Hello Jan
May I jump into the discussion? Jan you have just mentioned the word "salts"
isn't that one of the ingrediants for making very good quality soap? Hence
possibly helping make a great emultion during the first wash on the quality
esters. I am assuming that salts will remain in the whole process, not being
disolved in any manner from the methoxide right? Some salt should be drained
with the glycern right? Possibly leaving some salt in the unwashed ester.
My last two reactions have had the same feedstock, ( a very popular
restaurant which salts their fry's heavily, lol) both reactions were two stage
acid/base reactions becos the titration is consistantly over 14 ewwwwww!!!! .
Here are the wash results from both batches of Quality Tested BD:
Reaction #21 using 1500L unwashed oil as a feedstock:the resulting 1380
Litre batch of quality BD required 3.5 litres of pure 99% vinagar to break the
first wash emultion.
Reaction #22 using 1500L PREWASHED oil of the same feedstock : the
resulting 1450L batch only required 1 Litre of 99% pure vinagar, to break the
first wash emultion.
Jan does this observation make any sense? Think it could be salt?
-Rod.
Jan Warnqvist <[EMAIL PROTECTED]> wrote:
Hello Joe.
There were probably small amounts of mono- and diglycerides left in the
biodiesel, and/or possibly soaps which together are excellent emulsifiers. A
strong acid will divide the glycerides into fatty acids and glycerine ,and the
soaps into salts and fatty acids, which then goes into a fat phanse and an
aquaeus phase, possibly with the salts in the bottom.'
Best regards
Jan
----- Original Message -----
From: Joe Street
To: biofuel@sustainablelists.org
Sent: Friday, August 10, 2007 3:45 PM
Subject: Re: [Biofuel] Glycerine Settling Time
Hi Jan;
Ok your post agrees with what Andres said. So how do we explain Tom's
experiment then? To recap (Tom correct me if I miss something here) he took
washed esters that passed the methanol test and added water and (of course) no
emulsion when agitated. Whatever mono and diglycerides were in the esters were
small but present I assume, but yet no emusion. Then added some small quantity
of glycerol ( which had been separated from the soaps, FFA and salts) and
agitated again and did get an emulsion. I have had the feeling glycerin has
usually been the cause of emulsion problems when I have had them. No doubt a
poorly reacted batch is much more likely to have the problem but is that really
due to the glycerides or is it glycerin which hasn't settled. Remember we
started this discussion that the glycerin settles much slower in a poorly
completed run.
BTW as an addition to this discussion look what someone just posted on my yahoo
group! Using glycerin cocktail to BREAK an emulsion. Now that's radical!!??
http://www.biodieselcommunity.org/breakingemulsions/
Joe
Jan Warnqvist wrote:
Hi evereybody. I feel obliged to enter this discussion. Pure glycerine is not
a good emulsifier due to the fact that there are three OH-groups and that the
carbon s in the first and third positions are surronded by two hydrogene
atoms. This makes the glycerine hydrophilic in five places alltogether.
However, the mono- and diglycerides are excellent emulsifiers. Only small
amounts of these are sufficient to create stable emulsions. Would somebody
agree with me on that ? Jan Warnqvist ----- Original Message ----- From:
"Keith Addison" <[EMAIL PROTECTED]> To: <biofuel@sustainablelists.org> Sent:
Friday, August 10, 2007 9:53 AM Subject: Re: [Biofuel] Glycerine Settling Time
Hi Tom
Hi Keith,
Then if you do one-litre test batches first, especially with iffy batches of
oil,
Ooooops. I took Joe's point to be: If you have to re-process it is
possible to use info from the QT to determine how much (how little) methanol
you'll need to use.
I also took that point, there were others though. It's a useful method,
cheaper reprocessing, but I think we all agree that reprocessing itself is to
be avoided if at all possible. Or I thought we did anyway.
I think that both Joe and myself have "standardize(d) the process" so that
passing the QT is the rule, not the exception.
That's not what Joe said:
It makes sense. Glycerin is an emulsifier. Have you ever tried dosing the
batch again with a little methoxide? After you remove the glycerin it doesn't
take much to get the last bit of the reaction to go and settle out the
remaining glycerin. Of course this is well known already. Kenji and many
others do straight base catalysis as a two stage deal. You can do a methanol
test of sorts and the unreacted oil will settle out. Then you can use the
measured amount of unreacted oil in the methanol test vial to estimate the
percentage unreacted oil in your batch and dose accordingly with the
stoichiometric amount of methoxide. Assume neutral oil for this calculation.
Rod and I do this regularly if the batch fails the QT and it works like a
charm. Will save you settling time in the long run.
"Rod and I do this regularly if the batch fails the QT and it works like a
charm." That "if" makes it a little ambiguous, but the "regularly" bit puts a
question-mark on what's the rule and what's the exception. "Kenji and many
others do straight base catalysis as a two stage deal." Less methanol
notwithstanding, my question remains - why reprocess, as a standard procedure,
instead of avoiding the problem in the first place? Could be wrong, but it
sounds like Kenji and others might be doing this rather than doing a titration
- you know the old line: "There's no need for titration, just use 6.25 g". And
then using the methanol test to try to fix the regularly ensuing disaster. A
different version of that here in Japan is to put the stuff through a
centrifuge, though the product still doesn't pass any quality test or
standards test. What you describe is much the same as what I described,
doing (whatever) tests during the processing, adjusting
accordingly and conducting the whole thing as a single stage. >From Joe's
replies so far I can't tell if he (and Rod, and Kenji and many others) are
doing it that way or not, but it seems not: Your question (and mine): "Don't
you have to heat up the whole batch again? (Time and energy)" Joe's reply:
"This is all done right after draining the glycerin. I leave the heater on
during this period. Do the rough QT right away before wash test." Rough
QT? Anyway, how long is it settling before he drains the glyc?
I run a QT towards the end of the reaction because I do not want to
re-process.
Indeed not.
It takes me a few minutes and I like the certainty of knowing the BD is good
before I pump it into my settling tank. If the test should fail when I'm
making a batch for my car, I could use Joe's suggestion to help me better
approximate the amount of methanol to add. If the process has been
standardized, why bother?
I think this is a misunderstanding. I didn't say what you say below,
"standardized; can't fail", and I didn't mean that standardising the process
means there's no need for tests, whether in-process tests or 1-litre test
batches or whatever. Anything can fail. I'm all in favour of any tests that
are helpful at any stage. So I agree with all you say here. Indeed,
whatever "rough" might mean, using the methanol test to fine-tune the amount
of extra methanol needed for reprocessing is a useful technique. But I'm
not in favour of using reprocessing as a standard method, which, pending a
better explanation, seems to be what's being proposed here.
As you say:
there shouldn't be any batches failing the QT.
I've had a few failed batches in the past year. It seems to happen when
I think I have it all figured out; standardized; can't fail. On one occasion
the pump was making a bit of a "funny" noise when I came back to turn it off.
Turned out a bit of paper towel or something had gotten into the impeller;
inadequate agitation? Had I tested the BD before pumping it into the settling
tank I could have avoided re-processing. While condensed water in
bottom-of-the-barrel methanol or recovered methanol, contaminated caustic, etc
may rear their ugly head in 1L test batches prior to running a batch, I think
I would still run a QT prior to settling.
Big skies
:-) And broad horizons.
Big lunch to you, I just had a garden pizza with Brocolli, zucchini, green
peppers, sliced tomato, and chopped (v. mild) hot peppers. Mmmmm
Mmmmmm Mmmmmm
:-) Great Tom! A big lunch definitely helps when it comes to broad horizons.
But quite often it's quicker just to amble on out and eat a bit of garden in
the meantime, and pin one's hopes on a big dinner. On the other hand, I think
there just might be some poached Muscovy egg and stir-fried Swiss chard in the
offing... Man, it's going to be hard ever to go back to the city life. All
best Keith
Tom -----
Original Message ----- From: "Keith Addison" <[EMAIL PROTECTED]> To:
<biofuel@sustainablelists.org> Sent: Thursday, August 09, 2007 3:36 PM
Subject: Re: [Biofuel] Glycerine Settling Time
Hi Joe
Tom; It makes sense. Glycerin is an emulsifier. Have you ever tried dosing
the batch again with a little methoxide? After you remove the glycerin it
doesn't take much to get the last bit of the reaction to go and settle out the
remaining glycerin. Of course this is well known already. Kenji and many
others do straight base catalysis as a two stage deal. You can do a methanol
test of sorts and the unreacted oil will settle out. Then you can use the
measured amount of unreacted oil in the methanol test vial to estimate the
percentage unreacted oil in your batch and dose accordingly with the
stoichiometric amount of methoxide. Assume neutral oil for this calculation.
Rod and I do this regularly if the batch fails the QT and it works like a
charm. Will save you settling time in the long run.
Well, settling time is free. Acid-base aside, there's the two-stage
base-base process, which quite a lot of people use and like, but otherwise why
do more than one stage? Do you mean two separate stages, with a methanol test
in between? So you process it twice? Plus extra methanol. Why not do it in
a single phase? Todd Swearingen once suggested this here (discussing mixing
pump sizes):
To judge an appropriate reaction time, pull an exact amount of fluid (200 ml
would suffice) out of the reaction stream every half-hour or hour after an
arbitrary initial ~1 hour reaction period. Presuming that the contents of
the reactor are kept homogenous from the pump flow, the volume of the glycerol
cocktail that settles out of each sample will give you a fair gauge as to when
your reaction completed. The suggestion would be to continue the reaction
for ~1/2 hour beyond the point where your glyc cocktail volume stabilized.
That works. Then, surely, you can standardise the process, with the only
variable the amount of lye according to the titration level. Then if you do
one-litre test batches first, especially with iffy batches of oil, and you
have a clear idea of how your test-batch processing relates to your full-scale
processing, life should be easier and there shouldn't be any batches failing
the QT. What did I miss?
Big skies
:-) And broad horizons. Keith
Joe Thomas Kelly wrote:
Joe, I took a sample from my latest batch of BD destined for my boiler
(failed QT; but very little residue dropped out). It had settled for almost 10
hrs. That was yesterday morning. Today there is a small, but noticable,
bit of glycerine on the bottom. More settled out after the initial 10 hrs of
settling. I don't have any results with good BD to compare it with.
If it turns out that glycerine settles out slower from incomplete vs
complete reactions, it would answer the question I asked about getting
emulsions when I washed low quality BD after letting it settle overnight, but
not getting emulsions when it settled for a few days to a week. It would
also help with a friendly disagreement I have with a friend. He seems to think
that unreacted glycerides will settle out of the BD given time. He has taken
to going with about 16% (vol/vol) of methanol in his batches. His logic:
"Unreacted oil causes emulsions, right?"
"The emulsions I get in the first wash after settling the BD overnight are
due to the unreacted oil?" "When I let it settle for a week or more I
don't get emulsions, therefore the unreacted oil must have settled out."
More likely: Some unreacted glycerides are still there, but after a week
of settling more of the glycerine has settled out. Even a small amount of
glycerine compound the emulsifying effects of the unreacted glycerides .....
Yes? By the way, I always ask him "Did you do a quality test?"
His answer: "Oops, I forgot." Thanks Joe .... and Rod ..... for
bringing this to my attention A push to make a lot of BD for heat is just
around the corner. It might be best to include more settling time in the
schedule. Tom ----- Original Message ----- From: <mailto:[EMAIL
PROTECTED]>Joe Street To:
<mailto:biofuel@sustainablelists.org>biofuel@sustainablelists.org Sent:
Tuesday, August 07,
2007 3:02 PM Subject: Re: [Biofuel] Biofuel Quality Test Hey Tom; Take
a sample from your fuel after settling 6-8 hrs and set it asside in a mason
jar for the longer period and see what settles out. Rod believes that
glycerin settles slower in a poorly completed reaction. I believe he is
right. And yes it only takes a little glycerin to emulsify your wash. Joe
Thomas Kelly wrote:
Mike, I let mine settle for a week when I can. It washes much easier. I
doubt that it does anything for an incomplete reaction though. That is to
say, I don't think the unreacted oil will settle out. But: I have been
wondering about something. When I started making BD it would never pass the
methanol quality test. I inevitably got emulsions in the wash. Now, when I
make BD for my "oil"-fired boiler, I use only about 16-17% (vol/vol) of
methanol. The BD does not pass the quality test, but I don't have the same
emulsion problems. Is it because I let it settle longer (24+ hours vs 6 - 8
hrs)? Does the presence of a small amount of glycerine/soaps make that
much of a difference when trying to wash BD from an incomplete reaction?
Tom
<snip>
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