Hi everyone,

My name is Jake, and I'm working for a small biotech company (NECi, www.nitrate.com) that is developing a testing kit and equipment for testing glycerol in biodiesel. The kit is meant to be an easy kit that will test to the ASTM's standard of 0.02% glycerol by volume. Originally, we were thinking of marketing this test kit to major manufacturers, but as a biodiesel hobbyist myself, I wanted to see if there would be any interest with other folks doing it at home.

If you guys wouldn't mind taking some time to answer a few questions, I would greatly appreciate it. Please don't think I'm spamming the board, as we don't have an actual product yet, but we're just trying to gauge interest. I'd also be happy to answer any questions you all might have as well.

How are you currently testing to insure that your biodiesel is glycerol free? Using the “3-27” or soap titration method?

Do you have any interest in a more accurate method where you can actually quantify the amount of glycerol in your sample?

How about methanol in your waste glycerin?

To make the kit work, we’re developing a hand-held spectrophotometer that will interface with a smart-phone for reading the absorbance and store and track the data. This will likely be in the $150 range.

Is that something you would be interested in purchasing to use the kit, or is it cost prohibitive?

Thanks a lot folks,

Jake

Hi Jake,
I tend to go a bit overboard on testing, many years ago I worked in a lab(I think I'm re-living my youth)
I would be interested.

Hi Jake,
currently homebrewers do not have any method of assessing how much glycerol is present in their biodiesel. Those who use water washing dont have a problem. Glycerol is more soluble in water than soap so if they reduce the soap levels in their biodiesel to ASTM levels then they can be confident that the glycerol is taken care of as well.
However many homebrewers, myself included, use drywash systems for convenience and the ion exchange process can reduce the soap content to almost zero without having any effect on the glycerol content.
So the answer is yes we would be interested in a reliable, and not too expensive method of measuring glycerol content in our biodiesel.

Thanks so much for the feedback so far folks.

Another quick question. How do you think your testing process might go? For instance, would you do several batches at once, then test several at one time, or would you do a batch, test, do a batch, test, etc?

Thanks!

When a reliable method of removing a contaminant is established a test only needs to be conducted now and again.
For instance now I know I can reduce say the water in my biodiesel to less than 300ppm using a certain drying method, then as long as I use the same method I only test every 3rd batch.

Good idea. If it can be brought to market economically I believe it would be welcomed.

I try to encourage my customers to test every batch, 150litre or 300 litre. The three tests we currently do are for conversion, water content and soap content. These take 15minutes. If tests take any longer or are too complicated then I find they dont get done.
Home brewed biodiesel can vary from very dark (like coca cola) through to golden ( like beer) to almost colourless ( like water). Will this affect your test?

The color shouldn't make a difference, but that is something we'll have to experiment further with. The stuff we've played with so far has been from commercial producers and has been fairly clear, although it has been a variety of colors.

It is probably much more important that the sample contain no debris, which should obviously be taken care of by the time you'd be testing for glycerol concentrations.

Jack, To be clear are you talking about free glycerol, total glycerol or both? I use the 3/27 test to determine completeness or unconverted but a more definitive test might be interesting. I believe that there is still some uncertainty as to how much mono & di-glycerides remain even with a passing 3/27.
Have you given any thought to a test for "gums"? At one time there was controversy about the presence of gums in biodiesel. These gums were thought to come from lecithins, etc. I use the water wash method and make several hundred gallons of biodiesel in the summer to use the next spring & summer on my farm. I notice that after standing several months even in the cold winters we have here when I clean my totes there remains a residue of some soap, probably glycerol which is water soluble and a water in-soluble, not much but enough to plug a tractor fuel filter.
Good luck,