ABS helps Hanwha move ahead on ammonia-fueled gas turbine plans

Patrick Ryan, ABS senior vice president and CTO; Young-Chang Son,CTO at Hanwha Ocean; and Joseph Kelly, ABS consulting vice president, engineering. [Photo: ABS]

Ammonia-fueled gas turbines are emerging as another green powering option for ships. Korea’s Hanwha Ocean is moving ahead on plans for a 174,000 cubic meter LNG carrier with an an electric propulsion system powered by a dual fuel gas turbine. that can burn either ammonia or natural gas as fuel.

The project was unveiled a year ago at the Gastech 2023 event in Singapore when the design received an ABS Approval in Principle (AiP).

The gas turbine that serves as the cornerstone of the electric propulsion system, is a product of Hanwha Power Systems, which says that it has greatly enhanced the overall gas turbine efficiency by implementing an exhaust gas heat recovery power generation system (sCO2 power system) using supercritical carbon dioxide (sCO2) as a working fluid. That system, too, has received an ABS AiP.

The project appears to be moving right along, with ABS now reporting that it has completed a safety evaluation of ammonia dispersion on board the ammonia-fueled gas turbine powered LNG carrier.

ABS, in collaboration with Hanwha Ocean, conducted computational fluid dynamics simulations that modeled different ammonia release scenarios due to accidental leakages from the engine room, the pipeline and the bunkering stations on deck. The study is one of the most comprehensive in the industry, using multiple ammonia release scenarios.

The analyses found that the system complied with applicable ABS Rules regarding the toxicity and risks of accumulated ammonia gas. The three-dimensional, high-fidelity simulation results can also help Hanwha Ocean with improved ventilation arrangements, vent mast locations, gas release speeds and placement of air intakes for the manned spaces to further reduce risks in the detailed design stage.

ABS subsidiary, ABSG Consulting Inc., a leading global risk management company, conducted a quantitative risk assessment, helping to provide a better understanding of the likelihood of an incident and insight into potential threats, enabling Hanwha Ocean to design its mitigation plans accordingly.

“This project allowed ABS to combine its world leading modeling and simulation capability with our deep insight into the application of ammonia as a marine fuel,” said Patrick Ryan, ABS senior vice president and CTO. “The toxicity of ammonia is a safety challenge and so understanding its behavior in the event of a leak is a critical step toward enabling its wider adoption by the industry. Our analysis will help Hanwha Ocean continue to optimize its design to identify areas for enhancement and mitigate risks.”