Maximizing Flexibility in FLNG Design and Operation

1. Emerging Technology Allows Greater Flexibility for the Design and Operation of FLNG • By • Peter J H Carnell • Matthew Humphrys

2. Worldwide Higher Heating Value (HHV) Specifications • Spot sales complicated by differences in LNG specification • Lean LNG gives more marketing flexibility • Easier for user to add LPG than N2

3. Typical LNG Flowsheet

4. Transportation Study Results for Conventional Floating LNG (FLNG) • Based on Qmax LNG Vessels • Length 400m, breadth 80m, displacement 550,000Te • High Plant Utilisation Rate Required • Need Spare Storage Capacity to allow for loading delays • LNG Storage Capacity 350,000 m3 • LPG Storage Capacity 80,000 m3 • Condensate Storage Capacity 160,000 m3

5. Liquefaction Plant LPG Storage LNG Storage Condensate Storage Flare tower Accommodation Seawater intake reservoir Machinery Space Floating LNG Hull Layout • Comparable to the Worlds Largest Ship • Knock Nevis; Length 458m - Breadth 69m • Larger than Very Large Crude Carriers • Length 333m - Breadth 58m

6. Ship to Ship LNG Transfer Time Log • 2 – 3 day window for transfers • Difficult operation for two huge vessels • LPG & condensate needs additional transfer equipment & operations

7. Issues with Higher Hydrocarbons (C2+) on FLNG • LPG marketable, but adds complexity and reduces LNG storage (or increases vessel size) • LPG system increases fire risk by ~30% • C2 content of LPG limited to 2% (vapour pressure) • Excess C2 may exceed fuel gas demand • C2 –rich fuel gas may exceed NOx emission limit on gas turbine • ‘Slopping’ on FLNG can create variable Boil Off Gas, hence variable Fuel Gas composition & Wobbe Number • Impact on Fuel Gas burners

8. Catalytic De-Richment • Catalytic De-Richment (CDR) converts higher hydrocarbons (ethane up to naphtha) to methane • Well established technology developed for substitute natural gas (SNG) • Overall reactions: 4C2H6 + 9H2O  7CH4 + 7H2O + CO2 2C3H8 + 7H2O  5CH4 + 5H2O + CO2 4C4H10 + 19H2O  13CH4 + 13H2O + 3CO2 C5H12 + 6H2O  4CH4 + 4H2O +CO2

9. LNG Plant with Catalytic De-richment

10. Catalytic De-richment Reactors & reactions

11. Typical CDR Operating Conditions* Temp 275 °C: Press 30 bara: Steam/Carbon 0.833 * Patented catalyst

12. Potential Increase in LNG from Heavy Gases

13. Catalytic De-Richment • Catalytic De-Richment (CDR) converts higher hydrocarbons to methane • Increased LNG production • Simplified FLNG design • Well established technology • Reduces flaring where ethane in excess of fuel gas demand • Generates constant Wobbe number fuel gas • Lean LNG gives more marketing flexibility

14. Mercury Distribution

15. Why Must Mercury be Removed? • Avoid corrosion of equipment using aluminium alloys, copper alloys and some other alloys • LME (liquid metal embrittlement) • Amalgam corrosion • Process cheaper mercury-distressed crudes • Avoid emissions to environment • Comply with HSE directives & protect employees • Feb ’09 UN Environment Programme – World-wide treaty to limit Hg exposure LME

16. 2004 Moomba Explosion • Losses: • Caused by LME of aluminium heat exchanger inlet, by Hg • Leading insurers put the insured loss at A$320million (USD245 million) • Energy crisis in NSW & South Australia • Supplies were limited to 30-40% capacity • Cutbacks by major industrial customer • Job layoffs

17. PURASPEC Mercury Removal Technology • Uses variable valency metal sulphide • Hg + MxSy → MxSy-1 + HgS • Metal sulphide can be generated in situ from mixed metal oxide (patented co-removal of H2S & Hg) • Grades for gas and liquid hydrocarbons (LPG, condensate etc) • Can be used on saturated gas

18. Full Cradle to Grave Service • Optimisation of Mercury Removal Unit (MRU) design with customer • Data sheets and vessel drawings • Low PD radial flow designs possible • Provision of most suitable absorbent • Supervised loading and discharge • Recycling of spent absorbent • Absorbents are made from materials compatible with smelters • Only audited, approved smelters used • Certificate proves environmentally safe disposal

19. Recommended location of MRU Typical location of (carbon) MRU Regeneration Medium Compression Export Export Fuel Gas 4% 5% 25% 20% Cooling/ Al Heat Exchanger 19% Molecular Sieve/ Glycol Unit Separation Amine System <10 nanogram / Nm3 inlet specification NGL’s 90% 15% 65% LP Compression Amine Gas Oil 90% 100% 2% NGL’s Multiphase flow Separation Waste Water Water Glycol 2% 8% Wells Amine Overboard Oil Storage/ Export Mercury Distribution – Gas Processing Plant Mercury Survey Results 4%

20. Fit and Forget Technology • Intervention only required for charging and discharging • High mercury capacity gives long bed life • Sharp absorption profile means bed can cope with high excursions in mercury in feed and in the flow rate of feed

21. FPSO SE ASIA MRU on FPSO

22. Oil & Gas Platform Gulf of Thailand Offshore MRU

23. Conclusions • Catalytic De-Richment can be used to increase LNG production • Free up space for LNG storage or reduce size of vessel • Simplifies FLNG design and improves safety • Potentially reduce the need for flaring • Mercury removal essential • Location upstream of acid gas & water removal maximises protection of equipment, people and environment