Right now I'm doing a research paper on biodiesel from animal feedstock. im still new in this area and need guidelines as much as i can.
During the AE, the ratio of methanol:FFA is 20:1 right? Can i know is there are calculation on how to determine the ratio or calculation on hoe to get 20:1? Any old discussion/ old thread regarding this matter are welcome. Someone asked me how to get 20:1 ratio since most of journal/papers only show the value but not how to get the value.
Thank you in advance, Regards,
If I recall correctly, on this forum it was said for AE someone uses about 10% of methanol by volume for high titration vegetable oil. Do the papers you refer to talk about AE of pure free fatty acids?
basically im using high FFA content feedstock such as chicken fat. For FFA in chicken fat/oil is it consider as pure FFA? *feel confused for a while*
To make biodiesel from chicken fat/oil the oil should be without water in it. Animal fat/oil is a glycerol tri-fatty acid ester with some free fatty acids (FFA) in it. FFA means free fatty acid, it has no glycerol in pure free fatty acids. Three fatty acid molecules bond to one glycerin molecule minus three water molecules to make pure glycerol tri-fatty acid esters. Do you have any chemistry education cikuntut? I do not know how to post short papers with drawings on them on this forum. Try to look up the chemical molecular structure of fatty acids on Wikipedia. What is the titration number of your chicken oil? What type of equipment are you using? You can learn it academically but you can also learn by doing. AE does not work if the oil is too wet (too much water in it).
Not sure how the anwser above about water is relevant to the initial question but basically you need to find out how much FFA you have in your starting oil.
You then need to use the moelcular weight of the fatty acid and the molecular weight of methanol (both are commonly available in various texts and even web sites) and calculate the 20:1 ratio as 20 moles of methanol to 1 mole of Free Fatty Acid.
That is where the 20:1 ratio comes from.
Hope that helps.
If the chicken fat/grease or methanol have too much water in them acid esterification does not work as well. He's writing a paper on making biodiesel. The drier the better.
I did a calculation of 20 moles of methanol to 1 mole of lard fatty acids, I couldn't find information on chicken fat/oil. 20 moles of methanol is 809.7 milliliters. One mole of fatty acids in lard equals about 312.9 milliliters. I'm confused as to why this ratio was used for acid esterification, by a chemist.
"High free fatty acid content feedstock such as chicken fat." Is not the same thing as FFA. It is a mixture of FFA, monoglycerides, diglycerides, and glycerol trifatty acids. It is probably one or the other. I can explain how to calculate a 20 to 1 molar ration of methanol to lard, or a 20 to 1 molar ratio of lard derived free fatty acids. Which is it? It might be a long post. cikuntut? I do not have the information on average fatty acid molecular weight of chicken grease, but I do on lard.
The original question"how to get 20:1 ratio; calculation". In high school chemistry we were taught to always use units on numbers. For example, 2 centimeters, 2 grams, 2 moles. If we used a number in calculations we had to specify what it was a number of. What are the units on this 20 to 1 ratio? Is it moles, milliliters, grams, ratio by volume or what. There are many types of ratios. Fuzznag indicated it was moles. I can explain how to do the calculation a lot easier if I know what the 20 to 1 ratio refers to.
it's moles, methanol : ffa
" I don't know what I don't know until I know"
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If it is FFA (free fatty acids) then a titration number of NaOH or KOH is needed to establish how much FFA is present in the animal derived feedstock. I expect the 20:1 molar ratio may refer to total fatty acid content. But he said FFA, so I need a titration number and if it is KOH or NaOH used to get the titration number. If he wants the general calculation I can do that too, since it a paper rather than actual material he's got Thanks
If it is moles methanol to moles FFA ratio 20:1 then;Get the titration number in grams per liter for NaOH aqueous solution . Figure out the average fatty acid molecular weight of lard which is about 275 grams/mole. I haven't found information on chicken fat so I use lard as an example. Divide the titration number by 40 grams per mole to get moles of NaOH used per liter. This equals the moles of free fatty acids present per liter of liquid feedstock. Multiply this number by 20 moles per mole to get moles of methanol to use for acid esterification. That is one way to calculate your 20:1 molar ratio.
It is a molar ratio of methanol to free fatty acid content as measured by a titration test. We normally measure titration by mass using grammes so that mass flow can be set accordingly for oil feed, acid feed and methanol feed by simply knowing the molecular weight and calculating accordingly.
If you still don't want to believe me here is a link to a paper by Jon van Gerpen Becon center pilot pantif you look at page 11 you will see reference to the ratio being referenced to the measured FFA amount.
The 20:1 ratio you are looking at originally came from a Van Gerpen article that is floating around the web. They used varying ratios of methanol to FFA with the 20:1 being most commonly used since then. The article itself is free so a google search should turn it up. Also as mentioned this is the ratio of methanol to FREE fatty acids. The free being the important part. Most biodiesel producers will simply measure the amount of acid in an oil and assume that it is all FFA. This is what's called an acid number. To convert acid # to %FFA is a simple multiplication. Then to get the 20:1 you have to make an assumption about the average molecular mass of your oil. I've seen 282g/mol used most often but as mentioned above you can be as accurate as you want for your own specific oil source
THERE IS A LINK TO THE PAPER IN MY POST ABOVE, NO NEED TO GOOGLE!!!!
No sorry fuzz that wasn't the one I meant. There is another journal article regarding optimizing the acid esterification stage. The one you posted looks more like a feasibility/engineering study. I know I have it somewhere, I'll see if I can post when i get home and look through my records
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