DUAL FUEL ENGINES PART 5 - DOUBLE WALL PIPE VENTILATION SYSTEM

Summary

This video script offers an in-depth study of the double wall ventilation pipe system for fuel gas supply in dual fuel engines, particularly the MEGI engine. It explains the setup, including the gas valve train, double wall pipe structure, and the flow of fuel gas and fresh air. The script details the process from the deck to the engine room, the looping of gas to cylinders, and the role of ventilation fans and hydrocarbon sensors in maintaining safety and efficiency. The presenter encourages viewers to pause and take notes, emphasizing the importance of understanding the system for operational and safety purposes.

Takeaways

• 🚢 The video discusses a double wall ventilation pipe system, specifically for fuel gas supply in dual fuel engines, using a MEGI engine as an example.
• 🛠️ The double wall pipe system consists of an inner pipe for fuel gas and an outer pipe for fresh air circulation.
• 🔍 The fuel gas enters the double wall pipe from the gas valve train located in the Cargo Machinery Room (CMR).
• 🔄 The system includes a loop where the fuel gas is first introduced into the first cylinder and then circulated to other cylinders via U-pipes.
• ⛴ The return pipe is used for startup and purging, but the gas does not return to the cargo tank after engine use; it vents out through a silencer.
• 💨 Fresh air for the system comes from the starting air system, reduced from 30 bar to 1.5 bar, and is activated by a valve when the engine starts.
• 🌬️ Ventilation is maintained by two double wall pipe ventilation fans, which pull air through the system and vent it out with flame screens.
• 🔍 The system includes hydrocarbon (HC) sensors to monitor for leaks in the inner pipe, with alarms set at 30% and a trip at 40% HC levels.
• 🔧 The airflow and gas flow in the system are in opposite directions to ensure safety and proper ventilation.
• 📈 The video script serves as a base reference for understanding the setup and function of double wall pipes in dual fuel engine systems.
• 👨‍🏫 The presenter encourages viewers to pause the video for diagrams, take snapshots, and engage with the content for better understanding.

Q & A

What is the primary focus of the video script?

The primary focus of the video script is to explain the double wall ventilation pipe system, specifically for the fuel gas supply system in dual fuel engines, using a megi engine as an example.

What is the purpose of the double wall pipe system?

The double wall pipe system is designed to safely transport fuel gas from the cargo machinery room to the engine room while also providing a continuous flow of fresh air on the outer side of the pipe.

What is the function of the gas valve train in the system?

The gas valve train is where the fuel gas supply system connects, and it is the starting point from where the fuel gas enters the double wall pipe.

How does the fuel gas flow within the double wall pipe system?

The fuel gas flows from the gas valve train into the inner pipe of the double wall system, passes through a small coffin, and then enters the engine room. It loops from the first cylinder to the other cylinders via U-pipes.

What is the purpose of the return pipe in the system?

The return pipe is used during the start-up process to clear or blow off the lines and for ventilation purposes to purge the lines. It does not carry gas back to the cargo tank after the engine.

What is the role of the blue piping in the system?

The blue piping represents the fresh air supply that goes into the outer pipe of the double wall pipe system, ensuring continuous ventilation.

Where does the fresh air for the double wall pipe system originate from?

The fresh air comes from the starting air system, which is reduced from 30 bar to 1.5 bar by a reducing valve on deck.

How are the double wall pipe ventilation fans used in the system?

The double wall pipe ventilation fans are used to continuously ventilate the system by sucking air from one side and venting it out into the atmosphere with a flame screen.

What is the significance of the hydrocarbon sensors in the system?

The hydrocarbon sensors monitor the atmosphere around the double wall pipe system, helping to detect any leaks in the inner pipe. They trigger an alarm at 30% and a trip of the main engine at 40%.

What are the safety measures in place for the double wall pipe system?

Safety measures include flame arresters on deck vents to prevent sparks from entering the system, and relief valves to handle pressure rises in the system.