Mass Transfer Modeling of Conjugated Graetz Problem in Multi-Pass Mass Exchangers with External Recycle

Jr-Wei  Tu; Chii-Dong Ho

doi:10.6180/jase.2006.9.4.05

Mass Transfer Modeling of Conjugated Graetz Problem in Multi-Pass Mass Exchangers with External Recycle

Jr-Wei Tu¹ and Chii-Dong Ho This email address is being protected from spambots. You need JavaScript enabled to view it.¹

¹Department of Chemical and Materials Engineering, Tamkang University, Tamsui, Taiwan 251, R.O.C.

Received: March 10, 2006
Accepted: May 25, 2006
Publication Date: December 1, 2006

Download Citation: ||https://doi.org/10.6180/jase.2006.9.4.05

ABSTRACT

A new design of multi-pass mass exchanger with external recycle and the mass transfer in such a device have been investigated theoretically in this study. The analytical solutions were obtained by applying an orthogonal expansion technique associated with the eigenfunction expanding in terms of an extended power series. The influences of the design parameters (the subchannel height ratio, , and permeable membrane parameter, ) and operating conditions (the recycle ratio, R, and mass-transfer Graetz number, G_zm) on the outlet concentration and mass transfer rate were discussed and represented graphically. Comparing to the single-pass mass exchangers without external recycle, the mass transfer efficiency was improved by employing the multi-pass devices with external recycle. In economic sense, the optimal operating conditions, say R = 1, β_ab = β_cd = 1/3 and G_zm > 30 for ϒ= 10, were selected by considering both the mass transfer efficiency improvement and power consumption increment in this study.

Keywords: Mass Transfer, External Recycle, Multi-Pass Operations, Conjugated Graetz Problem

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