LNG LOADING DISCHARGING SEQUENCE OF OPERATION

At the end of this video, you will be able to learn or familiarise on the sequence of events of an LNG cargo operation.
From picking up pilot - Berthing Operation - up to Un-berthing Operation.
What are the sequence of events in between?
Lets discuss one by one, please don't skip the video and keep watching.
First is Ship’s mooring
This operation is where the ship will pick-up Pilot at the Pilot station and manoeuvre the ship to the berth or terminal and secure her with the mooring ropes or lines.
The mooring lines configuration should be in a manner that it will prevent the ship from moving away from the center of the terminal’s manifold hose or manifold arms.
Ship’s Manifold and the Terminal loading or discharging arms should be in line.
Next is Fitting Shore Gangway
When the vessel is securely moored, the shore gangway is rigged and placed on the ship’s side enabling access between terminal and ship.
Next is ESD Cable connection
It’s either electric or optical or both. Terminal will provide a cable connection to the ship. This connection will enable telephone communication between the terminal and the ship.
This cable is also the link between Terminal and Ship’s ESD system.
ESD stands for EMERGENCY SHUT DOWN. This is a button to press if something went wrong during the operation and this ESD will stop the operation in order to prevent further damage to both ship’s Equipment and Terminal’s equipment.
Next is Communication Check and Mooring Tension Monitor
This is an electronic system that monitor the tension of the mooring ropes. This is usually a laptop provided by the terminal. With this we will be able to know which mooring line needs adjustment.
Communication check is to simply check and test the telephone communication between terminal and ship. The ESD cable connection is also use for telephone communication.
Next is Safety Inspection
Terminal safety officer or Terminal’s representative and a ship’s crew will walk around the ship to check if all safety equipment or features are in place for example the Firefighting equipment. If there is any safety issue found, it should be rectify before starting the loading or discharging operation.
Next we have Pre-discharge or Pre-loading meeting
All relevant items in the Ship Shore Safety Checklist, as provided by the terminal, are to be completed by the Terminal Representative and the Chief Officer. If no safety checklist is provided by the terminal, or it is not to the same standard as that contained within ISGOTT,
The ISGOTT (5th Edition) Ship Shore Safety Checklist, including Part C Bulk Liquid Chemicals, must be used. Agreements specific to the ship and the cargo are to be made. This meeting is where we discuss all relevant steps and procedure on how to proceed or how to carry out the entire operation.
Chief officer and a terminal's representative will discuss and agreed on when and how things are to be done. Example of the items are what will be the agreed maximum and minimum loading or discharging rate. All limitations, when to stop and start, and all other questions will be discuss in this meeting.
Next is Arm Connection
Shore manifold arm will be connected to the ship’s manifold. Marine Loading Arm is used to load or unload the ship or vessel carrying the Petroleum products, chemicals, etc. Marine loading arms are made up of several sections of pipe (quick-connect fittings), connected by swivel joints.
The section on the shore side of the ‘apex’ of the loading arm is known as the inboard arm and the section on the tanker side of the ‘apex’ is known as the outboard section.
Next is N2 Purge and leak test of Arms
This will purge the system of contaminants, to make the atmosphere inside the manifold arms non explosive and to check for leaks. This is also to determine the maximum tested pressure in the manifold. The approved tested pressure should not be exceeded during the entire cargo operation.
Next we have Opening CTM -Custody transfer measurement (CTM) system for liquefied gas carrier
The CTM is a system which allows the quantity of cargo on board at any time to be accurately calculated and therefore provide a means by which the amount of cargo that is transferred either internally or between the ships and shore to be accurately quantified.
Such a system can be used on LNG carriers because the cargo is always same whereas on other type of vessels such as oil or LPG, large differences can occur between the cargoes carried on each voyage.
The quantity of cargo during CTM opening will be the official quantity to be use when calculating the total amount discharge or total amount loaded. This will also include the temperatures of the cargo being loaded or discharged.
Next step to be commented. too long for the description. hahaahaha
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[@wellanchored-deadslowahead9553]

Next is ESD Test (Warm) -
The Emergency Shut Down System is a quick closing system, which may be activated automatically or manually. It will close all deck valves and shut down all cargo machinery.
ESD test Warm - this refers to the condition on which the cargo lines or cargo manifold are still warm, meaning there were no passing liquid. During the testing, the time it takes to close the Manifold valves should not exceed 30 seconds. It should close within 30 seconds.
If it exceeds more than 30 seconds, then the valve closing should be adjusted prior commencing cargo operation.
Next is Arm cool down
Cargo systems are designed to withstand a certain service temperature; if this is below ambient temperature the system has to be cooled down to the temperature of the cargo before cargo transfer.
For LNG the stress and thermal shock caused by an over-rapid cooldown of the system could cause brittle fracture on Cargo lines and Cargo tanks. Cooldown operations should be carried out carefully in accordance with instructions.
Next is ESD Valve operation test (Cold Condition)
This is also known as ESD cold test. After cool down operation, cargo lines and valves are already exposed to low temperature; the operation of the valve might be affected due to low temperature in the system.
In this procedure, we are trying to check if the closing duration of the manifold valves are still working and within acceptable limits.
Next is Start of LNG operation
When cargo lines and cargo tanks are already cold, it is now ready to received or discharged bulk quantity of LNG. This is the official start of the cargo operation. When starting the operation, it should be done slowly and slowly increasing the loading or discharging rate until reaching the maximum agreed rate.

Next is Ramp down
Usually 1 hour before completion of cargo operation the ramp down stage begin. This is where the loading or discharging rate is reduce or decrease to prevent overflowing cargo tanks.
Next is Completion of Cargo Operation
When the agreed quantity to discharged or loaded is achieved then cargo operation will cease.
Next we have Arms and Line draining
On most LNG ships, the manifold is drained via the spray header to a cargo tank. Check that the spray valves are open on one tank. This is to get rid of all the liquid LNG that are still in the shore arm and manifold line and send it to the cargo tanks.
Next is Nitrogen Purging of Arms
LNG line are purged by passing an inert gas through their interiors to eliminate substances that increase the chances of combustion. Nitrogen gas is an ideal candidate for LNG tank purging due to its inert, non-combustible properties.
The manifold and shore arms should be purge before disconnection in order to have a non-combustible atmosphere during disconnection of shore arms.
Next is Closing CTM - Custody transfer measurement (CTM) system for liquefied gas carrier
The CTM is a system which allows the quantity of cargo on board at any time to be accurately calculated and therefore provide a means by which the amount of cargo that is transferred either internally or between the ships and shore to be accurately quantified.
Such a system can be used on LNG carriers because the cargo is always same whereas on other type of vessels such as oil or LPG, large differences can occur between the cargoes carried on each voyage.
The quantity of cargo during CTM closing will be the official quantity to be use when calculating the total amount discharge or total amount loaded.
This will also include the temperatures of the cargo being loaded or discharged. Ergo Quantity CTM open plus or minus Quantity CTM close equals the amount of cargo transferred.
Next is Arms Disconnection
When shore arm and manifold are purged, shore arms can now be simply disconnected from the vessels manifold.
Next is Post Discharged meeting
This meeting is held after cargo operation is completed. Discussion such as discrepancies or any suggestion will be brought up and sorted out. Doing all paper works, stamps and signatures.

Next is Disconnection of ESD cable
When all papers and operations are completed, ESD cable or communication cables between terminal and the vessel is disconnected. Vessel is preparing to sail out.
Next is Disconnection of gangway
When all visitors disembarked, prior vessel leaving port, shore gangway or ship’s gangway will be disconnected.
And Finally we have Ship Unmooring and Departure
With the guide of a Pilot, vessel will leave the terminal. Casting off mooring lines and heading out to sea.

[@Captrobinroy009]

👍👍

[@JohnJohn-yu1pd]

Excellent job! Thank you very much!

[@iwanfaesal5890]

Incredible video. Thanks a lot🙏

[@wellanchored-deadslowahead9553]

Thanks for the comment brother.. highly appreciated. Hope it help.

[@bangcarera]

Thank you sir!👏👏

[@wellanchored-deadslowahead9553]

Thanks bossing..

[@williamparreno9363]

My question sir is how to perform cooldown of LNG piping or valves from ambient temperature?

[@wellanchored-deadslowahead9553]

Cooldown operation is introducing liquid small amount of Liquid LNG to liquid lines slowly to avoid thermal stresses on pipe lines. Usually it take 1 hour to 1.5 hours depends on your vessel's manual and ship's conditions. usually you need to achieve -130 degree C to complete cooldown or as per agreed in the safety meeting. this is done by using spray pumps if discharging, and using shore pumps at minimum rate if loading operation. Cargo tanks and liquid pipe lines should have average temperature of -130 degree Celsius.

[@williamparreno9363]

Thank you very much sir for your info and response to my question. Thank you again

[@karyacarriaga]

👍👍👍

[@asquare69]

Hello Sir, Is there a way to calculate the stagger of tanks?

[@wellanchored-deadslowahead9553]

Yes sir. There is.

[@asquare69]

@@wellanchored-deadslowahead9553 is there some article I can read it. To learn about calculation.

[@MrEriclou]

Hello Sir i am wondering during discharging with LNG cargo. Are there any introduction of Inert Gas During discharging operation to fill the empty Space Volume or it is just LNG vapour Fills it automatically by Boil-Off of LNG Cargo Inside of the Tank itself?

[@wellanchored-deadslowahead9553]

No inert gas. Vapor return is use to maintAin positive preswure in tank. If no vapor return we can use vaporiser onboard

[@MrEriclou]

@@wellanchored-deadslowahead9553 thank you to the response sir. I am First time to board on a Gas tanker and my previous experience is oil tanker sir.

[@karyacarriaga]

👍👍👍