Could you run hot glycol instead of hot water?
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use more heat exchangers and keep them separate.
*edit or heat the glycol water with an appropriate heater
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Its always easier to recover propane out of the column than it is butane 
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thank you Sir!!
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I could have sworn @GrayWolf posted a design that uses a air pressure to push/evacuation the glycol to a reservoir, then switches to hot water, I cant find it so maybe im out to lunch
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It’s all about vapor pressure. At -40C I need a super low vacuum to evaporate butane. At room temp that value of vacuum is much less.
In theory it could work but you need a fast and deep vac.
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Yes! I have been thinking about this lately as well
Even at room temp it’s going to be a slog because in order to evaporate, it’s going to suck temperature and make the column cold. You know, Heat of Vaporization and whatnot. Unless there is some sort of HEX or heater keeping the fluid warm, it’s just going to cool everything down and slow to a crawl.
At my last lab, we were running a very large system (12" diameter material columns) and even with a heated jacket, that heat couldn’t penetrate to the center of our material baskets and we always had a frozen core of biomass after runs. This was even after applying hot fluid to the material column for ~2hrs during recovery.
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We use a pressure push system from the warm pump outlet before going into the condensing coil. It will completely dry the column.
I was running into this same issue after we started using a bit of crc but found I was running enough solvent that that last Lb or two in the column had nothing in it. Easy fix was to attach a pump to the top of the stack and T it into the sieve. I recover on the pot first to pull as much through the stack as I can but once pressure equalizes I pump off the column to -15hg and get my next one ready. No heating needed for me but my columns are just frozen not dry ice cold.