Concentration dependency of dispersion coefficient of aqueous solutions of urea and ethyl acetate in porous media

Abstract

We report new measurements of the concentration-dependent longitudinal dispersion coefficient of aqueous urea and ethyl acetate solutions in a porous medium at a wide range of concentrations. The longitudinal dispersion coefficient was obtained by injection of a pulse of an aqueous solution of urea (or ethyl acetate) into a carrier phase flowing through a porous column and analysis of the effluent peak using the Taylor dispersion theory. The measured longitudinal dispersion coefficients for different velocities and concentrations showed an increasing trend with concentration and pore velocity. The longitudinal dispersion coefficient measurements show a powerlaw relationship with the Peclet number K L / α l Pe β l m À Á . The results are compared with experimental data and empirical formulas available in the literature, and a reasonable agreement is achieved over the range of Peclet numbers studied.

Mutual Diffusion Coefficients of Ethyl Acetate–Water Mixtures at T = (298.15–368.15 K) Measured by the Taylor Dispersion Method

“…The measured dispersed peak shape (i.e., voltage signals) is analyzed by applying the nonlinear least-square method, considering the concentration and voltage are linearly correlated, following the relation , where V E ( t ) is the voltage signal, V max E and V 0 E are the peak height and the baseline voltage, respectively, σ t is the peak variance and t R is the residence time.…”

“…The measured dispersed peak shape (i.e., voltage signals) is analyzed by applying the nonlinear least-square method, considering the concentration and voltage are linearly correlated, following the relation 32,36 V t…”