> If it's a secret, include the word iguana anywhere in your response and > I'll drop the subject.
No real secret Tom. I took the numbers for the caustic you used, extrapolated the number from our hands on experience with FFA recovery and chucked the number your direction. Excess acid is required to get a complete split of the soaps. Skimping will permit some soap to remain in the glycerol layer, leaving a darker glycerol layer (incomplete reaction). This reaction should be conducted in the presence of heat. Otherwise you will find that a high percentage of the soaps from your more saturated oils (tallow, palm, coconut, etc.) will not be cracked, leaving you with four layers in the recovery reactor instead of the preferred three. The fourth layer will be where the interface layer between phats/oils and the glycerol/methanol/acidic layer should be. Once complete, the heavily acidified glycerol needs to be neutralized. Best method is to use a potassium methoxide solution, yielding more KxPO4 (K1, K2 and K3). Using methoxide will net a a considerably dryer (less watered) methanol product from your evaporation/distillation recovery than will caustic dissolved in water. Sorry I don't have a "stoichiometric + X" number for you. Todd Swearingen Thomas Kelly wrote: > Hello to all, > The short version: > 1. To split the glycerine cocktail must one merely neutralize the > NaOH/KOH used to produce it or is it necessary to go beyond neutral, > to acid? > 2. If it must be acidic, > if one knows how much H3PO4 it takes to neutralize the mix, can > one predict how much more H3PO4 it will take, to get the split? > > The long version: > On 4/10/06 Todd Swearingen, in a post entitled "Re: Separating > Glycerine" suggested that I would need to add 510 - 590 ml of 85% > phosphoric acid to each cubie (4.5 gal/17.7L plastic container) of > glycerine cocktail to achieve a split. > Sure enough, when I added 540 ml (lowest) - 580ml (highest) of > 85% H3PO4 to the next cubies of glycerine mix I got separation into > mineral precip, crude glycerine, & free fatty acids. > I've been wondering ever since how he was able to make the > calculation/prediction .... or is he just a good guesser? > > On 12/02/05 Bioclaire Nederland described how to calculate the > amount of H3PO4 to add for separation if one knew the amount of NaOH > used to process the WVO that yielded the Glycerine cocktail. (See > "separating Glycerine" & "separating Glycerine Mistake!"). > The explanation is based on the equation for neutralizing NaOH > using H3PO4. > H3PO4 + 3NaOH ------> Na3PO4 + 3H2O > 1 Mole (98g) of H3PO4 will neutralize 3Moles (120g) NaOH > > If one knows how much NaOH (or KOH) was used in the batch(es) > that produced the Glycerine cocktail it should be possible to > calculate how much H3PO4 it would take to neutralize (and split?) the mix. > > Here is where the problem, and questions come in: > The Glycerine mix I was using (4.5 gal/17.7L) containers each > came from two 76L batches (152 L WVO, total). > The oil I used for these batches titrated at 1.0 - 1.5 g NaOH/L of > WVO. (684 - 760 g of NaOH) > Adjusting for 85% H3PO4 (115g of 85% H3PO4 would contain the > 98g - i.e. 1M.- of H3PO4) and using the density of 85% H3PO4 (~ > 1.59g/ml), that I should only need 460ml of the 85% H3PO4 to > neutralize the lye used to process the oil. > Not all of the lye is in the glycerine cocktail. Some is in the > BD. I use 0.20 ml H3PO4/L of oil processed when I do my first wash > (15ml/76L batch or 30ml for two batches). This results in wash water > very close to neutral suggesting to me that approximately 50 g of the > lye used to process the WVO comes out in the BD, not in the Glyc. mix. > The 710g of lye that is in the glyc. mix should only take about 430 ml > of the 85% H3PO4 to be neutralized. > > None of the cubies would separate w less than 540ml of the 85% > H3PO4. This suggests that it takes more than merely neutralizing the > glycerine mix to get it to split. > (Answer to Ques #1?) > Note: I'm doing a lot of this in my basement or in a shed out > back, not a lab. > So how did you do it Todd? Neutralize + 20%? > If it's a secret, include the word iguana anywhere in your > response and I'll drop the subject. > Still puzzled > 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/ > > > >------------------------------------------------------------------------ > >Internal Virus Database is out-of-date. >Checked by AVG Free Edition. >Version: 7.1.385 / Virus Database: 268.5.1/327 - Release Date: 4/28/2006 > > _______________________________________________ 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/
