For the plug flow mode of dense-phase pneumatic conveying, three different types of plugs have been defined, and models for predicting the pressure drop in conveying pipeline have been established. In literature, the model for Plug-2 pressure drop is mechanistic and depends on several properties of the materials forming the plug. Therefore, modification of the model with experimentally corrected material properties is considered in this study. The parameters tested in this study are plug velocity, particle velocity, and the stationary layer height. Using the new functional relationships, the Plug-2 pressure drop model is modified and its predictions are compared with experimentally measured pressure drops obtained in conveying Plug-2. It is found that the modified Plug-2 pressure drop model matches experimental values well within the variation range of +/- 20%. Further, a detailed analysis of various types of related velocities is presented and a new type of plug, called 'Plug-2*', is developed. (C) 2019 Elsevier B.V. All rights reserved.