复杂输油管道系统的水击控制——大庆至铁岭输油管道的研究
Surge Control in a Complex Oil Pipeline System——Study on Daqing-Tieling Crude Oil Pipeline
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摘要: 大庆至铁岭输油管道建于70年代, 是一条复杂的双线、双泵机组互联的管道系统, 由于工艺落后、设备陈旧、能耗大, 目前正对其实施密闭输油工艺改造。为此, 依据该系统现状, 针对不同的工艺改造方案, 运用计算机技术, 对管道可能出现的各种水击事故工况进行了模拟, 分析了管道改建的条件、通信能力和沿线允许操作压力等因素, 建立数学模型, 用特征线差分方程进行数值计算的水击模拟软件, 对各种水击事故及控制保护措施进行了分析计算。控制保护措施主要有①输油泵站高、低泄压阀组成的自动保护装置, ②泵站调节阀的开关、调速电机变速和部分泵机组停启组成的自动调节系统, ③由通信系统向上下游泵站传递命令, 进行阀调节, 停运部分泵机组或调速电机降速, 以拦截水击事故产生的正负压力波。水击控制的方法主要是超前保护辅之以各站自动调节和保护, 最早拦截水击波措施的动作时间为事故后30s。Abstract: Daqing-Tieling Crude Oil Pipeline, completed in the 70s, is a father complex pipeline of double lines and double pump sets connected with each other. Due to the backwardness of its process and out-of-date equipment, much energy has been consumed, therefore renovation is being performed of the pipe to realize tightline operation for this pipeline. Simulations of various possible working conditions caused by surge accidents have been carried out through computers based on the present state of the system and different kinds of process renovation plans followed by the analysis on the conditions for pipeline improvement, communication capabilities, and allowable operating pressure etc., so that mathametics models were worked out. The surge simulation softwares were obtained through calculations of values by means of difference equation of characteristic curves. Analysis and calculation were also done on surge accidents and protection measures of different kinds, which are: ① Automatic protection devices made up of high/low position pressure relief valves at pump stations; ② Automatically regulated system of regulating valve switches, variable speed motors and restart of part of pump motor sets; ③The telecommunication system can be used to send commands to up/down stream pump stations for valve regulation, shutdown of part of the pump sets or making the variable speed motors slow down so as to stop the positive and nagative pressure waves caused by surge accidents.This kind of surge control method is mainly to provide protection in advance while making the automatic regulation and protection as the subdiary at each station. The time the action takes of the earlist stopple of surge wave is 30s after a surge accident.