TECHNOLOGY group Wärtsilä has released a new system to reliquefy boil-off gas (BOG) onboard gas carriers and LNG bunker vessels, and keep the cargo cool under all operating conditions. Its compact design enables it to be installed on existing vessels without extensive modification work.

“Wärtsilä has been a pioneer in BOG reliquefaction and the Compact Reliq is a continuation of our strong development activities in this field,” Kjell Ove Ulstein, director sales and marketing, gas solutions, Wärtsilä Marine Systems, said.

“As the global market for LNG applications expands in response to increasing environmental regulations, greater flexibility in meeting these growing needs is required. The Compact Reliq is an important and innovative new piece towards completing the puzzle.”


As with previous Wärtsilä reliquefaction systems, the Compact Reliq is based on Brayton technology. This allows a portion of the BOG to be utilised as fuel for the vessel, while the excess can be liquefied and sold with the LNG cargo. Liquefying the BOG instead of burning it in a gas combustion unit also has a positive environmental effect, as no gases are released into the atmosphere.

The Compact Reliq is compatible with Wärtsilä’s Operational Performance Improvement and Monitoring protocol, and can be fully integrated with the ship’s planned maintenance system.

An animation of the Compact Reliq can be seen here.