Hi Tom; Well from what I can find methanol should be larger than 3 angstroms BUT I would also be surprised if the zeolite had an absolute pore size. It is probably avareage pore size so it would adsorb a little methanol I would guess. But while ambient air does always contain some water it does not for all intents and purposes contain methanol so your air drying should result in methanol diffusing out of the material eventually whereas water would diffuse out from saturated zeolite (or into dry zeolite)until an equilibrium is reached between external and internal water content. even in the oven you have not removed all of it. In fact you never will. Desorbtion is always an exponential decay scene.
An evacuated desicator heated by the sun might work just fine. You might have to re-evacuate it a few times. When doing this if you first backfill the container with a hot dry gas it will help scavenge the water from the system. Admitting air to the hot container will approximate this but heated dry N2 would be preferable. BTW having a vacuum pump around does have a lot of advantages, you are right. For instance storing caustic in a vacuum bell prevents carbonation and also keeps it dry :) Joe Thomas Kelly wrote: > The Zeolite from the Control (3A Molecular Sieve and Methanol > Recovery) increased in mass by 13.6%. This was a bit alarming. > Joe Street suggested that it might be water absorbed from the air > while air-drying. > Tom Irwin suggested that while this is true, it might also have > absorbed methanol, as methanol might be small enough to fit through the > pores of the zeolite. > > Thinking that any methanol absorbed would not bind as strongly as > water to the zeolite, it might be driven off with very gentle heat. > > Oven temp 170F/ 77C > > Time (min) Mass(g) Change in Mass % Change > 0 454.0 - - > 15 447.6 - 6.4 1.4 > 30 445.4 - 8.6 1.9 > 45 444.5 - 9.5 2.09 > 60 444.1 - 9.9 2.18 > Does the loss of mass @ 170F represent "easy water" or methanol? (only > 2% of the 13.6% change in Control) > (Temp raised to 250F/ 121C) (total change; including 170F) > 0 443.9 - > 30 438.7 - 5.2 (15.3) > 60 434.7 - 9.2 (19.3) > 90 433.6 - 10.3 (20.4) (4.5) > 120 431.8 - 12.1 (22.2) (4.9) > (Temp raised to 350F/ 177C) > 0 431.8 - > 30 424.2 - 7.6 (29.8) > 60 415.1 -16.7 (38.9) (8.6) > (Temp raised to 400F/ 204C) > 0 415.1 - > 30 403.3 -11.8 (50.7) (11.2) > 60 397.7 -17.4 (56.3) (12.4) > > 12.4% of the 13.6% gain in mass .... a lot of energy expended doing so. > > Apologies to anyone who sees this as a waste of time and energy. It > was intended to help save time and energy during methanol recovery. > > Zeolite works best when it is absorbing water from vapors. > Regeneration requires very high energy input. Vacuum should be > included to reduce energy requirements. > Joe Street's idea of a heated trap upstream of the condenser, > collecting water vapor from the methanol vapors, and capable of heat + > vacuum regeneration, in situ, seems the way to go. It is, however beyond > what I had hoped to get away with. > Vacuum pump on a sealed solar oven? > Tom > > > > ----- Original Message ----- > *From:* Thomas Kelly <mailto:[EMAIL PROTECTED]> > *To:* biofuel@sustainablelists.org > <mailto:biofuel@sustainablelists.org> > *Sent:* Thursday, June 08, 2006 8:28 AM > *Subject:* Re: [Biofuel] 3A molecular Sieve and Methanol recovery > Results > > Tom Irwin, > You wrote: > " I think methanol may be smaller than 3A just based on your results." > > I was afraid of that, but it would explain the numbers. > > > "I don't know if water is more polar than methanol." > > I think water is more polar than methanol. > + + > H H > O vs. methanol w. region > - - of charge only > around the > alcohol (-OH) group > > "If not I don't think it will drive off bound water." > > I'm going to gently heat (100 - 150F) the zeolite from the Control. > I think that if there is significant loss of mass, it would be due > to methanol rather than water leaving the beads. If there is > little/no loss of mass, much of the gain was due to atmos. water, as > it is more tightly bound to the inner surface of the zeolite. > > > " I recall carbon dioxide being one of the most strongly held gasses." > > Interesting, because CO2 is charged, but not polar i.e. > > - O = C = O - The inner surfaces of Zeolite is > + charged ? > > " I hope this helps." > > It gives me direction for something to try on a rainy day. > If the zeolite does "dry" significantly at low temp,(drove off > methanol) then I'll have some fairly dry sieve to test the effect of > absorption of water from air on mass ..... cool clear weather > forecast for Sat. > Thanks Tom, > Tom K. > > ----- Original Message ----- > *From:* Tom Irwin <mailto:[EMAIL PROTECTED]> > *To:* biofuel@sustainablelists.org > <mailto:biofuel@sustainablelists.org> > *Sent:* Wednesday, June 07, 2006 5:47 PM > *Subject:* Re: [Biofuel] 3A molecular Sieve and Methanol > recovery Results > > Hi Tom, Joe and all, > > Air drying without heat is probably not the best way to go. > Zeolites will absorb moisture from the air. When I was ai Air > products we used to heat to 400C under nitrogen flow to a real > low dew point that I cannot remember exactly but -40 is stuck in > my memory. Then we would cool it under nitrogen flow then run > our gas separations. That's probably overkill for water/methanol > separations but it was pretty much our SOP for zeolites. It they > saw air then you regenerated prior to a test. > Some of what you are seeing could be chemisorption of the > methanol on the surface but the numbers seem too high. I think > methanol may be smaller than 3A just based on your results. I > don't know if water is more polar than methanol. If not I don't > think it will drive off bound water. I recall carbon dioxide > being one of the most stongly held gasses. I hope this helps. > > Tom Irwin > > > > ------------------------------------------------------------------------ > *From:* Joe Street [mailto:[EMAIL PROTECTED] > *To:* biofuel@sustainablelists.org > *Sent:* Wed, 07 Jun 2006 16:42:11 -0300 > *Subject:* Re: [Biofuel] 3A molecular Sieve and Methanol > recovery Results > > Hi Tom; > > Do you have any unopened zeolite? If it is vacuum dried (and > I suspect > it is) at the manufacturer, it may gain mass due to > adsorption of > moisture from the air. Take some out and weigh it and let it > sit out in > the same conditions as the other stuff you are air drying > and then weigh > it again. > > Joe > > Thomas Kelly wrote: > > > Hello to all, > > > > I have some concerns re: my recent results using 3A > Molecular Sieve to > > dry recovered methanol. > > > > Concerns: > > > > 1. I distilled 4 gal ( Containers #1 & 2), and had to > interrupt > > > > the process. > > > > Last 4 gal were distilled two days later (Containers #3 & 4). > > > > > > > > 2. Air drying: The Zeolite from the Control as well as from > > > > Containers # 1 & 2 were air-dried at the same time, for the > > > > same duration under “identical” conditions. > > > > Due to interruption of distillation and a week of rain, the > > > > Zeolite from Containers 3 & 4 was removed from the methanol > > > > after the same time period (24 hrs) as C, #1, & #2, but > stored > > > > in covered plastic containers until weather permitted, > and then were > > air-dried for the same length of time as the others under > as similar > > > > conditions as could be reasonably expected. > > > > > > > > I air-dried the Zeolite until it looked uniformly light > in color. > > > > The idea was to simply remove moisture (methanol) from the > > > > surface. > > > > > > > > 3. The Control gained mass. Although the methanol in the > > > > Control was not a newly-opened barrel, I reason to believe it > > > > to be reasonably pure. > > > > I had a concern going into the experiment that > > > > 3A Molecular Sieve might allow methanol to enter > > > > (3A = 3 angstrom units ~ size of pores in the beads) It is > > > > used to dehydrate ethanol. Water molecule = 2.8 angstrom > > > > units, ethanol = 4.4 angstrom units, methanol = I don’t know. > > > > I suspected/hoped methanol was larger than the pore size. > > > > I suspect that water adheres more strongly than methanol to > > > > the inner walls of the beads and tends to remain attached. > > > > Additional air-drying Zeolite from C, #1, and #2 (done after > > > > surface was dry and original measurements were recorded) > > > > resulted in continued loss in mass. At temps of only > > > > 72 F (22.2 C) and filtered light I don’t suspect much of the > > > > weight loss is due to water. > > > > > > > > 4. Zeolite, under the best of circumstances (exposed to vapor > > > > under pressure) can absorb up to 25% of its weight in water. > > > > Zeolite from container 3 increased in mass 23.1 % and > > > > zeolite from Container 4 gained 28.8%. What gives? > > > > > > > > The results are interesting in that a comparison of the > > > > zeolite exposed to the recovered methanol to the control > > > > suggests that there was little water in the first 4 gallons > > > > recovered. This is corroborated by the fact that I used the > > > > Control and the first 2 recovered gallons + about 1 gal. from > > > > the barrel to make a 91L batch of BD that passed the > > > > “methanol quality” test. I pan to use the second 2 gal. > in the > > > > next batch. (Maybe after a couple of hours of dry zeolite > > > > treatment). > > > > Tom > > > > > > > > > > > > ----- Original Message ----- > > *From:* Thomas Kelly <mailto:[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> > > *To:* biofuel@sustainablelists.org > <mailto:biofuel@sustainablelists.org> > > <mailto:biofuel@sustainablelists.org > <mailto:biofuel@sustainablelists.org>> > > *Sent:* Wednesday, June 07, 2006 11:41 AM > > *Subject:* Re: [Biofuel] 3A molecular Sieve and Methanol > recovery > > Results > > > > Hello all, > > > > > > 3A Molecular Sieve and Methanol Recovery > > > > I first separated the glycerine mix using Phosphoric Acid. > > This fragment has a high percentage of the excess methanol > > > > used to produce methyl esters. > > > > I then recovered the methanol using a simple still and > > condenser. The methanol flowed into containers that each > had 5 pounds > > > > (2270g) of new zeolite. Each container was marked > > > > such that in addition to the zeolite, there would be 2 > gal (7.6L) of > > methanol. Container #1 received the first 2 gal of recovered > > > > methanol, container #2 the next 2 gal, etc. > > > > My hope was, that by comparing final mass of zeolite to > initial > > mass, I could get a sense of how much water was coming > > > > over with the methanol and what was a reasonable cut-off > point for > > the process. A Control was included. The Control had 5 pounds > > > > of zeolite plus 2 gal of methanol from a methanol barrel. > This was > > presumed to be relatively pure methanol. > > > > This was done in my basement and backyard; not under > stringent > > laboratory conditions. I have some concerns regarding > > > > the procedure followed, and the results produced. The > following is > > simply a chart of the results gotten. > > > > Feel free to question/comment. > > > > > > > > Container Initial Mass(g) Final Mass (g) Change % > > Change % Change > > > > > > in Mass(g) in Mass vs Control > > > > > > > > Control 2270 2577.7 + > > 307.7 + 13.6 - > > > > > > > > 1 2270 2636.3 + > > 366.3 + 16.1 + 2.5 > > > > > > > > 2 2270 2671.5 + > > 401.5 + 17.7 + 4.1 > > > > > > > > 3 2270 2795.3 + > > 525.3 + 23.1 + 9.5 > > > > > > > > 4 2270 2924.4 + > > 654.4 + 28.8 + 15.2 > > > > > > > > > > > > Container Temp Range of Mix During Distillation > > > > > > > > 1 150 – 165 F (66 - 74 C) > > > > > > > > 2 165 – 177 F (74 - 81 C) > > > > > > > > 3 175 - 188 F (79.5 – 87 C) > > > > > > > > 4 188 – 210 F (87.5 – 99 C) > > > > > > > > > > Tom > > > > ----- Original Message ----- > > *From:* Thomas Kelly <mailto:[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> > > *To:* biofuel <mailto:Biofuel@sustainablelists.org > <mailto:Biofuel@sustainablelists.org>> > > *Sent:* Tuesday, May 23, 2006 8:37 AM > > *Subject:* [Biofuel] 3A molecular Sieve and Methanol recovery > > > > Hello to all, > > 3A molecular sieve is on its way. As I understand it, > > selectively absorbs water from a water-alcohol solution > thereby > > drying the alcohol ..... sounds too good to be true. > > In my previous attempt at recovering methanol from the > > crude glycerine split from the glycerine cocktail, a > combination > > of greed and stupidity on my part resulted in methanol w. > water > > in it. ("Water in Recovered Methanol?" 4/28/06). > > I've tweaked the condenser. I've tied the cooling of > > methanol vapors (----> much hot water) to my wash tank. > Will use > > the hot water generated by the cooling of methanol to > washing a > > batch of BD. > > I will keep close eye on temp. and be patient. Do not allow > > the temp to rise above 160F until distillation stops at > this temp. > > Distillate produced in 150 - 160F range was mostly > > methanol. Temp increase seemed to slow down at 150F. I > take this > > to mean a phase change is occurring (added heat is converting > > liquid Methanol to gaseous Methanol). Above 160F temp > seemed to > > rise more quickly. I take this to mean that much of the > methanol > > is gone. > > My plan is to have 4 containers, each with 5 lbs (~ 2.24 > > Kg) of 3A molecular sieve. Allow 2 gallons of distillate > to flow > > into each container. Occasionally swirl the contents of the > > containers over the next 24 hrs. > > I'll strain out the 3A molecular sieve and re-weigh. If it > > works, I should be able to dry the methanol and from the > changes > > in mass of the molecular sieve, get a sense of the actual > volume > > of methanol I can reasonably hope to recover from a given > volume > > of crude glycerine. I also hope to get a sense of the temp > > cut-off point. > > As I understand it, 3A molecular Sieve will absorb about > > 25% of its weight in water. If, for example the molecular > sieve > > in container 1 (1st 2 gal distillate) increases by 5%, > the next > > by 8%, the next by 15%, and the last by 25%, and > additional Mol. > > Sieve continues to gain mass, I would think that 6 or 7 > gallons > > of methanol is a reasonable > > expectation for the volume of co-product I'm distilling. > > Suggestions ... including "Stop, you have it all wrong!" > > would be appreciated. It's tues. Friday looks like a good > day to > > brew; Saturday, to wash/distill. There's time for > suggestions. > > Tom > > > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > Biofuel mailing list > > Biofuel@sustainablelists.org > <mailto: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 > <mailto: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 > <mailto: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 > <mailto: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/ > > ------------------------------------------------------------------------ > > _______________________________________________ > 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/ > _______________________________________________ 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/
