For enzyme-catalyzed reactions, batch processes using stirred tank reactors are the state-of-the-art production mode. The yield of the process may be limited by reaction equilibrium, product inhibition of the enzyme, low concentrations and possibly low reaction rates, while the recovery of the product may be limited due to thermodynamic constraints such as azeotropes. Using enzymes in an integrated reactive distillation process can overcome these limitations and provides a cost advantage over classic batch reactor processes. The aim of this paper is i) to report the successful pilot-scale experimental validation of an Enzymatic Reactive Distillation (ERD) process for the synthesis of butyl butyrate and ii) to establish a rate-based model for conceptual process design which can be quickly adapted to other systems. The main novelty is the application of a continuous RD column with enzymes as a heterogeneous catalyst provided in two different types of catalytic packing: loosely filled immobilized enzyme beads in standard packings with catalyst pockets and gauze packings with catalytic coating. Experimental pilot-scale experiments show the feasibility of ERD and allow the comparison of the different packing types based on catalytic performance as well as stability. Furthermore, these experiments are used to validate a predictive rate-based model to describe ERD which can be used to check the sensitivity of process and design parameters as well as to provide a quick adaption to other systems for quick evaluation.
- Process intensification
- Reactive distillation