Abstract:

Safety valve is a kind of pressure relief valve using the pressure of its own medium instead of any external force. Its calculation and type selection play a very important role in the safety of natural gas liquefaction equipment and pipeline system. For different process fluids and operating conditions, the traditional method is to use Excel according to the calculation formula stipulated in API 520, which takes time and has some errors in the calculation of some fluids. Based on the characteristics of natural gas, this paper adopts HYSYS process simulation software to simulate the fluid safety valve. By comparing the results of various methods in different cases with the results of manual calculation, the leakage volume and throat diameter are compared. The leakage volume of safety valve under most working conditions can be accurately calculated. Just a few types of parameters are to be filled in the HYSYS simulation software, and the calculation process is simple and easy to understand. It is especially suitable for the calculation of supercritical fluids and mixed fluids, providing references for engineers in related work, so as to improve work efficiency and accuracy. However, there may be a large difference between the results of multi-model method calculation, which requires engineers to make judgement.

Key words: safety valve, liquefied natural gas/LNG, HYSYS process simulation, type selection calculation