Influence of crossflow microfiltration on ceramic membrane fouling and beer quality

Abstract

In this article, an experimental investigation has been carried out to determine the types of fouling phenomena that occur during clarification of dilute malt extract (DME) and pasteurization of clarified beer (CB) by a tubular ceramic membrane in a crossflow pilot plant. Using the classical models, the predominant fouling mechanism responsible for flux decline was found to be complete blocking of the membrane pores followed by formation of a compressible cake layer of yeast cell in the case of DME clarification, whereas the internal fouling of the membrane occurs during pasteurization of CB. The effects of operating parameters, including temperature, transmembrane pressure, and crossflow velocity, on the steady-state permeate flux, as the key factor of crossflow microfiltration processes, were examined. For CB microfiltration, the steady-state permeation flux increased almost linearly with transmembrane pressure and the membrane could reduce the turbidity by 60%. For DME filtration, the maximum value of permeation flux (20 LMH) was obtained under medium transmembrane pressure of 1.1 bar and the highest crossflow velocity. The filtered beer quality parameters, such as haze, color, proteins, polyphenols and bitterness, were examined after 8 h of filtration to ensure the transmission of beer compounds that are essential for beer quality. The results of quality analysis showed that the ceramic membrane crossflow filtration, regardless of very low permeation flux, appears to be a reliable substitution for the traditional Kieselguhr filtration in beer clarification.

Keywords:

• Microfiltration
• Membrane fouling
• Beer
• Crossflow
• Classical model

Acknowledgment

The authors are greatly indebted to Iran Behnoush Co. for the beer samples and financial support of this project.