Date of Graduation
1997
Document Type
Dissertation/Thesis
Abstract
Large volumes of spent oil-in-water emulsions are produced in the metal-working industry. The treatment of oily wastewaters with conventional membrane separation technologies is limited by the low permeate flux observed at high oil concentrations due to difficulty pumping concentrated solutions at high recirculation velocities. In the high-shear rotary ultrafiltration (UF) unit, disk membranes are rotated at speeds up to 1,750 rpm to generate hydraulic turbulence which scours the membrane surface. Thus, the pump is required only to provide transmembrane pressure and a small amount of recirculation. The objective of this research was to perform a parametric waste-specific study on the effects of membrane rotation and transmembrane pressure on the limiting permeate flux to bridge the gap between the existing body of applied data and the need for additional controlled studies. Since this is the only comprehensive study of the effects of operating parameters on the performance of a high-shear rotary ultrafiltration system, both research and application-oriented engineers can benefit from the conclusions drawn from these experiments. Experiments were conducted using a high-shear rotary ultrafiltration system equipped with a 0.11 µm average pore size ceramic membrane. Experiments at a single operating temperature of 110 UF were conducted at discrete rotational speed/metal-working fluid concentration combinations over an applied pressure range of 15 to 75 psig and membrane rotational speeds from 500 to 1,750 rpm. Synthetic solutions containing 5 to 40% metal-working fluid were prepared in each experiment. The transition from pressure-controlled to mass transfer-controlled "limiting" permeate flux occurred at lower transmembrane pressures as hydraulic turbulence was decreased due to an increase in the thickness of the solute concentration boundary layer. Exponent values in the flux-Reynolds Number and solute mass transfer coefficient-membrane rotational speed relationships exceeded reported literature values for both conventional and mechanically enhanced UF systems. Thus, the overall greater effect of membrane rotation-induced hydraulic turbulence on mass transfer properties in the high-shear rotary UF system was attributed to the effective decoupling of feed pressurization/recirculation from hydraulic turbulence.
Recommended Citation
Viadero, Roger C., "Effects of membrane rotation and transmembrane pressure on the high-shear rotary ultrafiltration of an oily wastewater." (1997). Graduate Theses, Dissertations, and Problem Reports. 9949.
https://researchrepository.wvu.edu/etd/9949