The American Bureau of Shipping and Monaco-based LNG shipper GasLog have completed a joint development project demonstrating a new approach to evaluating LNG boil-off rate.
“By expanding the application of computational fluid dynamics (CFD) analysis to simulate the LNG BOR in cargo tanks, owners are able to better predict boil-off gas and account for it in future designs and operations of LNG carriers,” said ABS chief technology officer Howard Fireman .
LNG boil-off gas is the vapor phase of LNG carried in a cargo tank. Accurate assessment of the rate of LNG boil-off gas generation is critical for the design of the cargo tank and the boil-off gas processing system.
To support this collaborative project, a robust CFD analysis procedure was developed modeling the physics of heat transfer, boiling, phase change and vapor flow. Extensive simulations were run on a representative LNG carrier and actual BOR measurements were taken to demonstrate the accuracy of the analysis results, the duo said in a joint statement.
“By taking a collaborative approach with ABS on this project, we were able to demonstrate and prove the viability of CFD analysis to determine LNG BOR,” said GasLog FSRU project engineer Vassilis Millas . “Being able to predict BOR in various operating conditions will allow us to build efficiencies into future designs.”