The relationship of pressure to yeast viability is an unknown to me but if the liquid column is deep enough that should establish a viability zone and a piece of filter (plastic or plasticized paper?) could keep all the yeasties happy below that barrier. As to vapor pressure I think you are asking what it boils at. Perhaps you can find that on the web or in the library.
You will probably use less energy purifying by freezing rather than vaporizing The depression in degrees C for ethanol/water is % ethanol depression degrees C 5 2.09 10 4.47 15 7.36 20 10.92 30 20.47 40 29.26 50 37.67 60 44.93 68 49.52 I think freezing H2O only uses 1/3 as much energy as evaporating. Better check that as my memory isn't what it used to be. Another way, since it can be slow, is a cold trap in a sealed system. The alcohol will transport faster than the water. Vacuum systems where you pressurize the output of the pump in a cold trap have the product going through a pump and contamination is a given. If not for human consumption I suppose it doesn't matter but the energy requirements are higher than just a trap using ambient heat to transport the product. It doesn't have to boil and the cold trap condenser heat can be put back in the source vessel if using a refrigeration system. If your tank is at 125 F I would think 75F would get condensate at a good enough rate to keep concentration below yeast toxicity. Could get 75F probably by running household water through a tank and then to house. Most water is 55F or so I would think. I assume you use the sun to heat your tank. Slowest process of all but uses the least energy. Just some meandering round Robin Hood's barn but I think there is a seed or two in there. Kirk -----Original Message----- From: motie_d [mailto:[EMAIL PROTECTED] Sent: Friday, February 08, 2002 3:34 PM To: biofuel@yahoogroups.com Subject: [biofuel] Re: ethanol distillation --- In [EMAIL PROTECTED], "kirk" <[EMAIL PROTECTED]> wrote: > I think yeast croak or really slow down at 14% or higher.(14% =28proof) > That is also my understanding. The alcohol starts to kill the Yeast above 10%, and they are nearly all dead by 14%. On the temp side, 140F kills them off. That brings me back to the basis of my question. If I heat my fermentation tanks to (?)125F, so the yeast are still alive, how much vacuum will I need to apply to the tank, to start removing some of the Ethanol to keep the level below 10%? How much vacuum to do the same task at 100F? I would like to keep the Yeast alive and actively producing, without having to heat the massive quantities of water to do a traditional distillation. I'm trying to look ahead, at the whole process, and solve as many potential problems as I can see, before I start investing meager assets to it. I can overcome the heating problem rather economically. It's disposing of the heat after I've used it, that will be my shortcoming. I am trying to remove the heat disposal problem, by simply not putting the heat in to start with. I welcome any thoughts and commentary on my approach. Motie Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Please do NOT send "unsubscribe" messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.323 / Virus Database: 180 - Release Date: 2/8/2002 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.323 / Virus Database: 180 - Release Date: 2/8/2002 ------------------------ Yahoo! Groups Sponsor ---------------------~--> Get your FREE credit report with a FREE CreditCheck Monitoring Service trial http://us.click.yahoo.com/ACHqaB/bQ8CAA/ySSFAA/FGYolB/TM ---------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Please do NOT send "unsubscribe" messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
