DNV GL and partner present LPG ad LNG carrier designs

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Norwegian-German classification society DNV GL partners with several industry players to develope modern and efficient vessel designs for the LPG and LNG market.

At the Gastech 2017 conference in Tokyo, Korean shipbuilding giant Daewoo (DSME) and DNV GL presented the results of a[ds_preview] joint development project (JDP) for the design of an innovative, efficient LNG carrier based on today’s technology. The project focused on delivering a design which an owner can take straight to the yard and is ready for upcoming market trends and incoming regulations, »with an optimal size, hull form, and machinery and electrical systems«.

Johann Tutturen (Source: DNV GL)
Johann Tutturen (Source: DNV GL)

»When we look at today’s LNG market we predict that in the years to come we will see the rise of post-Panamax LNG carrier designs which are dimensioned to fit of the new Panama Canal. Capacities of over 175,000 m3 are feasible given the new restrictions,« says Johan Petter Tutturen, DNV GL – Maritime Business Director Gas Carriers.

A key consideration for the design was the shift towards lower, more energy-efficient transit speeds, the partners said. The hull and propulsion system have been optimized for three different operating profiles on a standard transpacific route (19.5, 16 and 12 knots). Calm water optimization resulted in gains of 6%, 2% and 5% over the reference design at each of the three operating profiles.

The design uses direct-coupled, two-stroke dual-fuel (DF) main engines and DF auxiliary engines, with LNG as the primary fuel. A combined gas turbine, electric and steam (COGES) propulsion system was chosen for the optimized machinery. For the portion of the boil-off gas used as LNG fuel a »High Manganese Steel Cargo Tank Independent Type B« was chosen and underwent closed mock-up testing using liquid nitrogen (LN2).

The design also incorporates DSME’s SloT (Ship Internet of Things) technology and their wireless computer network and integration system Smartship 4.0. In addition, the entire on-board computer environment underwent thorough testing to improve its cybersecurity, it was added.

Cooperation with CMM, HHI and Wärtsilä

Also at Gastech 2017 the classification society presented the results of a joint industry project (JIP) to develop a new LPG fuelled carrier design – LPGreen. It was launched during Posidonia 2016 together with project partners Consolidated Marine Management (CMM), Hyundai Heavy Industries (HHI) and Wärtsilä Oil & Gas.

Nikolaos Kakalis (Source: DNV GL)
Nikolaos Kakalis (Source: DNV GL)

»In order to increase the competitiveness of modern LPG carriers, novel ship designs need to simultaneously account for the market and trade route characteristics; excellent safety and ease of operation; cargo and fuel flexibility; and, overall energy efficiency combined with economic viability,« says Nikolaos Kakalis, DNV GL’s Manager for R&D and Advisory Services in South East Europe and Middle East. »Therefore, a holistic approach to the design of modern LPG carriers is required, taking into advantage market insight, technology innovation, advanced computer tools and industry-wide collaboration with strong partnerships.«

»The JIP has resulted in a new concept design that achieves state of the art performance on several fronts«, it was said, and added, that compared to the reference vessel, which is a high-quality vessel built to a standard design in 2016, there is an overall improvement of 6–9% in energy efficiency, depending on machinery configuration and fuel used. A redesign of the tank allows for a filling limit of 99% – a 1% increase in overall carrying capacity. Loading duration has been decreased by 30%, while the newly designed cargo handling system concept results in a 5% reduction in energy demand.

»Perhaps most importantly, LPGreen has demonstrated the technical feasibility of a LPG fuelled propulsion concept, which, depending on fuel prices and the development of a commercial and chartering framework, could result in a cut of up to 30% in fuel expenses« says George Dimopoulos, Principal Specialist in DNV GL and project manager for LPGreen.