We have used CO2 local application nozzles for some large tanks in an aircraft part mfg facility i was involved with. These are activated by detectors. The nozzles are pointed across the top surface of the tank.
Lots of variables here that need to be considered, just a few that come to mind:
-Do you have plastic ducts? I would bet you do, and my guess is they are large diameter based on the occupancy. The ducts will probably need sprinkler protection inside these if they are plastic/transporting comb vapors.
-I think you should be looking at sprinklers for this occupancy, in addition to local application systems for the tanks, but i dont know the details.
-Tank containment/driange as needed.
-Are your tanks heated? Hopefully by steam or hot water. IF electric immersion heaters - warning, you have an ignition source for combustible tanks if level drops. Lots of fires involving plastic tanks and electric immersion heaters.
-Interlocks for tank levels, heaters, etc.
I dont know your scope of involvement here, but this can be a big undertaking.