A gaseous diffusion column was designed, constructed, and its operation tested with a system of electrolytic hydrogen and carbon dioxide. The column contained one diffusion unit with two 6-inch diameter barrier areas. In the preliminary tests the flow rates of the hydrogen-carbon dioxide mixture were varied from 0 to 15 cubic feet per hour. Vacuum on the system was varied from 0 to 25 inches of mercury. Composition of the feed mixture was held constant at 50 mol per cent hydrogen and 50 mol per cent carbon dioxide. Temperature of the system varied with the surroundings from 75 to 85 °F. Barrier materials were of 0.008 inch thick fiber glass called Dexiglas mat obtained from Dexter and Sons, and 0.018-inch thick fiber glass Ultra Efficient Filter media mat obtained from Mine Safety Appliance Company.
It was found that the hydrogen permeated at a rate greater than could be explained by diffusion alone, but which could be closely accounted for when adsorption and adsorbed flow were taken into account. The separation of a system of carbon dioxide and hydrogen by means of a fiber glass barrier could be adequately represented as a combination of gaseous diffusion and of adsorbed flow. Agreement of observed values was within five per cent with an estimate of gaseous diffusion using Weller and Steiner's equation plus a value for adsorbed flow from a modified version of Russell's equation. The separation of hydrogen from carbon dioxide in the equipment as constructed increased as the pressure increased from 10 to 20 inches of mercury for flow rates of one to ten cubic feet per hour for the gaseous mixture which is contrary to that predicted by pure gaseous diffusion.
A permeability apparatus was constructed and operated with a system of .carbon dioxide and hydrogen. Composition of the feed mixture was either pure electrolytic hydrogen, pure carbon dioxide, or a mixture of 50 mol per cent hydrogen and 50 mol per cent carbon dioxide. Temperature of the system varied with the surroundings from 25 to 28 °C.
Barrier materials of 0.008-inch thick fiber glass called Dexiglas obtained from Dexter and Sons, 0.001-inch thick polystyrene from Dow Chemical Company, 0.001-inch thick cellulose acetate supplied by Celanese Corporation, and silicone rubber obtained from General Electric Company, Silicone Division, were used in this investigation.
The permeation of hydrogen and carbon dioxide checked previous work<sup>(69)</sup> which listed these barriers as having selective permeability to the gases used. The permeation of a mixture of carbon dioxide and hydrogen is in direct relationship with the adsorption of that mixture onto a powdered sample of the barrier material. / Ph. D.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/106290 |
| Date | January 1965 |
| Creators | Primrose, Russell Adrian |
| Contributors | Chemical Engineering |
| Publisher | Virginia Polytechnic Institute |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation, Text |
| Format | x, 166 leaves, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 20275546 |
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