Stud.	
  Techn.	
  Nora	
  Marie	
  Lundevall	
  Arnet	
  

Evaluation	
  of	
  technical	
  challenges	
  
and	
  need	
 ...
Preface	
  
This	
  project	
  report	
  is	
  written	
  as	
  a	
  part	
  of	
  the	
  five	
  year	
  Master	
  Degree...
Abstract	
  
The	
  shipping	
  industry	
  is	
  searching	
  for	
  cleaner	
  solutions	
  to	
  comply	
  with	
  upco...
Content	
  
1	
  Introduction	
  ............................................................................................
5	
  Regulations	
  .........................................................................................................
List	
  of	
  Figures	
  
Figure	
  1:	
  The	
  LNG	
  fuelled	
  fleet	
  .................................................
List	
  of	
  Abbreviations	
  
NG	
  –	
  Natural	
  Gas	
  
LNG	
  –Liquefied	
  Natural	
  Gas	
  
LEL	
  –	
  Lower	
 ...
1	
  Introduction	
  
1.1	
  Motivation	
  
“The	
  LNG	
  industry	
  is	
  the	
  fastest	
  growing	
  segment	
  of	
 ...
There	
  are	
  LNG	
  passenger	
  vessels	
  currently	
  under	
  construction	
  or	
  in	
  design	
  for	
  service	...
1.2	
  Underlying	
  Hypothesis	
  
The	
  industry	
  will	
  continue	
  to	
  introduce	
  technological	
  innovations...
2	
  LNG	
  
2.1	
  LNG	
  characteristics	
  	
  
Liquefied	
  Natural	
  Gas	
  (LNG)	
  is	
  Natural	
  Gas	
  (NG)	
 ...
distributions	
  can	
  also	
  originate	
  from	
  small-­‐scale	
  liquefaction	
  plants;	
  this	
  is	
  current	
  ...
3	
  LNG	
  Advantages	
  
For	
  the	
  shipping	
  industry,	
  as	
  in	
  all	
  other,	
  profit	
  is	
  crucial.	
 ...
3.1.3	
  Emissions	
  Requirements	
  
ECA	
  requirements:	
  
• Maximum	
  level	
  of	
  sulphur	
  in	
  fuel,	
  all	...
3.2	
  Economical	
  Advantages	
  
“The	
  marine	
  fuel	
  oil	
  market	
  is	
  a	
  large	
  global	
  market	
  sup...
3.2.3	
  Marine	
  Fuel	
  Costs	
  
Every	
  ship	
  requires	
  individual	
  calculations	
  with	
  respect	
  to	
  t...
4	
  Bunkering	
  	
  
This	
  chapter	
  will	
  define	
  LNG	
  bunkering,	
  present	
  the	
  various	
  bunkering	
 ...
4.3	
  LNG	
  Bunkering	
  Procedure	
  
Time	
  efficiency	
  and	
  safety	
  are	
  elements	
  of	
  paramount	
  impo...
4.3.1	
  Step	
  1	
  –	
  Initial	
  Precooling	
  1	
  
Filling	
  lines	
  are	
  precooled	
  during	
  mooring.	
  Va...
4.3.2	
  Step	
  2-­‐	
  Initial	
  Precooling	
  2	
  
The	
  fixed	
  speed	
  cargo	
  pump	
  at	
  the	
  discharging...
4.3.4	
  Step	
  4	
  -­‐	
  Inerting	
  the	
  Connected	
  System	
  
Inert	
  gas,	
  nitrogen	
  (green),	
  is	
  use...
4.3.6	
  Step	
  6	
  –	
  Filling	
  Sequence	
  	
  
For	
  the	
  filling	
  sequence	
  both	
  bottom	
  filling	
  a...
4.3.7	
  Step	
  7	
  –	
  Liquid	
  Line	
  Stripping	
  
The	
  liquid	
  that	
  remains	
  in	
  the	
  bunker	
  hose...
4.4	
  Equipment	
  
This	
  section	
  will	
  cover	
  some	
  of	
  the	
  essential	
  equipment	
  used	
  in	
  the	...
within	
  the	
  tank	
  are	
  to	
  be	
  provided	
  and	
  installed	
  in	
  such	
  a	
  way	
  as	
  to	
  be	
  co...
critical	
  for	
  the	
  receiving	
  ship.	
  In	
  other	
  words,	
  if	
  you	
  want	
  to	
  optimize	
  the	
  tra...
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
LNG fuelled ships bunkering
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LNG fuelled ships bunkering

  1. 1. Stud.  Techn.  Nora  Marie  Lundevall  Arnet   Evaluation  of  technical  challenges   and  need  for  standardization  for   LNG  bunkering     Trondheim,  June  10,  2013     NTNU   Norwegian  University  of     Science  and  Technology   Faculty  of  Engineering  Science  and  Technology   Department  of  Energy  and  Process  Engineering   Project  thesis     Source:  Swedish  Marine  Technology  Forum      
  2. 2. Preface   This  project  report  is  written  as  a  part  of  the  five  year  Master  Degree  Program  I  attend  at  the   Department  of  Energy  and  Process  Engineering  at  Norwegian  University  of  Science  and  Technology   (NTNU).  First  of  all  I  wish  to  express  my  gratitude  to  my  supervisor  Reidar  Kristoffersen.  During  the   semester  he  has  given  me  academic  guidance  on  report  matters  and  great  freedom  in  choosing  a   topic  of  interest.       The  project  report  consists  of  a  literature  review  regarding  LNG  bunkering.  The  topic  is  current  and   much  of  the  information  is  gathered  from  publications  made  within  the  last  five  years  and  from  direct   communication  with  people  in  the  industry.  The  list  of  people  who  have  contributed  and  whom  I  wish   to  thank  is  therefore  extensive.       The  report  is  written  in  cooperation  with  Det  Norske  Veritas  (DNV).  Lars  Petter  Blikom,  Segment   Director  for  Natural  Gas,  DNV,  has  been  my  industrial  supervisor.  I  would  like  to  thank  Mr.  Blikom  for   providing  me  with  assistance  on  the  topic  and  valuable  insight  form  the  industry.  His  support  and   encouragement  throughout  the  process  has  been  highly  appreciated.  I  also  wish  to  thank  the  natural   gas  team  at  DNV,  Erik  Skramstad  and  Katrine  Lie  Strøm  for  their  help  on  technical  matters.       Individuals  who  contributed  with  insight,  relevant  material,  outlining  and  establishing  the  basis  of  the   project  report  include;  Per  Magne  Einang  and  Dag  Stenersen  (MARINTEK/SINTEF),  Øystein  Bruno   Larsen  (BW  Offshore),  Ernst  Meyer  and  Henning  Mohn  (DNV),  Rolv  Stokkmo  (Liquiline),  Øystein   Klaussen  (Gassteknikk)  and  Jens  Kålstad  (Kongsberg).         Nora  Marie  Lundevall  Arnet     I  
  3. 3. Abstract   The  shipping  industry  is  searching  for  cleaner  solutions  to  comply  with  upcoming  regulations  on   emissions.  A  favorable  solution  is  to  use  Liquefied  Natural  Gas  (LNG)  as  bunker  fuel,  on  ferries  and   other  smaller  vessel  travelling  set  routes.  Implementation  of  innovative  solutions  in  the  large-­‐scale   LNG  distribution  has  been  successful,  but  the  industry  is  now  requiring  solutions  for  the  small-­‐scale   LNG  distribution  networks.  An  expansion  of  small-­‐scale  LNG  infrastructure  holds  a  great  potential  for   cost  effective  fuel  for  the  industry.       Several  LNG  bunkering  solutions  exist  today  and  new  projects  are  announced  frequently,  but  detailed   descriptions  are  rarely  published  due  to  the  intense  competition  in  the  emerging  market.  The  industry   is  also  faced  with  lack  of  standardization  within  certain  areas  of  the  bunkering  process.  Leaving   procedures  open  to  discretion  and  a  potentially  higher  risk  of  failure.       This  project  report  aims  to  evaluate  essential  aspects  relevant  to  the  emerging  LNG  bunkering  market   focusing  on  technical  challenges  and  need  for  standardization.  It  will  include  an  overview  of  LNG   safety  aspects,  a  technical  step-­‐by-­‐step  approach  to  LNG  bunkering  and  essential  equipment  used,   assessment  of  current  standards,  and  finally  a  discussion  of  critical  areas  for  LNG  bunkering  to   compete  with  current  solutions.           II  
  4. 4. Content   1  Introduction  ..........................................................................................................................................  1   1.1  Motivation  ......................................................................................................................................  1   1.1.1  Bunkering  ................................................................................................................................  1   1.1.2  New  Projects  ...........................................................................................................................  1   1.1.3  The  Drive  .................................................................................................................................  2   1.2  Underlying  Hypothesis  ...................................................................................................................  3   1.3  Main  Goal  of  the  Report  .................................................................................................................  3   1.4  Scope  of  the  Report   ........................................................................................................................  3   2  LNG  ........................................................................................................................................................  4   2.1  LNG  characteristics  .........................................................................................................................  4   2.2  LNG  Chain  .......................................................................................................................................  4   2.2.1  Gas  Field  (Reservoir)   ................................................................................................................  4   2.2.2  Liquefaction  Terminal:  Onshore  Processes  .............................................................................  4   2.2.3  Marine  Transport  ....................................................................................................................  4   2.2.4  Receiving  Terminal  ..................................................................................................................  4   2.3  LNG  Safety  Issues  ...........................................................................................................................  5   3  LNG  Advantages  ....................................................................................................................................  6   3.1  Environmental  advantages  .............................................................................................................  6   3.1.1  Alternative  Energy  Sources  .....................................................................................................  6   3.1.2  Emission  Control   ......................................................................................................................  6   3.1.3  Emissions  Requirements  .........................................................................................................  7   3.1.4  Natural  Gas  -­‐  The  Solution   .......................................................................................................  7   3.2  Economical  Advantages   ..................................................................................................................  8   3.2.1  Investment  Costs  .....................................................................................................................  8   3.2.2  Infrastructure  ..........................................................................................................................  8   3.2.3  Marine  Fuel  Costs  ....................................................................................................................  9   4  Bunkering  ............................................................................................................................................  10   4.1  LNG  Bunkering  Definition  .............................................................................................................  10   4.1.1  Engines  ..................................................................................................................................  10   4.2  LNG  Bunkering  Scenarios  .............................................................................................................  10   4.3  LNG  Bunkering  Procedure  ............................................................................................................  11   4.3.1  Step  1  –  Initial  Precooling  1  ...................................................................................................  12   4.3.2  Step  2-­‐  Initial  Precooling  2   .....................................................................................................  13   4.3.3  Step  3  –  Connection  of  Bunker  Hose  .....................................................................................  13   4.3.4  Step  4  -­‐  Inerting  the  Connected  System  ................................................................................  14   4.3.5  Step  5  –  Purging  the  Connected  System  ...............................................................................  14   4.3.6  Step  6  –  Filling  Sequence  .......................................................................................................  15   4.3.7  Step  7  –  Liquid  Line  Stripping  ................................................................................................  16   4.3.8  Step  8  –  Liquid  Line  Inerting  ..................................................................................................  16   4.3.9  Step  9  –  Disconnection  ..........................................................................................................  16   4.4  Equipment  ....................................................................................................................................  17   4.4.1  Tanks  .....................................................................................................................................  17   4.4.2  Valves  ....................................................................................................................................  18   4.4.3  Hose   .......................................................................................................................................  18   4.4.4  Loading  arms  .........................................................................................................................  18   4.4.5  Pipes  ......................................................................................................................................  18   4.4.6  Pump  .....................................................................................................................................  18   4.4.7  Emergency  Shutdown  Systems  (ESD)  ....................................................................................  19   4.4.8  Emergency  Release  Systems  (ERS)  ........................................................................................  19   4.4.9  Emergency  Release  Couplers  (ERC)  .......................................................................................  19   4.4.10  Control  and  Monitoring  Systems   .........................................................................................  19       III    
  5. 5. 5  Regulations  ..........................................................................................................................................  20   5.1  Standardization  Bodies   .................................................................................................................  20   5.1.1  International  Maritime  Organization  (IMO)  ..........................................................................  20   5.1.2  International  Organization  for  Standardization  (ISO)   ............................................................  20   5.1.3  Society  of  International  Gas  Tanker  &  Terminal  Operators  (SIGTTO)  ...................................  20   5.1.4  Oil  Companies  International  Marine  Forum  (OCIMF)  ...........................................................  20   5.1.5  European  Committee  for  Standardization  (CEN)  ..................................................................  21   5.2  International  Rules  and  Guidelines  ..............................................................................................  21   5.2.1  IMO  International  Gas  Code  (IGC)  .........................................................................................  21   5.2.2  IMO  International  Gas  Fuel  Interim  Guidelines  (MSC.285(86))  .............................................  21   5.2.3  SIGGTO:  Guidelines  for  LNG  transfer  and  Port  Operation   ....................................................  21   5.2.4  OCIMF:  Guidelines  for  Oil  transfers,  Ship-­‐to-­‐Ship  oil  bunkering  procedures  ........................  21   5.2.5  CEN  –  European  Standard  .....................................................................................................  21   5.2.6  Local  regulations  and  authorities  ..........................................................................................  22   5.3  The  ISO  Standard  –  ISO/TC  67/WG  10/PT1  ..................................................................................  22   5.4  Foreseen  Governance  of  LNG  Bunkering  Operations   ...................................................................  23   6  On  Site  .................................................................................................................................................  24   6.1  Best  Practice  .................................................................................................................................  24   6.2  Bunkering  Area  .............................................................................................................................  24   6.3  Purging  .........................................................................................................................................  24   6.3.1  Zero  Emission  Solutions  ........................................................................................................  24   6.3.2  Pressure  Testing  ....................................................................................................................  25   6.4  Filling  Sequence  -­‐  Tank  Pressure  and  Temperature  .....................................................................  25   6.4  1  Standard  Quality  –  Explanation  of  the  Term  .........................................................................  25   7  Discussion  ............................................................................................................................................  26   7.1  Standards  -­‐  Current  Situation  .......................................................................................................  26   7.1.1  Bunkering  vs.  Large-­‐Scale  Transfers  ......................................................................................  26   7.1.2  LNG  vs.  Conventional  Fuels  ...................................................................................................  26   7.1.3  Port  rules  ...............................................................................................................................  26   7.1.4  Bunkering  scenarios  ..............................................................................................................  27   7.2  ISO/TC  67/WG  10  .........................................................................................................................  27   7.2.1  Lacking  elements  ...................................................................................................................  27   7.2.2  Implementation  .....................................................................................................................  27   7.2.3  Equipment  .............................................................................................................................  28   7.3  Passengers  ....................................................................................................................................  28   7.4  Safety  Zones  .................................................................................................................................  28   8  Conclusion  ...........................................................................................................................................  30   Appendix  A  .............................................................................................................................................  31   Appendix  B  .............................................................................................................................................  32   Appendix  C  .............................................................................................................................................  33   Standardization  bodies   .......................................................................................................................  33   International  Maritime  Organisation  (IMO)  ...................................................................................  33   International  Organisation  for  Standardisation  (ISO)   .....................................................................  33   International  Electrotechnical  Commission  (IEC)  ...........................................................................  33   Society  of  International  Gas  Tanker  &  Terminal  Operators  (SIGTTO)  ............................................  34   Oil  Companies  International  Marine  Forum  (OCIMF)  ....................................................................  34   European  Committee  for  Standardisation  (CEN)  ...........................................................................  34   Reference  list  .........................................................................................................................................  36         IV    
  6. 6. List  of  Figures   Figure  1:  The  LNG  fuelled  fleet  .................................................................................................................  2   Figure  2:  The  Large  Scale  LNG  Chain  ........................................................................................................  4   Figure  3:  Explosion/Flammability  Curve  ...................................................................................................  5   Figure  4:  ECA  zones  ..................................................................................................................................  6   Figure  5:  Fuel  Emissions,  for  a  typical  existing  ship   ..................................................................................  7   Figure  6:  Lifecycle  economics  for  a  typical  ship  .......................................................................................  9   Figure  7:  Overall  Bunkering  Layout  ........................................................................................................  11   Figure  8:  Bunkering  Procedure  Step  1  ....................................................................................................  12   Figure  9:  Bunkering  Procedure  Step  2  ....................................................................................................  13   Figure  10:  Bunkering  Procedure  Step  4  ..................................................................................................  14   Figure  11:  Bunkering  Procedure  Step  5  ..................................................................................................  14   Figure  12:  Bunkering  Procedure  Step  6  -­‐  Bottom  Filling  ........................................................................  15   Figure  13:  Bunkering  Procedure  Step  6  -­‐  Top  Filling  (Spray)  ..................................................................  15   Figure  14:  Bunkering  Procedure  Step  7  ..................................................................................................  16   Figure  15:  IMO  Type-­‐C  Tank,  CRYO  AB  ...................................................................................................  17   Figure  16:  Dry  Break  Coupling  (Mann  Teknik  AB)  ..................................................................................  19   Figure  17:  Foreseen  governance  of  LNG  bunkering  operations  .............................................................  23         V  
  7. 7. List  of  Abbreviations   NG  –  Natural  Gas   LNG  –Liquefied  Natural  Gas   LEL  –  Lower  Explosion  Level   UEL  –  Upper  Explosion  Level   HFO  –  Heavy  Fuel  Oil   MDO  –  Marine  Diesel  Oil     MGO  –  Marine  Gas  Oil   mmbtu  -­‐  million  British  thermal  units   ECA  –  Emission  Control  Area   IEA  –  International  Energy  Agency   TTS  –  Truck-­‐to-­‐Ship   STS  –  Ship-­‐to-­‐Ship   PTS  –  Terminal  (Pipeline)-­‐to-­‐Ship     ERC  –  Emergency  Quick  Release  Connector/Couplers   ESD  –  Emergency  Shutdown  Systems     ERS  –  Emergency  Release  Systems   IMO  –  International  Maritime  Organization   ISO  –  International  Organization  for  Standardization   SIGTTO  –  Society  of  International  Gas  Tanker  &  Terminal  Operators   OCIMF  –  Oil  Companies  International  Marine  Forum   CEN  –  European  Committee  for  Standardization   NMD  –  Norwegian  Maritime  Directorate   EU  –  European  Union   IGC  –  IMO  International  Gas  Code   IGF  –  IMO  International  Gas  Fuel  Interim  Guidelines     Sorted  after  order  of  appearance  in  the  document.           VI    
  8. 8. 1  Introduction   1.1  Motivation   “The  LNG  industry  is  the  fastest  growing  segment  of  the  energy  industry  around  the  world.”  Global  oil   is  growing  about  0.9%  per  annum,  global  gas  at  2%,  while  Liquefied  Natural  Gas  (LNG)  has  been   1 growing  at  a  comparatively  soaring  4.5%.     The  International  Energy  Agency  projects  the  natural  gas  used  to  account  for  more  than  25%  of  the   world  energy  demand  (amounting  to  a  50%  increase)  by  2035,  making  it  the  fastest  growing  primary   energy  source  of  the  world.  For  LNG,  a  9%  share  in  the  global  gas  supply  was  estimated  for  2010;  by   2 2030  it  is  projected  to  account  for  15%.  “Lloyd’s  Register  believes  LNG  could  account  for  up  to  9%  of   3 total  bunker  fuel  demand  by  2025.”     1.1.1  Bunkering   4 Small-­‐scale  distribution  and  bunkering  of  LNG  has  been  booming  as  well.  LNG  was  created  as  a  way   to  transport  natural  gas  in  a  more  economical  way  over  long  distances,  as  it  is  reduced  to   th approximately  1/600  in  volume  through  liquefaction.  Transportation  and  handling  of  LNG  as  cargo   on  both  land  and  sea  have  been  proven  for  many  decades.  With  new  emission  regulations  the   potential  applications  for  LNG  is  expanding.  Among  these  applications  is  use  of  LNG  as  marine  fuel.   Particularly  attractive  for  marine  vessels  travelling  set  routes  such  as  tug  boats,  ferries,  and  support   vessels.  LNG  as  main  propulsion  fuel  is  no  longer  a  new  invention  and  the  technology  is  already   5 6 classified  as  proven.  The  first  LNG  fueled  ship  in  the  world  (Glutra)  was  launched  in  Norway,  in  2001.       The  transportation  sector  being  the  single-­‐biggest  contributor  to  oil  demand  in  many  countries   7 around  the  world,  is  always  looking  for  ways  to  cut  costs.  Vessels  running  on  LNG  instead  of  oil  are   8 already  saving  25%  on  fuels  costs  in  certain  markets.  Norway  is  currently  operating  38  gas-­‐fuelled   ships.  Based  on  intrinsic  advantages  LNG  has  as  a  fuel,  it  can  and  will  probably  be  adopted  on  an   international  basis.  In  response  to  increasing  demand,  construction  of  LNG  bunkering  infrastructure  is   9 under  development.       Development  of  a  worldwide  LNG  supply  chain  based  on  ship-­‐to-­‐ship  or  shore-­‐to-­‐ship  bunkering  is  of   10 paramount  importance  for  LNG  to  become  a  real  alternative  to  heavy  fuel  oil.  The  bunkering   solutions  most  widely  used  today  are  truck  and  terminal  supply.  Both  solutions  are  considered  less   feasible  as  trucks  provide  small  volumes  and  terminals  have  high  operational  cost.  Bunkering  from   vessel/barge,  on  the  other  hand,  is  much  more  flexible  with  respect  to  covering  several  sizes  and   locations  that  in  turn  lowers  both  cost  and  time  spent  on  bunkering.     1.1.2  New  Projects   11  “New  LNG  projects  and  applications  are  being  announced  daily  around  the  world.“     • In  Europe,  the  commission  has  set  aside  €2.1bn  to  equip  139  seaports  and  inland  ports  –   about  10  per  cent  of  all  ports  –  with  LNG  bunker  stations  by  2025.  The  plan  forms  part  of  the   12 new  EU  strategy  for  clean  fuels.   13 • Singapore:  developed  and  opened  an  open-­‐access,  multi-­‐user  import  terminal.     • In  Norway,  Skangass  in  cooperation  with  Gassnor  in  Risavika  Stavanger  is  establishing  a   bunker  terminal.     • “Washington  State  Ferries  (WSF)  is  exploring  an  option  to  use  liquefied  natural  gas  (LNG)  as  a   14 source  of  fuel  for  propulsion.”       1  
  9. 9. There  are  LNG  passenger  vessels  currently  under  construction  or  in  design  for  service  in   Argentina,  Uruguay,  Finland,  and  Sweden.   • The  M/S  Viking  Grace  was  launched  some  months  ago  and  is  the  world’s  first  large  passenger   15 vessel  to  be  powered  by  liquefied  natural  gas  (LNG)   • Break-­‐bulk  terminal  in  Rotterdam.     16 • Port  of  Antwerp,  creating  a  LNG  bunker  vessel.     • “LNG  bunkering  Ship  to  Ship”  report  carried  out  by  Swedish  Marine  Technology  Forum  in   cooperation  with  Det  Norske  Veritas  (DNV)  and  others.  The  document  is  a  procedural   description  of  how  LNG  bunkering  between  two  ships  should  be  done  based  on  a  real  life   17 example.     Currently  there  are  74  confirmed  LNG  fuelled  ships  contracted.  The  following  figure  includes   developments  in  the  fleet  and  future  expansions  plans  for  the  next  three  years.       •   18 Figure  1:  The  LNG  fuelled  fleet     1.1.3  The  Drive     The  reason  for  this  strong  increase  and  interest  in  LNG  as  a  marine  fuel  is  based  on  two  main  factors:   1. The  Marine  Environmental  Protection  Committee  part  of  International  Maritime   Organization  (IMO)  is  introducing  emission  controls,  constraining  the  extent  of  exhaust  gas   19 emission.  This  is  forcing  the  industry  to  rethink  its  fueling  options.     2. The  availability  of  natural  gas  has  increased  due  to  large  offshore  discoveries  and   unconventional  gas  finds  in  the  US  (shale  gas),  creating  lower  prices  on  natural  gas  compared   to  conventional  fuels.  This  creates  a  drive  in  the  industry,  as  consumers  are  able  to  obtain   commercial  saving  against  alternative  fuels.       2  
  10. 10. 1.2  Underlying  Hypothesis   The  industry  will  continue  to  introduce  technological  innovations  and  infrastructure  needed  to  supply   the  expanding  LNG  bunkering  market  as  long  as  there  is  a  cost  benefit  to  use  LNG  compared  to   alternative  fuels.  Over  the  last  decades  the  focus  in  the  market  has  been  on  technical  and  commercial   issues,  but  now  that  the  technical  solutions  are  in  place  and  markets  are  growing  the  industry  is   20 taking  a  closer  look  at  strategic  and  regulatory  matters.       As  LNG  marine  fuel  becomes  more  common,  regulations  and  standards  need  to  be  implemented   alongside  technical  and  procedural  developments.  Standards  are  necessary  as  it  ensures  a  level  of   safety  and  create  common  grounds  for  the  operators,  again  making  it  easier  for  the  LNG  industry  to   expand.       There  are  several  bodies  that  cover  various  aspects  of  currently  incomplete  legislation  for  the   industry.  One  of  the  regulatory  frameworks  is  the  upcoming  ISO/TC  67/WG  10  Technical  Report   (which  DNV  is  leading).  The  technical  report  will  be  a  high  level  document  scheduled  for  completion  in   2014.  “The  objective  of  the  ISO  TC  67  WG  10  is  the  development  of  international  guidelines  for   bunkering  of  gas-­‐fuelled  vessels  focusing  on  requirements  for  the  LNG  transfer  system,  the  personnel   21 involved  and  the  related  risk  of  the  whole  LNG  bunkering  process.”     Within  this  definition  there  are  several  questions  raised  as  to  what  it  should  cover  and  what  it  needs   to  cover  to  be  an  effective  “tool”  in  future  bunkering  expansion  and  to  answer  the  industry’s  current   demand  for  standardization.  Currently  it  is  the  opinion  of  the  industry  that  comprehensive   international  standards  cannot  be  created,  as  the  experience  of  bunkering  LNG  is  too  limited.   Nonetheless,  with  increased  use  there  will  be  a  need  for  international  standardization  and  guidelines.     1.3  Main  Goal  of  the  Report   The  topic  of  the  report  will  be  an  evaluation  of  LNG  bunkering  solutions,  with  main  focus  on   identifying  technical  challenges,  and  to  identify  potential  areas  for  industry’s  standardization.         1.4  Scope  of  the  Report   The  report  will  cover  LNG  characteristics,  safety  aspects  and  the  current  state  of  technology  for   bunkering  of  LNG.  Present  a  technical  step-­‐by-­‐step  overview  over  the  bunkering  procedure  and   essential  equipment  used.  It  will  further  discuss  problem  areas,  safety  issues  and  areas  where   standards  could  be  useful  to  promote  more  widespread  use.     The  report  is  limited  by  the  available  technologies  comprising  a  discharging  unit  to  receiving  ship  for   transferring  LNG.  There  are  many  actors  in  the  industry  but  the  experience  is  limited  and  the   solutions  are  proprietary.       3  
  11. 11. 2  LNG   2.1  LNG  characteristics     Liquefied  Natural  Gas  (LNG)  is  Natural  Gas  (NG)  cooled  to  about  -­‐162°C  (-­‐260°F)  at  atmospheric   pressure.  It  is  a  condensed  mixture  of  methane  (CH4)  approximately  85-­‐96mol%  and  a  small   percentage  of  heavier  hydrocarbons.  LNG  is  clear,  colorless,  odorless,  non-­‐corrosive  and  non-­‐toxic.  In   liquid  form  it  is  approximately  45%  the  density  of  water  and  as  vapor  it  is  approximately  50%  density   of  air  and  will  rise  under  normal  atmospheric  conditions.  LNG  is  called  a  cryogenic  liquid  –  defined  as   substances  that  liquefies  at  a  temperature  below  -­‐73°C  (-­‐100°F)  at  atmospheric  pressure.  The  process   th of  liquefaction  reduces  the  volume  to  1/600  of  its  original  volume,  providing  efficient  storage  and    22 transport.       2.2  LNG  Chain     23 Figure  2:  The  Large  Scale  LNG  Chain   2.2.1  Gas  Field  (Reservoir)   The  Chain  starts  with  gas  production. Raw  NG  comes  from  three  types  of  wells:  oil  wells  (associated   gas),  gas  wells,  and  condensate  wells  (both  non-­‐associated  gas).  NG  is  a  mixture  of  hydrocarbons.  It   consists  mostly  of  methane,  but  also  heavier  hydrocarbons:  ethane,  propane,  butane,  and  pentanes.   In  addition,  raw  NG  contains  water  vapor,  hydrogen  sulfide,  carbon  dioxide,  helium,  nitrogen,  and   24 other  compounds.  NG  quality  will  vary  depending  on  its  composition.  A  full  composition  example  of   NG  can  be  found  in  Appendix  A.   2.2.2  Liquefaction  Terminal:  Onshore  Processes   The  rich  gas  from  the  reservoirs  is  purified  to  increase  its  methane  content.  The  pre-­‐treatment   includes  removal  of  condensate,  carbon  dioxide  (CO2),  mercury,  sulfur  (H2S),  and  water  (through   dehydration).  After  pre-­‐treatment  the  natural  gas  is  now  classified  as  dry/lean  gas.  This  gas  if  further   25 refrigerated  and  eventually  liquefied  and  stored.     2.2.3  Marine  Transport   Large-­‐scale  LNG  is  shipped  from  the  liquefaction  terminal  to  the  receiving  terminal  by  LNG  carriers,   3 today  the  normal  capacity  range  for  carriers  is  145,000-­‐180,000m .     2.2.4  Receiving  Terminal   At  the  receiving  terminal  LNG  is  stored  in  large  cryogenic  tanks.  The  liquid  is  re-­‐gasified/vaporized  and   transported  to  local  market  via  the  gas  grid.  In  some  markets  a  portion  of  the  LNG  is  broken  into   smaller  cargoes  and  distributed  in  smaller  scale  by  rail,  road  or  smaller  LNG  vessels.  Small-­‐scale     4  
  12. 12. distributions  can  also  originate  from  small-­‐scale  liquefaction  plants;  this  is  current  practice  in  Norway   and  the  US.    The  small-­‐scale  distribution  scenarios  are  the  focus  of  this  project  report.       2.3  LNG  Safety  Issues   In  its  liquid  form  LNG  cannot  explode  and  it  is  not  flammable.  Hazards  arise  when  LNG  returns  to  its   gaseous  state  through  an  uncontrolled  release.  The  release  can  as  an  example  be  caused  by  a  tank   rupture  due  to  external  impact,  leaks  from  flanges  in  the  pipework  or  a  pipe  break,  etc.       The  hazards  can  be  divided  into  two  categories:   1. Cryogenic  effects  from  LNG   Exposure  to  a  liquid  at  -­‐163°C  will  cause  humans  to  freeze  and  steel  equipment  to  become   brittle.  Brittle  steel  can  break  and  cause  additional  secondary  failures.       2. Fire  and  explosion   Once  the  LNG  has  leaked,  it  will  form  a  pool  of  liquid  LNG.  This  pool  will  start  to  evaporate   and  form  a  cloud  of  gas,  primarily  consisting  of  methane.  This  gas  will  start  mixing  with  air   (with  a  20.9%  oxygen  ratio)  and  once  it  reaches  a  mixture  between  5-­‐15%  gas,  it  is  ignitable.   Outside  the  critical  level  an  explosion  or  fire  will  not  occur.  Below  the  lower  explosion  level   (LEL)  there  is  insufficient  amount  of  methane.  Similarly,  above  the  upper  explosion  level   (UEL)  there  is  insufficient  amount  of  oxygen  present.  The  critical  level  is  at  9%  ratio  of  NG  to   air.       Without  an  ignition  source,  the  gas  will  continue  to  evaporate,  disperse  at  ground  level  while   cold,  start  to  warm  and  rise  to  the  sky  (as  methane  is  lighter  than  air)  and  thereafter  drift   away  until  the  entire  liquid  pool  is  gone.  LNG  evaporates  quickly,  and  disperses,  leaving  no   residue.  There  is  no  environmental  cleanup  needed  for  LNG  spills  on  water  or  land.  If  an   ignition  source  is  present,  the  gas  cloud  could  ignite,  but  only  at  the  edges  where  the   methane  concentration  is  within  the  aforementioned  range.  There  will  be  an  initial  flash,  not   very  violent,  as  the  gas  cloud  ignites,  and  it  will  continue  to  burn  back  to  the  pool  as  a  flash   fire.  The  gas  will  continue  to  burn  as  it  evaporates  until  the  pool  of  LNG  is  gone.     For  an  explosion  to  take  place  the  gas  typically  needs  to  be  in  a  confined  space  (such  as   inside  a  building  or  vessel),  reach  the  right  mixture  with  oxygen  and  have  the  presence  of  an   ignition  source.  In  this  event,  there  could  be  an  explosion  causing  overpressure  and  drag   26 loads  and  potential  damage  to  life  and  property.       27 Figure  3:  Explosion/Flammability  Curve       5  
  13. 13. 3  LNG  Advantages   For  the  shipping  industry,  as  in  all  other,  profit  is  crucial.  The  provider  of  the  lowest  voyage  cost  for  a   particular  cargo  wins  the  customers.  In  all  cases  fuel  prices  top  the  expense  list  representing  50%-­‐70%   28 of  the  total  costs  of  owning  and  operating  a  ship.  For  LNG  to  be  a  viable  alternative  fuel  it  needs  to   be  price  competitive.  To  understand  why  the  industry  is  rethinking  it  fueling  options  and  how  LNG  is  a   sustainable  alternative,  this  chapter  will  present  some  of  the  advantages  of  LNG  as  marine  fuel.  The   main  source  used  is  “Greener  Shipping  in  the  Baltic  Sea”  DNV  Report,  June  2010.   3.1  Environmental  advantages       3.1.1  Alternative  Energy  Sources   Through  technological  developments  and  innovations  the  world  today  has  a  wide  range  of  alternative   energy  sources,  besides  its  hydrocarbon-­‐based  sources.  Examples  are  wind,  solar,  biomass,  nuclear,   and  hydro  electric.  For  the  shipping  industry  though,  most  of  these  alternative  do  not  apply:     • Electric:  entire  cargo  area  would  have  to  be  filled  with  batteries   • Biomass:  would  have  to  empty  the  world  of  organic  material   • Solar:  not  enough  surface  area  for  the  number  of  panels  needed   • Wind:  there  is  not  enough  stability  in  the  vessels  to  carry  the  turbines  on  deck.  Another  type   of  wind  source  used  in  the  past  is  sailing,  but  with  respect  to  increased  travel  time  this  is  not   an  option.     The  shipping  industry  needs  to  remain  or  further  increase  its  efficiency  and  consequently  has  no   29 carbon  neutral  alternatives  at  their  disposal.     3.1.2  Emission  Control   Heavy  Fuel  Oil  (HFO),  Marine  Diesel  Oil  (MDO)  and  Marine  Gas  Oil  (MGO)  are  all  current  conventional   bunkering  fuels.  Ship  based  fuel  is  a  large  part  oil  consumption  and  all  these  fuels  are  high  on   emission  rates.  If  carbon  neutral  options  are  out  of  the  question  how  will  the  shipping  industry  meet   future  emission  regulations  dictated  by  international  authorities?  In  2015,  the  allowed  SOx  emissions   from  ships  sailing  within  the  Emission  Control  Area  (ECA)  will  be  reduced.    These  standards  of   emissions  are  already  adopted  on  a  case-­‐by-­‐case  basis  in  European  inland  waterways  and  ports,  by   certification  from  the  relevant  Classification  Societies.  Further,  in  2016,  the  International  Maritime   30 Organization  (IMO)  will  put  the  new  Tier  III  levels  of  NOx  emissions  into  force.  These  regulations  will   impose  taxes  on  emission,  which  will  increase  the  cost  of  using  conventional  fuels.       31 Figure  4:  ECA  zones       6  
  14. 14. 3.1.3  Emissions  Requirements   ECA  requirements:   • Maximum  level  of  sulphur  in  fuel,  all  ships:   o 1,0%  by  July  1,  2010   o 0,1%  by  January  1,  2015   • Nitrogen  emission  for  new  buildings:   o 20%  reduction  in  NOx  emission  by  2011  (Tier  II)   o 80%  reduction  in  NOx  emission  from  2016  (Tier  III)   EU  fuel  requirements  now:   • 0,1%  sulphur  in  ports  and  inland  waterways   Global  requirements:   32 • 2020/2025:  sulphur  levels  less  than  0.5%  (date  TBD  pending  2018  review)   3.1.4  Natural  Gas  -­‐  The  Solution   Based  on  a  review  of  existing  marine  engine  technology  and  expected  technology  development,  ship   33 owners  currently  have  three  choices  if  they  wish  to  continue  sailing  in  ECAs  from  2015.     • Switch  to  low  sulphur  fuel  –  minor  modifications  to  present  MGO  and  MDO  systems,  but   availability  is  already  limited     • Install  an  exhaust  gas  scrubber  –  expensive  option     • Switch  to  LNG  fuel  –  will  comply  with  upcoming  regulations  and  to  contribute  to  global   emission  reductions,  natural  gas  is  a  viable  option.     Reductions  in  emissions  form  using  LNG  as  a  fuel   • CO2  and  GHG  20-­‐25%   • SOx  and  particulates  approximately  100%   • NOx  85-­‐90%     34 Figure  5:  Fuel  Emissions,  for  a  typical  existing  ship       7  
  15. 15. 3.2  Economical  Advantages   “The  marine  fuel  oil  market  is  a  large  global  market  supplying  about  300  million  tons  of  fuel  oil   35 annually,  and  the  price  developments  are  generally  following  that  of  crude  oil.”  Marine  fuels  on   long-­‐term  contracts  have  trading  prices  of  14-­‐15USD/mmbtu  (million  British  thermal  units)  for  LNG   36 and  107-­‐116USD/barrel  for  crude  oil.  (Ref:  International  Energy  Agency  (IEA))  The  prices  are   measured  in  different  units  as  the  substance  is  different,  but  if  a  conversion  is  made  directly  1  barrel   is  approximately  equal  to  5.55mmbtu.  This  means  that  crude  oil  prices  lie  in  the  range  from  19-­‐ 21USD/mmbtu.       The  LNG  price  is  based  on  large-­‐scale  sales,  not  distribution  in  the  small-­‐scale.  The  global  natural  gas   market  is  today  not  set  up  to  supply  LNG  in  small  quantities  to  consumers  such  as  ferries.  There  are   currently  no  functioning  markets  for  this,  and  no  reference  prices  consequently  exist.  There  are  many   small-­‐scale  LNG  developments  across  the  world,  but  contract  structures  and  prices  for  LNG  as  a   37 marine  fuel  is  uncertain  as  of  today.   3.2.1  Investment  Costs   A  switch  to  LNG  marine  fuel  necessitates  expenses  on  several  levels:  equipment  adaptation,   establishing  bonds  with  new  suppliers,  possibly  planning  new  shipment  routes  as  LNG  will  only  be   provided  in  certain  areas  and  training  of  personnel.  The  investment  cost  will  vary  significantly   between  ship  types  and  must  be  assessed  from  case  to  case.  Nevertheless,  the  added  investment  cost   of  choosing  LNG  fuel  for  new  ships  is  expected  to  decrease  in  the  future.  The  rate  and  extent  of  this   increment  will  largely  depend  on  the  number  of  LNG  fuelled  ships  being  contracted  (economies  of   38 scale).  Higher  volume  of  ships  running  on  LNG  will  create  the  motive  for  building  the  infrastructure   needed  to  support  small-­‐scale  supply,  which  in  turn  will  reduce  the  present  day  costs.       Ships  operating  in  the  Baltic  Sea  have  a  fairly  even  age  distribution  from  new  to  40  years  old.  The   replacement  of  old  vessels  is  continuous,  and  it  takes  about  10  years  to  replace  25%  of  the  sailing   39 fleet.     3.2.2  Infrastructure   If  distribution  and  process  costs  could  be  brought  down  to  similar  levels  as  for  oil  by  economics  of   scale,  the  current  fuel  prices  indicates  a  great  economic  potential  for  LNG.  The  infrastructure  for  LNG   bunkering  today,  however,  does  not  allow  for  the  LNG  prices  to  remain  at  this  level.  As  soon  as  LNG  is   broken  into  smaller  volumes  and  distributed  further  through  the  small-­‐scale  chain  prices  increase   drastically.  Small-­‐scale  liquefaction  and  distribution  expenses  are  the  main  contributors  to  this  price   increase.  The  potential  savings  for  the  ship-­‐owner  would  then  be  eliminated.  In  order  to  bring  down   the  price  of  LNG  for  bunkering,  it  must  be  bought  from  full-­‐scale  liquefaction  plants  and  efficient   40 distribution  chain  must  be  established.       The  industry  is  already  well  aware  of  these  issues  and  is  searching  for  effective  solutions.  Trough  the   EU  initiative  to  establish  139  ports  (as  mentioned  in  chapter  1),  LNG  will  be  accessible  and  a  ship  will   not  have  to  limit  its  routes  to  specific  bunkering  areas.  Similar  initiatives  are  taken  all  over  the  world.   To  remove  the  cost  of  establishing  small-­‐scale  liquefaction  terminals,  bunkering  from  vessel  barge  is  a   maintainable  alternative.  Ship-­‐to-­‐ship  transfer  is  the  scenario  with  the  best  projections,  both  with   respect  to  flexibility  in  bunkering  location  and  range  in  volume  supply.  The  various  bunkering   scenarios  will  be  discussed  in  the  next  chapter  ‘4  Bunkering’.     8  
  16. 16. 3.2.3  Marine  Fuel  Costs   Every  ship  requires  individual  calculations  with  respect  to  travelling  time  and  distance,  fuel   consumption  and  production  costs.  Overall  it  is  estimated  that  ships  with  an  economical  life  of  15   years  or  more  will  economically  benefit  from  using  LNG  as  a  fuel.  The  advantage  is  greater  with   increasing  fuel  consumption.  The  example  calculation  represents  a  typical  Baltic  Sea  cargo  ship  of   41 approximately  2,700  gross  tons,  3,300  kW  main  engine  and  5,250  yearly  sailing  hours.     Figure  6:  Lifecycle  economics  for  a  typical  ship     The  engine  size  and  consumption  levels  in  this  example  are  modest.  Still,  it  is  clear  that  MDO  is  the   most  expensive  option  and  LNG  is  found  to  be  a  superior  alternative.  The  results  are  favorable  to  such   an  extent  that  it  is  even  reasoned  to  be  profitable  without  ECA  requirements.         9  
  17. 17. 4  Bunkering     This  chapter  will  define  LNG  bunkering,  present  the  various  bunkering  scenarios,  provide  a  detailed   technical  description  of  the  bunkering  procedure,  and  present  approved  equipment.       4.1  LNG  Bunkering  Definition   “The  definition  of  LNG  bunkering  is  the  small-­‐scale  transfer  of  LNG  to  vessels  requiring  LNG  as  a  fuel   for  use  within  gas  or  dual  fuelled  engines.  LNG  bunkering  takes  place  within  ports  or  other  sheltered   42 locations  at  the  base  case.”  Bunkering  should  not  be  considered  in  the  same  context  as  large  scale,   commercial  transfer  of  cargo  between  ocean-­‐going  LNG  carriers.  This  larger  operation,  where   3 volumes  are  typically  above  100,000m  is  covered  separately  under  preceding  technical  releases  and   43 standards.   4.1.1  Engines   The  ship  owners  have  two  options  with  regards  to  engine  design:  dual  fuel  engines  or  LNG  lean  burn   mono  fuel  engines.  Dual  fuel  engines  run  on  both  LNG  and  conventional  fuels  from  separate  tanks.  It   is  a  flexible  solution  for  varying  availability  in  LNG.  In  LNG  mode  these  engines  only  consume  a  minor   44 fraction  of  conventional  fuel.  Bunkering  procedure  for  dual  fuel  engines  is  a  process  that  can  take   place  simultaneously  for  both  fuels.  The  procedure  described  below  is  however  limited  to  the  LNG   transfer  system.       4.2  LNG  Bunkering  Scenarios   Truck-­‐to-­‐Ship  (TTS):  micro  bunkering,  discharging  unit  is  a  LNG  road  tanker  size   3 approximately  50-­‐100m .   • Ship-­‐to-­‐Ship  transfer  (STS):  discharging  unit  is  a  bunker  vessel  or  barge  with  size  200-­‐ 3 10,000m .   • Terminal  (Pipeline)-­‐to-­‐Ship  (PTS):  satellite  terminal  bunkering  serves  as  the  discharging  unit   3 and  supply  sizes  are  approximately  100-­‐10,000m .     PTS  and  TTS  are  the  most  established  bunkering  scenarios  per  today  and  they  are  both  classified  as   onshore  supply.  STS  will  also  take  place  while  the  receiving  unit  is  at  dock  or  in  a  port  environment,   but  both  units  involved  in  the  transfer  are  seaborne  and  the  transfer  is  therefore  classified  as   offshore.  Use  of  STS  makes  the  bunkering  location  more  flexible  than  PTS  and  it  can  supply  higher   volumes  than  TTS.  Developments  within  this  scenario  are  the  most  feasible  and  are  therefore   45 essential  in  making  LNG  competitive  against  other  marine  fuels,  especially  for  larger  ships. •   10  
  18. 18. 4.3  LNG  Bunkering  Procedure   Time  efficiency  and  safety  are  elements  of  paramount  importance  when  it  comes  to  the  bunkering   procedure.  Developing  a  suitable  procedure  is  fundamental  in  obtaining  these  facets.  The  industry  is   currently  developing  solutions  to  achieve  similar  duration  of  bunkering  operations  for  LNG  as  for   conventional  fuels.       As  LNG  bunkering  is  evolving,  technology  improvements  and  innovations  are  added  continually.  The   process,  being  relatively  new,  is  not  yet  regulated  or  standardized  (will  be  discussed  further  under   section  ‘5  Regulations’)  and  therefore  there  are  several  elements  that  could  vary  for  each  individual   bunkering  case.  Nevertheless,  this  section  aims  to  provide  a  description  suited  for  various  needs  and   different  bunkering  scenarios.  Variations  in  bunkering  procedure  depending  on  scenario  will  be   mentioned.       In  this  section  of  the  report  there  will  be  no  elaborations  on  general  principles,  conditions,   requirements,  safety  aspects  and  communication  related  to  the  process.  The  same  applies  to  details   exclusively  relating  to  bunkering  of  fuels  other  than  LNG,  in  the  case  of  dual  fuel  engines.  The  focus   will  be  on  the  technical  aspects  of  the  procedure  and  the  equipment  used.       The  main  source  for  this  part  of  the  report  is  the  short  film  “Step  by  step  Bunkering  by  DNV”.   Additional  details  have  been  acquired  from  discussions  with  individuals  from  the  industry  (se  preface   for  names)  and  the  report  ‘LNG  ship  to  ship  bunkering  procedure’  by  the  Swedish  Marine  Technology   Forum  et  al.         46 Figure  7:  Overall  Bunkering  Layout   The  diagram  is  schematic  not  to  scale,  especially  when  it  comes  to  pipe  length.     Initially  all  valves  are  closed  as  shown  in  the  diagram.  The  transfer  hose  is  not  connected  until  step   three  but  included  in  this  diagram.  The  first  step  takes  place  during  ship  mooring,  or  in  the  case  of   ship-­‐to-­‐ship  transfer  during  the  bunker  vessels  mooring  up  against  the  receiving  ship.  Discharging  unit   can  be  either:  terminal,  truck  or  bunker  vessel/barge.  Variations  in  design  and  layout  can  take  place,   but  overall  this  is  a  representative  example  of  a  layout  and  it  gives  a  good  basis  for  explaining  the   bunkering  procedure.       11  
  19. 19. 4.3.1  Step  1  –  Initial  Precooling  1   Filling  lines  are  precooled  during  mooring.  Valves  V2,  V5,  V8  and  V9  are  opened.  The  system  needs  to   be  cooled  down  slowly,  otherwise  one  part  will  contract  and  another  not.  Improper  cooling  could  also   lead  to  pipe  cracking.  The  precooling  sequence  depends  on  cargo  pump,  design  of  the  discharging   47 unit  and  size  of  installation.  The  cold  LNG  (blue)  exits  tank  1  form  the  bottom,  and  slowly  “pushes”   the  warmer  NG  (red)  in  the  pipes  into  the  top  of  tank  1.       Figure  8:  Bunkering  Procedure  Step  1     During  this  stage  both  units  must  check  temperature  and  pressure  of  their  respective  LNG  tanks.   Within  the  tank,  temperature  is  directly  correlated  with  pressure.  If  the  temperature  of  the  receiving   tank  is  significantly  higher  than  the  discharging  (classified  as  a  “warm”  tank),  there  will  be  an  initial   vaporization  when  starting  to  transfer  LNG.  As  the  pressure  of  the  tank  might  be  too  high  for  the  LNG   transfer  to  be  initiated.  This  will  increase  the  tank  pressure  and  can  trigger  the  pressure  relief  valve  to   open  if  the  pressure  exceeds  the  set  limit.  The  pressure  of  both  tanks  must  be  reduced  prior  to  the   48 bunkering  in  case  of  a  high  receiving  tank  temperature.    When  the  levels  in  the  receiving  tank  are   low,  the  rate  of  evaporation  and  heat  ingress  to  the  tank  increases,  causing  a  higher-­‐pressure  build-­‐ up.       The  transfer  of  LNG  requires  a  certain  pressure  difference,  which  generally  is  determined  by  the  cargo   pump  capacity  and  the  pressure  in  the  receiving  tank.  The  larger  the  pressure  difference,  the  more   3 efficient  the  transfer.  For  TTS  bunkering  with  capacities  of  50  m /h,  a  typical  cargo  pump  can  deliver   at  around  4  barg.  In  a  warm  tank,  the  pressure  may  be  as  high  as  5  barg.  To  be  able  to  conduct  the   transfer  you  need  a  lower  pressure  in  the  receiving  tank  than  what  is  delivered  by  the  pump.       12  
  20. 20. 4.3.2  Step  2-­‐  Initial  Precooling  2   The  fixed  speed  cargo  pump  at  the  discharging  unit  also  requires  precooling.  Valves  in  step  1  remain   opened  and  additionally  valves  V3,  V4  and  V6  are  opened.  For  transfers  where  the  pressure   difference  between  the  discharging  and  receiving  unit  is  greater  than  2barg,  tank  1  pressure  will  be   49 utilized  as  a  driving  force.  This  makes  the  cargo  pump  redundant.       Figure  9:  Bunkering  Procedure  Step  2       4.3.3  Step  3  –  Connection  of  Bunker  Hose   All  previously  opened  valves  are  now  closed.  Dedicated  discharging  units  may  be  fitted  with   specialized  hose  handling  equipment  (i.e.  hose  crane)  or  loading  arms,  to  deliver  the  bunker  hose  to   the  receiving  ship.  The  hose  is  connected  to  the  manifold.  Each  manifold  are  to  be  earthed  and  the   receiving  ship  shall  be  equipped  with  an  insulating  flange  near  the  coupling  to  prevent  a  possible   50 ignition  source  due  to  electrostatic  build-­‐up.  One  or  two  flexible  hoses  will  be  connected  between   the  units  –  one  liquid  filling  hose  and  one  vapor  return  hose  if  needed.  For  smaller  transfers  with   3 capacities  range  of  around  50-­‐200m /h,  and  where  the  receiving  tank  is  an  IMO  type  C  tank  with  the   possibility  of  sequential  filling,  a  vapor-­‐return  hose  will  generally  not  be  needed.  For  larger  transfer   rates  a  vapor  return  line  may  be  used  in  order  to  decrease  the  time  of  the  bunkering.  Still,  it  is  the   pressure  regulating  capability  of  the  receiving  tank  that  determines  whether  a  vapor  return  line  is   required  or  not.  This  step  will  visually  look  like  the  initial  drawing  of  the  entire  system  (Figure  7).     13  
  21. 21. 4.3.4  Step  4  -­‐  Inerting  the  Connected  System   Inert  gas,  nitrogen  (green),  is  used  to  remove  moisture  and  oxygen  (below  4%)  from  tank  2  and   associated  piping.  Inerting  is  accomplished  by  sequential  pressurization  and  depressurization  of  the   system  with  nitrogen.  Presence  of  moisture  in  the  tanks  or  pipes  will  create  hydrates,  which  is  a  form   51 of  ice  lumps  that  will  be  difficult  to  remove  from  the  system.  Oxygen  in  the  system  is  a  risk  as   explained  in  section  ‘2  LNG’.  Valves  opened:  V10,  V11,  V12  and  V16.     Figure  10:  Bunkering  Procedure  Step  4     4.3.5  Step  5  –  Purging  the  Connected  System   The  remaining  system  is  purged  with  NG  (until  it  reaches  97-­‐98%  ratio),  to  remove  remaining  nitrogen   according  to  engine  specifications.  Valve  V16  is  closed  prior  to  purging.  Valve  V15  is  opened,  natural   gas  is  now  moving  out  from  the  receiving  tank.  Venting  trace  amount  of  methane  through  the  mast   (vent  2)  is  current  practice.  Valve  V10  should  be  closed  quickly  after  the  pipes  have  been  cleaned  so   as  not  to  let  too  much  methane  escape  to  the  surroundings  through  the  vent.  The  industry  is  now   52 looking  for  zero  emission  solutions.       Figure  11:  Bunkering  Procedure  Step  5       14  
  22. 22. 4.3.6  Step  6  –  Filling  Sequence     For  the  filling  sequence  both  bottom  filling  and  top  filling  (the  shower/spray)  can  be  used.  For  top   filling  valve  V15  remains  open,  for  bottom  filling  it  is  closed  and  valve  V13  is  opened.  To  start  the   transfer  from  tank  1  to  tank  2  valves  V3,  V4,  V7,  V8,  V11  and  V12  also  have  to  be  opened.  Common   practice  is  to  start  with  top  filling  as  this  will  reduce  the  pressure  in  the  fuel  tank  (tank  2),  and  then   move  over  to  bottom  filling  when  a  satisfying  pressure  is  achieved.  A  high  pressure  in  the  receiving   tank  will  make  it  harder  for  the  LNG  transfer  to  take  place  and  the  pump  would  have  to  work  harder.   An  example  of  a  tank  filling  sequence  and  associated  acceptable  levels  is  given  in  section  6.4.     Figure  12:  Bunkering  Procedure  Step  6  -­‐  Bottom  Filling   Figure  13:  Bunkering  Procedure  Step  6  -­‐  Top  Filling  (Spray)     3 Transfer  speed  range  from  100-­‐1000m /h  depending  on  scenario,  tanks  and  equipment,  and  whether   bottom  or  top  filling  is  used.  Bottom  filling  can  take  much  higher  volumes  than  top  filling.  Bottom   filling  is  therefore  preferred  with  respect  to  time,  but  it  is  important  that  the  tank  pressure  allows  for   this  to  take  place.  Sequential  filling  i.e.  alterations  between  top  and  bottom  filling  during  the  transfer   is  also  standard  practice,  to  control  the  pressure  in  the  receiving  tank.       This  rate  can  be  withheld  during  the  transfer  until  agreed  amount  is  reached.  The  transfer  is  to  be   monitored  on  both  ships  with  regards  to  system  pressure,  tank  volume  and  equipment  behavior.  This   53 procedure  is  to  be  performed  for  each  tank  regardless  of  fuel  type.  Maximum  level  for  filling  the   LNG  tanks  is  98%  of  total  volume  according  to  class  rules,  but  is  normally  lower  for  system  design   reasons.     15  
  23. 23. 4.3.7  Step  7  –  Liquid  Line  Stripping   The  liquid  that  remains  in  the  bunker  hoses,  after  the  pump  has  stopped,  must  be  drained  before   disconnection.  Valves  V3,  V4  and  V11  on  discharging  unit  is  closed,  while  valve  V6  is  opened.  This   valve  links  to  the  top  of  the  fuel  tank  (tank  2).  This  process  creates  a  pressure  build-­‐up  due  to  a  rise  in   temperature  in  the  remaining  liquid  left  in  the  pipes  and  hose.  LNG  residuals  in  these  areas  are  forced   into  both  tanks.  Subsequent  opening  and  closing  of  the  shipside  valve  V12,  pushes  the  remaining  LNG   54 into  the  receiving  ships  tanks.     Figure  14:  Bunkering  Procedure  Step  7     4.3.8  Step  8  –  Liquid  Line  Inerting     Remaining  natural  gas  in  liquid  line  is  removed  by  inerting  gas  (nitrogen)  for  safety  reasons.  Valves  V6,   V7,  V8  and  V15  are  closed,  while  V10,  V11,  V12  and  V16  are  opened.  Venting  trace  amount  of   methane  through  the  mast  is  current  practice.  The  industry  is  now  looking  for  zero  emission   55 solutions.       4.3.9  Step  9  –  Disconnection   Upon  confirmation  of  transferred  amount  and  quality,  the  vessel  may  commence  disconnection  of   56 the  transfer  hose,  unmooring  and  departure.       Bunkering  time  will  vary  depending  on  bunkering  scenario,  transfer  rates,  system  and  equipment   57 design,  capacities,  and  the  use  of  vapor  return.  For  an  example  of  time  spent  see  Appendix  B.       16  
  24. 24. 4.4  Equipment   This  section  will  cover  some  of  the  essential  equipment  used  in  the  transferring  process.  Information   from  this  part  is  obtained  from  the  following  sources:  M.  Esdaile  and  D.  Melton,  Shell  Shipping,  LNG   Bunkering  Installation  Guidelines  SST02167,  2012  and  LNG  ship  to  ship  bunkering  procedure,  Swedish   Marine  Technology  Forum  and  DNV  Class  rules.     4.4.1  Tanks   58 Figure  15:  IMO  Type-­‐C  Tank,  CRYO  AB     4.4.1.1  Storage  Tank  –  Discharging  Unit   All  tank  types  -­‐  A,  B,  C  and  membrane  tanks  are  approved  for  LNG  cargo.  There  are  major  differences   in  usage  and  regulations  between  tanks  A  and  B  vs.  C.  If  tanks  A  and  B  are  to  be  used  it  is  seen  as  an   exception  and  several  risk  analysis  would  have  to  be  completed  for  each  individual  case,  to  document   its  safety.  The  tanks  are  categorized  correspondingly:     • Atmospheric  tanks:  Typically  atmospheric  tanks  would  be  IMO  type  A  and  B  tanks  or   membrane  tanks  and  have  a  design  pressure  below  0.7  barg.  The  atmospheric  tanks  cannot   be  pressurized  and  it  is  therefore  necessary  with  additional  equipment  for  pressure  control   and  deep-­‐well  pumps  to  ensure  sufficient  LNG  flow  to  the  engines.  In  order  to  operate  and   empty  the  tank  in  case  of  pump  breakdown,  redundancy  of  the  deep-­‐well  pumps  is   necessary.  The  main  advantage  with  an  atmospheric  tanks  is  its’  high  volume  utilization,  due   59 to  the  prismatic  shape.     • Pressure  tanks:  Tanks  with  pressure  above  0.7  barg  are  normally  type  C  tanks.  These  tanks   are  made  after  recognized  pressure  vessel  standards  given  in  the  IGC  Code.  There  are  several   designs  available;  cylindrical  tanks  with  or  without  vacuum  insulation,  or  bi-­‐lobe  tanks.  All   60 LNG  fuelled  ships  today  have  vacuum  insulated  IMO  type  C  tanks.   4.4.1.2  Fuel  Tank  –  Receiving  Ship   For  the  LNG  fuel  tank,  several  containment  systems  are  feasible,  with  many  new  tank  designs  under   development.  These  tanks  are  made  after  recognized  pressure  vessel  standards  given  in  the  IGC  Code.   The  tanks  are  cylindrical,  pressurized,  double  skinned  tank  systems  including  a  venting  system  for   discharging  excess  vapor.  These  features  are  crucial  in  vapor  management  and  maintaining  low   61 temperatures.       Type  C  tanks  have  a  maximum  operating  pressure  of  about  10  barg  and  are  approved  by  several  class   3 62 societies  as  fuel  tanks.  The  size  of  the  tank  will  vary  but  the  size  range  today  is  40-­‐250m .  The  tanks   are  equipped  with  both  bottom  filling  and  top  spray  features.  Through  spraying  sub  cooled  LNG  into   the  vapor  space  (gas  pillow)  of  the  tank  the  cold  liquid  will  condense  the  vapor  and  reduce  the  tank’s   pressure.  This  process  eliminates  the  need  for  a  vent  return  in  the  tank.  This  function  of  the  tank   63 could  create  a  100%  fill  situation.  To  comply  with  the  issue  of  overfilling,  the  tank  has  a  high-­‐level   switch,  which  will  activate  an  alarm.  This  will  automatically  shut  down  the  transfer  system  as  it  is   directly  linked  to  the  vessel’s  ESD  system.  As  previously  stated,  tanks  for  liquid  gas  should  not  be  filled   to  more  than  98%  full  at  the  reference  temperature,  where  the  reference  temperature  is  as  defined   in  the  IGC  Code,  paragraph  15.1.4.  Means  of  measuring  the  liquid  level,  both  volume  and  height,     17  
  25. 25. within  the  tank  are  to  be  provided  and  installed  in  such  a  way  as  to  be  compliant.  The  preferred   means  of  level  measurement  is  a  radar  type  tank  measurement  system,  or  similar  technology,  which   64 is  also  able  to  measure  corresponding  pressures  and  temperatures  within  the  tank.     The  benefits  of  using  Type-­‐C  tanks  are  standard  tanks  with  long  experience,  high  bunkering  rates,   easy  installation,  and  the  ability  the  handle  pressure  build-­‐up  in  cases  of  zero  consumption.  The   65 disadvantages  are  space  requirements  due  to  its  cylindrical  shape.       4.4.2  Valves   The  valves  used  are  manifold  trip  valves  that  can  handle  both  liquid  and  vapor  transfers,  and  need  to   comply  with  regulations  set  in  EN1474.    A  manually  operated  stop  valve  and  a  remote  operated  shut   down  valve  in-­‐series,  or  a  combined  valve,  should  be  fitted  in  every  bunkering  line  on  both  units   66 (discharging  and  receiving).  The  valves  should  be  controlled  from  the  control  room  of  both  units.     4.4.3  Hose   The  flexible  cryogenic  hose(s)  with  a  single  wall  construction  are  used.  Insulation  should  be  applied  to   the  hose  for  safety  reasons  but  should  not  limit  the  flexibility  of  the  hose.  The  hoses  are  connected   67 via  electrical  insulated  flanges  made  of  steel,  an  emergency  quick  release  connector  (ERC).   68 Maximum  velocities:  vapor  30m/s  and  liquid  7-­‐10m/s.  Minimum  requirements  for  hoses  are  defined   by  the  international  standards:  EN  1472-­‐2  and  IGC  chapter  5.7/IMO  document  MSC.285(86).     Approved  bunker  hoses:  EN  12434,  BS  4089,  EN  1474  part  1  LNG  Transfer  arms  (being  revised  as  an   ISO),  EN  1474  part  2  LNG  Hoses.   4.4.4  Loading  arms   Loading  arms  will  be  subjected  to  the  requirements  of  the  new  ISO  LNG  bunkering  standard.  They   shall  be  designed  in  accordance  with  ISO  /  DIS  28460  and  EN  1474-­‐1,  Section  4,  Design  of  the  arms.   Weight,  size  and  handling  of  the  equipment  classified  as  cryogenic  will  affect  the  safety  assessment  of   the  given  operation.     The  equipment  used  during  TTS  today  does  not  include  loading  arms.  Hose  dimension  will  for  such   operations  be  around  4  inches.    For  STS  operations  the  dimensions  would  be  considerably  higher,  10   inches  or  more.  In  addition  to  that  you  have  torque  by  relative  movement  of  the  ship  in  relation  to   each  other,  making  the  need  for  loading  arms  necessary  to  ensure  that  the  hose  does  not  come  into   69 contact  with  water  or  the  steel  deck.  PTS  will  also  use  hoses  larger  than  TTS.  Additionally  the   installation  is  fixed  which  makes  the  option  to  use  loading  arms  even  more  favorable  as  it  secures   equipment  and  strengthens  safety  elements.     4.4.5  Pipes   Main  piping  systems  in  both  units  are:  liquid  bunker  line,  gas  return  line  and  nitrogen  supply  system.   The  pipelines  are  equipped  with  several  flow  meters  to  measure:  volume  delivered,  pressure  and   temperature  for  monitoring  of  the  operation.  Pipes  containing  LNG  or  associated  vapor  shall  be   double  walled  pipe  configurations  in  stainless  steel  with  perlite  filling  under  a  permanent  vacuum.     Pipe  work  should  be  fully  compliant  with  IGC  Code,  Section  6.2.     4.4.6  Pump   The  pump  is  designed  for  handling  cryogenic  material.  It  is  theoretically  possible  to  transfer  between   tanks  in  the  presence  of  a  delta  pressure  of  2  barg  or  more.    Seeing  as  the  pressure  difference  could   be  hard  to  control  and  maintain,  it  may  be  difficult  to  transmit  without  a  pump.  A  frequency   controlled  drive  for  the  pump,  which  will  allow  pump  speed  to  be  regulated  and  the  transmission  rate   70 accordingly  with  respect  to  pressure  and  temperature  is  recommended.  The  time  it  takes  to  refuel  is     18  
  26. 26. critical  for  the  receiving  ship.  In  other  words,  if  you  want  to  optimize  the  transmission  rate  to   optimize  the  time  of  bunkering  a  variable  speed  pump  will  make  it  easier  to  achieve.   4.4.7  Emergency  Shutdown  Systems  (ESD)   “The  primary  function  of  the  ESD  system  is  to  stop  liquid  and  vapor  transfer  in  the  event  of  an  unsafe   71 condition  and  bring  the  LNG  transfer  system  to  a  safe,  static  condition.”  LNG  vessels  commonly  refer   to  the  emergency  shutdown  system  (ESD)  as  ESD1  and  the  emergency  release  system  (ERS)  as  ESD2.     4.4.8  Emergency  Release  Systems  (ERS)     To  comply  with  the  necessary  release  requirements,  an  ERS  is  usually  substituted  by  a  break  away   coupling  known  as  an  emergency  release  coupler  (ERC).     4.4.9  Emergency  Release  Couplers  (ERC)   The  ERC  unit  is  to  be  fitted  at  the  receiving  units  manifold  between  the  flexible  hose  and  the  flange   connection  of  the  receiver.  The  ERC  is  to  incorporate  integral  automatic  valves  that  will  close  when   separated,  either  by  nature  of  its  design  or  by  remote  motorized  operation.  Its  function  is  to  prevent   release  of  liquid  or  vapor  to  the  surroundings  through  rapid  closure.  Under  excessive  tension  it  serves   as  a  weak  link  providing  automated  release  to  avoid  the  hose  from  breaking.  It  allows  for  quick   connection  and  disconnection.  The  system  design  must  take  into  account  possible  ice  build-­‐up  and  its   72 effects  on  operation.  This  would  generally  be  a  requirement  for  all  types  of  equipment  in  contact   with  cryogenic  material.     Figure  16:  Dry  Break  Coupling  (Mann  Teknik  AB)   4.4.10  Control  and  Monitoring  Systems   Control  and  Monitoring  Systems  need  to  comply  with  the  IMO  document  MSC  285(86).  All   installations  need  to  be  equipped  with  control  monitoring  and  safety  systems.  The  most  essential   monitoring  system  is  gas  detection.  The  areas  that  are  critical  for  supervision  are  areas  where   unintended  release  of  gas  can  occur  such  as  manifold  areas,  double  walled  pipes  and  enclosed  areas   73 containing  pipe  work  associated  with  the  bunkering  operation.       The  control  and  monitoring  system  should  be  directly  linked  to  the  ESD.  The  individual  shutdown   initiators  will  vary  for  each  installation.  Minimum  control  and  monitoring  requirements,  on  both   distributing  and  receiving  units,  are:   1. Position  (open/closed)  and  high-­‐pressure  detector  in  all  bunker  manifold  valves.   2. Operation  of  any  manual  emergency  stop  push  button,   3. ‘Out  of  range’  sensing  on  the  fixed  loading  arm,   4. Gas  detection  (above  40%  LEL),   5. Fire  detection,   6. High-­‐pressure  and  high-­‐level  detectors  in  receiving  LNG  tank,   7. High/low-­‐pressure  and  high-­‐level  detectors  in  distributing  LNG  storage  tank.     19  

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