The warming up of cargo tanks is performed in preparation for an upcoming dry dock. This operation is carried out after the tanks have been emptied using the spray pumps. The primary objective is to make the tanks free of liquid and to warm the LNG vapor inside the tanks.

The process is conducted using the high-duty compressor (HD compressor) onboard. The vapor is pushed from the HD compressor to the LNG heater, where the temperature increases. The warmed vapor is then reintroduced into the cargo tank from the bottom, ensuring that any remaining liquid also evaporates.

Exercise Overview:

1. Initial Setup:

• The exercise begins by preparing the necessary equipment, including the HD compressor and the warm-up heater.
• The required pool pieces need to be inserted correctly, and the valves must be opened to establish the proper lineup.
• The generators must also be prepared accordingly.

2. Assessment Process:

• The assessment starts when the HD compressor is activated and the temperature rises in the warm-up heater. The user must successfully achieve 40°C at the warm-up heater outlet temperature.
• During the Assessment, the user must also maintain the cargo tank pressure within the prescribed limits, as outlined in the milestones.

3. Completion Criteria:

• The exercise is considered complete when the user successfully achieves the required temperature and maintains the correct tank pressure.

4. Evaluation:

• The final evaluation is based on how the user responds to various remarks, Cautions, and alarms presented during the course of the exercise, as well as their ability to navigate the procedure efficiently.

Participants will be able to effectively demonstrate the process of warming up cargo tanks on
LNG ships to achieve a liquid-free state, understanding the necessary safety protocols,
operational procedures, and the importance of maintaining safe conditions during this
process.

Key Components:

1. Understanding the Warming Process:

• Explain the purpose of warming up cargo tanks to remove residual LNG or
  other liquids, ensuring the tanks are ready for gas operations.
• Identify the significance of achieving a liquid-free state for safety and
  operational efficiency.

2. Operational Procedures:

•  Detail the step-by-step process for warming up cargo tanks, including:
  • Pre-warming checks and preparation of the cargo tanks and
    associated systems.
  • Controlled introduction of warm LNG vapour to raise the temperature
    of the tanks.
  • Monitoring temperature and pressure throughout the warming
    process.
• Explain how to manage flow rates and ensure proper ventilation to facilitate the removal of liquid.

3. Monitoring and Verification:

• Demonstrate the use of temperature gauges and pressure monitoring
  systems to ensure effective warming.
• Describe methods to verify that the cargo tanks are liquid-free.

4. Practical Demonstration:

• Simulate the warming 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 warming cargo tanks to achieve a liquid-free
  state.
• Accurate execution of the warming procedure and effective monitoring.

By achieving this objective, participants will gain the knowledge and skills necessary for safely and efficiently

warming up cargo tanks on LNG ships, ensuring they are liquid-free and ready for subsequent operations.

Warming up of Cargo tanks-Step 2 Intro and Line up

Warming up of Cargo tanks-Step 2 Operations and Assessment

Milestones

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

1. Set Vapour Line Valves.
2. Set the valve connecting the Emergency Vent Line and No.1 Vent Mast.
3. Set the Warm Up heater outlet valves on the Vapor Line.
4. Set The Cargo Liquid Line to No.1 Vent Mast Valve.
5. Connect the Elbow Spool piece connecting the Liquid line to the No.1 Vent Mast.

• Assessment Phase – Operational flow and Assessment:

6. Achieve 20°C on Warm-Up Heater Outlet Temperature.
7. Monitor Cargo Tank Temperature.
8. Stop HD Compressor when Warming Up is completed.

Actions During the Exercise:

Deviation From Exercise:

• After starting or resuming the operation, the user should not open any non-required valves or close any required ones. If this happens, a caution message will be shown, instructing the user to undo the previous action. Failure to correct it will result in the exercise being terminated.

Not Maintaining HD Compressor Flow:

• The user must ensure that the HD Compressor flow remains between 11,500 m³/h and 12,500 m³/h.
• Failure to maintain the flow will trigger various alarms, with a high-priority alarm generated if the issue persists.
• 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:

1. Set Vapour Line Valves:

2. Set the valve connecting Emergency Vent Line and No.1 Vent Mast:

3. Set the Warm Up heater outlet valves on the Vapor Line:

4. Set The Cargo Liquid Line to No.1 Vent Mast Valve:

5. Connect the Elbow Spool piece connecting the Liquid line to the No.1 Vent Mast:
   • Connect the spool below the Valve CL700. If the spool piece is connected properly, the blinking will stop.

• Assessment Phase – Operational flow and Assessment:

6. Achieve 20°C on Warm-Up Heater Outlet Temperature:
   • Adjust the valve CG 922 to reduce the WU heater Vapour outlet temperature to 20°C.
7. Monitor Cargo Tank Temperature:
   • Once the warming up of the tanks is resumed, the temperature of all cargo tanks will begin to rise.
   • During warming up, the cargo tanks’ temperature will increase from -90°C to +20°C, indicating warming up of the cold vapour.
8.  Stop HD Compressor when Warming Up is completed:
   • Once the temperature reaches 20°C, the user will receive confirmation of completion, the HD Compressor must be stopped.
   • Once it is stopped, the exercise is completed.

Proper line up for warming up step 2: