Recovery of Ethanol from NaCl/NO3/Water mix
Recovery of Ethanol from NaCl/NO3/Water mix
(OP)
I have a waste stream composed of:
Ethanol ~50% +/- 20% (denatured)
Water ~50% +/- 20%
NaCl ~1-3%
NO3 (nitrate) ~0-3%
organic compounds 1-3%
I would like to recover the (denatured) ethanol for reuse, and minimize the volume of other stuff to dispose of. (I can tolerate up to 30% water in the recovered ethanol, but I need to get rid of the nitrate, organics and NaCl)
Distillation is the most obvious route, but it is difficult to obtain a permit and it requires an explosion proof area which I don't have.
I have looked at membranes, but so far the ethanol and NaCl molecules are too close in size to separate efficiently.
volume is maybe 20-100L / Batch.
I don't mind to have an outside contractor deal take the material offsite to do the recovery, then return the ethanol.
Anyone have any ideas?
(present facility location Ontario, Canada... shipping any significant distance likely won't be economical)
Thanks
Ethanol ~50% +/- 20% (denatured)
Water ~50% +/- 20%
NaCl ~1-3%
NO3 (nitrate) ~0-3%
organic compounds 1-3%
I would like to recover the (denatured) ethanol for reuse, and minimize the volume of other stuff to dispose of. (I can tolerate up to 30% water in the recovered ethanol, but I need to get rid of the nitrate, organics and NaCl)
Distillation is the most obvious route, but it is difficult to obtain a permit and it requires an explosion proof area which I don't have.
I have looked at membranes, but so far the ethanol and NaCl molecules are too close in size to separate efficiently.
volume is maybe 20-100L / Batch.
I don't mind to have an outside contractor deal take the material offsite to do the recovery, then return the ethanol.
Anyone have any ideas?
(present facility location Ontario, Canada... shipping any significant distance likely won't be economical)
Thanks





RE: Recovery of Ethanol from NaCl/NO3/Water mix
RE: Recovery of Ethanol from NaCl/NO3/Water mix
RE: Recovery of Ethanol from NaCl/NO3/Water mix
That way you will not be susceptible to any contamination issues with recycled material.
Your waste volume seems to be so small that it would preclude trying to recycle. It would not be economical.
RE: Recovery of Ethanol from NaCl/NO3/Water mix
Presently I am at pilot plant scale and I need to find a good solution that is scaleable to full production.
When i get to full production then the quantities produces will be very large.
The cost to purchase new ethanol, plus the cost to dispose of the waste works out to a lot of money.
Distillation economics work out a little better at large scale, but i'm still hoping to find a more elegant solution. Even if I can just reduce the ultimate size of the still or the waste volume it will help.
Freezing is looking a little less practical than at first glance unfortunately.
RE: Recovery of Ethanol from NaCl/NO3/Water mix
What about pervaporating off the ethanol?
RE: Recovery of Ethanol from NaCl/NO3/Water mix
RE: Recovery of Ethanol from NaCl/NO3/Water mix
I think you'll find distillation may be the best option (and probably the reason it's commonly used still to remove alcohol from solution)
I know that in Australia Dangerous Goods and hazardous Zones legislation keeps getting more and more stringent, so the cost of a recovery plant would have to be weighed up against the cost of dumping and replacing. You'd also probably need to register the still with the ATF (or whoever looks after alcohol excise regulations in the US)
If you're only after 20-100L then you'll find a small pot still (similar to those you can get for making "essentail oils") could be used. Seeing as this is only a pilot scale unit, the DG regulations wouldn't be anywhere near those required if you were making a distillation plant capable of 1000L/h.
I think you'll find you just need a small clearence area for the pot still. Better in a well ventilated area. Rather than requiring a completely explosion proof zone.
RE: Recovery of Ethanol from NaCl/NO3/Water mix
here is a link to a brazilian experiment (the undisputed kings of ethanol) where they used precisely that.
It might not get the kind of purification that you're looking for, but it's probably more energy efficient than distilling and can be done continously for the full scale operation.
RE: Recovery of Ethanol from NaCl/NO3/Water mix
RE: Recovery of Ethanol from NaCl/NO3/Water mix
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RE: Recovery of Ethanol from NaCl/NO3/Water mix
I used to work in a company specialized in ethanol distillation, I kept some of the home-made spreadsheets. I can make a quick simulation (mass and heat balance) if I have time. What is your expected full capacity?
However, excuse my little experience, but I am doubtful about the capability of a flash to remove dissolved compounds, especially organics (it will depend on their boiling temperature and solubility in ethanol; if they are not too close to the ethanol's, you can work on the condensation temperature but maybe you'll need an absorber). Same goes for salt and nitrates (I don't know their solubility in ethanol).
RE: Recovery of Ethanol from NaCl/NO3/Water mix