Why fuel pumps matter

Liquefied natural gas (LNG) is widely viewed as the fuel of the future. But in order to be both safe and cost-efficient, LNG operations need to be combined with the right fuel pump. This is why Wärtsilä has developed the Wärtsilä Svanehøj EFP, a specially designed ECA fuel pump that meets the market’s demands for highly efficient, environmentally friendly LNG-compliant solutions.

The new Wärtsilä Svanehøj ECA fuel pump (EFP) is the latest cutting-edge product to come out of Wärtsilä Svanehøj, Wärtsilä’s centre of excellence for pump technology that has been delivering top-of-the-range deepwell cargo pumps for marine and offshore applications for more than 50 years. More than 5,000 of its pumps are currently handling LNG and liquefied petroleum gas (LPG) operations every single day, on board more than 1,000 gas carriers around the world.

High-quality pumps support safety and cost-efficiency

A high-quality fuel pump is a key enabler of safe LNG operations. Furthermore, using the right fuel pump can also help deliver benefits in terms of reliability, performance and cost-efficiency.

The new Wärtsilä Svanehøj EFP, developed in close cooperation with LNG fuel gas experts, is set to become a key part of Wärtsilä’s product portfolio as global demand for high-quality, reliable LNG-based fuel gas systems continues to grow.

Jim Rise is a sales development manager responsible for the LNG fuel pump market at Wärtsilä Svanehøj. As LNG is the fuel choice of the future, Rise predicts that the Wärtsilä Svanehøj EFP will form a key part of that future at sea.

LNG is the future

“Going forward, we can expect to see more emission control areas (ECAs) around the world, with increasingly stringent emission limits,” Rise says. “There are three fuel options when sailing in an ECA zone: low-sulphur marine gas oil, scrubbers, or LNG-fuelled engines. LNG is the cleanest solution and is already emerging as the preferred fuel choice for newbuildings operating in ECA zones.”

According to the latest estimates from DNV GL and Clarkson, the global LNG-fuelled fleet is predicted to exceed 1,000 vessels by 2020. Meanwhile, global consulting firm EY expects LNG demand in 2030 to be almost double what it was in 2012*.

“While LNG is the current fuel of choice for ECA operations, other fuel types may also be used in the future,” Rise says. “For example, the recently converted Stena Germanica is equipped with Wärtsilä dual-fuel engines, to operate on methanol. The Svanehøj EFP is designed to handle all these new fuel types, including methanol and ethane – hence the name CA fuel pump.”

Cost savings with a high-quality LNG pump

LNG can be transferred from a tank to a vessel in two ways. One option is a pressure build-up unit (PBU), which heats the LNG, thus turning the liquid to gas. This increases the pressure in the tank, thereby forcing the LNG into the gas handling system and to the engine. The other option, which is more reliable, is to use a fuel pump.

“Less heat and less pressure in the tank means safer operations,” Rise explains. “And not only that, this solution is also more cost-effective. When LNG is transferred using a pump instead of building up pressure in the tank, the design pressure of the tank can be reduced from 10 bar to 4 or 6 bar, resulting in considerable cost savings. The savings on the tank design often exceeds the price of the pump several times over.”

The Wärtsilä Svanehøj EFP is a long-shafted cryogenic deepwell multistage centrifugal pump designed for continuous operation, 24 hours a day, seven days a week, 365 days a year. The Wärtsilä Svanehøj EFP can be used in any LNG fuel system and is also an ideal part of the Wärtsilä LNGPac.

The Wärtsilä LNGPac is a complete fuel gas handling system for LNG-fuelled ships that includes the bunkering station, LNG tank and related process equipment, the control and monitoring system and, as of now, the Wärtsilä Svanehøj EFP. It can be bought as a standalone product or as part of a propulsion system, complete with a Wärtsilä LNG engine.

Only LNG pump of its kind

The new Wärtsilä Svanehøj EFP is based on the same proven design concept used by Svanehøj cargo pumps all around the world, making it completely different from any other LNG pump on the market.

“The Svanehøj EFP is a so-called deepwell pump, which means that the pump is inside the tank, but the drive motor is kept separate, outside the tank,” Rise says. “This makes it possible to use standard motors and bearings, and eliminates the risk of heat transfer from the motor to the LNG.”

The Svanehøj EFP is extremely safe compared with other products. It is not sensitive to extreme weather, thermal conditions or sloshing. Instead, the pump ensures steady, reliable fuel gas supply with a fast response time.

Safety and reliability

As all the electrical components associated with the pump are located outside the fuel tank, there is no heat transfer from the motor to the liquid gas. This secures both cost-efficient and safe operations, as excessive heat from the motor does not create increased boil-off gas or pressure in the tank.

Aside from safety, the most important feature of a fuel pump is reliability.

“First and foremost, a fuel pump has to be reliable,” Rise says. “It is designed to run 24/7 for several years, without any stops or repairs. It has to be able to vary the fuel pressure according to engine load with a fast response time.

“A reliable fuel pump is an essential service on board a ship,” he continues. “If the fuel supply fails, the ship can’t sail or manoeuvre. Although there will be back-up systems, a broken pump still means longer time spent in port, resulting in loss of revenue.”

 All the materials that handle the liquid gas in Wärtsilä Svanehøj’s pumps are made of cryogenic stainless steel. All the other components are made from high-quality materials, with years of documented service in marine applications.

Five-year service interval 

The Wärtsilä Svanehøj EFP uses proven technologies and parts that have been in operation on board gas carriers for many decades. Its design is based on a hermetically sealed pump that uses standard ball bearings to ensure a long service lifetime. The recommended service interval for the Wärtsilä Svanehøj EFP is 25,000 operating hours or every five years.

When it does require service, the pump has been divided into three separate service areas, allowing access to the motor, bearing and pump at any time, even with gas pressure in the tank. This makes service more straightforward and guarantees peace of mind, with a secure fuel supply that can easily be restored in case of emergency.

© 2018 Wärtsilä