Hi! who intersted in producting bio-diesel.
I tried two different way to product bio-diesel.
First..using Methanol with lard, it is perfect.
Second..using Ethanol with lard,at this time seperated glycerin but
problem is when temperature is going down bio-diesel become solid.
My qustion is why under same temperature methanol bio-diesel remain
liquid but ethanol bio-diesel become solid.
(one litter Lard + 175ml 96% Ethanol + 13grams KOH..under 60c stir...my method)
Are there any specific recipe producting bio-diesel with lard and Ethanol?
Please let me have answer somebody knows it.This message has been edited. Last edited by: mongolian,
Sounds like you have a few problems, don't know much about the oil (FFA, water etc) but here's some ideas.
I think the biodiesel went solid because you haven't reacted much. Did you use 175mL methanol and then 175mL ethanol?
The molar mass of methanol is 32g/mol. The molar mass of ethanol is 46 g/mol. So on a weight basis you have to add 46/32=1.44 times the ethanol on a mass basis. ~1.25 on a per volume basis. Say you used 175mL of methanol for a liter of oil, that works out to about 218mL ethanol.
Next 96% ethanol is on the low side for the reaction. 98+ is much better. Get denatured (anhydrous) if you can. That 4% water is all going to soap.
A little help from a portuguese chemistry student...
The explanation for the problem you have is very simple. I gonna try and make it very clear for everyone.
We have diferent types of organic molecules (I'm going to use the destilates of petroleum, because almost everyone knows them) like methane gas wich has only one carbon atom and 4 hydrogen atoms, at normal pressure and temperature it is a gas. Ethane, propane and buthane are all gases too with chains of 2, 3 and 4 carbons. Gasoline as chains with 8 carbon atoms, but it is a liquid. Asphalt has an even bigger chain and it is very sticky, and it is more a "solid" than a liquid.
The main conclusion to make from this is that hidrocarbons with larger chains tend to get heavier and form liquids (or solids) than those with small chains.
Biodiesel for our disgrace solidifies with lower temperatures due to its high molar mass. This effect gets even worse when ethanol is used.
When ethanol is used the chain of the biodiesel is bigger so it is more likely to solidify. So it is better to use methanol for it prodution in cold climates, even so it could solidify but it is less difficult to keep it in liquid state.
One of th advatages (other than the fact that it is not carcinogenic) of using ethanol rather than methanol is the higher energy content, since you have more carbons on the chain you have more energy. Of course also depends on the kind of oil you use to produce the biodiesel.
I hope my reply was usefull to you or to someone that came up with this problem.
While the hydrocarbon chemistry is sound that isn't the case when dealing with biodiesel. The picture I attached is from the biodiesel handbook by Knothe, Krahl, and Gerpen. In most cases the longer chains actually lower cloud points.
When dealing with fats the length of the chain isn't as important as the degree of saturation (How many double bonds the chain has) the more saturated a fat the more 'liquid' it is. Tallow has many unsaturated chains.
Cloud_points.JPG (28 Kb, 39 downloads)
Mongolian; How much glycerin product did you get? If I'm going to do it, it will take a week or more.
What type of pig did your lard come from. My good friend tells me that the biodiesel made from Cinta Senese Pigs is the best.
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