To comprehensively study the theoretical system of the pneumatic conveying of a material, the first step should be to study its conveying characteristics. Here, we develop a CFD-DEM coupling model for simulating the pneumatic conveying of polyacrylamide and build a set of pneumatic conveying test beds to experimentally verify the accuracy of the model. The horizontal pipes in this study are divided into three sections, including the acceleration section after feeding, the section with bends at both ends, and the section with a bend at only one end. The pressure drop characteristics of these three horizontal pipe sections are investigated through simulation. Then, the relationship between the pressure drop and the solid-gas ratio for only the pipe section with bends at both ends is discussed. The results show that there is a turning point with an optimal solid-gas ratio of 20.44 that corresponds to the minimum pressure drop. (C) 2020 Elsevier B.V. All rights reserved.