Corn syrup clarification by microfiltration with ceramic membranes

Abstract

The performance in clarifying corn syrup of three different microfiltration ceramic membranes made in our laboratory was investigated. From preliminary MF tests at laboratory scale, it was found that the composite ceramic membrane with average hydraulic pore size radius of rh ≈ 0.5 m (CM05) performed better than the other two membranes (rh ≈ 0.14 m and rh ≈ 0.75 m). Further studies of corn syrup clarification with the CM05 membrane at bench scale, with and without air backpulsing, were performed. The effects of transmembrane pressure (p = 10.3–103.4 kPa) and the feed flow velocities (v = 1.32–3.18 m/s) on permeate flux at T = 60 ◦C were analyzed. Permeate fluxes without back-flushing decreased considerably during the first hour of operation; around 60–70% of the initial permeate flux. Membrane fouling responsible for the permeate flux decline during the operation time was evaluated by applying different blocking models and cake filtration model. Results indicate that a good fitting correlation between the experimental data and pore blocking models was achieved. When back-flushing procedure was applied high efficiency of average permeate flux (J ≈ 95–105 L/m2 h) was obtained. From these experiments, sequential back-flushing is recommended to achieve the highest flux values and allow the filtration cycle to continue over longer periods of time. The turbidity, insoluble residue, and total protein rejection performances of CM05 membrane were significantly higher than those obtained using the traditional rotary vacuum filtration (RVF) process.