On vacuum: Once a vacuum is pulled on the chamber, the power required to pull the vacuum will be proportional to the rate of withdrawal of mass or volume at the vacuum pressure. If you're not pulling off much or any water, there won't be much change in vacuum, requiring little extra power.
To minimize the power otherwise, limit the amount of space in the chamber above the liquid to minimize the work required by the vac pump. Is a waterheater shell thick enough to avoid imploding with much vacuum? How thick are their shells? A better alternative might be an ordinary water pressurization tank---I have one that's about 5feet tall, a little over 2feet diameter and has perhaps 1/4inch thick walls. It easily handles positive pressure to 100psi---would likely handle any vacuum which could be pulled. -Myles Twete, Portland > -----Original Message----- > From: girl mark [mailto:[EMAIL PROTECTED] > Sent: Monday, April 28, 2003 2:46 PM > To: biofuel@yahoogroups.com; [EMAIL PROTECTED]; > [EMAIL PROTECTED] > Subject: [biofuel] vacuum drying! > > > I just recently got an almost-free still (industrial solvent > recovery still > with a huge vacuum unit, salivate, salivate) and started > thinking about the > options that opens up for other fuels (ethanol).. I didn't > set it up yet as > we're trenching for power for it next weekend at the > earliest, and I don't > know for sure that its entirely intact. > > with my electric heating setup, I've had a hard time dewatering > extra-bad-quality WVO. Since I do two-stage process, I can > handle high ffa > content, I just hate dewatering, and I'd like to expand the > range of crappy > oil (McDonald's...) I utilize. > > anyway I had a thought that someone else might be able to > utilize sooner > than I would. How about pulling a vacuum on a container of > WVO (such as an > electric water heater) and distilling off the water vapor at > a lower temp? > I haven't built such a unit but it seems like one way to get > around the > awful energy use issues for dewatering since up to a point, > it takes less > energy to operate a vacuum pump than it does to operate a heating > element. Refrigerator compressors can pull some vacuum and are free. > > Does anyone know offhand how much vacuum the fridge > compressors pull? I was > thinking additionally about using one of my 55gallon drums > for this- turn a > closed head drum upside down, thread a heating element into > the larger > bung, weld a couple of fittings into what is now the top, and > connect them > to a source of vacuum and an outlet for the water vapor. I > know that drums > can't handle much vacuum, too, but water heaters are free as > well so one > could try that if it collapses a drum (I prefer drums as they're more > portable). > > can someone point me to where I would find info on how much > vacuum one > needs to lower the boiling point of water, and by how much? > > thanks, > mark > e > > > ------------------------ Yahoo! Groups Sponsor > ---------------------~--> > Get A Free Psychic Reading! Your Online Answer To Life's > Important Questions. > http://us.click.yahoo.com/O10svD/Me7FAA/AG3JAA/FGYolB/TM > -------------------------------------------------------------- > -------~-> > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Biofuels list archives: > http://archive.nnytech.net/ > > 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/ > > ------------------------ Yahoo! Groups Sponsor ---------------------~--> Get A Free Psychic Reading! Your Online Answer To Life's Important Questions. http://us.click.yahoo.com/cjB9SD/od7FAA/AG3JAA/FGYolB/TM ---------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/ 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/
