Pd-based composite membranes

H. Klette, Y. barring, H. Raeder, R. Bre-desen, A new method for preparation of Pd-based composite membranes in Proceedings of the 8th International Conference on Inorganic Membranes, Jul. 18-22, 2004, Cincinnati, OH, Adams Press, Chicago, IL... 

Li A, Grace JR, Lim CJ (2007) Preparation of thin Pd-based composite membrane on planar metallic substrate Part U. Preparation of membranes by electroless plating and characterization. J Membr Sci 306 159-165... 

Figure 11.11 shows a 12 inch length ceramic (zirconia) coated porous metal support tube and two Pd-based composite membrane elements of 4 inch and 12 inch length respectively. 

Figure 11.11 Pd-based composite membranes and a substrate tube element.

In this chapter we have shown that the main trend in Pd-based membrane development is towards thinner membranes, particularly composite membranes. The relatively demanding operation conditions in many important applications require further work in terms of membrane development in combination with optimisation of reactor design and operation conditions. The encouraging industrial involvement in the development of the membrane, module and reactor technology is a key factor for successful implementation. Current state-of-the-art shows capability of small scale industrial membrane production of the most common Pd-based composite membranes. Their stability has been verified for thousands of hours under realistic conditions, but in processes free of some of the most hazardous components, e.g. sulfur. 

Coke is another problem associated with metal when an initially defect-free Pd-based composite membrane is used in high temperature catalytic applications. The further diffusion of these deposited carbonaceous impurities into the bulk phase of the membrane can lead to defects in the membrane (Lu et al., 2007). Lin (2001) has conducted some systematic investigations into this. Figure 2.24 shows the permeance and separation results of a thin Pd/Ag membrane prepared by sputter deposition before and after being exposed to a graphite ring (surrounding the membrane disk) at 600°C... 

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