A Macrokinetic Modeling of Membrane Microfiltration Processes

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Abstract
Membrane microfiltration techniques have been developed and utilized mostly in the fields of gas purification and aerosol filtration. They were recently applied to medical, pharmaceutical, liquor, and food processings. Membrane microfiltration behavior is characterized by intrapore diffusive deposition of fine particles, surface pore blocking, and the formation of a thin cake layer on the filter surface. The intrapore diffusive deposition process predominates and it can be regarded macroscopically as a first-order rate process. The surface pore blocking process is also described by a first-order rate equation. Thus the filtration characteristics, such as filtration rate and filtration resistance, can be evaluated by using the macrokinetic models derived from first-order rate equations. The microfiltration processes were simulated numerically by these models and the calculation results agreed well with experimental observations. The backflushing stages must be included in a practical microfiltration process. A first-order rate process was proposed for the detachment process of collected particles from filter pores. Membrane microfiltration systems with backflushing stages were also evaluated macrokinetically and the effect of backflushing on the filtration performance was manifested numerically.