Re: Hydrogen production without fossil fuels
Posted by Amaranth Rose on Feb 13, 2004 at 22:58
(65.172.150.222)Re: Hydrogen production without fossil fuels (True)
YAY!! Way to go!! GOOD JOB!!! I'm proud of you!
I'm really glad you didn't quit. I'd have felt like a lousy teaacher. Hey, wait. I am a lousy teacher. Oh, well.
Good luck in future.
BTW, fermentation with ordinary Saccharomyces cerevisiae (cereal grain yeast) will give you about 12-15% ethanol; certain special varieties such as sherry yeasts may get you to 20%, under batch condtions. It's possible that using either selection techniques or genetic engineering you could perhaps push that up another 10%. Using continuous culture conditions might affect results either way as well. Using some kind of rotating biological contactor technology it might be possible to collect the ethanol due to its relatively high vapor pressure in vapor form in a gas stream and condense it directly. If you have to distill it, it might be possible to use heat from a solar furnace. Geothermal energy might be another possiblility.
Either way you're only going to get 95% ethanol, because at 95% ethanol/5% water the mixture forms an azeotrope at ambient pressures that can only be separated further using molecular sieve technology. This would be a waste for fuel production, anyway, since immediately upon exposure to water, even the water vapor in air, it will "draw" water until it is diluted to 95% ethanol.
At any rate, the absolute limit for practicality is 95%; fuel probably doesn't need to actually be that hot. 70% ethanol burns pretty well, as I recall....