Effect of Fibrous Bed Permeability on Steady-State Coalescence

Abstract

The effect of fibrous bed permeability on the efficiency of steady-state coalescence was investigated. Bed permeability was changed by compression of polyurethane fibers. The effect of bed permeability was followed based on the effluent oil concentration and critical velocity. An oil-in-water system was used as the model of unstable emulsion, with the drop size smaller than the pore size of the fibrous bed in all experiments. Different fluid velocities, bed lengths, and fluid-flow orientations were applied. The results indicate the existence of two regions of dependence, with a break point at a defined range identified as a critical one. Empirical equations were derived by describing the effluent concentration and critical velocity as a function of the bed permeability and length.

Effect of the Nature of Different Polymeric Fibers on Steady-State Bed Coalescence of an Oil-in-Water Emulsion

“…Hence, it would be necessary to determine the value of the bed critical permeability for each material and work with a bed of higher permeability to obtain optimal separation conditions. 8 Velocities The oil concentration in the effluent was determined by IR spectrometry from a carbon tetrachloride extract, after addition of HCl to obtain pH 2, to stabilize the oily water samples.…”

“…The critical velocity was determined from the exponential dependence of the effluent oil concentration on the fluid velocity, in each particular experiment. In our studies, the critical velocity (v k15 ) 8 is the fluid velocity determined at a point when the effluent oil concentration reaches 15 mg L -1 , this concentration often being quoted as the tolerable level in oily water. As the working velocity is a crucial factor for equipment size and capital costs, the goal of optimization is to find the conditions corresponding to its maximum, which must be below the critical velocity.…”

“…Hence, it would be necessary to determine the value of the bed critical permeability for each material and work with a bed of higher permeability to obtain optimal separation conditions. 8 Velocities of 16-70 m h -1 for the constant oil-in-water emulsion and constant mean drop diameter were applied. A selected velocity was kept constant for 1 h, and composite samples were taken in the last 15 min in 5 min intervals.…”

Oil Removing from Emulsions Using Commercial Resins

“…Researches have shown that coalescer is effective in reducing high levels of oil and grease in appropriate particle size range that achieve technically and economically efficient oil-water separation [7][8][9]. Oil droplets are captured by the solid medium, forming oil films on the surfaces during the coalescence process; then the stable oil emulsions are demulsified upon continued growth of the collected oil droplets [10,11].…”

Removal of emulsified oil from oily wastewater (oil-in-water emulsion) using packed bed of polymeric resin beads

“…Coalescers are basically improved filtration systems using designed filtration medium, usually modified polymeric resins, which destabilize emulsion and accelerate the coalescence of dispersed oil droplets and provide high adsorption capacity and oil-removal efficiency [24]. These characteristics are important due to hydrogen bonding between oil molecules and the free hydrophobic part of the fixed surfactant.…”