Optimal configuration design for double-flow thermal-diffusion columns with external recycle

Optimal configuration dimensions for double-flow thermal-diffusion columns, established via an impermeable or a permeable-barrier, with external recycle both ends, are investigated theoretically for the H2O–HDO–D2O system. The analytical solutions are obtained using an eigenfunction expansion in terms of a power series. The predicted degree of separation is represented graphically with channel thickness ratio, recycle ratio, and aspect ratio as parameters. Compared to classical Clusius-Dickel thermal-diffusion columns of the same working dimensions, significant improvements can be realized and the improvements from permeable-barrier devices are higher than those which impermeable-barrier devices.