Wärtsilä Supplying Re-liquefaction Plant For Three Carriers
By Jack Burke31 August 2017
Wärtsilä will supply its re-liquefaction plants to three new liquefied natural gas (LNG) carriers currently under construction.
One ship is being built at the Samsung Heavy Industries (SHI) yard in South Korea for the international owner and operator Gaslog. The others are for Norway based Knutsen and are also being built at the Hyundai Heavy Industries (HHI) yard in South Korea. The order was booked for the Gaslog ship in April 2017 and for the Knutsen ships in May/June 2017.
The plant ordered for these vessels includes Wärtsilä’s latest mixed refrigerant (MR) technology, an energy efficient solution for smaller liquefaction applications, the company said. This new installation will have a capacity of 1.5 – 2.5 tons/hour (t/h). The Wärtsilä equipment is scheduled for delivery commencing February 2018.
The boil off gas (BOG) re-liquefaction process is based on reversed nitrogen Brayton cycle refrigeration technology, combined with a process solution for separating nitrogen from the BOG. This means that the process is a closed nitrogen cycle for extracting heat from the boil-off gas. Typically, the re-liquefaction system is used to control the cargo tank pressure by liquefying boil-off gas. They have the capability to handle all boil-off gas (100% capacity) or only excessive boil-off gas not burned in the engines (partly liquefaction), the company said.
“We are proud of the success of Wärtsilä’s advanced re-liquefaction plants based on MR technology, and this success is reflected in these latest orders. Wärtsilä is a total LNG solutions provider with products, systems, and solutions for applications throughout the entire value chain,” said Timo Koponen, vice president, Flow & Gas Solutions at Wärtsilä Marine Solutions.
Gaslog has been a customer of Wärtsilä for many years and several ships in its fleet are fitted with Wärtsilä solutions. Knutsen’s two latest vessels delivered in 2016 are fitted with Wärtsilä’s nitrogen based re-liquefaction plants.