HOERBIGER develops innovative Explosion Protection
[ Published in HOERBIGER@MOTION 02/2011 ]
The Castillo de Santisteban, the latest vessel of the Spanish shipping group Empresa Naviera Elcano, S.A. (ENE), is one of the safest tankers in the world. It was designed with the transport of liquefied natural gas (LNG) in mind. The MAN engines specially developed for this type of vessel are protected from the consequences of explosions in the entire exhaust gas system by a newly developed Safety Package from HOERBIGER. In maritime ship transport, this is a first.
Approximately 200 ocean-going vessels supply the world with liquefied natural gas (LNG), independently of pipelines. Innovations from MAN and HOERBIGER have turned the Castillo de Santisteban, the latest tanker of the Spanish shipping group Empresa Naviera Elcano, S.A. (ENE), into one of the safest LNG carriers on the globe.
MAN Diesel & Turbo SE from Augsburg, Germany, had been commissioned by ENE from Madrid with equipping the new construction of the LNG carrier with five dual-fuel 51/60DF engines. The innovative technology allows the engines to be optionally operated with liquefied natural gas (LNG) or with heavy fuel oil (HFO).
MAN not only attended to the propulsion system, but also to safety: the standard equipment of MAN engines includes HOERBIGER pressure relief valves. They protect both the engine's crankcase and the intake and exhaust pipes directly on the engines.
Moreover, in the planning of the Castillo de Santisteban, the EVM valve technology developed by HOERBIGER came into play as a safety package for the entire exhaust tract for a marine application for the first time. Previously, bursting disks performed this function, with the membrane rupturing in the event of overpressurization. The disadvantage is that once the membrane is destroyed, the engine must be shut down and the bursting disk replaced.
In an effort to avoid downtime and replacement costs, the shipping company quickly decided in favor of an alternative that in the long run will be considerably more cost-effective compared to the bursting disk–although initially this decision entailed added investment expenditure. This alternative is the newly developed HOERBIGER EVM valve series.
Now, a total of 30 pressure relief valves of the 735 EVM type protect the five exhaust tracts–safety equipment that will not result in immediate engine shutdown, as is the case with bursting disks. One of the benefits of the HOERBIGER construction is that the flame arrester is already integrated in the design. With a bursting disk, it would have had to be installed separately. Another argument is that the risk of downtime is minimized during the replacement of bursting disks: when the ship is stopped because the engine is shut down so that the bursting disk can be removed, in the worst case the ship owner is required to pay the charterer money for the loss. A valve, however, is a regenerative system that closes again after the excess pressure has been relieved and where no extended idle engine time occurs. Moreover, bursting disks are wear and tear parts. Compared to the significantly more robust valves, they require frequent replacement.
Such an innovative solution can only be implemented in lockstep between the engine and valve manufacturers. Here, the long-standing cooperation between MAN and HOERBIGER proved of value. In addition, the Spanish shipping group ENE is known as a company that welcomes innovations and is open to new solutions. This was another key aspect in developing the new safety concept.