quote:

Originally posted by farmbrew:
I tried Jan's 27/3 test and I had a very very small drop settle out. I tried the reprocessing test and nothing dropped out and I got a gelatin substance within twenty minutes.

Hi Farmbrew

Have a look at this thread. Does it help?

http://tech.groups.yahoo.com/group/biodieselbasics/message/12002

Thanks Paulus

I am trying another 10 gal. batch and going to mix a .5 hour longer to see if I can get both tests to be positive. If that does not work I will try a little more KOH I am useing 22% meth. by volume.

If the original Jan Warnqvist test used 225ml of methanol and 25ml of biodiesel, how did we end up at 27ml of methanol and 3ml of biodiesel, if it is to reduce the amount of methanol used then why not use 9ml of methanol and 1ml of biodiesel?
or is this too little to see anything?

Chug

I use 1 in 9. It works fine in a small glass bottle with screw cap. I also find I can get a pretty good handle on the reaction by putting the biodiesel in 0.25 ml at a time.

I remember reading that this test may be affected by the type of oil and that it might not work well with fish oil, probably too soluble. I have made some biod from tallow and think it should be pretty good, high conversion, but even 0.25 ml will not dissolve in 9 ml methanol. Some crystallizes out. I would expect tallow esters to be less soluble. Perhapse for tallow we need to do it hotter than room temp.

Has anyone else noticed this?

I warmed the sample to 36 degrees C and found the crystals melted. At this temp I was able to put in the full 1 ml of biod. No liquid settled out but the glass started to show traces of oil adhering inside and the liquid was cloudy. I would call this appearance "just scraped in" if was an oil at room temp.

Neutral,

I have not tested different types of oil, but big changes in tempurature changes the result of the test for sure. I susspect that polyunsaturated oils like corn and canola will skew this test towards passing more easily (with some unreacted TG.) and more saturated oils will skew it towards failing more easily (even with high conversion).

Andrew

neutral,
I have made bio from tallow and I tested it with 1 in 9. It really good soluble (dissolve immediately) at room temperature (in thailand about 30 C) and then I add another 1 ml of BD in the same vial (now 2 in 9) dissolve immediately. I hope this hlep. I'm waitting for tomorrow to see anything drop out.

Tilly,

Have you thought more about how long to allow this test to settle before we interpret it?

I now consider that 30 min. is enough. If there is no cloudiness, it takes less time than that to be sure there is no precipitate. However, when it is cloudy right after shaking sometimes nothing precipitates, and sometimes, there is a small amount of precipitate that takes up to 30 min. to settle out.

Some more info in the intro post on when to interpret it may be helpful.

I think telling people that cloudy has no meaning (from Rick's info) and telling them the result is immediate could lead some to think they have a pass when they actually have a moderate amount of unreacted triglyceride.

Your thoughts?

Andrew

Hello Andrew

My limited experience suggests that if it is bright and clear immediatly, that is a pass. I have never seen one fail that goes bright and clear within a second.

I have never seen a cloudy one drop out a precipitate after a few minutes.

If you do the test with tallow on a cool day you will see crystals forming after a few minutes. I would suggest that tallow needs to be done hot enough to just get the crystals to melt, say three minutes in a microwave.

Tilly,

quote:

if it is bright and clear immediatly, that is a pass. I have never seen one fail that goes bright and clear within a second.

I agree. I am talking about the ones that are cloudy, with no immediate precipitate.

As you say, it could be that chemisty is not the same in both locations... If I pull samples every 15 or 20 min. from a batch as it runs, the last 1 or 2 samples before it reaches passing will usually be cloudy, no immediate precipitate, but a small amount will precipitate after 10-30 min. This is with corn oil.

To me, this result is a close fail.

Andrew

I had something strange happen with an old 3/27 test. I do it in a small Venetian flask. The last test I did showed no precipitate and cleared very quickly. I happend to leave this one in the flask I do the test in and now 2 weeks or so later, I was showing it to someone interested in BioD and much to my dismay, there was now a lot of precipitate(unconverted oil?), maybe 1/8 of a teaspoon. I've looked at it a few times previously over the past couple of weeks and there wasn't any precipitate. Why would there suddenly be at this late date?
Does anyone know why a

"I have never seen a cloudy one drop out a precipitate after a few minutes."

Happens all the time to mine.

There have been a few questions on this thread about the difference between the 27/3 test and the pHLip test. There is a compairson posted on B100 Supply The article explains how the pHLip test works and at the bottom lays out a compairson, point by point.

In this thread Tilly posted an objection to the price compairison that has it's roots in what quality of methanol is appropriate for the 27/3 test.

I cross posted this here because this is an important issue for this test.

So what is the consensus? What source of methanol should be used in this test?

Rick,

Good question. To be proper, perhaps we should get a few bottles of Heet from different places and make sure they are consistent. Or, get some specs from the producer.

In the mean time, let's keep using heet. It seems to have much less variation than the race fuel.

I also think we should work towards a standard temp. range and a standard amount of settle time. I use 30. min. Others have ideas?

Andrew

Steve,

I get my methanol from a race fuel supplier. Like most people in my area.

quote:

what grade do you think HEET is ?

I don't think it matters as long as it is consitent from month to month and place to place.

Andrew

Hey Jackstraw,
I noticed the same thing if I left a passed test sitting around for weaks. I'm pretty sure the methanol evaporates to the point that it cannot keep the BD in solution. I found that if I added methanol to fill the flask back up to its original level, the BD re-dissolved and looked just as perfect as before.\

Happy BDing
Chris

A few observations about the "Quality" of HEET Methanol from other list members

uniquewater "I'm a chemist with access to a GC/MS and ran this stuff on the instrument, because I've read posts on using the ISO for titrations and the HEET as a methanol source.
Not only is the stuff overpriced, but it is definately NOT pure. I think if your going to produce biodiesel you want a "clean" product and you won't get it with the HEET."

Sign of the Dollar "When I mady a test batch using the HEET crap, I got horrible results. Most of the stuff around here in those little bottles has absorbed water over time

Tilly,

But is heet the same every time? That is the important part.

Andrew

Steve,

quote:

If it is tech grade then it would be maybe less than 95% up to maybe 99%. Do you think that range is close enough to call it a standard ?

It sounds like you think it might be a range of quality.

quote:

of course not.

Do you have any thing to support that?

Andrew