海上平台火灾事故往往造成一个火区内多个设备受火,传统计算方法的火炬泄放负荷由受火的单个设备最大泄放流量加和得到,结果较保守。对于原油这种宽沸点混合物,实际泄放流量随时间动态变化,受火的多个设备并非在同一时间达到最大泄放流量,有必要采用系统动态模拟方法进行实际泄放状态研究。运用HYSYS软件建立系统动态模拟,分析火灾泄放中泄放参数动态变化过程,并对初始液位和压力进行敏感性分析。结果表明，初始液位为影响泄放流量的主要因素,应考虑在高高液位下进行泄放计算。通过与传统计算方法比较,系统动态模拟方法明显减小火炬泄放负荷,能优化系统设备和管线尺寸。研究成果可供类似工程参考。

The fire event on offshore platform often results in multiple equipment fires within a fire zone. The traditional method of calculating the flare relief load is obtained by summing the maximum relieving flow of all equipment under fire, which delivers conservative results. For a wide boiling point mixture such as crude oil, the actual relieving flow rate varies dynamically with time, and the multiple equipment under fire do not reach their maximum relieving flow rate at the same time. It is necessary to use the process system dynamic simulation method to study the actual relieving state. In this paper, the HYSYS software is uses to simulate the dynamic state of the process system. The dynamic process of the relieving parameters during fire relief was analyzed and sensitivity analysis of the initial liquid level and pressure was carried out as well. The results show that the initial liquid level is the main factor influencing the relieving flow rate, and the relief calculation should be performed under High-High liquid level. Compared with traditional method, the process system dynamic simulation method significantly reduces the flare relief load and optimizes the flare system design and vent line size. The result can be used as reference for projects of the same nature.