Heavy water hydrogen exchange process

As part of the Manhattan District Project during World War II, a small plant to produce heavy water 6 Mg/a) was built by Standard Oil Development Co. at Trail, B.C. and was operated by Cominco from 1944 to 1956 (14). It was based on steam-hydrogen catalytic exchange plus steam-water equilibration coupled to water electrolysis. However, byproduct heavy water from this process is economic only if the electrolysis cost is borne by the hydrogen product, which at Trail was used for ammonia production. In any case, the small scale of operation imposed by electrolytic capacity and the large exchange tower volume have made this production method economically unattractive. 

All of the previously mentioned plants except those employing distillation of water were parasitic to a synthetic anunonia plant. Their deuterium-production rate is limited by the amount of deuterium in ammonia synthesis gas. To produce heavy water at a sufficient rate, a growing industry of heavy-water reactors requires a deuterium-containing feed available in even greater quantity than ammonia synthesis gas. Of the possible candidates, water, natural gas, and petroleum hydrocarbons, water is the only one for which an economic process has been devised, and the dual-temperature hydrogen sulfide-water exchange process is the most economic of the processes that have been developed. 

Figure 13.40 Material flow sheet for first stage of Sulzer dual-temperature methylamine-hydrogen exchange heavy-water process. [AT] = deuterium content of hydrogen relative to natural water containing 135 ppm. Flow quantities, kg-mol/h.

In many respects, the case history presented by D. W. Jones and J. B. Jones of the DuPont Company is typical, They reported studies conducted on a pair of columns in use at Dana, Indiana, and Savannah River, Georgia, for a heavy-water process using dual temperature exchange of deuterium between water and hydrogen sulfide at elevated pressures. 

There have been many assessments and comparisons of heavy-water processes in Canada during the past three decades (15, 31, 32, 33). Despite the wide range of alternatives studied, none that can ofier unlimited production are able to compete with the GS process—deuterium exchange between water and hydrogen sulfide—which was chosen by the US AEG for their large-scale production needs nearly 30 years ago (34). 

Wynn, N. P. Lockerby, W. E. Heavy Water Processes Using Amine-Hydrogen Exchange, Annual International Conference of the Canadian Nuclear Association, 18th, 1978. 

The third important concept introduced by Taylor was the use of model reactions, "yard sticks" to determine the mode of activation of molecules by surfaces. For hydrogen activation, Taylor(15) proposed the conversion of ortho to para hydrogen as a measure of the catalytic activity of a surface. This turned out to be more complicated than was first realized. A physical magnetic effect was also operative as was shown among others by Diamond and Taylor(27) for the case of rare earths and by Turkevich and Selwood.(25) Later Laroche and Turkevlch(29) used magnetic resonance to quantify the catalytic effect of charcoal and to differentiate it from dissociative process. The discovery of deuterium opened up the use of isotope exchange reactions as delicate "model reactions" for elucidation of the activation of molecules. Immediately after H. Urey announced the discovery of heavy water in 1932, Taylor(30) realized its potential as a tool in catalytic research and engaged in a massive production in Princeton of heavy water. 

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