Stripping of acetone from water in a microchannel device

A liquid-vapor/gas separation microchannel device (channel length: 282.5 mm, channel width: 1 mm, gas channel depth: 1 mm, liquid channel depth: 100/300 μm) was developed and used as microstripper to remove acetone from water using dry nitrogen as carrier gas. The interface between the liquid and vapor/gas phases was stabilized by means of a flat sheet microporous hydrophobic/oleophobic acrylcopolymer membrane on polyester support. The separation efficiency of the microstripper was investigated with respect to two liquid channel depths (100 and 300 μm) for countercurrent flow arrangement by varying alternatively the liquid flow rate and the carrier gas flow rate. All experiments were carried out at room temperature (23 °C) and at atmospheric pressure. For all investigated process parameters in this work, fully developed laminar flow has been established in both fluid channels. Almost 100% acetone removal from the feed aqueous solution (5 wt% acetone) could be achieved in the microstripper with the liquid channel depth of 100 μm for a liquid flow rate of 0.025 ml/min (liquid residence time: 68 s) and for a carrier gas flow rate of 163 ml/min (gas residence time: 0.1 s). Furthermore, it was found that the overall volumetric mass transfer capacity coefficient KLa of the microstripper was strongly dependent on the liquid channel depth, while hardly affected by the liquid and carrier gas flow rates. The average value of KLa for a liquid channel depth of 100 μm was found about 0.091 s−1. It is approximately five times greater than that for a liquid channel depth of 300 μm. This results indicates clearly the potential of device miniaturization to enhancing the separation efficiency of the microstripper.