醤油火入れ澱のクロスフロー膜ろ過濃縮における懸濁物質濃度増加の透過流束に及ぼす影響

Abstract

Cross-flow ultrafiltration and microfiltration have been used to recover soy sauce products from the brewing soy sauce lees for 20 years. To select appropriate membrane module and operating condition for the filtration of soy sauce lees, it is important to analyze the relation between permeate flux decline at varying operating conditions and fouling formation in the batch-concentration-filtration quantitatively. The cross-flow filtration apparatus with 0.006 m2 polysulfone flat-sheet membrane (pore size, 0.2μm) module was used at a constant transmembrane pressure and different cross-flow velocity in both permeate-recycle-and batch-concentration-filtration. Flux decline in the batch-concentration-filtration showed good agreement with the cake-filtration-model proposed in the present study by the Runge-Kutta-Gill method in which the lift velocity at initial concentration was defined as a steady-state flux in the permeate-recycle-filtration and the lift velocity in the batch-concentration-filtration decreased with VRF (volume reduction factor) to the 0.9th power. The lift velocity of soy sauce lees which contain particles of wide range particle size distribution had larger dependence on the particle concentration than that of the suspensions containing latex or yeast shown in the literatures. The cake filtration model applied in the batch-concentration-filtration of soy sauce lees with cross-flow microfiltration membrane was useful to design the process of soy sauce recovery from soy sauce less.