Introduction

Objective

Around 2008, we started the development of a numerical implementation of generic reaction diffusion equations for reactors using enzyme immobilization on small porous particles. The objective was (and still is) to provide a simple interface to solve reaction diffusion equations.

The immobilization of enzymes is a requisite for the re-use of these catalysts in repeated cycles in batch configuration or in continuous reactors. The recovery and/or retention of the enzyme catalyst is technical and economically feasible when micrometric or milimetric particles are used. The covalent attachment of the enzyme molecule to a porous solid support have shown high stabilization with different enzymes. Therefore, immobilization is neccessary and convenient for the efficient utilization of enzymes in technological processes and industrial settings.

Simulation of the concentrations of substrates and products is, nevertheless, harder than expected due to the complexity of the reaction and diffusion processes.

The reaction takes places then in a heterogeneous system composed by the solid catalysts particles and the bulk liquid. The catalysis process is carried out inside the particle porous instead of the bulk liquid solvent. The immediate consequence of this fact is that, along with the reaction, mass transfer occurs inside the particle and between the particle and the bulk medium. The modeling of this heterogeneous process must considers reaction and diffusion components in the reactor performance equation.