I have been going to school at Auburn University in Montgomery and they have an engineering club that is trying to make biodiesel. They spent $6000 for a Biodiesel reactor and when it got there all it had was one 50 gallon tank and one 20 gallon tank, one harbor freight pump, and a bunch of valves, no mixer, it relied on pump mixing. Anyway, they made their first batch Saturday after titrating in a high tech chemistry lab. They titrated 4 times to make sure it was right, then when they made the bio it looks good with glycerin on the bottom and everything, but it has a thin clear layer (about an inch thick) on top. They only made 20 gallons. I have made lots of biodiesel but I have never seen a thin layer on top, it looks almost like water. But water would be on bottom, not top. What could this be?

 

Most likely, Soap.

 

Dunno about the clear layer thing, haven't seen that yet. If it was water, it'd be on the bottom, if it was alcohol, it'd be in solution... Anyway, try to seperate it from what looks like fuel, then before ya try to wash it, do a 27/3 test. If it does not 'pass' - don't wash it or you'll likely get a nice emulsion!

BTW, if ya get an emulsion, no big deal. Its not that hard to 'break' if ya have some glycerin. I helped a friend break an emulsion last weekend. He had put the emulsion stuff in cubies to free up the machine so we could run another batch of bio. We poured 1/2 to 2/3's of the emulsion out of each cubie and added glycerin to almost fill cubie and shook it up. In 5 minutes we had beautiful seperation of biodiesel and glycerin...


Dear God! $6k for plastic (read: DANGEROUS ) tanks and the worst china has to offer! Thats just mean, and maybe abit naive on the purchasers part.

Recommend they get a BioPro unit. The 190 is about $8k (you can buy it from Northern Tool w/free shipping and even financing). It is all tig-welded SS, uses a 2 stage reaction (uses sulphuric acid to make more fuel from higher FFA oil) and is fully automated. No titration required, but you could cater the chemicals abit closer to each batch's needs by titrating. After loading ingredients (not unlike a cookie recipe), you just push a button and it automagically goes thru the 2 reactions. After 24hrs, ya jus drain the glycerin off and push another button and it goes thru wash and dry cycles. After a total of 48hrs, you pump (which is included/attached to unit) 50 gals of ASTM-grade B100 into your diesel vehicle, SCHOOL BUS, tractor, generator, whateva!

 

Yeah, I know about the reactor. I built mine out of 55 gallon drums, I have less than 100 dollars in it, and mine has a manual mixer(also built by myself). They are going to use what they have since they already got screwed on it. All of my bio pretty much has a thin layer of soap looking stuff, but its a thin layer of jelly like stuff, not clear liquid. I'm going back tomorrow to see what it looks like. I just wonder if the bio under the thin layer is good?

 

I have noticed a clear layer in my sight gauge after reacting. I ignore it. I figured if it was methanol it would be in solution with the biodiesel. I also know that after methanol removal and settling for 48 hours, I only have some residual glycerin (jelly like) in the bottom, but no soap.