Converting Existing LNG Carriers for Floating LNG Applications

摘要

Despite the recent economic downturn and reduced need for LNG, long-term demand will be strong and opportunities to convert existing LNG carriers (LNGC) into floating LNG plants are growing. Costs, schedules, and permitting challenges for onshore LNG production facilities have trended upward making it difficult for project developers to get financing. Cost reduction strategies across the LNG value chain have resulted in significant changes in LNG shipping. To increase fuel efficiency, LNGC capacity has doubled in the past 30 years, and propulsion technology has migrated from steam to high efficiency diesel and dual fuel engines. Smaller, less efficient LNGCs are being displaced by new ships and the owners of the older LNGCs are seeking new roles for their vessels. This paper explores the opportunities and challenges of converting existing LNGCs for Floating LNG Liquefaction FPSOs (FLNG), Floating Storage and Regasification Units (FSRU) and Floating Storage and Offloading Vessels (FSO) service.The costs of onshore LNG terminals with storage facilities, protected jetty, and cargo transfer equipment have increased sharply whereas converting an LNGC for liquefaction, regasification or storage creates a self-contained LNG terminal that can reduce overall LNG terminal cost by 30% to 50% compared to onshore alternatives.Converting LNGCs into floating LNG plants raises myriad design challenges when developing a project. Specific project requirements will lead LNG project developers to choose the appropriate LNGC for conversion. Below is a partial list of topics, taken from experience, that require engineering study. These will be discussed further in this paper.1. Delivery flow rate and composition requirements2. Products to be marketed3. Project location specifics4. Gas pre-treatment or LNG processing requirements5. Appropriate ship type and size from available vessels6. Liquefaction or regasification technologies7. Equipment space requirements8. Vessel motion impact on process and storage9. Mooring and berthing systems10. Offloading configuration and methods11. Fitness for service and life extension, Class requirements12. Required utilities and integration with ship systems