Q-Flex is a type of ship, specifically a membrane type liquefied natural gas carrier.
Q-Flex vessels are propelled by two slow speed diesel engines, which are claimed to be more efficient and environmentally friendly than traditional steam turbines. Q-Flex carriers are equipped with an on-board re-liquefaction system to handle the boil-off gas, liquefy it and return the LNG to the cargo tanks. The on-board re-liquefaction system reduces LNG losses, which produces economic and environmental benefits. Overall, it is estimated that Q-Flex carriers have about 40% lower energy requirements and carbon emissions than conventional LNG carriers.
The capacity of a Q-Flex vessel is between 165,000 m3 and 216,000 m3. Until the entry into service of the Q-Max-type carrier, it was the world’s largest LNG carrier type with a capacity of 1.5 times that of conventional LNG carriers.
The first Q-Flex LNG carrier was delivered by Hyundai Heavy Industries in late 2007. The installed re-liquefaction system is developed and delivered by Hamworthy and approved and certified by DNV. Q-Flex LNG carriers are built also by Daewoo Shipbuilding & Marine Engineering Company and Samsung Heavy Industries.
As of August 2008 there are 16 named Q-Flex LNG carrier: Al Hamla, Al Gharrafa, Duhail, Al Ghariya, Al Aamriya, Murwab, Fraiha, Al Huwaila, Al Kharsaah, Al Shamal, Al Khuwair, Al Oraiq, Umm Al Amad, Al Thumama, Al Sahla and Al Utouriya. All these vessels are owned by holding companies established by the Qatar Gas Transport Company (Nakilat) and different shipping companies such as Overseas Shipholding Group, Pronav and Commerz Real, and they are chartered to Qatar’s LNG producers Qatargas and RasGas. In total, contracts have been signed for the construction of 31 Q-Flex vessels.