Session 11: Pipelines on oil tanker Flashcards
What are the different types of pipeline systems on a oil tanker?
-Ring main system
-Free flow system
-Direct line system
What are the advantages of a ring main system?
-In this system any tank can be discharged by any pump. Thus different grade of the cargo can be loaded
-This system is used by product carrier
What are disadvantages of a ring main system?
-it is expensive to build due to the extra length of the piping required
-Extra bend is required. Therefore decreasing rate
-Risk of leakage from radius of bend exists
What are the advantages of a free flow system?
-Less pipeline
-less bend
-less friction
-more pressure cause very high discharge rate
This system is used by crude carrier
What are the disadvantages of free flow system?
-is not flexible
-risk of contamination exists if more than one grade discharge
-risk of overflow exists if level of all tank does not carefully monitored
What are the advantages of a direct line system?
-quick loading and discharging
-short pipe line
-less bend
-less loss of pressure
-direct line to provide better suction
-time of washing the line is short
-system is cheaper than other system
-leak is minimized
-easy to operate so less training is required
This system is used by crude carrier
What is the disadvantage of a direct line system?
inflexible to load multiple grades
What am I referring to here:” process of completely removing or draining the residual liquid or sludge from the tank, pipelines, or cargo holds that standard pumping equipment cannot fully empty”
stripping
What is the working principle or a centrifugal pump, and what are its limitations?
Working principle: centrifugal force
Limitations:
-It requires high suction head therefore when the cargo nearly finishes the chances are it will lose suction
-Air bubbles may trap into pump casing which will increase the temperature of the pump as damage the impellers by creating cavitation
Use:
-to discharge or strip the tanks
-very low discharge rate
-can run dry without any problem
-to discharge high viscous cargos
What am I?
Positive displacement pump
-Mostly used by product carriers carrying animal fats, oils etc..
-cargo itself works as a lubricant of this pump
What am I?
Screw pump
what is venturi effect when talking about eductors?
when a fluid (like water or air) goes through a narrow space, it moves faster. And when it moves faster in that narrow space, the pressure in that area drops or becomes lower.
So, just like when you put your thumb over the hose, if you make a part of a tube or pipe narrower, the fluid going through that narrow part will speed up, and the pressure will go down. That’s the Venturi effect! It’s like magic, but it’s just science!
Explain the use, working principles and limitations of centrifugal pump?
- Use: Commonly used to move liquids through a piping system.
- Working Principle: Spins liquid with a rotating impeller to build up velocity, then converts that velocity to flow.
- Limitations: Not good for very high-viscosity (thick) liquids or for very high pressures.
Explain the use, working principles and limitations of positive displacement pump.
- Use: Accurate flow rate, good for thick liquids.
- Working Principle: Uses mechanisms (like gears or pistons) to push or displace a set amount of liquid with each cycle.
- Limitations: Needs relief valves to avoid overpressure. Can get damaged if run dry.
Explain the use, working principles and limitations of screw pump.
- Use: Handles both liquids and gases, including thicker liquids.
- Working Principle: Uses screws to push the liquid from one end of the pump to the other.
- Limitations: Wear and tear between the screw and casing can be an issue.
