(89b) LNG Transfer in Harsh Environments – Introduction of a New Tandem Mooring Concept

One of the most challenging questions with regard to the technical part of the LNG supply chain has not been answered satisfactorily: How can LNG be safely and reliably transferred between a floating terminal platform (FPSO, FSRU, etc.) and a shuttle tanker in harsh environmental conditions?

The problem consists of two main technical issues: The first is the vessel mooring configuration (e.g. side-by-side, tandem), the second is the type and appropriate handling of the transfer lines for the cryogenic liquid. As both problems influence each other, it is rather difficult to develop a convincing solution and the Industry has not found it yet.

The innovative offshore LNG loading system "Maritime Pipe Loading System 20" is proposed by IMPaC, an innovative engineering company that has been involved in many projects for the international Oil and Gas Industry since 25 years and the German project partners Nexans and Brugg, leading manufacturers of vacuum insulated, flexible cryogenic transfer pipes, and the Technical University Berlin, Institute of Naval Architecture and Ocean Engineering, where numerical analysis and model tests have been carried out.

The new concept basically works with a unique vessel tandem mooring configuration, developed and patented by IMPaC. In comparison to standard operations used in the oil business for about 40 years, the concept introduces a harbour-like structure at the aft end of the LNG terminal platform. The complete transfer system comprising the terminal and the shuttle tanker has advantageous motion characteristics in harsh environmental conditions during cargo transfer. Results are reduced technical requirements and costs with increased safety for the cargo transfer system based on flexible transfer lines.

These lines are developed by the partners Nexans and Brugg: The corrugated metal pipes used in the MPLS20 transfer system provide a permanently monitored double containment system, so that all relevant safety issues are well addressed, as required by EN1474-2/-3. Thus, LNG transfer can take place even under heavy environmental conditions which makes this new concept superior to other approaches such as side-by-side configurations using composite hoses.

The new LNG Offshore Transfer System based on flexible cryogenic pipes offers a wide range of applications, not only for the LNG industry but also in the LPG and crude oil industry.