Modeling the Transverse Shell-side Mass Transfer in Hollow Fiber Membrane Contactors at Low Reynolds Numbers

To understand the mass transfer behaviors in hollow fiber membrane contactors, ozone fluxes affected by various conditions and membranes were investigated. For physical absorption, mass transfer rate increased with liquid velocity and the ozone concentration in the gas. Gas flow rate was little affected when the velocity was larger than the critical value, which was 6.1 × 10−3m/s in this study. For chemical absorption, the flux was determined by the reaction rate between ozone and the absorbent. Therefore, concentration, species, and pH affected the mass transfer process markedly. For different absorbents, the order of mass transfer rate was the same as the reaction rate constant, which was phenol, sodium nitrite, hydrogen peroxide, and oxalate. Five hydrophobic membranes with various properties were employed and the mass transfer behavior can be described by the Graetz–Lévèque equation for the physical absorption process. The results showed the process was controlled by liquid film and the gas phase conditions, and membrane properties did not affect the ozone flux. For the chemical absorption, gas film, membrane and liquid film affected the mass transfer together, and none of them were negligible.

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Mass Transfer and Fluid Hydrodynamics in Sealed End Hydrophobic Hollow Fiber Membrane Gas-liquid Contactors

Journal of Applied Membrane Science & Technology ◽

10.11113/amst.v2i1.1 ◽

2017 ◽

Vol 2 (1) ◽

Author(s):

S. Kartohardjono ◽

V. Chen

Keyword(s):

Mass Transfer ◽

Hollow Fiber ◽

Packing Density ◽

Hollow Fiber Membrane ◽

Gas Absorption ◽

Outer Diameter ◽

Fiber Membrane ◽

Membrane Area ◽

Wide Range ◽

Membrane Contactors

Hollow fiber membrane modules have been extensively used as gas-liquid contactor devices to provide a high surface area within a small volume. Hollow fiber membrane contactors have been demonstrated in a wide range of application such as in gas stripping and gas absorption. In this study the performance of sealed end hydrophobic microporous hollow fiber membranes contactors were evaluated to remove dissolved oxygen from water via vacuum degassing process. Hollow fibers membranes used in the experiment were hydrophobic microporous polypropylene of 650 μm in outer diameter, 130 μm wall thickness and nominal pore size of 0.2 μm. Based on the experimentalresult the sealed end membrane contactor can remove oxygen from water as high as 3.4-gram oxygen per square meter of membrane area per hour. The oxygen flux decreases with increasing module-packing density for the same water velocity. The same effect also occurred for the mass transfer coefficient of the membrane contactors. The mass transfer coefficients were independent of fiber length within the range of study. Hydrodynamics analysis of the contactors showed that at the same Reynolds number pressure drops increase with increasing packing density due to an increase in friction between fibers and water.

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