Experiment Study of Pigging Characteristics in Horizontal Gas-Liquid Flow Pipeline With Different Pig Sizes Available to Purchase

During pigging process of long-distance pipeline, pig seals wear due to abrasion on pipe wall, the diameter of seal decreases and even to be smaller than pipe inner diameter as a result. This study has researched the characteristics of pigging processes using pigs different in diameter in horizontal experimental pipe. In the study, mandrel pig with two seals was chosen for experiment. Five pigs different in size were used, and pigging experiments under various flow conditions were carried out in a horizontal air-water flow experimental loop. During experiment, the features of pigging process from pig launcher to trap were observed, the liquid holdup and pressure were detected and collected, pig velocities in different sections of pipe were measured, the velocity of pigging slug front and length of the slug were also measured. The relationship between pig movement and flow conditions was analyzed, the methods to calculate velocity of pigging slug front and length of the slug were obtained and the results calculated were similar to the results measured. Based on the results of experiment, some suggestions were proposed for pigging operation in real pipeline.