Experimental Study on Measuring Diffusion Coefficients of various Organic Solvents and Solids with varying Geometries in Air

摘要

Molecular diffusion is fundamental to mass transport and understanding the basic mechanism of this phenomenon and quantitative estimation of the same is critical to mass transfer operations viz. distillation, absorption/stripping, liquid-liquid extraction etc. In this project, two contrastingly different cases were selected to experimentally measure binary diffusion coefficients. It is important to highlight the fact that any industrial mass transfer operation involves multi-component system; however, suitable binary system data can be effectively used to estimate the multi-component system. Similarly, for any unit operation involving more than a single-phase (and hence presence of an interphase), it is the local or overall mass transfer co-efficient which explains the mass transfer operation prevailing within the system and can be effectively measured in wetted wall column experiments. However, suitably measured diffusivity data can easily be used in estimating the mass transfer coefficients using fundamental concepts of various predictive theories like (film, penetration, surface renewal and boundary layer). In this work, several organic solvents viz. benzene, toluene, acetone, carbon-tetrachloride were used to measure their diffusion coefficients in air at widely different temperatures and at atmospheric pressure. Similarly, solids of different geometries (both spherical as well as cylindrical) were chosen to measure the diffusivity. Naphthalene balls (C10H8) were used to study the diffusion phenomenon in spherical geometry and camphor pellets (C10H16O) were used to study the cylindrical system