超临界流体安全阀泄放的动态模拟研究

Dynamic simulation study on the relieving process of the safety valve in supercritical LNG pipeline

关键词:  液化天然气  动态模拟  安全阀  超临界流体

Key words:  liquefied nature gas  dynamic simulation  safety valve  supercritical fluid

摘要:

针对某液化天然气接收站的超临界液化天然气管线安全阀火灾泄放工况,阐述了应用传统计算方法解决类似复杂工况的局限性。提出采用Hysys Dynamic流程模拟软件,建立超压泄放的动态模型,通过模型计算验证火灾工况下所选安全阀喉径面积的合理性,并基于此模型研究了安全阀泄放过程中系统压力、温度、泄放流量等参数随时间的动态响应过程。计算结果表明,建立的动态模型可仿真模拟液化天然气管线安全阀的实际放空过程,准确地验证液化天然气管线所选取的安全阀喉径面积是否能够满足泄放要求,同时为安全阀的准确选型提供一种较为准确合理的程序和方法 。 

Abstract:

In this paper, the limitation of the traditional method to determine the relieving rate of supercritical fluid had been expounded based on a case study of real specified LNG terminal. Furthermore, a dynamic model on the relieving scenario of the LNG pipe safety valves had been developed by a process simulation software HYSYS Dynamic. The rationality of the orifice area required in safety valve could be validated by the model under the hydraulic expansion and fire scenarios. In addition, the main variables including pressure, temperature and relieving rate could be identified in respond to the time. The study clearly showed that the established dynamic model could simulate the real relieving process of the safety valve in the LNG pipeline, verify the designed orifice area in safety valve could satisfy the requirements, and provide a comparatively reasonable method for the model selection of the pressure valve.