Two-dimensional steady state hydrodynamic analysis of gas—solids flow in vertical pneumatic conveying systems

Abstract

Pneumatic conveying, as a mode of solid particles transportation, is widely used in the petroleum, chemical, petrochemical, gas processing and food processing industries. Within the last decade, there has been increasing demand for an optimized utilization of this technology, particularly in the energy conversion processes. Such optimized utilization of this technology requires good understanding of the hydrodynamic behavior of gas-solids mixture flow in pipes and the capability to predict such behavior. Empirical correlations have been developed in the literature for predicting some of the more commonly sought design variables such as pressure drop. Most of such correlations were developed using one-dimensionally based experimental data. Apart from being limited to the data-base used in developing them, they ignore the effect of radial non-uniformity of the basic variables such as solid velocity, void fraction, etc. More recent experimentations confirm this non-radial uniformity of such important design variables as solid velocity and solid concentration. We present a two-dimensional steady state two-phase hydrodynamic model to describe upward co-current pneumatic conveying of solid particles in vertical pipe. The model incorporates viscous dissipation terms in both the gas phase and the particulate phase. Numerical solution was obtained using the numerical method of lines. The predicted system variables and their distributions under different operating conditions agree with the observed behavior of the system reported in the literature. The predicted solid velocity profiles using this model agree reasonably well with available experimental data.