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.

Solar enhanced separation of volatile components from a liquid

Abstract: A process and apparatus for separating volatile components from a volatile-containing liquid by a stripping gas flowing countercurrent to the liquid. Separation of the volatile components is enhanced by heating the liquid with radiant solar energy and agitating the liquid as it flows.

Countercurrent heat-exchanger

Abstract: A counterflow plate-type heat exchanger has heat exchange areas which are arranged at an oblique angle relative to the stack direction. This arrangement enables channels to be formed having a smaller width for the passage of fluid than the distance between the plates in the stack direction. As a result, a high rate of heat exchange can be obtained. Corresponding inflow and outflow channels are arranged on opposite lateral sides of the stack. This provides for fluid flow through the stack from one side to the other in a manner such that the entire heat exchange area is contacted by fluid. The channels narrow in the inflow direction and widen in the outflow direction in order to provide optimum flow conditions in the exchanger.

Design Procedures for Solid-Liquid Extractors and the Effect of Hydrodynamic Instabilities on Extractor Performance

Abstract: A design method is proposed for countercurrent mass transfer cascades with crossflow stages, and unsteady operated fixed beds in a countercurrent arrangement. The separation performance of these cascades is calculated from mathematical models and compared with a purely countercurrent extractor. The models are based on simple equations describing mass transfer in a single stage fixed bed. The results are presented as concise correlations between the number of true and exterior apparent transfer units. Asymptotic values of the mass transfer coefficient for transient diffusion processes in cocurrent and countercurrent extractors are calculated for particles with simple geometry. Comparing the extraction efficiency calculated from the exact solutions of the diffusion equations and the values obtained from the asymptotic mass transfer coefficient shows that differences are small under normal operating conditions for countercurrent extraction. The use of the asymptotic values in design calculations is discussed. Due to the commonly observed viscosity and density gradients in the solvent phase, non-uniform flow of liquid through the layer of solids subjected to extraction can occur. Then some fraction of the solids is not efficiently contacted with the solvent. Experiments show that a concentration gradient rather than a concentration jump in the liquid flowing through an inert packing material reduces the effect of channelling. The effect of mass transfer between the packing and the surrounding liquid on flow stability is studied. The results indicate that channelling can reduce the extraction efficiency in solid-liquid extractors.