Surge Control in a Complex Oil Pipeline System——Study on Daqing-Tieling Crude Oil Pipeline

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 Due to the backwardness of its process and out-of-date equipment, much energy has been consumed, therefore renovation is being performed of the pipe to realize tightline operation for this pipeline.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.