Countercurrent exchange

About: Countercurrent exchange is a research topic. Over the lifetime, 2255 publications have been published within this topic receiving 28687 citations. The topic is also known as: Countercurrent exchange.

Hollow fiber gas permeator with countercurrent or cocurrent flow: series solutions

Abstract: The problems in the numerical solution of boundary value problems encountered in hollow fiber binary gas permeatbrs having cocurrent or countercurrent permeate flow with axial pressure drop inside the fiber bore are discussed. A series solution technique is developed to express each product composition and the pressure ratio as a power series in terms of a dimensionless membrane area for shell side constant-pressure feed flow. Cocurrent or countercurrent rating or design problems require the solution of elther one algebraic equation, two coupled algebraic equations, or three coupled algebraic equations to determine the unknown quantities of interest. Calculated product and reject compositions, stage cuts, and closed-end pressure ratios compare quite well with those from numerical solutions for practically useful low to moderate cuts over a wide range of parameters. Cocurrent rating calculations requiring solution of only one algebraic equation are recommended for shortcut procedures since flow pattern effects are significant but not large.

Cryogenic rectification system for lower pressure operation

Abstract: A double column cryogenic rectification system wherein lower pressure column (42) bottoms undergo additional rectification within a once-through downflow reflux condenser (41) by countercurrent direct contact flow with vapor generated by condensing higher pressure column shelf vapor (70) enabling the higher pressure column (40) to operate at a reduced pressure thus reducing feed compression power requirements.

Apparatus for liquid-liquid countercurrent extraction

Abstract: An apparatus for countercurrent extraction of a dissolved material from a first liquid phase to a second liquid phase is disclosed. The apparatus comprises overflow provision for each of the liquid phases with preferably adjustable overflow for the lower liquid phase whereby desired control of interface level can be obtained.

Kinetics of Continuous Hydrolysis of Olive Oil by Lipase in Microporous Hydrophobic Membrane Bioreactor

Abstract: Kinetics of the continuous hydrolysis of olive oil by Candida cylindracea lipase in a microporous hydrophobic membrane bioreactor (flat membrane or hollow fiber module) was studied. A general equation for outlet conversion was derived on the assumption that flow of oil is of plug-flow type when the reversible Michaelis-Menten equation was applied in “surface phase”. The cases of first-and zero-order kinetics and the diffusion-controlled case through micropores were also analyzed as limiting cases. The theoretical considerations indicate that the flow rate of oil divided by the total membrane area, F/A, is an important operating parameter which governs the performance of the microporous hydrophobic membrane bioreactor. Analyses of batch lipolysis data reported by three research groups showed that the hydrolysis reaction of oil obeyed the first-orded reversible kinetics. Experimental data for the flat membrane bioreactor (countercurrent operation) obtained by the authors agreed with the reversible first-order kinetics in a wide range of F/A, while the data for the hollow fiber module (countercurrent operation) agreed with the reversible first-order kinetics only at higher F/A. Lower rates of hydrolysis at lower F/A seemed to be due to non-uniform flow of oil through the hollow fibers. The new concept of “equivalent droplet size” is proposed to compare the performance of the membrane bioreactor system with that of the emulsion system.