Sciencemadness Discussion Board

solid fat to bio fuel,need some pointers

Little_Ghost_again - 2-10-2015 at 10:41

Hi,
I have probably looked in the wrong places, and I have searched Bio Fuel sites. I have found loads and loads of information on turning waste vegetable oil into fuel using Transesterfication (sp?), most sites seem to say to stay away from solid fats and they are not worth the effort, however I have access to solid fat but very little waste veg oil.
Can someone please point me in the direction of how to convert solid fat into bio diesel, The closet I have come is using an acid rather than a base, however this information seemed more related to waste veg oils with a high FFA content.
I dont want spoon feeding but I would greatly appreciate pointing in the right direction or knowing what process I should be looking at. I thought bio fuel sites would be the place, but like I say they dont really give much info on solid animal fats.
Many thanks

UC235 - 2-10-2015 at 11:10

Solid fat can be used to make biodiesel. It's substantially identical to liquid oils except the melting point is higher. The product biodiesel should still be a liquid, but it will have higher gel point, so it needs to be blended with regular diesel or liquid oil-derived biodiesel if you intend to use it in cold weather. the highest melting FAME you're likely to encounter is methyl stearate at 31-35C when pure. Mixture with lower melting components will depress that m.p. considerably unless you're making biodiesel from fully hydrogenated soybean oil or fully hydrogenated tallow which would be composed almost entirely of tristearin.

The upside is that solid fats have less unsaturation and are more shelf stable than liquid oils which tend to polymerize and undergo peroxidation fairly easily.

The only difference in making biodiesel with solid fat is that you may have to warm the reaction mixture a bit more during transesterification to ensure it stays liquid.

Little_Ghost_again - 2-10-2015 at 12:51

Quote: Originally posted by UC235  
Solid fat can be used to make biodiesel. It's substantially identical to liquid oils except the melting point is higher. The product biodiesel should still be a liquid, but it will have higher gel point, so it needs to be blended with regular diesel or liquid oil-derived biodiesel if you intend to use it in cold weather. the highest melting FAME you're likely to encounter is methyl stearate at 31-35C when pure. Mixture with lower melting components will depress that m.p. considerably unless you're making biodiesel from fully hydrogenated soybean oil or fully hydrogenated tallow which would be composed almost entirely of tristearin.

The upside is that solid fats have less unsaturation and are more shelf stable than liquid oils which tend to polymerize and undergo peroxidation fairly easily.

The only difference in making biodiesel with solid fat is that you may have to warm the reaction mixture a bit more during transesterification to ensure it stays liquid.

Fantastic and thank you! Ok I now have a direction to pursue :D thanks alot its been driving me mad