Conceptual design for a process to recover volatile solutes from aqueous solutions using silicalite

A novel method to recover dilute volatile solutes from aqueous solutions places pure silicalite powder in the annular space between two concentric porous pipes. Solute-rich fluid flows through the silicalite bed. When the bed is fully loaded, it is regenerated by passing steam through heat exchange tubes that are in intimate contact with the bed. In the case of ethanol, this system is able to produce 24wt% ethanol from a 1wt% solution in a single step. Because butanol is more nonpolar, the system is able to produce 50wt% butanol from a 1wt% solution in a single step. It is estimated that recovering 1% ethanol costs $0.0493/ L of 95% EtOH, whereas recovering 1% butanol costs $0.0277/L of pure BuOH. This cost is less than 4% of the selling price of butanol, which suggests this is a promising technique for product recovery in the acetone/butanol fermentation. This technology also has potential uses in removing volatile solutes from polluted water