The risks of marine transportation of LNG and LNG-fuelled ships

Transcription

1 The risks of marine transportation of LNG and LNG-fuelled ships Maritime responsible choises for the Baltic Sea July 26, 2012 Mauri Lindholm Technology Inc

2 General - about LNG as marine fuel In the near future we ll see the first LNG-fuelled ships in the Finnish waters and elsewhere in the Baltic Sea As soon as the necessary LNG infrastructure develops and is built up it is evident that the especially the short sea shipping sector will go more for gas-fuelled ships Good examples are found in Norway Ship operators, authorities and rescue organisations need to be aware of the basics of LNG fuel, it s safe handling and related safety precautions Slide 2

3 CONTENTS What is LNG? LNG as fuel Why LNG? Challenges of LNG as fuel LNG-fuelled ships something new? LNG ship and tank types LNG-fuelled ships of today Future ship types suited for LNG fuel Status of related rules and regulations Current safety satndards Scope of IGF Code Main design issues Machinery space configurations Conclusions Slide 3

4 What is LNG Natural gas in liquefied form at about -160 C, cryogenic temperature Densified gas, liquid takes 1/600 of the volume of gaseous form Main component is methane CH 4 Colourless, odourless, non-toxic, non-corrosive gas Gaseous methane is lighter than air About 20% more energy per mass unit than Heavy Fuel Oil Lightweight liquid, density 0.42 to 0.45 t/m 3 more volume than other fuels storing takes much Flammable, but high self ignition temperature high: 595ºC Flammable only in between 5% - 15% mixture with air Slide 4

5 LNG as fuel - in comparison to fuel oils Burned in lean mixture in combustion engines Low combustion temperature 80-90% reduction in NOx emissions Contains no sulphur 100% reduction in SOx emissions Simplest hydrocarbon with little carbon and much hydrogen 25-30% reduction in CO 2 compared with oil Clean combustion, no visible smoke or soot Low maintenance of engines High heat value: 50 to 55 MJ/kg (Medium Diesel Oil 43 MJ/kg) Slide 5

6 Why to go for LNG fuel Environmental aspects: cleaner fuel, lower emissions Availability and distribution of LNG is improving LNG offers low fuel costs, potentially lower than heavy fuel oil World gas resources are vast, larger than those of oil Annual increase of LNG production growing 7 to 8% Proven technology: Wide scale transportation, handling and utilisation since early 70 s Newest codes provide guidance and safety measures for ships using gas as fuel Slide 6

7 Why to go for LNG fuel (continued) More stringent emission limitations for shipping industry, IMO s new requirements coming into force gradually Introduction of Emission Control Areas Requirements of environmentally efficient ship desigs (EEDI) Fullfilling of most stringent emission requirements without any additional purification of exhaust gases Proven storage and handling technology are available Proven gas engines are available, dual fuel engines can burn either oil or gas with immediate change-over High thermal efficiency, low maintenance of engines Slide 7

8 Emission Control Areas Slide 8

9 Medium speed gas engines Medium speed gas engines look like ordinary oil-burning diesel engines. They are available in various sizes and in two main types. Lean burn type (gas only) and dual fuel types (oil or gas). Large slow-speed engines can be designed for gas burning but are not yet in marine use. Dual-fuel engine (Wärtsilä Finland) Lean burn engine (Bergen Diesel) Lean burn engine (Caterpillar) Slide 9

10 Challenges of LNG as fuel Methane is a fossile, not renewable fuel Methane is one of the greenhouse effect gases release of methane should be minimized to nil in all phases from LNG production to transportation, storing and burning Handling and storing of flammable cryogenic fuel requires dedicated materials, equipment and procedures Dual-fuel engines let very small amounts of methane gas through into exhaust gas - methane slip Slide 10

11 LNG-fuelled ships something new? Large LNG carriers have been built and operated for more than 40 years, the number of existing fleet is growing and exceeds 300 ships With only a few exceptions all LNG tankers are using gas as secondary or primary fuel - so-called natural boil-off of cargo is utilised as part fuel, the rest can be vaporised from LNG or fuel oil is used - earlier all LNG carriers were with steam turbine machinery, today diesel-electric machinery with dual-fuel engines have taken over and is a more common choise in new ships Slide 11

12 LNG-fuelled ships something new? (continued) Alternative cargo tank concepts have been developed; - prismatic membrane tanks and spherical tanks for larger ships - pressure vessel type tanks for smaller ship applications International codes for technical solutions and safety are well established and well followed All phases of LNG handling is taken care by qualified personnel on land and onboard ships In general LNG ships and LNG storing and transportation have excellent safety record Slide 12

13 LNG carrier types Membrane type tanks Moss type tanks Pressure tank type Slide 13

14 LNG fuel tanks - Vacuum insulated LNG fuel tanks Slide 14

15 LNG fuel tanks - Vacuum insulated LNG fuel tanks Material: stainless steel (inner & outer shell). Pressure: Operational 4 to 6 bar, max. design 9 to 10 bar. Slide 15

16 LNG fuelled machinery - LNG fuel tank system (typical configuration) Slide 16

17 LNG fuelled ship of today LNG carrying ships The large LNG carriers transporting LNG from overseas production plants to worlwide market (hundreds of ships) Smaller LNG feeders taking care of local distribution of LNG (tens of ships) LNG bunker ships (only a few existing) Slide 17

18 LNG fuelled ship of today (continued) Coars guard patrol ship Barenz Sea, Norway World s smallest LNG carrier Pioneer Knutsen (1100 m 3 ) Slide 18

19 LNG fuelled ship of today (continued) World s first gas-fuelled ferry Glutra, Norway Other LNG fuelled ships Car/passenger ferries (many in Norway) Offshore supply and service ships (many in Norway) Patrol and coast guard ships (some) Smaller cargo ships, tankers, river ships (some) Car/passenger cruise ship (under construction) 100 dwt chemical tanker Argonon, Holland 2012 Slide 19

20 LNG fuelled ship of today (continued) Pioneer Knutsen Coral Methane Slide 20

21 LNG fuelled ship of today (continued) LNG shipping industry has an excellent safety record No shipboard fatalities over the life of the industry associated with cargo No major losses of cargo and only one minor LNG onboard fire (lightning strike near vent riser, cargo tanks not affected) Two groundings resulting in major hull breaches without cargo loss Slide 21

22 Future ship types suited for LNG fuel Any ship types Modifications of existing ships machineries for LNG fuel Short sea shipping sector most potential, with regular routes and dense traffic Small ferries, pilot boats, patrol boats Small river and coastal tankers, dry cargo and tourist ships soon ordered with gas fuel Offshore supply and service ships, icebreakers and ice management ships Plans for large cargo ships, container ships Plans for large passenger ships The first LNG-fuelled ships in Finland: Large car-passenger ship Viking Grace (early 2013) Patrol and rescue vessel for the Finnish coast guard (2014) Slide 22

23 LNG-fuelled passenger ships Viking Grace (2013) Slide 23

24 Future ship types suited for LNG fuel Icebreaking Platform Supply Vessel LNG feeder LNG bunkering ship Slide 24

25 ARC 105 PSV - LNG-fuelled version - general arrangement (with one gas fuel tank) 1 x 590 m3 LNG tank corresponding to ~ 1/3 of the required LNG fuel capacity! Slide 25

26 ARC 105 PSV - LNG-fuelled version - general arrangement (with two fuel tanks) 2 x 590 m3 LNG tanks corresponding to ~ 2/3 of the required LNG fuel capacity! Slide 26

27 Status of related rules and regulations GAS CARRIERS IMO IGC (International Gas Code) - Intended for design and construction of gas carriers SIGTTO & OCIMF industry standards - standardisation, cargo operations, mooring, ship-to-ship cargo transfer Classification society rules since 2001 GAS-FUELLED SHIPS Norwegian maritime directorate, National authorities Class rules and guidelines (DNV, LR, GL, ABS) IMO published Resolution MSC.285(86), Interim Guidelines on Safety for Natural Gas-Fuelled Engine Installations in Ships IGF Code (2014) BUNKERING AND PORT OPERATION OF LNG Less experiece and documentation Guidance by industrial parties and classification societies ISO, Safety authorities, national rules The International Maritime Organization (IMO) is in the process of developing an International Code on safety for ships using natural gas and other low-flashpoint fuels. Slide 27

28 Current International Safety Standards - for gas-fuelled ships In addition to the IMO Interim Guidelines, several classification societies have published rules or guides for gas-fueled ships. Among them are Det Norske Veritas (DNV), Lloyd s Register (LR), Germanischer Lloyd (GL), and the American Bureau of Shipping (ABS). Each of these classification society standards are closely aligned with the IMO Interim Guidelines, and in some cases provide more comprehensive requirements. Slide 28

29 Scope of IGF Code Provides safety measures for ships using gas/ low flashpoint liquids as fuel including liquefied gas tankers. Is intended to address natural gas fuel, other gas fuel types such as butane, hydrogen, propane and low flashpoint liquids like ethanol, methanol and synthetic fuels. Will cover the energy conversion systems of relevance (low and high pressure combustion engines, gas turbines, boilers, fuel cells) Should only address issues not already covered by SOLAS and serve as an addition to SOLAS. Should revoke the interim guidelines and parts of the IGC Code. Should be set into force with SOLAS 2014 Slide 29

30 Machinery space configuration of gas-fuelled ships Two choices for engine room arrangement: 1. Inherently Safe Engine Room Gas piping ducted all the way into the engine (as to IGC code) All gas pipes in the engine room are enclosed in double pipe/duct that can withstand the pressure during pipe rupture Double piping or ducting can be pressurized and filled with inert gas or ventilated and with gas detection The rooms around can be ordinary machinery spaces without any special requirements Mandatory concept for high pressure piping (>10 bar) but can be applied in low pressure installations (Major equipment suppliers have ready applications for the above) Slide 30

31 Machinery space configuration of gas-fuelled ships 2. Emergency Shutdown (ESD) machinery space At least two separate machinery spaces required No common boundaries are accepted unless the boundary can withstand an explosion in one of the rooms. Simple geometrical shape, incinerators, inert gas generators or other oil fired boilers must not be located in the space Ventilation of the engine room compartment of at least 30 air changes/h Gas detection system with at least 3 detectors in engine room The fuel supply automatically shut down All non-explosion protected equipment is to be electrically disconnected Redundancy of detection system Pressure in the gas supply piping within the machinery spaces is not to exceed 10 bar Slide 31

32 Tank placement Fuel tanks below deck - Compressed Natural Gas (CNG) not accepted - Secondary barrier around LNG tank called tank room - tank material stainless steel or equivalent - Designed to withstand pressure build up - Thermal isolation towards ship steel - Distance from bottom at least B/15 or 2 m (the lesser) - Distance from side at least B/5 or 11.5 m (the lesser) Fuel tanks above deck Both CNG and LNG accepted Location at least B/5 from ship s side Drip tray arranged below tank Slide 32

33 Main principles of gas safety Explosion risk! Generally: Avoid gas in flammable mixture with oxygen and ignition sources in same location Limit the possibility for gas spreading in the ship Gas pipes through the ship to be in double enclosure Tank connections to be in special gas tight compartment High ventilation rates in spaces with gas sources Avoid gas concentration in the flammable range (5-15%) Suction ventilation to avoid leakage to surrounding spaces Limit the possibility for gas spreading in the ship Secondary barrier around gas tank as required by the IGC code Slide 33

34 LNG fuelled Diesel-electric machinery - typical arrangement in a supply vessel LNG fuel tank Cold Box room Gas Valve unit rooms Gas Tank room Gas Diesel Gensets Slide 34

35 LNG fuelling at shore base at large LNG plant from a local LNG fuelling station by an LNG bunker ship by an LNG truck (source from larger storage or plant) ++ proven concepts (ships, transfer hoses, procedures) ++ can serve other consumers in the area Slide 35

36 LNG Infrastructure Elements of infrastructure are there! Slide 36

37 Conclusions The use of natural gas as fuel is a promising and safe technology for complying with upcoming air emission limitations. LNG supply and distribution infrastructure needs to be built further in the Baltic Sea area. Recently approved ship concepts have been determined to provide an equivalent level of safety to the by using the IMO Interim Guidelines as a baseline standard. It is hoped that shipowners, designers and authorities will benefit from reviewing these considerations when developing conceptual designs for gas-fueled ships. Training and good co-operation between land and marine safety organisations need to be maintained to cover all phases of the LNG transportation and handling. Slide 37

38 Technology Inc No technology gaps or major challenges to be seen. We would be happy to work on a real project proposal to you! THANKS! Slide 38

39 Copyright of all published material including photographs, drawings and images in this document remains vested in and third party contributors as appropriate. Accordingly, neither the whole nor any part of this document shall be reproduced in any form nor used in any manner without express prior permission and applicable acknowledgements. No trademark, copyright or other notice shall be altered or removed from any reproduction. Slide 39