Hi, I am developing a biodiesel lab for my environmental chemistry class. I have a method for *making* the bio-d., but I am looking for a safe & easy way of *testing* it.

I'd like my students to quantitatively (if possible) compare the energy "punch" of a sample of bio-d. and a sample of more traditional fuel.

I have some ideas, but being a bit fire-phobic, I'm not sure how safe some of them are.

Any suggestions? Thanks.

Alas but the flash point of biodiesel is much higher than any of it's cousins. I believe it is up about 300F as opposed to 150F of petro diesel. This kind of makes it difficult to compare fuels as diesel and biodiesel require high pressure to ignite properly.

Maybe a small engine (diesel if you compare it to petrodiesel)??

You could test for impurities in the fuel. I recall making aspirin in college that would have given you a gut-ache in exchange for your headache due to low purity. Hey you could also measure conversion rates, that was the underlying theme of the aspirin lab, how much unreacted salicylic acid was in final (allegedly cleaned) product.

By looking at the unwanted byproducts that may be introduced (to engines) as fuel you may touch on environmental issues caused by those of us whose hearts are in the right place but whose actions may unwittingly cause damage.

Why am I still the mad scientist, even at a high-tech company ;-) ?

Jedi - Thanks for suggesting a small engine. At first I thought it was a far-out idea, but I have a colleague in mechanical engineering down the hall who can probably hook me up.

K. Dragon - I like your ideas for testing purity, efficiency, yield, properties. I do plan to do some of this. In addition, your point about discussing environmental impact is incredibly important. I'm going to try very much to have the students be skeptical/analytical about the claims and praises of green technologies.

I am still happy to accept more ideas, if anyone else out there has additional easy ideas for burning biodiesel.

Muchas gracias!

If you are going to use a small diesel engine to test out you fuel, you might also want to conect a small generator to the rig. I have found that an old welder does the trick and load can be applied using base board heaters as a load bank. This would also serve as a physics lesson for your students.

Convert2diesel

Thoes who refuse to recognise history are doomed to repeat it (author unknown)

i do a couple of tests myself. you can test for quality of burn and moisture content is you take a paper coffee filter anddip part of it in your fuel, diesel included.
first, notice the 'wicking' distance and speed of penetration between two fuels.
next, light it. if it has water, it will spit a little
then, look for smoke entrails.
finally, test for heat content by using a large wick lantern and place under a pan of water. measure temp rise over a few minutes. compare petrol to bd to alky to??
you cand also place a drop between two pieces of glass and compare how far it spreads, and if you put between two pieces of metal, you can test ffor lubricity.

if you want to have fun, take your washed and settled bd and add drops of 20-30% hydrochloric acid and it should turn to milk. let settle over night and see if you have some super light esters on top.
this is true 'lamp' oil.

i also found a drop of bd on the lips keeps them moist, and an eydropper full force fed to the neighbors cat induced very high speed followed by a natural enema action 15 minutes later.

i dont know if your school would allow that though.......
also, you can measure elect. resistance across bd and get an idea if there is some water or catalyst in it.
btw....use koh if possible

during water wash on the first run, you can add small amounts of vineagar for quicker separation. the amount of vineagar added will show the amount of reidual koh and also give you an idea of the ph. it will look like milk at first and when you add the vinny, it will separate rapidly.


i have found a watered down version of the soap will kill bugs and the bd will kill plants in heavy application, not by toxicity but rather by smothering...same with mosquitos.

skip....pest free division

[This message was edited by skip on 29 August 2002 at 12:46 AM.]