This exercise is carried out onboard an LNG carrier, where liquid LNG is provided by the shore and converted into vapor using onboard LNG vaporizer equipment. The LNG vapor is then introduced into the cargo tanks from the top, replacing the heavier inert gas present inside the tanks. The inert gas is extracted from the bottom of the tank and released into the atmosphere.

The exercise is divided into two main steps:

1. Step 1: Release of inert gas to the atmosphere.
2. Step 2: Once the LNG vapor is sufficiently present, it cannot be released into the atmosphere. Instead, it is sent to shore via the HD compressor onboard the LNG carrier.

Exercise Overview:

1. Prerequisites and Setup:

Setting up the correct configuration of emergency shutdown systems. Starting the manifold water curtain. Preparing gas measurement instruments for use. Preparing the LNG vaporizer. Opening the required valves and connecting the necessary hoses (or “spool pieces”).

2. Assessment Process:

The assessment begins when the actual flow of LNG starts from the shore. The user must ensure the following during the assessment:

• The vapor flow is maintained between 11,500 to 12,500 m³ per hour.
• The LNG vapor outlet temperature reaches 40°C.
• All gas sampling points are monitored to assess the current atmosphere status.

3. Part 1 Completion: The first part of the exercise is completed when the LNG vapor properties are visible on the gas detectors, confirming the proper replacement of Inert gas by LNG vapor inside the tank.
4. Part 2: HD Compressor Operation: The second part of the exercise involves preparing the HD compressor and generators for use. The user must ensure the correct lineup by opening the required valves and connecting the necessary hoses. Once the HD compressor is started, the warming-up process begins as part of the assessment.

• During this phase, the user must continuously monitor the tank pressure, ensuring it remains between 7 kPa and 18 kPa throughout the process.

5. Completion Criteria:

• The exercise is considered complete once the tank pressure is correctly maintained within the specified range.
• The user is assessed based on how well they respond to various remarks, questions, and alarms that arise during the exercise.

Learning Objectives for the Exercise

Participants will be able to effectively demonstrate the process of gassing up cargo tanks on LNG ships, understanding the safety protocols, operational procedures, and the significance of maintaining safe vapor conditions.

Key Components:

Understanding Gassing Up:

• Explain the purpose of gassing up cargo tanks to prepare them for loading LNG.
• Identify the importance of creating a safe vapor environment and managing temperature and pressure.

Operational Procedures:

Detail the step-by-step process for gassing up cargo tanks, including:

• Preparation and inspection of gassing equipment.
• Connection of vapor lines to the cargo tanks.
• Control of gas flow rates and monitoring pressure during the operation.

Monitoring and Verification:

• Demonstrate the use of pressure gauges and gas analyzers to monitor the gassing up process.
• Describe how to confirm that vapor conditions are within safe operational limits.

Practical Demonstration:

• Simulate the gassing-up process in a controlled environment or through hands-on training exercises.
• Role-play scenarios to address potential challenges or deviations from the procedure.

Assessment Criteria:

• Ability to articulate the significance of gassing up cargo tanks.
• Accurate execution of the gassing-up procedure and effective monitoring.

By achieving this objective, participants will acquire the knowledge and skills necessary for safely and efficiently gassing up cargo tanks on LNG ships, ensuring safe and effective operations.

Gassing up of Cargo tanks and Systems-Part 2 Intro and Line up

Gassing up of Cargo tanks and Systems-Part 2 HD Compressor preparation

Gassing up of Cargo tanks and Systems-Operations and Assessment

Milestones

• Learning and Training Phase – Pre-Requisites for the start of operation:

1. Connect Manifold Arm L3, V.
2. Open Required Valves for Line-Up and Connect Spool Pieces.
3. Prepare HD Compressor and Generators for Use.
4. Start the HD Compressor.

• Operational flow and Assessment:

5. Monitor Cargo Tank Pressure.

Actions taken during the exercise

Deviation from Exercise

• After starting or resuming the cooldown, the user must not open any non-required valves or close any required valves.
• If this occurs, a caution message will appear, instructing the user to undo the previous action.
• If the user fails to correct the mistake, the exercise will be terminated.

Not Maintaining the Inlet and Outlet Flow

• The user must ensure that the LNG vaporizer outlet flow and vapor to shore flow remain between 11,500 m³/h and 12,500 m³/h.
• If the flow falls outside this range, alarms will be triggered. If the issue persists, a high-priority alarm will be issued.
• If the user cannot restore the flow, the exercise will be terminated within one minute.

Alarms & Remarks

Step-by-Step Procedure

• Learning and Training Phase – Pre-Requisites for the start of operation:

Milestone 1 – Connect Manifold Arm L3, V

1. Locate the highlighted manifold arm positioned above the liquid manifold.
2. Click on the highlighted arm to initiate the connection process.
3. Once all required arms are successfully connected, the milestone will be marked as completed.

Milestone 2 – Open Required Valves for Line-Up and Connect Spool Pieces

• Open the following valves:
  • CG705
  • CG903
  • CG915
  • CG900
  • CL701
  • CG071
• And connect the spool piece above the valve CL701.

Milestone 3 – Prepare HD Compressor and Generators for Use

1. The HD Compressor requires at least two generators to be running.
2. To start the generators, navigate to the PMS page (accessible either through the side navigation or by clicking the “number of generators running” indicator on the HD Compressor page under High Duty Compressor 1 or 2).
3. Once on the PMS page, turn on one of the three generators that is not currently running. By default, one generator should already be running.
4. Once the required number of generators are running, go to each of the two HD screens and perform the following:
   • Start the Aux LO Pump.
   • Switch on the Heater for the Oil Reservoir.
5. Ensure the inlet and outlet valves on the HD compressors are opened.

Milestone 4 – Start the HD Compressor

• After preparing the HD Compressor, start the compressor to begin the warming-up process.

Once the above prerequisites are met, the “Resume Gassing Up” button will become available on the control panel. Click this button to continue the gassing up process.

• Operational flow and Assessment:

Milestone 5 – Monitor Cargo Tank Pressure

• Monitor the pressure inside the cargo tank to ensure it remains between 7 kPa and 18 kPa for a period of time.
• Once this pressure is maintained, the exercise will be considered complete.

Proper lineup for gassing up step 2: