Doh! don’t want to ignore those. Vacuum jacketed stainless.
Don’t have a clue atm. but understand that like the solvent they have a heat capacity and will need to come along for the temp drop. call it 200lb at a guess.
Math shown was for 100gal.
It was done for 20C => -20C
but that doesn’t change the energy that needs to be removed, just how hard it is to remove it 
lets start at ambient. and lets assume that we’re in a poorly controlled warehouse in summer…so that actually means 35C.
Because it happens.
It’s also my expected solvent boiling temp in the recovery still
lets go to -60C. because it’s hard. but looks like it might be the right response.
how fast? I gave a rational for wanting to get from 20 to -20 in a hr over here…suggesting I need to go from +35 to -60 in that time-frame without throwing liqN2 at the problem seems like asking for a BIG chiller…but one hr temp on a 100gal of solvent would match up nicely with 100gal/hr folks would like to see out of their solvent recovery rigs. So lets call it one hr (also allows scaling to 1600gal “over-night”).
Can I convince you to show your work?
If you teach the village how to size their chillers, or at least double check the consultant they hired, there won’t be as many folks like the OP running woefully undersized chillers…