Parametric study of ultrafiltration membrane system & development of fouling control mechanism
Abstract
The use of membrane in treatment of refinery wastewater is very limited in part because of the fouling phenomena. This thesis presents a parametric study of a re-circulating flow ultrafiltration (UF) membrane system by filtrating both clay and oily clay wastes; the hybrid spring-membrane system under investigation consists of tubular membranes in a U-shaped steel casing and helical springs investigates through Computational Fluid Dynamics (CFD) simulations and experiments for fouling control. Experimental evidence shows that the permeate flux is a strong function of TMP, cross-flow velocity, concentration, temperature as well as emulsified oil. Increasing TMP, temperature and cross-flow velocity improved permeate flux for clay and oily claywater. It is also found that the hydrophobic membrane experienced quick fouling after introduction of oil due to increase in total resistance; the performance was diminished by approximately 10%. CFD results revealed that the spring significantly change flow pattern and particle distribution in membrane channels. In addition, wall velocity, and shear stress as well as turbulence kinetic energy were greatly enhanced and varied intensely. These fluctuations deterred the formation of concentration polarization. The generation of eddy currents effectively increased local mixing and suppressed concentration boundary development. Fluxes of tubular ultrafiltration (UF) membrane were improved by 25%, 20% and 10% for the two springs, spring in first tube, and spring in second tube scenarios, respectively. The excellent agreement between the experimental and simulation results suggests inserting spring in membrane tubes is an effective way helps improving membrane performance. Furthermore, it is found the mechanism of spring wire diameter and space effect on fluid is complicated, and the optimum design of spring geometries must be carefully evaluated.
Degree
M.S.E.
Advisors
Nnanna, Purdue University.
Subject Area
Mechanical engineering|Materials science
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