Preliminary Experiments on Hydrogen Isotope Separation by Water-Hydrogen Chemical Exchange under Reduced Pressure

A pressure-reducing method is used effectively in a water distillation process to enhance the equilibrium separation factor. The feasibility of the technique is established through application to a water-hydrogen chemical exchange process using a prototype separation column. Isotope separation experiments examining the water-hydrogen chemical exchange reaction are performed for column pressures of 12-101 kPa, and the separation factors for hydrogen and deuterium are obtained. The HETP (Height Equivalent to a Theoretical Plate) values were distributed in the range of 6 to 15 cm. By reducing the pressure in the column, the process temperature can be lowered without reducing the molar fraction of water vapor in the gas stream. It confirmed that the separation factors under reduced pressure are larger than under atmospheric pressure. This fact demonstrates the effectiveness of reduced pressure in water-hydrogen chemical exchange processes.