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Topic: Is vacuum distillation best to recover iso amyl alcohol and manufacturing esters?

I'm planning to set up a distillation unit for distilling fusel oil to recover iso amyl alcohol and manufacturing esters from it. I've been suggested to go for vacuum distillation through use of watering pump and reboiler of falling film evaporator type. The column will be about 10m high having a diameter of 0.6m. Is this the right way to go? Which packing should I consider? Will vacuum distillation break the azeotrope formed between water and ethanol?
  • Avatar Michael R. Resetarits Forum Moderator 22 Posts

    Re: Is vacuum distillation best to recover iso amyl alcohol and manufacturing esters?

    Generally, when pressure drop reduction is important, engineers choose packings instead of trays. The question that you asked, though, is more of a processing question than a distillation question.  Nevertheless, I passed your question along to Dan Summers, of Sulzer Chemtech, and he provided the following input for you:
    1.)   I would use structured packing if the water content of the feed is low
    2.)   Yes they need to go to vacuum
    3.)   Watch out though – amyl alcohol forms a second liquid phase with water.  If two liquid phases – may want to reconsider trays
    4.)   No pressure will break the ethanol-water azeotrope in my experience
    The Fusel draw is loaded with all kinds of aldehydes, ketones, esters and other alcohols in an ethanol-water mixture.  Typically the water content is low (less than 10%).  Ordinarily in fuel ethanol plants, they simply add the fusel oil back in with the ethanol.  Why do you want to split out the amyl alcohol from such a nasty stream?

    Editor's Note: Mike Resetarits, technical director of Fractionation Research Inc., is our new distillation expert.

  • Avatar Avinash Patil Community Member 4 Posts

    Re: Is vacuum distillation best to recover iso amyl alcohol and manufacturing esters?

    Last edited: 4 October 2012 at 8:48am
    Amyl alcohol( especially iso amyl) is produced from fusel oil by batch Distillation. Amyl Esters can then be manufactured out of it. Amyl alcohol or esters find many uses and it is a viable business so it makes sense to produce it provided enough fusel oil can be sourced.We have engieered few such plants in India. Packed Columns are best, but vacuum offers no specific advantage as none of the azeotrope will shift or vanish. Going for vacuum will only increase the column diameter. There are many azeotropes of C2 to c4 alcohols with water but amyl which is C5 alcohol specifically iso amyl can be separated at bp range of 128 to 132 deg C at atm pressure. The Fusel oil stream is indeed very nasty one, but it has many uses. Pl refer to attached paper / contact @
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