The inerting of cargo tanks is carried out once the LNG vapor inside the tanks has been warmed up. The process involves replacing the LNG vapor with inert gas, preparing the vessel for the upcoming dry dock. The primary goal is to remove the flammable LNG vapor from the tanks and make them safe for entry and inspection.
The exercise uses the inert gas generator onboard both vessels. The inert gas, being heavier, is introduced into the tanks from the bottom, while the lighter LNG vapor is extracted from the top. This process is known as the displacement of LNG vapor with inert gas.
Exercise Overview:
- Initial Setup:
- The initial steps involve setting up the equipment, installing the required school pieces, and opening the necessary valves for the correct lineup.
- The ballast pump is used, and the inert gas generator is prepared for operation.
- Assessment Process:
- The assessment begins when the inert gas generator system is activated, and gas is delivered to the tanks.
- The user must carefully monitor the tank atmosphere and check the samples from the sampling points.
- The objective is to reduce the methane content inside the tanks to less than 2% by volume.
- Completion Criteria:
- The exercise is complete when all cargo tanks are inerted, and the gas meters indicate the presence of inert gas, with the methane content reduced to the required level.
- Evaluation:
- The final evaluation is based on the user’s response to various remarks, cautions, and alarms during the exercise, as well as their ability to navigate the procedure efficiently and safely.
