输气管道置换优化研究

置换是输气管道投产试运过程中的重要工艺环节,是复杂的扩散、对流过程。文中介绍了输气管道投产前用氮气置换空气的几种方法,阐述了它们的工作原理与实施步骤,对比分析了它们的优缺点,优选了置换方式,并采用Fluent流体模拟软件建立了输气管道氮气置换数学模型,进行了三维稳态和非稳态数值计算,研究了置换过程中混气段长度随管径、管长、流速变化规律,将理论推导、数值计算和现场数据进行了对比,验证了理论结果的正确性,为现场施工提供了科学依据。

Study of the Nitrogen Gas Replacement Technology of Gas Transportation Pipeline

The nitrogen gas replacement,as an important technical segment of the gas transmission pipeline dried before it goes on stream,is a complex diffusion and convection course.The paper introduces principles and operation steps for different replancement methods used to fulfill the replacement of the gas transmission pipeline by nitrogen gas,and optimised the means of the nitrogen gas replacement by analyzing their merits and defects.A nitrogen gas replacement mechanism model of gas transportation pipeline is established by using Fluent which is a fluid simulation software,triaxial stable-state and nonsteady-state numberical calculations counducted,the pattern of regular changes in the replacement process researched,which are the aerating length changes along with the pipe diameter,the pipe length and the velocity of flow.Besides,the results of theoretical derivations and mathematical calculations are compared and verified with the site data.The comparison and verfication show that the research can optimize the nitrogen gas input in the process of nitrogen gas replacement,offering reliable support and scientific reference for field building.