Steam plant operation improvement

Experience has shown that there is an improvement potential for boiler operation in terms of general use and maintenance of the boiler and steam plant system.

Applicability and assumptions

This measure is most valid for crude and product tankers, of all ages, as they are the ship types most frequently equipped with large oil fired boilers, where cargo handling and discharge can be vast steam consuming operations. In these cases the condenser performance (sub cooling) and hot well temperatures are of higher relevance. The measure is assumed to be implemented to a greater extent on the larger ships and, therefore, the potential is assumed greater for smaller ships.

The measure involves updating the related procedures, installing/using some new sensor equipment, minor retrofits like new insulation for steam piping on deck, training of crew and some additional maintenance to minimize steam consumption and leakages, and optimize efficiency of steam production. Such updates can relate to areas like tank cleaning, general monitoring and reduction of the steam consumption and leakages, monitoring and tuning of the boiler performance, optimal cargo heating, etc. For boiler performance several aspects are important, but especially control and adjustment of excess air on boiler, feed water temperature, drum pressure, and ambient air temperature and humidity. For steam leakages regular maintenance on disc type steam traps based on performance monitoring is usually advised.

Cost of implementation

The cost of this measure’s initiatives has been estimated at $20,000 (USD) per ship per annum.

Reduction potential

The reduction potential for boiler consumption has been estimated in the range of 10% to 30% of the total boiler fuel oil consumption, with larger reductions per percentage on smaller ships than on larger ships. The reduction potential is also assessed to be the same for new builds as for ships already in operation as this is an operational measure, and it is assumed that new vessels will have the same operational pattern as the existing ships.

The benefit from the measure will come in terms of reduced fuel consumption due to less steam needed on board in addition to more effective production of steam.

Other References

1. Air pollution and energy efficiency / IMO energy efficiency appraisal tool
2. Third IMO GHG Study 2014 / International Maritime Organization (IMO) / Smith, T.W.P.; Jalkanen, J.P.; Anderson, B.A.; Corbett, J.J.; Faber, J.; Hanayama, S.; O'Keeffe, E.; Parker, S.; Johansson, L.; Aldous, L.; Raucci, C.; Traut, M.; Ettinger, S.; Nelissen, D.; Lee, D.S.; Ng, S.; Agrawal, A.; Winebrake, J.J.; Hoen, M.; Chesworth, S.; Pandey, A. / 2014