Waste heat recovery and reuse is a strategic approach, followed by several process industries to reduce their net energy requirement, as this would translate ultimately into reduced operating costs of the plant. Cement manufacture is an energy-intensive activity and since long, efforts were focused on means to reduce the energy demand of this industry. Dry route process, addition of precalcinator and use of suspension preheater (SP) system were the major process modifications that resulted in considerable reduction in the net specific energy requirement, which stands at present at approximate to 3350kJ/kg cement clinker. This coupled with the recovered waste heat represents the total heat requirement of cement manufacture. It is estimated that 75% of the total heat recovery happens in the vertical transport duct (riser) of the SP system alone. Literature sources provided only sketchy details of the SP system, prompting the present study of hydrodynamics in a laboratory experimental setup that is close, in its features, to the industrial riser. The materials investigated are air-sand and air-limestone, the solids taken in different particle sizes. In the range of parameters studied, pressure drop increased with increase in gas velocity, particle size, solid feed rate, or material density. The acceleration length varied over the range of 32-61% of the test section length. Further, the data are consolidated into an empirical equation, for acceleration length (L-A), that reads as . It is believed that a study of this nature will help adoption of this mechanism to reclaim waste heat in diverse other industries.