Numerical Simulation of Pigging Operation in Gas-Liquid Two-Phase Flow Pipelines

Accumulation of liquid and solid impurities will result in increase of overall pressure drop and remarkable decrease of pipeline flow efficiency during the process of multiphase pipelines. Hence, it is necessary to conduct pigging operation in multiphase pipelines so to ensure transportation efficiency. According to the two-phase flow behavior under a pigging operation, four flowing sections could be present in horizontal isothermal gas-liquid two-phase flow pipelines. Then a pigging mathematical model was built up in this paper by use of a mixed Eulerean-Lagrangean method to achieve coupling the pig movement with the fluid quasi-steady state flow. Finite difference method and Euler method were utilized to develop the model. Based on this model, a computer program was developed to numerically simulate pigging dynamics and the flow parameters such as volume flow rate of gas and liquid phases, pressure and liquid holdup were analyzed as well. The results from numerical simulation show that it is suitable to utilize the numerical simulation method developed in this paper to obtain the distribution of parameters of the pigging operation, namely, to trace the pig operation conditions inside multiphase pipelines.