Ultrafiltration of soybean oil/hexane extract by porous ceramic membranes
Resource
Journal of Membrane Science 154 (2): 251-259
Journal
Journal of Membrane Science
Journal Volume
154
Journal Issue
2
Pages
251-259
Date Issued
1999
Date
1999
Author(s)
Lee, En-Hsien
Abstract
This study investigated the ultrafiltration of soybean oil/hexane extract (miscella) using porous ceramic membrane. The evaporation energy can be saved in the soybean oil production by pre-separating a portion of hexane through the ceramic membrane. Raw soybean oil/hexane extract with 33 wt% of oil was used without pretreatment. A cross-flow ultrafiltration was performed using an anodisc membrane with a pore diameter of 0.02 μm and thickness of ~ 1 μm. The concentrations of oil/hexane mixture were measured by UV adsorption at a wavelength of 458 nm. The separation mechanism was suggested to be the hindrance diffusion of soybean oil. Agitation in the feed side significantly increased the rejection of soybean oil. A small stage cut could also yield a higher rejection. Above observations were attributed to the reduction of concentration polarization by increasing the shear rate and small permeate flux, respectively. The optimum separation was achieved under the conditions of 4 kg/cm2 transmembrane pressure, 0.04 stage cut and 120 rpm agitation speed. The concentration of soybean oil decreased from 33 wt% of feed to 27 wt% in permeate, that is, near 20% rejection. A gel-layer polarization model was proposed to estimate the gel concentration and thickness. The gel concentration was found 43-53 wt%. Agitating feed side reduced gel thickness, thus enhanced the rejection and permeate flux.This study investigated the ultrafiltration of soybean oil/hexane extract (miscella) using porous ceramic membrane. The evaporation energy can be saved in the soybean oil production by pre-separating a portion of hexane through the ceramic membrane. Raw soybean oil/hexane extract with 33 wt% of oil was used without pretreatment. A cross-flow ultrafiltration was performed using an anodisc membrane with a pore diameter of 0.02 μm and thickness of approximately 1 μm. The concentrations of oil/hexane mixture were measured by UV adsorption at a wavelength of 458 nm. The separation mechanism was suggested to be the hindrance diffusion of soybean oil. Agitation in the feed side significantly increased the rejection of soybean oil. A small stage cut could also yield a higher rejection. Above observations were attributed to the reduction of concentration polarization by increasing the shear rate and small permeate flux, respectively. The optimum separation was achieved under the conditions of 4 kg/cm2 transmembrane pressure, 0.04 stage cut and 120 rpm agitation speed. The concentration of soybean oil decreased from 33 wt% of feed to 27 wt% in permeate, that is, near 20% rejection. A gel-layer polarization model was proposed to estimate the gel concentration and thickness. The gel concentration was found 43-53 wt%. Agitating feed side reduced gel thickness, thus enhanced the rejection and permeate flux.
Subjects
Ceramic membrane; Concentration polarization; Non-aqueous separations; Soybean oil; Ultrafiltration
Other Subjects
Binary mixtures; Ceramic materials; Diffusion; Gels; Mathematical models; Mechanical permeability; Paraffins; Polarization; Pore size; Porous materials; Ultrafiltration; Vegetable oils; Ceramic membranes; Crossflow ultrafiltration; Gel-layer polarization model; Hexane; Transmembrane pressure; Membranes; hexane; soybean oil; ceramic membrane; mixture; separation; ultrafiltration; article; ceramics; diffusion; energy conservation; evaporation; food processing; membrane; permeability; porosity; priority journal; shear rate; ultrafiltration; ultraviolet spectroscopy
Type
journal article
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