LNG

In view of the growing trend towards Dual-Fuel Diesel engines, despite their several years of experience with various grades of Diesel fuel, an appropriate level of readiness will be required of all those crew members involved with bunkering and monitoring of LNG fuel aboard ship. While traditional bunkering procedures are required to be followed to ensure maximum security and safety, the requirements for LNG bunkering are even more rigid. For instance, given that each flange or coupling connection is a potential spillage hazard, requiring absolute caution in connecting/disconnecting, the number of such connections should be held to a minimum. Furthermore, the LNG Bunkering Rules and Procedures shall include a mandatory "Emergency Shut-Down Procedure" (ESD), drill to be practiced periodically. In this regard, the eventual enforcement of ECA and SECA legislation is fast approaching, and the new Emission Control Area (E.C.A.) for North America takes effect August 1, 2012, requiring ships to burn fuel oil with a maximum of 1.0% sulfur content. This in turn will be reduced to 0.1% as of January 1, 2015, hence, conversion to LNG appears to be the most logical solution, and in this light, Ship-Owners are advised to consult with the major fuel refineries and Classification Societies for training programs that cover Formal LNG Bunkering Procedures. Meanwhile, it is reasonable to assume that as the demand for LNG as a marine fuel increases, and that suppliers develop the capability for economic mass production of same, comparable to that of conventional liquid fuels, that the price of such fuel will gradually decrease to a more competitive level and that bunkering stations for LNG will become established all around the world. There are currently numerous LNG carriers equipped with DF (dual fuel) main propulsion Diesel engines, capable of burning cargo-boil-off gas, built by MAN-B&W and by Wartsila. The choice of LNG is evidently encouraged by proven claims of lower exhaust emissions resulting from higher efficiency, cleaner burning characteristics, reduction in NOx and particulate levels averaging 75 percent, with almost zero levels of SOx.

However, LNG is not without its limitations, one of which is that LNG storage tanks have to be heavily insulated to maintain a constant temperature of minus 165 degrees Celsius. However, the insulation is required not only to preserve the ultra-low temperature of the LNG tanks, but also to protect the ship structures from the effects of the cryogenic temperatures of the LNG, given that super-low temperature within the tanks, can lead to "Thermal embrittlement" of metal. Additionally, aboard ship the required storage space for such tanks is estimated to be as much as 250 percent larger than that required for conventional Diesel fuel tanks of corresponding fuel capacity. Another cost factor to be contended with is in the design and construction of LNG Bunker Tanks, since unlike conventional marine fuel storage tanks that are not pressurized, LNG Bunker Tanks are designed, built and classed as "Pressure Vessels", and therefore subject to design and construction rules similar to those of steam boilers and compressed air storage tanks for use aboard ship, somewhat similar to the A.S.M.E. design and construction rules for "fired pressure vessels, (steam boilers) and "unfired" pressure vessels, (starting air tanks) requiring U.S. Coast Guard Approval and Inspection. . Accordingly, the International Maritime Organization (IMO) has published IMO Interim Guideline MSC 285(86) adopted in 2009, as a preliminary version of the IGF-Code and the Rules for LNG-fuelled ships that have been published by the various Classification Societies based on several years of experience with LNG as a Marine Fuel. This document specifies approved criteria for the arrangement and installation of LNG-fuelled engines and related systems and fixtures, intended to ensure a level of technical integrity regarding the safety and reliability of same comparable to that of conventional oil-burning machinery. Meanwhile, the International Maritime Organization is in the process of compiling a new Code that is expected to be incorporated into the SOLAS in time for the next revision due in 2014. Accordingly, Ship-Owners of LNG-fueled vessels will be required to apply for permission of the Harbor Master or equivalent authority prior to entering port.

LNG-Related Research - Currently, considerable funds are being expended in the research of technical solutions and cost-effective methods of improving the safety and efficiency of LNG-powered main propulsion machinery in an on-going research and development program pioneered by Germanischer Lloyd, and partners. In addition to Germanischer Lloyd, this group includes TGE Marine Gas Engineering, MAN-B&W, and NEPTUN Stahlkonstruktion. Among other things, this effort includes the conversion of an existing oil tanker from conventional Diesel fuel to LNG, to serve as a full-scale model to provide engineers with a life-size platform on which to install, test and/or modify their technical concepts to determine feasibility, efficiency, etc., for the ultimate refinement of all phases involved in developing the most cost-effective LNG-burning marine propulsion plant possible. Additionally, a conceptual design for a conventional feeder container vessel, of approximately 1,200 TEU capacity, and equipped to burn LNG, provides the Group yet another life-size platform on which to develop and test innovative features, not only pertaining to cargo stowage, operating range, etc., but also the radical design of LNG-specific bunker tanks and ultimately, the operational cost/benefit analysis of such a vessel compared that of conventional vessels of comparable cargo capacity. So while there is still much to be learned about LNG by operating engineers, there is also much information available from the manufacturers of LNG-burning marine Diesel engines such as MAN-B&W; Wartsila and Rolls-Royce, supported by highly qualified service engineers, on call, and capable of solving problems on-site.