Advantages of composite pressure vessels over metal

The composite structure of different steels was used earlier in China, such as the composite of stainless steel and low-alloy steel, and the belt-wound thin-walled inner cylinder pressure vessel. The development of filament wound high-pressure hydrogen storage containers in China started late, which is much behind foreign countries. In recent years, many compressed natural gas (CNG) composite gas cylinders with similar working conditions as hydrogen storage containers have been manufactured, and some experience has also been accumulated for reference. Compared with manufacturing pressure vessels, it has the following typical advantages:

1. Light weight. Traditional high-pressure vessels are mostly steel metal vessels. Due to the limited strength of metal, to increase the working pressure of the vessel, the thickness of the vessel must be increased, which increases the quality of the vessel. The composite pressure vessel is composed of a very thin metal alloy lining or non-metal lining, and the outside is wound with fibers. The low density of reinforcing fibers (1.5-2.1g/cm3) and high strength (tensile strength up to several gigapascals) greatly reduces the mass of the container.

2. Anti-knock and monitorable. The traditional single-layer structure pressure vessel cannot realize the automatic treatment of the leakage of the storage medium and the automatic monitoring of the online safety status. Once the crack occurs, it will continue to expand, causing the container to explode. The composite pressure vessel is a multi-layer structure. Although the inner lining has crack propagation, the cracks will be stopped between the layers, and then the outer layer will still play a role in bearing pressure, so that there is time for proper and safe handling. In addition, a safety monitoring system can be designed for important composite pressure vessels. After the inner lining leaks the medium, the automatic monitoring device for the online safety state of the outer layer will automatically alarm in time to avoid accidents.

3. Easy to manufacture and adjustable cost. The single-layer structure pressure vessel "thick plate coil welding", especially the "simple forging welding" manufacturing technology, has high manufacturing cost and low production efficiency, and hidden and sprouted corrosion, fatigue and other crack defects are difficult to avoid. However, the single layer of the composite pressure vessel is not required to be very thick, and the welding amount is small and easy. The special winding machine for carbon fiber is wound with a high degree of mechanization. Another advantage of carbon fiber is that the cost is adjustable, and its cost mainly depends on the performance of the fiber material. For some products with low performance requirements, relatively cheap fiber materials can be used.

4. The container structure design is flexible. The single-layer thick-walled vessel has little flexibility in structural design, and its impact resistance is not good. In addition to the inner lining, the composite pressure vessel can flexibly change the design of the inner and outer layer materials according to functional needs to meet various application needs, and can be equipped with an online safety state automatic monitoring device for the inner layer, the outer layer and the interlayer, or to block radiation, etc. A device with a special function. In summary, composite pressure vessels are widely used in various fields because of their excellent comprehensive properties, and in-depth research on them will definitely promote the country's economic development.

At present, various countries are actively developing lightweight high-pressure hydrogen storage containers, ranging from steel hydrogen storage containers, metal-lined filament winding reinforced hydrogen storage containers to fully composite filament winding hydrogen storage containers, all want to reduce the mass of the container to reduce the bulk density and improve the container. Working pressure to improve hydrogen storage density, so as to meet the needs of industrial development.