Finland’s Wärtsilä has created a new cargo-pump control arrangement designed to optimise operations for shipowners and reduce the initial purchasing price of onboard equipment. The latest-generation controller includes a frequency converter package within the cargo-pump system that creates an opportunity to integrate its capabilities with other equipment on board.
Wärtsilä Marine Solutions sales manager for pumps and valves Morten Brandborg explained “The frequency converter package is normally only utilised when the cargo-pumping system is in use, which is mainly during port stays – so for only a very limited time in the vessel’s overall operations. To derive more benefit from this technology we have made it possible to utilise the frequency converter package for other applications on board.”
For example, the company’s latest-generation cargo-pump control technology allows the frequency converter to be used in conjunction with the bow thruster. Mr Brandborg said that “Normally the bow thruster would either be of a fixed-pitch type, with its own separate frequency converter, or it would be of a controllable-pitch type, which would represent a more expensive initial investment, with higher maintenance costs. Either way, with our new system, the owner can benefit from improved operational efficiency and a reduction in costs.”
Wärtsilä estimates that for a fixed-pitch bow thruster arrangement, the saving would be over €85,000 per vessel. Moreover, the company points out, the bow thruster would have the same functionalities and no additional operational restrictions.
Another example of the extended use of the cargo-pump control system enabled by Wärtsilä’s latest system relates to shaft-generator control. Mr Brandborg explained: “It is often a classification society requirement that vessels should have an alternative form of propulsion to be used as a ‘take-me-home’ function in case of a main engine breakdown. We have now made it possible to use the control system from the cargo-pump arrangement for this purpose, using the frequency converter to start and run the shaft generator.”
Up to now this could only be achieved either by having a separate frequency converter for the shaft generator, which is expensive and requires additional space on board, or by adopting a pony motor solution, which presents the risk of damaging the clutch on the main shaft line.
Wärtsilä believes its approach is lower cost and more reliable, and that it also creates an opportunity to introduce a booster mode. “This is especially useful when sailing in ice conditions, as we can now offer a solution where the shaft line can be boosted with additional power through the shaft generator,” said Mr Brandborg.
The new integrated cargo pump control option is considered particularly beneficial for smaller and medium-sized chemical and product tankers. A number of vessels of this type were equipped with the new-generation system in the past year, and several similar projects are now underway.
Wärtsilä sees a growing demand for electric cargo-pump solutions and is developing some interesting new solutions focused on using its digital and electric technology. The company recently announced a new shuttle tanker concept, developed in partnership with Teekay, which will feature Wärtsilä cargo and ballast pumps.
For offloading operations, Wärtsilä can supply this new shuttle tanker design with either electric-driven pumps for pump-room installation, or with electric-driven deepwell cargo and ballast pumps that eliminate the need for a separate pump room and interconnecting pipelines in the cargo holds.
The company points out that the space gained from eliminating the pump room can be used either to increase cargo capacity or to shorten the engine room. The latter permits a reduced hull length, cutting building costs and allowing for better DP capability due to a leaner side profile.