Hi Chris >Hi Kieth, >What mean is if you use the value from the site plus excess of 60%, you will >get 194.43 mL. Compare that value to what I derived from Sap (182.2), we see >that we have almost the same amount except that I didn't go through >calculating molecular mass, etc.
Okay, got it now... trouble is the Sap value then sort of decides the excess amount for you. I'd rather deal with it as a separate matter as it should be varied according to circumstances (unlike the stoichiometric amount). >I use very little excess amounting to only 1.8% to make an even 200mL. > >Sorry for my English. I hope I made it clear this time. Your English is just fine, Chris - it's entirely better than my Tagalog! :-) Regards Keith >Regards, >Chris > >-----Original Message----- >From: Keith Addison [mailto:[EMAIL PROTECTED] >Sent: Monday, June 02, 2003 8:50 PM >To: biofuel@yahoogroups.com >Subject: RE: [biofuel] Follow up:How much MeOH to use/Glycerol >VolumeYield > > >Hi Chris > > >It's good to hear from you, Kieth. > >:-) Bit erratic these days, sorry... > > >I use very little excess in my trials. Using the value from journey to > >forever of 121.52 mL for soy and add 60% excess, we 194.43 mL. I don't > >think our values differ at all. You got it right using experimentally > >derived amout of excess. I just went around the guess work. > >Chris I don't understand this - are we using different terms for the >same thing (or the same terms for different things?) ? > >In the above para, I'd put "121.52 mL for soy" as the stoichiometric >quantity, with 60% the excess required to push the process towards >completion - the stoichiometric quantity is constant, the excess >varies somewhat, depending, as that page explains: >http://journeytoforever.org/biodiesel_meth.html >How much methanol? > >But you say: > > >I use very little excess in my trials. > >You mean excess beyond the 60% excess? > > >It doesn't take that much excess to drive the reaction forward. The excess > >only comes in the later part of the reaction to increase concentration and > >the chances of collission. > > > >Let me rephrase my statement. 200mL MeOH/Liter is a good all around ratio > >"to start with" for any type of oil, fresh or used. Biodiesel is a good > >solvent for oil so you should be able to wash it even if conversion is not > >complete. > >Maybe not if you're left with a whole bunch of unconverted >monoglycerides to emulsify it. See: >http://journeytoforever.org/biodiesel_bubblewash2.html >Bubblewashing 101: Girl Mark >- Emulsification >- Emulsion Explained > > >I actually use 250mL for coconut and palm. Sap determine MeOH > >volume for coco is 247.4 and palm is 145. > >It was discussion here some time ago on how much methanol is required >for coconut oil that led to Christian and I doing the "How much >methanol?" page - what was quite clear was that the advice that x >amount of methanol achieved 98% conversion but y amount only 95% or >less was obviously simplistic: it depends on the oil. > >Regards > >Keith > > > >Regards, > >Chris > > > > > > > >-----Original Message----- > >From: Keith Addison [mailto:[EMAIL PROTECTED] > >Sent: Monday, June 02, 2003 9:47 PM > >To: biofuel@yahoogroups.com > >Subject: Re: [biofuel] Follow up:How much MeOH to use/Glycerol > >VolumeYield > > > > > >Hello Chris > > > >18-19% stoichiometric quantity for soy and corn? That's 6-7% more > >than other estimates, and would mean that none of us is using > >sufficient methanol excess - which we are doing, judging from the > >results and the tests we subject the product to. We wouldn't be > >getting near completion if these figures are accurate, we wouldn't be > >able to wash the stuff for one thing, it'd just emulsify. No washing > >problems here though, nor any other problems. > > > >You said earlier that 200ml/l is a good all-round ratio, but on your > >figures here for soy, that would leave you with only 1.8% excess, > >nowhere near enough. And how would that square with your figures for > >coconut and palm oil? Or am I reading you wrong? > > > >Best > > > >Keith > > > > > > > > >Soybean Oil > > >SAP No: 185-195(mean: 190) > > > Vol. MeOH: 182.2 mL + excess > > > Vol. Glycerol Yield: 70.78 mL > > > Vol. BD Yield: 1112.28 mL > > > > > >Corn Oil > > >SAP No: 196 > > > Vol. MeOH: 187.54 + excess > > > Vol. Glycerol Yield: 78.00 > > > > > > Coconut Oil > > >SAP No: 258 > > > Vol. MeOH: 247.4 + excess > > > Vol. Glycerol Yield: 102.9 > > > > > >Palm Oil > > >SAP No: ~247 > > > Vol. MeOH: 245 + excess > > > Vol. Glycerol Yield: 101.94 > > > > > >Assuming complete conversion and no loss, yields should be the above > >values. > > >I have found them consistent with my experiments. > > > > > >Regards, > > >Chris > > > > > >-----Original Message----- > > >From: Christopher Tan [mailto:[EMAIL PROTECTED] > > >Sent: Sunday, May 25, 2003 12:24 AM > > >To: biofuel@yahoogroups.com > > >Subject: RE: [biofuel] RE: How much methanol should you use? > > > > > >SAP values give how many moles of fatty acid are in fresh oil. Even if >the > > >oil is used, the moles of fatty acid should remain the same, except, of > > >coarse, for the addition of FREE fatty acid from the food cooked. You >just > > >need a little more to add to the Sap determined stoichiometric ratio to > > >account for the additional ffa's. Since I am talking about stoichiometric > > >quantity of fatty acid in the oil, and therefore the MeOH needed, I'd say > > >that Sap determined stoich values are more accurate regardless of the > > >process. It says so in the article that, "it doesn't make much sense > >anyway > > >if the stoichiometric ratio is wrong in the first place". > > > > > >By the way, Journey to Forever is great. I've learned so much about > > >biodiesel in the 2 months since I first browsed the site. > > > > > >Christopher > > > > > > > > > > > > > > > > > > > > >-----Original Message----- > > >From: Keith Addison [mailto:[EMAIL PROTECTED] > > >Sent: Saturday, May 24, 2003 1:41 PM > > >To: biofuel@yahoogroups.com > > >Subject: [biofuel] RE: How much methanol should you use? > > > > > >Hello Christopher > > > > > > >I would just like to comment on Christian Lenoir's work regarding the > > > >stoichiometric ratio of methanol to use. His findings are way bellow >the > > > >amount that should be use. > > > > > >But that's explained very clearly on that page - that you need the > > >stoichiometric amount PLUS an excess. How much excess you need is > > >also discussed. There's a lot of confusion about this (as also > > >explained there) because some people want to lay down the law on how > > >much methanol is best REGARDLESS of the type and condition of the oil > > >in question, and of the fact that different oils have different > > >stoichiometric ratios. One advantage of doing it this way is that it > > >shows how the different values are arrived at. > > >http://journeytoforever.org/biodiesel_meth.html > > >How much methanol? > > > > > > >I commend his efforts but it would have been > > > >easier and more accurate > > > > > >More accurate? I don't think so. > > > > > > >had he simply used the saponification value of > > > >specific oil instead of going through his trouble. The mole of methanol > >to > > > >be used would simply be the sap value (which is just the mole of KOH). > >You > > > >just have to do the conversion. Aleks Kac's 200mL MeOH/Liter is a good > >all > > > >around ratio for any type of oil, fresh or used. > > > > > >Good if you're doing Aleks's acid-base process, yes, which is why it > > >says at the end: "With the "Foolproof" acid-base two-stage method, > > >don't worry about it, just follow the instructions." But you won't > > >get too far with only 20% if you're trying to use a single-stage > > >method to process, say, coconut oil (only 3.7% meth excess v/v oil? - > > >no way!), or WVO titrating at 10 ml or so. > > > > > >Best > > > > > >Keith > > > > > > > > > >Regards, > > > >Christopher Tan > > > >Philippines ------------------------ Yahoo! Groups Sponsor ---------------------~--> Get A Free Psychic Reading! 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