Over the Road Tube Trailers
Transporting hydrogen via over-the-road tube trailers is a common method for delivering compressed gaseous hydrogen across various distances, especially when pipeline transport is not feasible or available. This method involves high-pressure tanks mounted on trailers, which are then towed by trucks to their destination. Here’s a detailed look at the process, design, and considerations involved in transporting hydrogen using over-the-road tube trailers:
Design & Construction
- High-Pressure Tubes: Tube trailers are equipped with multiple high-pressure cylindrical tanks (tubes) designed to safely contain hydrogen gas compressed to pressures typically ranging from 200 to 500 bar (approx. 2,900 to 7,250 psi), though newer designs may operate at higher pressures to increase carrying capacity.
- Materials: The tubes are usually made from advanced materials, such as high-strength steel or aluminum, to handle the high pressures while minimizing weight. These materials are selected for their durability, resistance to hydrogen embrittlement, and ability to maintain integrity under pressure and over repeated use cycles.
Transportation Capacity
- Modularity and Scalability: The capacity of a tube trailer can vary depending on the number and size of tubes it carries. This modularity allows for scalable transportation solutions based on the volume of hydrogen needed at the destination.
- Volume of Hydrogen: The amount of hydrogen gas that can be transported is directly related to the pressure rating of the tubes and their total volume. Higher pressures allow for more hydrogen to be transported per trip, enhancing efficiency.
Safety Considerations
- Regulations and Standards: Transportation of compressed hydrogen gas by road is subject to stringent regulations and standards that govern the design, operation, and maintenance of tube trailers, including safety features to prevent leaks and ensure structural integrity.
- Safety Features: Tube trailers are equipped with safety devices, including pressure relief valves to release gas if pressure exceeds safe limits, and emergency shut-off systems. Regular inspections and maintenance are crucial to ensure the trailers remain safe for transport.
Operational Use
- Versatility: Tube trailers are used to transport hydrogen to various end-users, including industrial sites, hydrogen refueling stations for fuel cell vehicles, and power generation facilities. They offer flexibility in delivery to locations not served by pipelines or where demand does not justify a dedicated pipeline.
- Loading and Unloading: Hydrogen is loaded into the tubes at a filling station where it is compressed into the tubes. Upon reaching the destination, the hydrogen is offloaded through a regulated system that safely reduces the pressure to dispense the gas.
Advantages & Limitations
- Advantages: Tube trailers provide a flexible and relatively quick way to distribute hydrogen without the need for pipeline infrastructure. They can serve remote locations and supplement existing supply chains.
- Limitations: The main limitations include the cost of transportation, limited carrying capacity compared to pipelines or liquid hydrogen transport, and the energy required for compression.
In summary, over-the-road tube trailers are a crucial part of the hydrogen distribution network, offering a flexible and reliable method for transporting compressed hydrogen gas to various users across different industries and applications.