Current trends for the floating liquefied natural gas (FLNG) technologies

Natural gas (NG) and liquefied NG (LNG), which is one trade type of NG, have attracted great attention because their use may alleviate rising concerns about environmental pollution produced by classical fossil fuels and nuclear power plants. However, when gas reserves are located in stranded areas and a portion of the offshore reserves is a significant amount of the total gas reserves, LNG is not suitable because (i) installation of pipelines for the transfer of NG to onshore LNG facilities is expensive and difficult, and (ii) it still has environmental and security problems. As a result, there are many efforts to excavate and monetize these stranded and offshore reserves with floating facilities where offshore liquefaction of NG is possible. Therefore, the development of floating LNG (FLNG) technology is becoming important. Although the FLNG technologies have advantages over conventional LNG technologies, there are still several roadblocks. To overcome the challenges, modular designs related to the main and typical stages of the FLNG process - gas pretreatment, liquefaction and regasification topsides, hulls, mooring, and transfer systems should be enhanced. Regarding FLNG ongoing operations and future plans, there are six nations (Argentina, Brazil, Kuwait, UAE, UK, and USA) operating FLNG, and a variety of FLNG liquefaction projects will be finished soon. Shell and Petrobras are making rapid strides to build FLNG facilities, and Flex LNG, Hoegh LNG, SBM Linde, MODEC, and Saipem are also building their FLNGs. In this review paper, we initially review the LNG concept and compare it with FLNG. In turn, new and typical FLNG technologies are introduced and the main challenges are also explained with insight into how these challenges are overcome. The main market drivers for FLNG industry are also considered.