A Model To Predict the Concentration of Submicrometer Solid Particles in Viscous Media Confined inside Horizontal Cylindrical Channels

Abstract

As light oil reserves dwindle, the extraction and processing of heavy crude oils are becoming increasingly important. The use of ultradispersed catalysts (nanometric catalytic particles dispersed in the oil) is considered to be a promising way to upgrade these materials. To simulate such processes, mass transfer of the ultradispersed particles must be estimated. However, an adequate mathematical expression to describe the motion of these particles through viscous media in a horizontal cylindrical channel is still missing. In this paper, we developed and solved a time-dependent, two-dimensional convective−dispersive model, which simulates the transient deposition and suspension of ultradispersed particles immersed in a viscous medium, inside the cross section of a horizontal cylindrical channel in a stagnant situation. The results of the modeling are compared with a series of experiments that permit knowledge of the concentration of the ultradispersed particles inside a horizontal cylinder. These experiments were performed using particles in the submicrometer range (average sizes of 198 nm) and fluid media with diverse densities and viscosities. The effect of the fluid medium properties and the initial particle concentration in the calculation of the dispersion coefficient was also studied. The conditions needed to maintain the solid particles suspended in the liquid medium, contained in a vessel with cylindrical geometry, are also unveiled by the presented model.