External mass transfer model for a recirculated packed-bed batch reactor on the hydrolysis of palm olein using immobilized lipase

Abstract

The application of immobilized enzyme in organic synthesis is gaining popularity as it offers advantages over conventional chemical reactions. A recirculated packed-bed batch reactor (rpbbr) can be used for immobilized enzyme systems. However, external mass transfer limitation is significant in an rpbbr, especially at large scales. This study investigated the external mass transfer coefficients in an rpbbr. The effect of mass flow rate, one of the key parameters affecting the external mass transfer resistance, was considered. The hydrolysis of palm olein using immobilized lipase was used as a case study. A mass transfer correlation model of the form jd = k ren-1 was developed based on the literatures. The colburn factor, jd, which is a function of reynolds and schmidt numbers, can be related to the external mass transfer coefficient, km. The values of k and n were determined by conducting experimental work in the rpbbr at different mass flow rates. It was found that the values of k and n are 0.056 and 1, respectively. Since the average mass transfer coefficients can be correlated in terms of dimensionless groups which characterize the flow conditions, this model can be used for the design of reactors, particularly scaling-up.