Gases, centrifugalizing

Canyover solid or liquid, polymer gas OFS compressor is known able to handle dirty gas vriih sold panicles, entrained liquidl or polymer gases. Centrifugal compressor can tolerate some solid or liquid, but OIS compressor and reciprocating compressor cannot tolerate solid, liquid, or polymer gases. 

The UFg is then isotopicaHy enriched by gaseous diffusion or gas centrifuge processes for nuclear appHcations. 

I. D. Heriot, Cranium Enrichment by Gas Centrifuge, EUR 11486EN, for the Commission of the European Communities, Urenco Ltd., Luxembourg, Belgium, 1988. 

A number of special processes have been developed for difficult separations, such as the separation of the stable isotopes of uranium and those of other elements (see Nuclear reactors Uraniumand uranium compounds). Two of these processes, gaseous diffusion and gas centrifugation, are used by several nations on a multibillion doUar scale to separate partially the uranium isotopes and to produce a much more valuable fuel for nuclear power reactors. Because separation in these special processes depends upon the different rates of diffusion of the components, the processes are often referred to collectively as diffusion separation methods. There is also a thermal diffusion process used on a modest scale for the separation of heflum-group gases (qv) and on a laboratory scale for the separation of various other materials. Thermal diffusion is not discussed herein. 

In the United States, a group of domestic investors, including Duke Power, and Urenco, have appHed for permission to constmct a new gas centrifuge plant in Louisiana. 

The ratio of these two equations gives the radial separation afforded by the gas centrifuge under equiUbrium conditions, that is, for no internal gas circulation. An equiUbrium separation factor between gas at the axis of the centrifuge and gas at the periphery is therefore given by ... 

It should be noted that the separation factor for the centrifuge process is a function of the difference in the mol wts of the components being separated rather than, as is the case in gaseous diffusion, a function of their ratio. The gas centrifuge process would therefore be expected to be relatively more suitable for the separation of heavy molecules. As an example of the equiUbrium separation factor of a gas centrifuge, consider the Zippe centrifuge, operating at 60°C with a peripheral velocity of 350 m/s. From equation 68, OC is calculated to be 1.0686 for uranium isotopes in the form of UF. ... 

Mass Transport. An expression for the diffusive transport of the light component of a binary gas mixture in the radial direction in the gas centrifuge can be obtained directly from the general diffusion equation and an expression for the radial pressure gradient in the centrifuge. For diffusion in a binary system in the absence of temperature gradients and external forces, the general diffusion equation retains only the pressure diffusion and ordinary diffusion effects and takes the form... 

The preceding two equations may be used to write the gradient equation for the countercurrent gas centrifuge in an alternative form. If the ratio of the actual gas circulation rate in the centrifuge to the circulation rate that rninimizes the stage length T/Tq is designated by m, then equation 74 may be rewritten... 

Maximum Separative Capaeity and the Separative Effieieney. The separative efficiency of a gas centrifuge used for isotope separation is best defined in terms of separative work. Thus, the separative efficiency E is defined by... 

Theoretical Formulation of the Separative Efficiency. The separative efficiency E of a countercurrent gas centrifuge maybe considered to be the product of four factors, all but one of which can be evaluated on the basis of theoretical considerations. In this formulation the separative efficiency is defined by... 

Fig. 14. Hypothetical velocity profile models for a countercurrent-flow gas centrifuge, (a) The optimum velocity profile ia a countercurrent gas centrifuge.

The Martin Veloeity Profile. It has been suggested (50) that the velocity profile in a gas centrifuge in which the countercurrent flow is caused by a temperature difference between the circulating gas and the end caps is given by... 

A. S. Berman, A Theory of Isotope Separation in a Tong Countercurrent Gas Centrifuge Rept. K-1536, Union Carbide Corp., Nuclear Div., 1962. 

H. M. Parker and T. T. Mayo, IV, Countercurrent Flow in a Semi-Infinite Gas Centrifuge Rept. UVA-279-63R, Research Laboratories for the Engineering Sciences, University of Virginia, ChadottesviUe, 1963. 

J. L. Modfied Minimum Principle for Stationay Flow in a Gas Centrifuge Re t. EP-3912-325-64U, Research Laboratories for the Engineering... 

R. J. BShando, A Finite Difference Solution of Onsager s Modelfor Flow in a Gas Centrifuge Rept. UVA-ER-822-83U, University of Virginia, ChadottesviUe, 1983. 

D. G. Avery and E. Davies, Uranium Enrichment by Gas Centrifuge Mills Boon Ltd., London, 1973. 

An ethylene gas centrifugal compressor required the following operating conditions ... 

Uranium carbonates, 25 430-432 Uranium chlorides, 25 438-439 Uranium compounds, 25 421-434 handling, 17 529 Uranium dioxide, 25 422-423 Uranium-enrichment process gas centrifuge, 25 413-415 Uranium exploration, 25 398 URanium Extraction (UREX) process, 25 420... 

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