Friction behavior of waxy oil deposit removal using polymeric bristled brushes

Pigging is the most effective and common way to remove the wax deposits in pipelines. The discs, cups, or brushes of a pig are executing components for waxy oil deposit removal. In this study, a homemade experiment setup was built and employed to conduct the waxy oil deposit removal experiments with various wax concentration at different scraping speeds using polymeric bristled brushes. An explanation model was established to analyze the formation of waxy oil deposit chips. The entire removal processes were captured and the resistant friction forces were measured during the experiments. Our results show that there are three stages in the scraping process: (a) brush deforming; (b) steady scraping; (c) brush leaving; In the scraping stage, the frictional resistant force was found to decrease as the scraping speed increases. The frictional resistant force increases as the wax concentration increases. There is obvious stick-slip phenomenon in the steady scraping process. The wax concentration influences the shape of the chips. The shape of the high wax concentration deposit chips is saw-toothed.