joanne Duff writes: >During my research I have found that the use of molecular sieves is >widespread, however the companies who provide them tend to design a >unit specific to that particular sieve. They have proved very >unhelpful with regards to advice, ideas for flowsheets etc.
The support structure for the molecular sieve mostly serves to keep the beads of zeolite from scraping against each other and wearing down, both during the adsorption phase and when being "regenerated" with dry nitrogen gas or whatever. I just throw the beads into the wet ethanol, shake it up, and filter 'em out a few hours later. There's a bit of brown powder in the bottom every time, so I suppose my beads will wear out eventually, but I've been working with the original 10 pounds ($8.50 a pound from Adcoa, not free!) for 6 mos. now and have probably only lost 50 ml in dust..... Regeneration is pretty energy-intensive (I use an oven set to 550 F for about 1.5 hours with frequent stirring). Concentrated solar would be a nice way to do it, and vacuum would help as well. All that energy has to be balanced against the additional energy and equipment required to achieve the additional 5% of dehydration possible in a fractionation, but I'm sure you're aware of the tradeoffs. I'm actually more interested in some of the less exotic adsorbents, like rice husk ash, portland cement, corn grits, etc. Right now I'm experimenting with portland cement -- I'll report any results to the list. ------------------------ 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/
