- Vessel performance and Efficiency
- Niomar Marcano
Rooters
GMT 14:06
18th Apr 2007Dear Dr. Vis,
I am very much interested in knowing how to evaluate the performance and combustion efficiency in a vessel when there is a change in the type of fuel used. For instance, how to evaluate vessel performance when has to switch fuel from heavy fuel oil to low sulphur fuel. Which are the typical guidelines to follow in that case?
Thanks a lot in advance. - Dr. Ram Vis
Viswa Lab Corp.
GMT 20:27
18th Apr 2007
IP: x.x.203.241The main property of the fuel which you should watch is ignition and combustion, assuming that the other parameters including density, viscosity, catfines and vanadium are all within acceptable limits. Since CCAI is not a reliable indicator, running the two fuels through the fuel tech instrument will give you a very good idea of the equivalent cetane number of the fuels. This property will determine how much more power the better fuel will generate and also if there will be any problems due to late burning etc.
What is Rooters? - Niomar Marcano
Rooters
GMT 15:59
3rd May 2007
IP: x.x.0.121Dear Dr Vis,
Thanks a lot for your reply. From the vessel performance point of view, which variables should be considered in order to evaluate combustion efficiency: cylinder exhaust temperature, black smoke on the chimney, fuel consumption, maintenance, etc ???.
Rooters is a very small company of consultants in combustion and IT - Dr. Ram Vis
Viswa Lab Corp.
GMT 19:38
3rd May 2007
IP: x.x.203.241The best indication is the keep the fuel control lever in the same position. Release the governor and run the engine on the two fuels one after the other. Apart from other parameters, the good fuel should run at relatively higher rpm. In my opinion this is the best simple test that can be carried out. - "All other things being equal" would be a normal caveat when looking at efficiency.
When comparing one fuel to another one can compare their different qualities but in practice you might see another result entirely and that might be due to other changed factors such as load, pitch, sea conditions etc.
Even running the same fuel you will see variability in the performance.
One way to look at efficiency is to look at the results achieved e.g. distance run against fuel used and for load carried.
Simply logging the fuel used on a daily basis may not enable you to do too much about improving efficiency but there are a number of solutions available for real time monitoring of fuel efficiency when measured in terms of fuel used against performance achieved and, with a real time display (from the fuel flow meters and GPS data) you may find some improvements in ship management.
With such a system you can then log data on minute by minute intervals and be able to evaluate this data against changes in fuel used and any other events or conditions. A typical solution is the FUSION system by Flow Technology Inc. The interest in such systems is growing simply because in some cases it can enable vessels to save fuel and also because it can provide an indicator of other performance factors such as comparing one engine against another or one vessel against another.
