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Abstract
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In this work, a 2D mathematical model was proposed for the physical absorption of CO2 gas from gas mixture by using Silica and Alumina nanofluid in a hollow fiber membrane contactor. In this model both of axial and radial diffusion were considered. The nanofluid flows in the fiber lumen and gas mixture circulate counter – courrently to the solvent flow. Viceversa, if The nanofluid flows in the shell side, then the gas mixture circulates counter-currently to the nanofluid in the lumen side. Computational fluid dynamic technique was applied to solve the model equations considering the non-wetted condition of the membrane. The CO2 removal efficiencies, the outlet CO2 concentration, the absorption flux and mass transfer coefficient are parametrically simulated by using the operational parameters such as solvent and gas volumetric flow rate, porous, weight fraction of nanoparticle, fiber geometrical characteristics, the nanoparticle diameter and number of fiber. The nanoparticles in weight fraction of 0.1wt%, 0.25wt%, 0.5 wt% have been applied. When the gas flow rate is increased, CO2 removal efficiency decreases from 35.9% to 10.7% for solvent flow in lumen and decrease from 36.7% to 10.8% for solvent flow in shell. When the silica nanofluid flow rate is increased, CO2 removal efficiency enhances from 22.3% to 35% for solvent flow in lumen and enhances from 23.9% to 36.9% for solvent flow in shell. When the 0.5% wt silica nanofluid flow rate is increased, CO2 molar flux enhances from 0.27554 to 0.4351 (mol/m2.h) for solvent flow in lumen and enhances from 0.48679 to 0.65508 (mol/m2.h) for solvent flow in shell and also, the overall mass transfer coefficient enhances from 0.01685 to 0.029 (m/h) for solvent flow in lumen and enhances from 0.0334 to 0.0516 (m/h) for solvent flow in shell. When the number of fibers is increased from 70 to 400, CO2 removal efficiency enhances from 19.62 to 50.1 for solvent flow in lumen and enhances from 21.43 to 54 for solvent flow in shell
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