Ian, I think you'll have to ask Bob what it is that is off the mark for him and lends to whatever quandry he may or may not be in.
Acid/base works. It just requires some pretty good understanding of what is going on in the reaction, what enhances the reaction and what actions are less than beneficial on the operator's part. There are perhaps only three things that I would suggest to modify in the acid/base process. 1) Allow a 24 hour reaction period, of which at least sixteen are under agitation. 2) Drain off any glycerol that settles out prior to moving to the base stage. As most of the acid will reside there after settling, this will reduce the amount of base catalyst consumed in neutralizing the acid. 3) The eighty mililiters of methanol suggested in the acid stage is sufficient only for conversion of feedstock up to approximately forty percent FFAs. It's almost impossible to imagine any WVO coming from a restaurant that would be that degraded. (If it is, they should be shut down by the local health department.) But it is theoretically possible. Oils that degraded or more will require more methanol in the acid stage and less methanol in the base stage. Todd Swearingen Ian & Theresa Sims wrote: >Some reassurance please. >After months of single stage manufacture and reactor modifications I was >about to jump into the Foolproof method. But now Bob in a, I assume well >equiped Lab can't get the process to work completely. >What Gives? How much chance do I have in a back yard with home made and >jerry rigged equipment. >Alex Kac also states that mixing methanol and sulphuric acid together is can >cause serious problems. Once again what gives? > >Cheers Ian > > >----- Original Message ----- >From: "bob allen" <[EMAIL PROTECTED]> >To: <Biofuel@sustainablelists.org> >Sent: Saturday, December 31, 2005 1:42 PM >Subject: Re: [Biofuel] acid/base method for conversion of wvo to FAMEs > > > > >>Appal Energy wrote: >> >> >>>Bob, >>> >>>Why not drain the small amount of glycerol that settles out of an >>>esterification? The majority of the sulfuric will come out with it. That >>>lessens the amount of base catalyst needed for the follow-up >>>transesterification. >>> >>> >>again, this is just what I observed: no glycerin settled out after the >>acid stage. Waiting 8 hours >>realistically means another day. Additionally, if I do wait and do get >>some glycerin to settle out >>with my conditions, wouldn't you think that methanol also would be part of >>the cocktail, thence >>affecting the equilibrium? >> >> >> >>>Fewer chemicals in, fewer problems out. >>> >>>Todd Swearingen >>> >>> >>> >>>bob allen wrote: >>> >>> >>> >>> >>>>acid/base method for conversion of wvo to FAMEs >>>> >>>> >>>>In my lab I have had little success with the acid/base method for >>>>biodiesel production. When my >>>>students and I tried to duplicate the foolproof method >>>> >>>>http://journeytoforever.org/biodiesel_aleksnew.html >>>> >>>>we invariably obtained incomplete reactions, plus the longer preparation >>>>time was less attractive. >>>>The following is my modification of that procedure which works for us, >>>>and takes less time, but >>>>requires more catalyst. >>>> >>>> >>>>Dissolve 1 ml sulfuric acid in 150 ml methanol and add to 1 liter liter >>>>dry wvo, heat to about 60 >>>>Celsius for one hour. Then dissolve 4.9gm NaOH in 50 ml methanol and >>>>add to the reaction >>>>mixture. Continue heating for an additional hour, stir for one more hour >>>>and then let set for 8 or >>>>more hours. workup as usual. >>>> >>>>Now for the why more catalyst. Basically the sulfuric acid used >>>>neutralizes some of the base >>>>catalyst, hence more must be add to get back to the desired concentration >>>>of catalyst. If you don't >>>>know moles and equivalents, the following may be abstruse. >>>> >>>>1 ml sulfuric acid is 36 milliequivalents, therefore its presence in the >>>>reaction mixture >>>>neutralizes 36 milliequivalents of NaOH. The simple base catalyzed >>>>method requires 3.5 grams NaOH >>>>which is 90 milliequivalents. Subtract 36 from 90 and you get 54 >>>>milliequivalents of base left. >>>>This corresponds to to only 2.1 grams NaOH active active catalyst, the >>>>remainder having been >>>>converted to Na(2)SO(4), sodium sulfate. In round numbers then you have >>>>to add an additional 1.4 >>>>grams of NaOH on top of the 3.5 grams called for in the simple procedure. >>>> >>>>The following instructions are intended for an advanced audience, >>>>thoroughly familiar with the >>>>simple procedure. To minimize costs we still do a titration. If the wvo >>>>titrates at greater than >>>>1.4 ml, we use this modification, less we use the simple procedure. >>>> >>>> >>>>All this having be said, I actually use KOH in my procedure but have done >>>>the calculations with >>>>NaOH, it works either way, one just has to adjust the molar proportions. >>>> >>>>Acknowledgment should be given to Kelly Verbel and Josh Lisko, students >>>>who worked with me on this >>>>part of our biodiesel project. >>>> >>>> >>>> >>>> >>>_______________________________________________ >>>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/ >> >> >> >> >>-- >>No virus found in this incoming message. >>Checked by AVG Free Edition. >>Version: 7.1.371 / Virus Database: 267.14.8/215 - Release Date: 27/12/2005 >> >> >> > > >_______________________________________________ >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/
