Can someone advise me of what a multi arm catalyst distributor in the regen looks like? This is with a spent cat riser carrying 100% of air and catalyst. This was a design probably done way back in 1940s (long long before I was born :).. Can someone guide me of how this thing works and even if there are any design guidelines to design one? I have heard of one refinery in California (Martinez) which has this 12 arm distributor, called dodecapus...