This exercise takes place towards the completion of the discharging process. The goal is to ensure that a small amount of liquid (the “heel”) remains in one of the cargo tanks at the end of the operation. The spray pumps are activated in recirculation mode, and the user must stabilize the cargo pumps when needed, as the pumps may become unstable due to the lower liquid levels in the cargo tank.

Exercise Overview:

1. Initial Setup:

• The exercise begins with the user stabilizing the pumps as the liquid levels decrease.
• The user must reduce the tank levels in a controlled manner, bringing them to the desired levels specified in the milestones.

2. Assessment Process:

• The user is required to take action based on remarks, cautions, and alarms received throughout the exercise.
• The discharging process continues until the desired “heel” volume remains in the cargo tanks. The user has to successfully negotiate the stabilization of the Cargo pumps.

3. Completion Criteria:

• The exercise is complete once the required amount of liquid remains in the tank as heel, and the discharging process has been successfully carried out according to the specified steps.
• The user must also complete the final procedures, including line draining, to ensure the correct heel quantity is achieved.

4. Evaluation:

• The user is evaluated based on their ability to respond to various remarks, alarms, and cautions during the exercise, and how effectively they manage the ramp-down and heel-completion process.

When planning an LNG (Liquefied Natural Gas) discharging operation some potential learning objectives for a training program focused on the discharge of LNG (liquefied natural gas):

• Understanding LNG Properties: Explain the physical and chemical properties of LNG, including its boiling point, density, and flammability.
• Safety Procedures: Identify and apply safety protocols and emergency response procedures specific to LNG operations.
• Discharge Process: Describe the step-by-step process of discharging LNG from a tanker to a storage facility.
• Equipment Familiarization: Demonstrate knowledge of the equipment used during the LNG discharge process, including pumps, hoses, and vapor return systems.
• Regulatory Compliance: Understand the relevant regulations and industry standards governing LNG discharge operations.
• Environmental Considerations: Assess the environmental impact of LNG discharge and identify measures to minimize potential risks.
• Monitoring and Control: Explain the monitoring systems in place to ensure safe and efficient LNG discharge, including temperature and pressure controls.
• Incident Management: Recognize potential hazards during the LNG discharge process and develop strategies for risk mitigation and incident management.
• Communication Skills: Demonstrate effective communication and coordination with team members and other stakeholders during the discharge operation.
• Practical Application: Engage in hands-on training to apply theoretical knowledge in real-world LNG discharge scenarios.

Discharging-Ramp down and completion-Operation and Assessment

Exercise Milestones

• Assessment Phase – Operational flow and Assessment:

1. Run Spray Pump in Recirculation Mode
2. Stabilize Cargo Pump When Needed
3. Achieve All Tank Levels
   • 3A: Tank 1 level (100 ± 25m³).
   • 3B: Tank 2 level (200 ± 50m³).
   • 3C: Tank 3 level (200 ± 50m³).
4. Complete Unloading Process
5. Close Double Shut Valves on Liquid Lines
6. Set ESD to Blocking Mode
7. Complete Line Draining (60m³)
8. Achieve Total Heel Quantity (1500 ± 100m³)

Actions During Exercise

• Valve Mismanagement:
  • Do not open any non-required valves or close any required ones after starting or resuming discharging.
  • A caution message will prompt you to undo any incorrect action.
  • Failure to correct the action will terminate the exercise.
• High Crossover Pressure:
  • If crossover pressure reaches 4 bar, reduce the pump flow rate.
  • If pressure reaches 5 bar, reduce it within 1 minute, or the exercise will terminate.
• Pump Trips:
  • If more than two pumps trip during the exercise due to low liquid levels or safety concerns, the exercise will terminate.

Alarms & Remarks

Step By Step Procedure

• Assessment Phase – Operational flow and Assessment:

1. Run Spray Pump in Recirculation Mode

• A remark will appear when a tank level drops to 1.5 meters, instructing you to start the spray pump in recirculation mode.
• If the tank level drops to 1 meter, the exercise will terminate.

Steps to Start the Spray Pump:

1. Open the discharge valve between 25% to 30%.
2. Open the return/filling valve to 95% or more.
3. Open the master valve to 5% or less.
4. Ensure at least two generators are running.
5. Start the spray pump by selecting the specific pump icon.

Tank-Specific Valve Details:

2. Stabilize Cargo Pump

• When a tank level drops to 800mm and both pumps are running:
  • A caution will appear to throttle discharge valves to achieve a 47A output for each pump.
• When a tank level drops to 350mm and one pump is running:
  • Adjust the discharge valve to achieve a 43A output.

3. Pump Trips

• Two pumps running:
  • If the level drops to 660mm, stop one pump.
  • Failure to stop one pump will cause an automatic trip at 600mm.
• Single pump running:
  • If the level drops to 195mm, the pump will automatically trip unless level override is enabled.
  • If level override is enabled, the trip occurs at 185mm.

4. Achieve All Tank Levels

• Tank 1: 100 ± 25m³.
• Tank 2: 200 ± 50m³.
• Tank 3: 200 ± 50m³.

5. Close Double Shut Valves

• When all pumps are stopped, close the double shut valves within 1 minute.
• Failure to do so will terminate the exercise.

6. Set ESD to Blocking Mode

• Navigate to the ESD Systems page under the ESD tab.
• Set the system to blocking mode.

7. Line Draining

• After setting the ESD system to blocking mode:
  • Open the return valve of Cargo Tank 4.
  • Drain 60m³ of cargo into Cargo Tank 4.

8. Achieve Total Heel Quantity

• After line draining, ensure the total tank volume is within 1500 ± 100m³.