Abstract
A double-pass mass exchanger with external recycle by inserting a permeable barrier to divide a circular tube into two subchannels of uniform wall concentration, resulting in substantially improving the mass transfer rate, has been investigated theoretically. The mathematical formulation to such a double-pass concentric circular mass exchanger with external recycle, as referred to conjugated Graetz problems, and theoretical analysis on mass transfer efficiency improvement have been developed using an orthogonal expansion technique in power series.
The analytical results show that considerable improvement in mass transfer is obtained with a suitable adjustment of the permeable-barrier position and recycle ratio. The numerical example in mass transfer efficiency by arranging the recycle ratio were illustrated with the mass-transfer Graetz number as a parameter. The effects of permeable-barrier position and recycle ratio on the mass-transfer efficiency improvement as well as on power consumption increment have been also discussed.
