Gas protection system for pure gas prime movers

Rolls-Royce is supplying a gas-shielded propulsion system for two new multi-purpose vessels to keep them operational even under difficult conditions. The two special ships are being built as replacements for two predecessor vessels by Abeking & Rasmussen, the shipyard based in Lemwerder, Lower Saxony.

In line with a German government directive that requires reductions in CO2 emissions from governmental vessels, the two vessels are powered by gas-electric propulsion systems based on four medium-speed Bergen B36:45L6AG units from Rolls-Royce, each delivering 3,600 kW. The two 95-metre long special ships will be called out on the North and Baltic Seas to deal with accidents, fires or unable-to-manoeuvre vessels.

Specially certified engine configuration enables use in explosive environments

Rolls-Royce is not only the engine and generator supplier, but provider of a special solution in the form of the gas protection specially developed to allow the engines to remain operational even if, for example, the ambient air has been contaminated with explosive gases following a gas tanker accident.

“Obviously the engines are there to burn gas, but if gas gets into the combustion chamber in an uncontrolled way via the intake air, the engine will become unmanageable,” explained Rolls-Royce project manager Christian Prinz.

The system adjusts the engine power output in relation to the amount of gas in the intake air. In short, the more gas there is in the intake air of the engine, the less gas fuel is fed to the engine via the gas control valves. If the gas volume is too high, special quick-acting flaps shut off the intake of gas and air and the engine comes to a stop.

“With these ships, we’ve combined the decades of experience we have under our belt in the field of medium-speed gas engines from Rolls-Royce with our highly specialized gas protection expertise to create an effective solution for our customer,” said Knut Müller, Vice President Marine at Rolls-Royce.

Rolls-Royce has been supplying medium-speed gas engines for over 20 years.