Kiz,
For scaled down layout size refineries, I'd say but Carl and Mark provide great representations. And tanks are in a ton of sizes etc.
If you really want to get a view of the Exxon plant next time you are in Baton Rouge, go up to the top of the new state capitol and look out form the observation deck. its to the north, and pretty impressive. For those wanting to know what we're discussing:
http://binged.it/1ui7ijp Exxon pretty much fills up the frame.
I'm going to do a version of their Polyolefins plant:
http://binged.it/1lOOTT9
