液相乙烷输送管道放空工况研究

Study on Venting Condition of Liquid-phase Ethane Transmission Pipeline

针对乙烷具有较低的临界温度和临界压力,放空过程中易发生相变的问题,建立乙烷管道瞬态放空模型,分析放空过程中管内乙烷参数响应规律。结果表明液相乙烷管道放空经历三个阶段,第一阶段压力迅速下降,液相乙烷进入气液两相区。第二阶段是气液共存阶段,温度压力沿着相态包络线逐渐下降,管内气相持续增加。第三阶段乙烷由气液两相全部变为气相,温度开始升高。分析了不同放空管径、初始压力、初始温度等因素的影响机制,提出“大管径+稳定时间+小管径”的液相乙烷管道放空方式,为液相乙烷管道放空系统设计提供参考与借鉴。

In view of the problem that ethane has low critical temperature and critical pressure and is prone to phase change during venting,the transient venting model of ethane pipeline was established to analyze the response law of ethane parameters in the pipe during the venting process.The results showed that the liquid-phase ethane pipeline emptying went through three stages,the first stage was a rapid pressure drop and the liquid-phase ethane entered the gas-liquid two-phase region.The second stage was the gas-liquid coexistence stage,in which the temperature and pressure gradually decreased along the phase envelope and the gas phase in the pipe continued to increase.In the third stage,ethane changed from all gas-liquid two-phase to gas-phase,and the temperature started to increase.The influence mechanisms of different venting pipe diameters,initial pressure and initial temperature were analyzed,and the liquid-phase ethane pipeline venting method of"large pipe diameter+stabilization time+small pipe diameter"was proposed to provide reference for the design of liquid-phase ethane pipeline venting system.