CASE: Additional cooling arrangement for feeder pump circulation

During a port stay, or in a low-load situation, pressure from the feeder circulation ensures that there is sufficient pressure and readiness for engine startup in the booster circulation. With practically no fuel consumption or low fuel demand, the fuel temperature in the feeder circulation is prone to rise.

When running on fuel oil, a temperature increase in the feeder circulation is not typically an issue, however when using MGO it is critical to maintain a low enough temperature to avoid pump problems. If the fuel temperature rises, the fuel viscosity will drop, which can cause subsequent pressure losses and reduce the fuel’s effectiveness as a lubricant. This in turn can lead to a range of fuel system malfunctions including that of fuel pumps and machinery with moving parts in the fuel circulation system.

As vessels are unique in their systems and chosen propulsion methods, individually tailored solutions are required. The risk of pump issues can be mitigated with additional cooling arrangements or with the introduction of variable frequency drives (VFD), whilst the maintenance of the correct booster circulation pressure and readiness for problem-free engine start-up, can ensure all potential issues are reduced.

For example, if the fuel pump circulation is operated through a conventional starter system, with the pump operating continuously, an additional cooling arrangement for the feeder pump circulation will maintain the correct MGO temperature. In such cases, changes to the fuel system piping (including fuel, cooling water and  electrics) are needed.

Another alternative is to add frequency converters to optimise the fuel pump rpm. In low load situations, and low fuel demand, the variable frequency drive will lower the pump rpm to an optimised level where heating and pressure issues do not occur. If this alternative is chosen, changes to electrics and related documentation are required.

How Auramarine can help

Once we get your enquiry, our team of experts will conduct a technical review of your system, provide a needs analysis and a proposed solution. The drawings and other documentation are updated accordingly, and approvals (also for classification) can be arranged on an agreed case by case basis. Project management support is also available as required. The installation can be carried out by the vessel owner’s chosen installation partner or by a shipyard. After the delivery of equipment, we can provide commissioning and installation supervision, and provide ongoing support with our lifecycle services and spare parts services.