Integration of cross-flow filtration in the beverage industry

The market for membrane technology in the food and beverage industries increased during the last two decades to a market volume of about € 150 million and is now the second biggest industrial market for membranes after municipal water treatment in Europe. The aim of this study is to highlight new application concepts for membrane processes either by replacing conventional separation processes or by combining membrane processes with conventional separation technologies to achieve optimised solutions. The first part of this work demonstrates potential applications in the fruit juice industry. In this industry, kieselguhr filtration or ultrafiltration is used to clarify apple juice by removing suspended solids or other high molecular solids such as proteins and starch. A new concept combining a high-speed separator with spiral wound ultrafiltration modules will be proposed as an alternative to kieselguhr filtration or ultrafiltration as stand alone unit. Further, for the concentration of apple juice a combination of reverse osmosis and evaporation will be discussed in comparison to only evaporation. The focus in the second part of this work is on the brewing industry. In the traditional brewing process clarification of beer after fermentation and maturation is achieved by a separator followed by kieselguhr filtration. Microfiltration will be introduced as a replacement for kieselguhr filtration to clarify the beer by removing yeast, micro-organisms and haze without affecting the taste. Another novel use of cross-flow microfiltration in breweries is the recovery of beer from tank bottoms. After fermentation, yeast with 1.5 to 2 % of the total beer volume settles at the bottom of the fermentation vessels. By using microfiltration the beer, which would be lost if not recovered, can be separated from the yeast. Overall this work demonstrates the potential of membrane processes in the beverage industry and the importance of process optimisation and integration