Helium purification system with PSA and membrane.

High purification of gases by diffusion through polymer membranes

“…This conclusion also follows from Eqs. (19) and (25) in which the sep aration factor increases with increasing Q B /W ratio. Figure 7 presents experimental and calculated val ues of the separation factor for the case of germane cleaning of phosphine.…”

“…In this case, a p = 1, b р = 0, and d р = 0 in Eq. (19) and we obtain from Eq. (26) that (27) where L in and L 1out (mol/s) are the flow rates of the mixture at the membrane module inlet and the outlet of the high pressure side, respectively.…”

“…It can be used both indepen dently and in combination with other separation methods. For example, Asahara and Taneda [19] described a scheme for producing helium containing less than 10 -3 vol % impurities, in which the processes of diffusion through a polymeric membrane and pres sure swing adsorption are combined. The production of hydrogen and helium with a total impurity concen tration less than 10 -2 vol % using the polymer mem branes alone was proposed in [20].…”