Process Considerations and Calculations

The engineer dealing with membrane processes is confronted witir the usual set of tasks associated with operations of this type. In the area of design, we wish to establish the type of membrane and the total area required for a 

In all these endeavors, rigorous or approximate, transport parameters play a key role and must be addressed first. They are dependent on a number of variables, including flow conditions, membrane and module geometry, and the specific membrane process being addressed. Thus, the flow can be laminar or turbulent, involve gases or liquids, or take place in hollow-fiber or spiral-wound geometries. We listed some of these features and the resulting transport parameters in Table 8.8. 

We note, first, that transport resistance is on the fluid side in most cases the main exception is gas permeation, which, because of the much higher diffusivities involved, is controlled by the membrane resistance. When fluid flow is laminar on the core side, mass transport will be in the entry region 

Mass Transfer and Separation Processes Principles and Applications 

This local balance of solute transport was first described by Brian in analytical form as follows  

Reverse osmosis spiral wound Reverse osmosis hollow fiber Gas separation hollow fiber 

Reverse osmosis hollow fiber (bore-side fed) 

Note Water permeability for contemporary RO membranes is in the range mol/m%Pa. 

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