Thanks for the answer! I've been going a little nuts.

Burn rate per what? Coal surface area?

Yep. I didn't say, because Wikipedia makes it sound standard. Sorry, I'll try and be a bit more exact next time. Wouldn't any other unit of measurement just derive from it and the complexities of fluid dynamics, given the way solid fuel combustion in an oxidising atmosphere works?

It's for a small, fully enclosed regenerative furnace design. If it was a fire pit of similar you're right that this would be a bad question, but I can assume an exact uniform temperature and as much air as it needs, so the basic chemistry is useful. It doesn't even have to nail it the rate down precisely. The question I'm trying to answer is how much flow I need per load to stay fuel lean, and I'm probably going to add 50% margin anyway.

Something may exist in an older HVAC/power plant engineering handbook somewhere in the world though.

Geez, I really hope it doesn't come to scouring the globe for ancient tomes. It might be easier just to make a table myself at that point, unless I can figure out which one has the table in advance.

Edit: The size of fuel granual to be used is open ended right now, too.