of the year in the SECA emission control areas of Europe, to be called ECAs after Jul 1, 2010, only residual fuels with a maximum sulfur content of one per cent is permitted. The restriction on using high sulfur residual fuels requires switching to either a low sulfur residual or in many cases to a distillate MDO/MGO fuel.
On the West Coast of the United States a similar ban has been in force since July 1, 2009. following the California Air Resources Board’s (“CARB”) curb on the use of high sulfur fuels. This indeed presents an opportunity to learn from the experience of our fellow seafarers with the introduction of such a far reaching change
While the benefits of the cleaner emissions are applauded, the application of the new regulations is not without hazards. A higher number of propulsion failures directly associated with switching over from one fuel to another have been reported by authorities on the US West Coast.
Due to fuel temperature considerations, the changeover from one fuel to the other is not immediate but must be a gradually spread out over a period that can easily last from 30 to 60 minutes. The injection equipment must be protected from rapid temperature changes in order to allow the temperature of the fuel pumps to decrease from up to 150°C in residual fuel operation to a maximum 50°C (MGO) – 60°C (MDO) in distillate fuel operation. Failure to do this gradually, could lead to seizure of the fuel pump due to low viscosity of the diesel fuel and thermal shock. This delay needs to be taken into account in the ship’s navigational planning of arrival or departure to ensure an orderly fuel change-over prior to entering the ECA.
During changeover there is a period when two very different fuels are mixing for an extended period of time. In this phase there is a danger that asphaltenes of the residual fuel may precipitate out of the mixture as heavy sludge, which in turn can cause clogging of fuel filters and separators, sticking of fuel injection pumps (asphaltene deposits on plunger and barrel), and plugged fuel nozzles.
Longer term effects such as using a lubrication oil that is not matched to the fuel in use, can lead to cylinder liner lacquering on four-stroke engines with prolonged operation on low sulfur (mainly distillate) fuels. The lacquer fills-in the honing grooves of the liner which results in difficulties in maintaining a good oil film, high lubricating oil consumption, accelerated liner wear, less efficient heat transfer from the piston etc., in other words expensive repair bills!
Let’s hope that lessons are learned from the experience of others and these problems are avoided.