What are types of tanker cargo pipelines?

There are three basic types of pipeline systems:

  1. Direct system
  2. Ring main system
  3. Free flow system.

Direct line system

Advantage:
  • Quick loading & discharging.
  • Short pipe line.
  • Less bend.
  • Less loss of pressure due to pipe line friction.
  • Direct line to provide better suction.
  • Time of washing the line is short.
  • System is cheaper than the other system.
  • Leak is minimized.
  • Easy to operate so less training is required.
  • It is easy to separate each cargo.
Disadvantage:
  • In case of leaking the control of leakage is difficult.
  • This system is very inflexible.

39

Fig : Direct line system

Ring main system

Advantage:
  • In this system any tank can be discharged by any pump. Thus different grade of the cargo can be loaded.
Disadvantage:
  • It is expensive to build due to the extra length of the piping required.
  • Extra bend is required. Thus decreasing in rate.
  • Risk of leakage from radius of bend exists.

38

Fig : Ring  main  system

Free flow system

Advantage:
  • Main pipe line is not used for discharge.
  • Less pipe line.
  • Less bend.
  • Less friction & more pressure cause very high discharge.
Disadvantage:
  • Is not flexible.
  • One grade is dischargeable if more risk of contamination exists.
  • Risk of overflow exists if level of all tank doses not carefully monitoring.

38

Fig: Free flow system

Points to Pounder for all types of Pipe lines
THE FREE FLOW SYSTEM
THE DIRECT LINE SYSTEM
THE RING MAIN SYSTEM
Used on large crude Used on VLCC Used on Product
Carriers   Carriers
Carry only one garde Carry two or three grade Carry several
Of cargo Of cargo Different products
Large gate valve built in Simple lines leading in the  
The bulkhead Tanks  
Stern trim cause the oil Due to straight length of Due to the number of
To flow to the Pipeline, there is better Bends, joints and valve
Aftermost tank Suction & less loss of It take longer time
  Pressure  
Suction main cargo pump Fewer valve & bends Due to the number of
Situated in aft Means less erosion & leak Bends, joints and valve
    Means more erosion &
    Leaks
  Less maintenance More maintenance
  Required Required
  Thorough washing of line is Thorough washing of
  Not possible unless the Line is possible without
  Washing are flushed into Flushing into the tank
  The tank & discharged  
  From there  
  Due to fewer valves leaks  
  Are difficult to control  
  Valve    segregation not Required two valve
  Provided Segregation
    Between products
  The initial cost of fitting The initial cost of
  Is less than ring main Fitting is higher
 

System

 

RAVI PRAKASH

About the author

Amit Sharma

Graduated from M.E.R.I. Mumbai (Mumbai University), After a brief sailing founded this website with the idea to bring the maritime education online which must be free and available for all at all times and to find basic solutions that are of extreme importance to a seafarer by our innovative ideas.

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