In additon, a fractionating column requires a reflux, the partial return and recycling of distillate product from the condenser back down the fractionating column which increases the energy tax (energy costs) of purifying the methanol.
Mike McGinness bob allen wrote: > without getting into excessive detail, the boiling point of a mixture is > the weighted average of the stuff present. At first you have pure > methanol coming off. as the temperature rose, increasing amounts of > water contaminated the alcohol. > > You need a fractionating column to obtain pure methanol. > > Joe Street wrote: > > 3A sieves will work but are normally used for getting tiny amounts of > > water out of solvents to bring them into the low ppm range. They will > > work of course but you might saturate them and have to do a second > > stage. There is a significant energy input into regenerating the seives > > as well. You have to bake them at well over 100 degrees C more like > > 200, but you can get by with lower temps if you bake them out with > > vacuum. Try putting a thermometer in your condenser and monitor vapour > > temperature to get a better endpoint and you will have an easier time. > > You have answered some of my own questions. I have recovered some > > methanol but not tried to use it yet. Sounds like if straight > > distillation is carefully done the methanol is dry enough to use without > > further drying. Great news and thanks for the post! :) > > > > I have some excellent references on solvent drying I can mail you if you > > want. No soft copy sorry but I might be able to scan them. > > > > Joe > > > > Thomas Kelly wrote: > >> Good day to all, > >> After splitting the glycerine coproduct from roughly 1200L of > >> processed WVO, I distilled approximately 100L of the > >> glycerine/methanol component. > >> The first drops of methanol began to fall from the condenser at > >> 145F. As the temp rose to 150F there was a steady flow of clear liquid > >> from the condenser. Throughout the day I turned the heat off when the > >> flow was steady and back on when it slowed. > >> I filled a 4.5 gal (17.7L) cubie with clear liquid and started a > >> second one. At this point the temp was over 160F. I let the still run > >> up to 200F. At this point the second cubie had 4 gallons of clear > >> liquid (and it was now 1AM) giving a total of 8.5 gal. I was thrilled > >> with the result (and tired). I used the first 4.5 gal (17.7L) to run > >> one batch, and while that was settling ran a second batch using the > >> second 4 gal of recovered methanol. > >> The first batch washed OK, but was a little slow to separate. It > >> failed the methanol quality test. > >> The second batch did not even pass the wash test. > >> I have been making consistenly high quality BD for several months ... > >> thank you JtF and list members. I don't think I made mistakes in > >> measurement or titration. > >> My question: > >> As my distillation temps rose towards 200F (93C) could I have been > >> including water in my distillate? (The methanol recovered at lower > >> temps performed better than the methanol recovered at higher temps.) > >> If so, can I use Zeolite "molecular sieves" in the future to remove it? > >> > >> Thanks, > >> Tom > >> ------------------------------------------------------------------------ > >> > >> _______________________________________________ > >> Biofuel mailing list > >> Biofuel@sustainablelists.org > >> http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org > >> > >> Biofuel at Journey to Forever: > >> http://journeytoforever.org/biofuel.html > >> > >> Search the combined Biofuel and Biofuels-biz list archives (50,000 > >> messages): > >> http://www.mail-archive.com/biofuel@sustainablelists.org/ > >> > >> > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > Biofuel mailing list > > Biofuel@sustainablelists.org > > http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org > > > > Biofuel at Journey to Forever: > > http://journeytoforever.org/biofuel.html > > > > Search the combined Biofuel and Biofuels-biz list archives (50,000 > > messages): > > http://www.mail-archive.com/biofuel@sustainablelists.org/ > > > > -- > Bob Allen > http://ozarker.org/bob > > "Science is what we have learned about how to keep > from fooling ourselves" Richard Feynman > > _______________________________________________ > Biofuel mailing list > Biofuel@sustainablelists.org > http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): > http://www.mail-archive.com/biofuel@sustainablelists.org/ _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
