Study on the Response Behavior of Large Steel Seamless Cylinder Pressure Relief Devices Under Different Fire Conditions

The pressures relief devices (PRDs) are widely used on long tube trailers, and can automatically open in a fire accident to relieve pressure when the pressure exceeds the set value to keep the cylinder safe from explosion. However, there is a big difference in the structure selection of PRDs and the calculation methods of the effective discharge area between different standards such as GB/T33215, API521 and CGA S-1.1. The overall fire test and local fire test of large capacity steel seamless cylinder were carried out to obtain the response behavior of different PRDs with different discharge areas, and the change law of temperature and pressure during the pressure relief process. Results showed that the requirements of safety release of cylinders in the fire environment were satisfied by the effective discharge area calculated by API521, CGA S-1.1 and GB/T33215, and the inner temperature and pressure were greatly affected by the different discharge orifices. In the same cases that the PRD were isolated from fire by steel plate, the single rupture disk device has a faster response than the combination rupture disk/fusible-plug devices.