Abstract
In this work, pre-centrifuged rough lager was submitted to several clarification tests using a bench-top plant equipped with 0.8-µm ceramic hollow-fiber (HF) membranes. The experimental quasi-steady state permeation flux (Jss) was found to be dependent on the transmembrane pressure difference (TMP) and feed crossflow velocity (vS) in the ranges of 0.5-4.5 bar, and 0.5-6 m s-1, respectively. Once Jss had been empirically modelled, it was used to design appropriately the membrane clarification unit. By referring to a medium-sized brewery, a rough-grade feasibility study allowed the operating costs (co) of such a unit to be minimized at ~0.50 € hL-1 by setting vS at 4 m s-1 and PF at 5 bar. By operating at vS=2.5 m s-1 and PF=3.5 bar with periodic CO2 backflushing (i.e., the same conditions used to pilot 0.45-µm polyethersulphone HF modules at the Heineken brewery in Zoeterwoude, NL), co reduced to 0.47 € hL-1. Finally, by combining an enzymatic treatment with rough beer membrane clarification and stabilization at room temperature, co was further lessened to 0.4 € hL-1.
