On the selection of safety valves for liquefied hydrocarbon equipment

Fully open safety valve series A41: a burst disc is installed in front of the safety valve, and the flow then goes to an on-ground flare or an elevated flare.

The friend upstairs got it mixed up. A42 is a fully open safety valve, while A41 is a slightly open safety valve.

For the liquefied hydrocarbon equipment you mentioned, the selection of safety valves is usually determined based on the properties of the medium, the operating conditions, and the specific requirements of the system. In your case, since the medium is a liquid mixture of C4 and C5 liquefied hydrocarbons, for such flammable and explosive media, it is recommended to use a fully open safety valve. Because full-open safety valves can open completely quickly when the set pressure is reached, allowing for rapid pressure release, they are suitable for handling such hazardous media. As for whether a rupture disc needs to be installed, a rupture disc is a safety device used to release pressure instantly when it exceeds the design pressure, thereby preventing damage to the equipment or more serious accidents. In the use of liquefied hydrocarbons, it is generally recommended to install a burst disc in front of the safety valve, especially when the safety valve is unable to handle rapid pressure increases under extreme abnormal conditions. A burst disc can serve as a backup protection for safety valves, providing an additional layer of safety. Your current plan mentions connecting a safety valve to a flare, which is suitable for safely burning the released gases in order to avoid environmental pollution and safety risks. In summary, it is recommended to use fully open safety valves and install rupture discs in front of them to enhance the safety of the system. At the same time, ensure that the piping design from the safety valve to the flare system complies with safety regulations. .