The importance of measuring diffusion coefficients in reactor design and simulation

Abstract

Glucose is extensively employed to produce sorbitol through catalytic hydrogenation. In the process development, parameters such as fluid dynamic conditions, temperature, and diffusion coefficients must be evaluated. To optimize the production of sorbitol, it is necessary to know the diffusion coefficients of the reacting system. In this study, they were determined at different solute concentrations and temperatures. Diffusion coefficients can also be estimated using models, such as Wilke-Chang and Hayduk and Minhas correlations. The values between 25 °C and 45 °C are similar to the experimental data, while at 65 °C, both models significantly overestimate the experimental results. As for the ternary systems, at 25 °C, both glucose and sorbitol are essentially transported by their concentration gradient. Finally, simulations of reactors operating in laminar flow conditions were made, estimating the diffusion coefficients using the Wilke-Chang correlation and determining them experimentally, showing that the glucose conversion profile along the axis of the reactor was different.