Author Topic: Alternative Ethanol Sources  (Read 16451 times)

drewtam

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Re: Alternative Ethanol Sources
« Reply #50 on: November 27, 2013, 07:07:45 PM »
Are you sure that's a problem for iso-butanol?

Quote
Unlike ethanol, which is fully miscible in water, isobutanol has limited water solubility (about 8.5%).
http://www.hydrocarbonprocessing.com/Article/3081332/Bio-isobutanol-The-next-generation-biofuel.html


Seems like it will self separate for the most part.
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charby

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Re: Alternative Ethanol Sources
« Reply #51 on: November 27, 2013, 07:33:12 PM »
It depends on the isomer, but... really really cold.  It would make good antifreeze.

So you could freeze the water out if?
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zxcvbob

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Re: Alternative Ethanol Sources
« Reply #52 on: November 27, 2013, 09:44:38 PM »
So you could freeze the water out if?

Perhaps, I don't know.  I'm not a chemist.  I'm just pretty sure conventional distillation will not work, and freezing is very energy-intensive too. 

I assume they are using acetone–butanol–ethanol fermentation (Clostridium) to produce the butanol.  Maybe they are using some other higher-yield process.
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Firethorn

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Re: Alternative Ethanol Sources
« Reply #53 on: November 27, 2013, 11:51:12 PM »
What is the freezing point of it?

Per wikipedia, -151F, -102C.

Though I'm not sure we'd be needing to hot/cold distill.  You see, current rules call for anhydrous ethanol(<1% water) for use as a fuel additive - and the allowed water is less than you can get using economic distilling methods(4.4%), so they already have to use alternative methods.  Molecular seives, dessicants, etc...  Ethanol plants should already have an alternative drying process in place.  Besides, depending on the process they're already making and drying the ethanol, so they might not need to remove water later.

Seems like it will self separate for the most part.

At that low of a water content, you might not need to seperate it out more.  I was just reading about using 'wet' alcohol as an additive instead of the anhydrous stuff, and they saw some positive outcomes.  Remember water injection?

It depends on the isomer, but... really really cold.  It would make good antifreeze.

Looking at the spec sheet I'd agree, but only in very specific circumstances.  It doesn't mix with water well, so diluting it is out.  While it's freezing point is nice and low, it's boiling point is only a smidge above water's.  It's highly flammable.  Less dense than glycol, so you'd need to oversize whatever it is.