Effect of vapor bubble size on the hydraulic parameters of a reactive distillation column for the production of renewable aviation fuel

Abstract

Reactive distillation is an intensified technology that has demonstrated interesting economical and operational advantages in the production of renewable aviation fuel. In reactive distillation, conversion reactions as well as separation of products take place in a distillation column with solid catalyst. In one of the less-studied configurations of these type of systems, catalyst containers are placed on the floor of the sieve trays of the column; this is advantageous in reaction-separation operations from the point of view of selectivity and conversion. This paper presents a CFD-based model for the simulation of a sieve tray with catalyst containers working under the operating conditions of a column used for the production of renewable aviation fuel through reactive distillation. Modeling of a non-isothermal liquid-vapor flow through the system was considered in this case. The developed model was used to analyze the effect of the vapor bubble size on two of the most important hydraulic parameters in sieve trays: clear liquid height and froth velocity. From the analysis of the obtained results, it can be concluded that the model is capable to provide a fairly good agreement with the observed experimental behavior reported for a similar system. In addition, it was observed that those tray designs that produce bigger bubbles tend to promote a higher clear liquid height and a lower froth velocity. This implies a higher contact time as well as a better interaction between both phases, which in turn promotes an increase in the conversion reaction rates and the separation efficiency of the products.