Separating hydrogen from reformate, are we?  Is your product the hydrogen, or is it the reformate?  You forgot to mention a key parameter:  pressure.  What's your feed pressure, and required/available discharge pressure for the hydrogen?  Any membrane which you plan to use will of course have a significant pressure drop across it.

I don't have any vendors to suggest to you, but there are membrane suppliers out there with a variety of membranes (metallic and otherwise) for this job.  I think you can count on the need for cooling the reformate a long way below 800 C, though.

Some vendors for H2 separation.

Air Liquide [my choice, OTOH they pay me to say that  *-)]
Air Products
UOP

these are all polymeric membranes and there are probably others.  Last I checked, there are no fully commercialized ceramic membranes for gas separation.  Metallic membranes are available but are aimed at ultra high purity applications (tritium/helium, GC H2 etc) As they use Pt/Pd as the membrane, I'm not sure passing your stream over them would produce reactions anyway.  

Polymeric membranes means cooling to 80-90° C, and a compression step, so the economics of this versus competing technologies are unclear.  

I would try H2 companies (such as AP and AL), and the membrane engineering section of eng-tips, where I think this was discussed once.

Dave Hasse
dave.hasse@airliquide.com
(see, I told you they pay me to say that)

There are some high temp metal membrane units.
This is the best ref that I could find.
http://www.alleghenytechnologies.com/wahchang/pages/products/hmm/hmm.htm

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