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.”