Process Intensification in a Double-Pipe Reactor with Additively Manufactured Internal Inserts

Abstract

The polycondensation reaction to produce polydextrose can be intensified by using micro-process engineering. Fluid Guiding Elements are additively manufactured internal inserts that have already shown their potential to intensify heat transfer in double-pipe heat exchangers. This study investigated the intensification of the polydextrose yield when these internal inserts were used. Different reactor lengths and internal inserts geometries, as well as different operating conditions, were analyzed. The experiments showed that the reactant concentration had no effect on the product yield. Furthermore, it was shown that the process could be intensified at higher temperatures, with relatively low residence times and lower pressures. It was confirmed that the good heat transfer characteristics of the internal inserts allow them to continuously evaporate water during the reaction and to further reach the required reaction temperature, thus shifting the equilibrium towards the desired product. These findings are of special significance for the optimization of the polycondensation reaction of polydextrose.

A Simplified Approach for Calculating Heat Transfer Coefficients for Fluid Guiding Elements with Alternating Redirections of Flow

“…1) tackle this challenge by dividing the fluid flow into multiple partial flows and alternately guiding these partial flows to the wall, where the fluid can be heated or cooled [1]. These thin-walled inserts can be retroactively installed in existing tube-and-shell heat exchangers to improve their thermal efficiency or filled or coated with catalyst for reaction applications [2][3][4]. By altering their geometry, the heat flux into the fluid can be modified deliberately.…”