Continuous Separation of Gaseous Mixtures by Thermal Gravitational Diffusion

Abstract

For the continuous separation of gases by thermal gravitational diffusion, a rectangular diffusion cell (internal dimensions, 51 x 51 x 1 cm) was constructed and tested. For the thermal gradient, one large wall was provided with a water jacket and cooled with tap water. The opposite large wall was heated against a specially wound, vertical electric furnace. Gas flow through the vertical diffusion chamber was horizontal. This arrangement provided three mutually transverse driving forces, thermal gradient, gravity, and gas flow. Separations were made in diffusion cells with a structure-free diffusion chamber, with a chamber containing loosely packed silica fibers (vertically aligned), and with a chamber containing porous stainless steel barriers (also vertically aligned). The structurefree cell produced the best helium-nitrogen separation, the cell with silica fibers the best nitrogen-argon separation, and the barrier cell the best neon isotope enrichment No significant dependence of the separations upon from was found in any of the cells with flow rates from no flow to about 9% of the total internal volume per minute (150 ml per minute at room temperature). (auth)