Development of a relative velocity factor comparing inlet flow rates of gas pipeline tees can predict the maximum erosion position inside the tee. A simulation model combining the k-ε turbulent and Lagrange discrete phase models allows analysis of the maximum erosion of tees based on path line, pressure, turbulent intensity, and relative tangential velocity in the tee. Results of the simulation are similar to those found in a failed tee in China’s Dina gas field. Particular gas sources and erosion can result in solid particles (dust) in gas pipelines (OGJ, Mar. 12, 2007, p. 52). These particles can cause further erosion and damage the pipelines.1 Defects caused by erosion can greatly affect pipeline safety (OGJ, Jan. 6, 2014, p. 94). As key components of natural gas pipelines, tees typically gather gas from two paths or separate flow into two paths. Studies on tee erosion remain limited and have focused mainly on simulations and laboratory tests.2-6 This article investigates damage to tees with two inlets and one outlet under working conditions in the Dina gas field by combining the k-ε turbulent and Lagrange discrete phase models. Flow-field analysis in tees reveals the i...