Splash247: Babcock recycles onboard heat to cut reliquefaction load

Published by Splash247

Lloyd’s Register has granted approval in principle to Babcock LGE’s ecoAPEX cargo-handling technology for LPG, ammonia and ethane carriers.

The system connects two energy-intensive processes that conventionally operate independently aboard dual-fuel gas carriers.

Reliquefaction equipment removes heat from cargo boil-off gas, while the fuel-gas system adds heat to low-temperature fuel before it reaches the engines. ecoAPEX uses heat exchange between the two systems to offset part of both duties.

Babcock has combined the arrangement with a higher-capacity piston-ring compressor designed to increase reliquefaction output without requiring additional input power.

The company claims integrated energy management can improve the system’s coefficient of performance by up to 19%, with the compressor contributing a further improvement of approximately 14%. The combined architecture is said to lift reliquefaction efficiency by up to 33%, cut its energy consumption by around 25% and reduce loading and cooldown times by 14%.

Those figures are based on a design case involving commercial propane containing 5 mol% ethane, seawater at 36C and simultaneous reliquefaction and fuel demand. Actual performance will depend on cargo composition, ambient conditions and the overlap between the two processes.

For ultra-large ethane carriers, Babcock said the additional capacity could allow designers to remove one complete reliquefaction and refrigeration package.

The heat-exchange connection can be bypassed, allowing the cargo and fuel systems to operate independently during maintenance or when their energy requirements do not coincide.

The approval validates the concept’s technical basis but does not cover a commercial installation. Babcock has not disclosed a customer, vessel, equipment order or deployment schedule.