A New Small-Scale LNG Distribution and Bunkering Facility: - An Approach to Risk Based Design and Verification
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- Institutt for marin teknikk 
LNG is the preferred solution to meet environmental requirement and a great market growth is expected within few years. Lack of suitable infrastructure, regulation and bunkering practices poses challenges to the industry, however these barriers are currently being broken. Connect-LNG is in a conceptual phase of developing an innovative solution for LNG distribution and bunkering at inshore locations. A study of industry legislatives, normal industry practice, LNG properties and historical accident statistics, provided the basis needed to perform a HAZID of the concept. LNG is considered a hazardous cargo. The main hazards are identified as:? Cryogenic temperatures (injury to people and to non cryogenic materials)? Fire, explosion or asphyxiation from potential LNG spillage? Overpressure (thermal expansion and shock waves from potential Raphid Phase Transition (RPT)The main regulation related to the concept is ISO Interim TS 18683 - Guidelines for systems and installations for supply of LNG as fuel to ships, which is expected to enter into force during 2013. Additionally, NS-EN ISO 28460 Installation and equipment for liquefied natural gas ? Ship to shore interface and port operations and NS-EN1473 European Norm for Installation and equipment for liquefied natural gas- Design of onshore Installation have shown high degree of relevance. Also, legislatives related to Ship-to-ship transfer are considered highly relevant. Safety requirements are generally imposed by the established regulates yielding large-scale LNG handling. However, the brutality of the consequences is often proportional to the quantity LNG handled, inherent safety. Thus for medium-to-small scale LNG facilities, the consequences of an unwanted event is assumed to be smaller.The following national regulative acts are important for the validation and responsibility decision between the relevant authorities: DSB topical guidelines, Major Accident regulations, The regulation of Fairways, The Port and Harbor Act. The authorities area of responsibility can be summarized in the following table:Authority Responsibility DNV LNG - carrier design approvalThe Norwegian Maritime Directorate LNG - carrier operation and crew safety DSB - Decisive power, approval of onshore facility and formal decision unit in the future. Inquire municipal authorities and public perceptionKystverket - Adequate safety in LNG carrier approaching area, ISPS Certification and piloting serviceMunicipal authorities - Decisive powerLocal port authorities - Decisive power, commonly landholderOperator (Skagerak Naturgass) - Responsible for safe operation, sufficient maintenance of facility according to given regulationThe conceivable safety distance for operation of the reel LNG can be summarized in the following table.Safety zone DistanceOnshore, around LNG storage tank: 25 metersAt sea, around the loading LNGC and buoy configuration: 50 metersAt sea, around the filling line: 12,5 metersThe main, required inbound systems are listed below:- ESD valve on buoy (Hydraulically self-contained)- Breakoff coupling in the light loading hose- QC/QD coupling towards the shipside - Butterfly valves for normal operational control (open/close)- Hose rupture safeguarding (to be located onshore)- Riser annulus monitoring: Optical fibersThe results from the HAZID and from general industry feedback recommend a self-reliant system. This implies a further inherent operational execution and the requirements related to a minimum of manning at the onshore facility are maintained.