Norway-based CGR Arctic Marine’s innovative Liquid Methane Bunkering Vessel design combines pure gas generators, an energy management system featuring a 1.5MWh battery pack and shore-power connections.
Norway-based Kanfer Shipping has entered into an exclusive agreement to market CGR Arctic Marine’s 96-metre 6,000cbm Liquid Methane Bunkering Vessel (LMBV)
The vessel will feature CGR Arctic Marine’s multi-purpose volatile organic compound (VOC) recovery plant. The Cryogenic Gas Recovery (CGR) system is built into a 10-foot container unit, and the flexibility of the design means it can be used for a range of tasks including LNG bunkering, tank decontamination, purging, inerting, vapour recovery and gassing-up operations.
Liquid nitrogen is used as the coolant in the CGR system, and it never mixes with the cargo vapour stream, leaving the unit as a pure gas. The liquid nitrogen is vaporised against a heat transfer fluid, because a direct heat exchange between the liquid nitrogen and the cargo vapours would result solidification of most of the hydrocarbons at the extremely low temperatures. Instead, the temperature of the heat transfer fluid is adjusted as a function of the nature of the compound to be liquefied.
Onboard the vessel, the VOCs are liquefied in a cargo condenser by heat exchange with the chilled heat transfer fluid. They then flow to a separator, and the condensate is pumped from the liquid collector to storage. The vaporised nitrogen can be used for purging or blanketing of the cargo containment system.
CGR Arctic Marine says that an integrated control system makes it easy to adjust for flow and concentration fluctuations. Few moving parts make the compact and transportable GRS unit very reliable, low on energy consumption and low on maintenance requirements.
The LMBV features a single type “C” cargo tank which improves hull utilisation, reduces tank weight and insulation surface area compared to more typical multi-tank designs. The vessel has a plug-in hybrid power system consisting of modular lithium-ion battery packs (1.2- 1.5MWh) and redundant pure gas generators (2 x1500kW) in a containerised engine room. Pure gas was chosen over dual fuel engines to reduce complexity and cost. During normal operation, the generators are fuelled with boil-off gas. LNG is also available from a separate LNG container installed on deck.
The combination of the emissions-free cargo system and battery power means that the generators can be turned off to provide silent bunkering without pollution.
A high degree of vessel manoeuvrability is achieved via a joystick-controlled set of redundant 360-degree pod thrusters and a powerful bow thruster. The forward positioned superstructure provides good visibility of the vessel and cargo area, and the cargo handling control station also has full deck view at bridge level.
The 3,550dwt vessel’s modular design reduces construction time and costs, making it ideal for fast track projects, says CGR Arctic Marine. The company, also based in Norway, holds a Chinese patent for single-tank bunkering vessels. The China Classification Society issued an approval in principle certificate for the design in April 2019.
The LMBV was designed in cooperation with Shanghai Ship Design & Research Institute (SDARI). CGR Arctic Marine, Chinese shipyard Wuzhou Shipbuilding, and SDARI announced a multilateral agreement for the design and construction of a 6,000cbm LNG bunkering vessel at the Marintec conference in Shanghai in December 2019.