Other Exchange Reactions for Deuterium Enrichment

Distillation is a countercurrent process which maintains liquid-vapor equilibrium, usually in a vertical column containing packing, thin wetted walls, or bubble-cap 

The properties of a fractionating column which are important for isotope separation are (1) the throughput or boil-up rate which determines production (2) HETP (height equivalent per theoretical plate) which determines column length (3) the hold-up per plate which determines plant inventory and time to production (4) the pressure drop per plate which should be as small as possible. The choice of a particular column is invariably a compromise between these factors. The separation in a production column is of course less than it would be at total reflux (no product withdrawal). The concentration at any point in the enriching section can be calculated from the transport equation (see, e.g., London 1961) 

Power consumption in distillation is an important consideration. In the ideal limit, as for any separative process, it is only necessary to introduce an amount of energy equivalent to the entropy of mixing, 

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