Peter, All the biodiesel that we've ever made, save for an odd gallon or two, has been with KOH. Thus the catalyst in the glycerin layer and the soap is KOH.
KOH is generally used in liquid soap manufacture. NaOH on the other hand is generally used in bar soap. As you can guess, all the soap that we've made from the settled crude glycerin layer has been liquid, not bar. Still, for those who have little experience with making bar soap, it shouldn't take but a little trial and error to get it down using the crude glycerin layer. The website you mention seems to have done just that. www.eline2000.com/eline/articles/barsoap/barsoap.htm All the "back calculating" that I mentioned before is more for those who want to stay as close as possible to whatever "cookbook recipe" they might be trying to roughly adhere to. The website author is correct about the ease with which one can overdo the caustic and create a bar that leaves your skin bone dry and flakey, no matter how much glycerin is in it. So that leaves you with three directions to take. 1) Keep tight tabs on how much free catalyst is in the crude glycerin feedstock. 2) Experiment with different amounts of caustic that eventually give you a bar that your skin is pleased with or 3) Neutralize the catalyst, which will break down the soap and separate the glycerin and the recovered FFAs, permitting you to "start from scratch." Number 3 is a rather wasteful step if all you intend to do is manufacture soap. It does have stronger purpose when your production of biodiesel exceeds your soap needs, which doesn't take long. Be aware that the soap from this feedstock (after the methanol is removed) is heavily glycerated. If an oil is originally 7% FFA, the glycerin in the crude layer will be approximately 79 ml (53%) and the FFAs will be approximately 70 ml (47%) for every liter of oil processed. Yet in the original feedstock the glycerin would only be 7.9%. You can see that the glycerin ratio changes drastically depending upon which feedstock is being used. Thus the "ultra-glycerated" end soap when using the crude glycerin/FFA layer. It's rather amazing that a bar soap can support such a high glycerin ratio and still be a bar. As for the continued boiling you mentioned after removing the crude filtered glycerin from heat, that is the methanol boiling out until the fluid cools down to ~160*F. If you're not dealing with much volume and are in no hurry, you might try simply leaving the container open, perhaps in the sun, covering it with a piece of stretched nylon hose and letting the alcohol simply evaporate over time. This would save you much of your energy inputs. (Please see VOC comment below though.) As for the "sad but true" comment, it is in reference to the high solubility of biodiesel in methanol, leading to high percents of residual methanol that hang in the biodiesel layer, rather than as much as most people think settles out in the crude glycerin layer. It is this methanol that yields so much of the milky color in the first wash. Also, methanol is a volatile organic compound (VOC). Evaporation with no recovery or simply dumping wash water in the sewer are not at all appealing choices from an environmental perspective. (One note here...when a person does conduct catalyst/glycerin/FFA recovery as mentioned at http://journeytoforever.org/biodiesel_glycsep.html all the methanol that is in the crude glycerin/alcohol/FFA layer (or as close to "all" as one can get in a chemical reaction) settles out into the glycerin layer, leaving a layer of "pure" FFA feedstock for soap or fuel.) Of course, one can always take an empty, black, 100# open-head keg that the caustic comes in (~20 gallons), hook up a 2" diameter exit pipe from the center of the lid leading to a condensor immersed in a shaded water bath (an old, beat up but vapor tight radiator with a drain line running from the bottom of the condensor through the bottom of the water bath and into a collection jug.), place a pot of the crude glycerin/alcohol/FFAs inside on a raised grill (as close to the top as possible, as heat rises), afix the air tight lid and expose the keg to full sunlight. Walla!!!! One solar methanol recovery unit (a solar "pot still"). Todd Swearingen ----- Original Message ----- From: pcooke04102 <[EMAIL PROTECTED]> To: <biofuel@yahoogroups.com> Sent: Friday, August 30, 2002 3:23 PM Subject: [biofuel] Re: boiling glycerine/soap and thanks but another q > Thanks for the info Todd and Keith, > for both the washing advice and the great info on FFAs and soap > making-but just a couple more qu's..... > > Todd have you seen the recipe at > www.eline2000.com/eline/articles/barsoap/barsoap.htm > > What do you think? is it a questionable or sound process described so > simply? > > Anyway, I will be using a double boiler from now on although it > appears I have not burned any of the oils (hopefully)-I probably did > heat the FFA oils/crude glyc too fast-I will now be wary of acrolein. > How fast is too fast? > Also, the glyc/wvo mix that I did bring to a boil was still boiling > after 15-20 min. will it settle down at that kind of temp and stop > rolling/ boiling when all the methanol has boiled out? Or will it > keep rolling? I'm just trying to get an idea of how long it will > take, once boiling to evap that methanol out of 2 litres or so of the > glyc/FFAs. Every recipe just says boil it off but gives no indication > of what to look for when the meth might be out of there. > > Also Todd, I'm curious from one of the last statements you made in an > earlier reply to this which was > > Sad, but true... > > http://www.biodiesel.org/resources/reportsdatabase/reports/gen/ge > > n014.pdf A little bench top testing makes it pretty obvious to > > anyone that an enormous range of biodiesel will dissolve in > > methanol. Which makes evaporative recovery from the biodiesel > > extremely important in all production, whether commercial or > > backyard, whether home biodieselers want to believe so or not. > > Sad but true what... I couldn't open the link but am wondering what > you are refering to. Air emissions from the Methanol during the > process and from the waste glycerine? > > Thanks again for the help/advice and expert info-PC > > > > Yahoo! Groups Sponsor > ADVERTISEMENT > > > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Biofuels list archives: > http://archive.nnytech.net/ > > 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 the Yahoo! Terms of Service. > > ------------------------ Yahoo! Groups Sponsor ---------------------~--> 4 DVDs Free +s&p Join Now http://us.click.yahoo.com/pt6YBB/NXiEAA/MVfIAA/FGYolB/TM ---------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/ 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/
