ASTM Test Results

[Jeff_Retired]

Just completed lab testing on my Bio and passed. The total glycerine test was my greatest concern to ensure reactions were complete. My total glycerine was 0.165%  (.24 max). I noticed that Monoglycerides were 0.137% contributing to most of the total. I use a dry wash process and was wondering if this result is considered normal.
Thanks Jeff

[Tony]

Hi Jeff, not something I've tested beyond titrated soap test (down to 30ppm or so).  How are you measuring quantities and differentiating from monoglycerides?  I'm interested in this part of your process as I'd really like to be able to measure mono/diglyceride content in my fuel.  But it sounds like you have access to a handy lab!

[Jeff_Retired]

Hi Tony. Handy as far as UPS goes. Midwest labs is where I had the tests performed per ASTM test procedure D6584 and I guess it requires the glyceride components.  Cost for the TG test alone was $150. Not something I will do very often.   Following is the Glycerine data.


Total Glycerin 0.165 % mass  ASTM D6584
Free Glycerin 0.006 % mass
Triglycerides as Triolein 0.004 %
Diglyceride as Diolein 0.019 %
Monoglyceride as Monoolein 0.137 %
Jeff

[Jeff_Retired]

Asked this question to the testing lab and following is their reply.

I would say it is a "good" quality biodiesel.  We really do see numbers all over the place, but all your results "pass" the ASTM D6751 pass/fail requirements, so you could say any passing result is a good result?  The Monoglycerides do make up a fairly high % of the total, but still low enough to be a passing result.  It is typical of a "good" biodiesel, in that your Monoglycerides are the highest, your Diglycerides are the second highest, and your triglycerides are the lowest.  In almost all "passing" results the mono.s should be the highest, then di, then tri-, if that gets out of whack and the diglycerides or triglycerides are the highest component that usually throws the Total Glycerin out of spec.

On your other results, acid # is good (anything below 0.50 is good), moisture pretty typical (always pretty low on a final product), sodium and potassium look good (below 5ppm combined).

[Tony]

Well that's excellent news for us settle and drywashers.  Goes to show that water isn't required!

Can you clarify your process in making this batch?

I know you've done one and two stages in the past - do you demeth everything (bio and glyc together) or just the bio?

[Jeff_Retired]

Hello Tony.
I used the 2 stage no titration process. I settle out a lot of glycerine after the first stage but don't try to get it all. After the second stage, I settle for about 2 hours draining glycerin. I then increase temperature to 165F and demeth as much as possible using the GL  venturi procedure for about 2 hours recovering close to the amount of methanol I added in the second stage draining glycerine as it settles. I know this is not necessarily efficient but my goal is to get rid of the methanol. I then transfer to a settling tank and air bubble with an aquarium pump over night. Let settle for two days and test for soap. On the last batch, I had 70ppm soap going into the dry wash tower. Virtually no visible soap settling but a little glycerin did settle.  Presumably as a result of getting rid of the last bit of methanol.  I may be putting more effort into the methanol removal but I know it is bad for dry wash resin and more importantly my engine and there is no easy way to tell if  it is all gone that I know of short of lab testing.  I built my reactor with the thought of using the WBD but I am concerned with the process reversal possibility and again you don't know it occurred without lab testing. I am focused on making good bio  from a repeatable process not methanol recovery.
Jeff

[greasemonkey]

Roughly how much does the lab testing cost?

[Jeff_Retired]

I had only a few of the many tests possible performed to keep costs down and others I could do myself. I read up on what each test accomplished and there was in my opinion some duplication. For example test to show a complete reaction.
Free and Total Glycerine $150
Acid Number $60 (To confirm my test results)
Moisture by KF $30 (To confirm my test results)
Potassium $51
Sodium $51
Total $342
I set it up with the lab to start with Total glycerine and proceed to the next test only if the current one passed.  i.e. Don't care what the acid number was if total glycerine failed. Luckily, they all passed.
Jeff