LNG厂站安全阀背压和天然气放散管道计算

Calculation of Relief Valve Back Pressure and Natural Gas Release Pipeline at LNG Plant Station

安全阀背压的确定应与天然气放散管道联系起来。采用BWRS方程,建立数学模型,通过各管道压力关系、各管道温度关系、始端节点的比焓关系和末端节点的压力关系,构建出方程组。采用牛顿-拉弗森方法求解,得出各节点的密度、温度、压力,进而分析出安全阀的背压取决于放散量、天然气组成、安全阀前天然气的压力和温度、环境温度、放散管道各管段的长度和管径等许多因素。

The determination of back pressure of relief valve should be related with the natural gas release pipeline.The BWRS equation is used to establish the mathematical model.The equations are constructed by the pressure relations of each pipeline,the temperature relations of each pipeline,the specific enthalpy relations of the initial and end nodes,and the pressure relations of the end nodes.Newton-Laffson method is used to solve the problem,and the density,temperature and pressure of each node are obtained.Furthermore,it is analyzed that the back pressure of the relief valve is determined by many factors,such as the amount of release,the composition of natural gas,the pressure and temperature of natural gas in front of the relief valve,the ambient temperature,the length and diameter of each section of the release pipeline.