June 20 2013

 Greek Section’s Report for the June 20^th, 2013 Technical Meeting

on: “LNG Carriers, An Update on Technology”

Report by:  John Kokarakis

The Greek section of SNAME concluded the monthly presentation program before the summer recess on June 20^th 2013.   The title of the 9^th monthly presentation was “LNG Carriers, An Update on Technology” authored by Messrs R. Gilmore, S. Hatzigrigoris and A. Spertos. All of the authors work for Maran Gas which has at the present the largest new-building program of LNGs on a worldwide basis.  The meeting was attended by 49 members and 32 non-members, a record braking attendance for the season. This event was expected highly by all members which desired to listen to the latest technological developments on gas carriers.  Exploration and mining of gas has increased the need for LNG carriers. The shipping industry has responded as is depicted by current and projected order book both in Greece and abroad. The 2015-activated expansion of Panama Canal will affect the size of future designs similarly to other types of ships. At the same time crossing through the Canal will result in reduction of the transportation cost by 30% or more depending on the mode of operation of the prime mover.

An important development is that the inevitable boil-off rate is being reduced from 0.15% to 0.10% and even lower descending towards 0.08%. These better boil-off rates have been achieved by design modifications on the containment system as well as the type and dimensions of the insulation. The authors presented the improvement in boil-off for the NO-96 containment system by 0.025% replacing the perlite insulation by glass wool. Addition of foam panel pushes the boil off towards 0.100% per day. Similarly increase of the insulation thickness in the Mark III containment system causes a reduction to 0.095% per day. New containment systems like the SCA (Samsung Heavy Industries), the Mark V and the HMCCS (Hyundai Heavy Industries) yield reductions also below the barrier of 0.10% per day.

These days new propulsion options are utilized by the designers leading to less complex and more energy-efficient plants.  The triple fuel diesel electric (TFDE), the slow speed diesel with reliquefaction (SSDR), the MSDF (medium speed dual fuel) and the gas injected MEGI are amongst the options, replacing the traditional steam plants of LNG carriers. The latter option is able to burn a wide mixture of gas and heavy fuel oil. During maneuvering liquid fuel oil is utilized due to its better response/performance under transient conditions. The gas delivered for the MEGI type of mover is at 300 bar pressure done by large high pressure compressors. All options result in low SOx emissions. Further the TFDE option complies with the NOx limits set by Tier III. On the other hand the MEGI option has the lowest acquisition (CAPEX) and operational cost (OPEX) with a respectable 50% propulsion plant efficiency.

Last but not least the authors presented options available to the operator to reduce fuel consumption. Such measures can be related to both the design and operation of the vessel. A specific example was presented related to the optimum bow shape. By the end of the presentation nobody in the room had any doubt that the LNG industry is going through a period of dramatic expansion and evolution.

The presentaition can be found below:
20.06.2013 Messrs. Hatzigrigoris, Gilmore, Spertos' Presentation.pdf