Atomic Energy of Canada Limited

Fred W Molson

John P Butler

James Den Hartog

John H Rolston

John W Goodale

In one embodiment of the invention a catalyst packing module is provided which greatly enhances the vapour-liquid transfer rate in the overall hydrogen-liquid water isotopic exchange reaction between streams of gaseous hydrogen and liquid water. The catalyst packing module comprises alternate layers of plane sheet and corrugated sheet and is produced by rolling at least one plane sheet and at least one corrugated sheet together into a right cylinder in a jelly roll configuration. The plane sheet is a woven, knitted or felted cloth of a textile material which wicks water over its surface and the corrugated sheet is an open mesh of metal coated with a porous matrix of polytetrafluoroethylene with exposed, partially platinized carbon particles therein. This catalyst packing module maximizes the hydrophilic surface area per unit volume of packing for the vapour-liquid transfer reaction and also the surface area of the support material (carrier) for the hydrophobic catalyst. Although the packing is tight, high gas and liquid flow can be used without flooding the bed because the hydrophilic surfaces are separated by hydrophobic spacers and because the hydrophilic surface have a wicking action. In other embodiments of the invention the packing module is used to advantage for any gas-liquid transfer reaction but in this application the corrugated mesh is a metal cloth, does not support a catalyst and is made hydrophobic with, or of, some suitable polymeric material such as polytetrafluoroethylene, polyethylene, polystyrene, polymethacrylate, polypropylene etc.

Ordered bed packing module

For the exchange of hydrogen isotopes between streams of gaseous hydrogen and liquid water, wherein the streams are at a temperature in the range 273 to 573K are brought into contact with one another and a catalytically active mass, an improved catalytically active mass is provided comprising an inherently hydrophotic, porous, polytetrafluoroethylene matrix and partially platinized carbon particles dispersed throughout the whole of the porous polytetrafluoroethylene matrix in the weight ratio of 1:1 to 3:1 of polytetrafluoroethylene to partially platinized high surface area carbon particles. The inherently hydrophobic, porous, polytetrafluoroethylene matrix allows the catalytically active metal to catalyze the hydrogen isotope exchange reaction between hydrogen gas and water vapor in the presence of liquid water while retarding loss of activity of the catalytically active metal by contact of the metal catalyst with liquid water. This catalyzed chemical isotope exchange proceeds simultaneously with isotope exchange from water vapor to liquid water by a non-catalyzed, physical evaporation and condensation exchange reaction. The efficient coupling of these two isotopic transfer steps which results in a rapid overall isotopic exchange between hydrogen and liquid water without a pronounced loss of activity of the catalytically active mass is dependent upon the weight ratio of the catalytically active platinized carbon to the polytetrafluoroethylene matrix being in the above mentioned range of 1:1 to 3:1.

Catalytically active mass for the exchange of hydrogen isotopes between

A process for the exchange of hydrogen isotopes between streams of gaseous hydrogen and liquid water is described, wherein the streams at a temperature in the range 273 to 573 K are brought into contact with one another and a catalytically active mass comprising an inherently hydrophobic, porous, polytetrafluoroethylene matrix and partially platinized carbon particles dispersed throughout the whole of the porous polytetrafluoroethylene matrix in the weight ratio of 1:1 to 3:1 of polytetrafluoroethylene to partially platinized high surface area carbon particles. The inherently hydrophobic, porous polytetrafluoroethylene matrix allows the catalytically active metal to catalyze the hydrogen isotope exchange reaction between hydrogen gas and water vapor in the presence of liquid water while retarding loss of activity of the catalytically active metal by contact of the metal catalyst with liquid water. This catalyzed chemical isotope exchange proceeds simultaneously with isotope exchange from water vapor to liquid water by a non-catalyzed, physical evaporation and condensation exchange reaction. The efficient coupling of these two isotopic transfer steps which results in a rapid overall isotopic exchange between hydrogen and liquid water without a pronounced loss of activity of the catalyst is dependent upon the weight ratio of the catalytically active platinized carbon to the polytetrafluoroethylene matrix being in the above mentioned range of 1:1 to 3:1.

Process for the exchange of hydrogen isotopes between streams of gaseous

A process for the exchange of hydrogen isotopes between streams of gaseous hydrogen and liquid water is described, wherein the streams of liquid water and gaseous hydrogen are simultaneously brought into contact with one another and a catalyst packed bed assembly while at a temperature in the range 273.degree. to 573.degree. K. The catalyst packed bed assembly may be composed of discrete carrier bodies of e.g. ceramics, metals, fibrous materials or synthetic plastics with catalytically active metal crystallites selected from Group VIII of the Periodic Table, partially enclosed in and bonded to the carrier bodies by a water repellent, water vapor and hydrogen gas permeable, porous, polymeric material, and discrete packing bodies having an exterior surface which is substantially hydrophilic and relatively non-catalytically active with regard to hydrogen isotope exchange between hydrogen gas and water vapor to that of the catalyst bodies. The catalytically active metal crystallites catalyze the hydrogen isotope exchange reaction between hydrogen gas and water vapor in the presence of liquid water while the polymeric material retards the loss of activity of the catalytically active metal crystallites caused by contact thereof by the liquid water. This catalyzed chemical isotope exchange proceeds simultaneously with isotope exchange from water vapor to liquid water by a non-catalyzed, physical evaporation and condensation exchange reaction and the addition of the discrete hydrophilic packing serves to increase this rate of isotope exchange between the water vapor and the liquid water. In other embodiments the catalyst structure and hydrophilic packing structure comprise a mixture of corrugated and flat metal sheet or gauze or a mixture of corrugated metal sheets or gauze packed or rolled such that fluid flow passage interstices are provided between the sheets and with the catalytically active metal crystallites deposited on some of the metal sheets or gauze.

Growing community of inventors

Petawawa, Canada

Fred W Molson