Hello Roderick. A definiyion is on its place:
A salt is basically a compound built up from the reaction of a metal and an
acid.There are other salts too, but we can leave them for now. This means that
soaps are salts, since they are built up from metal ions (Na+ or K+ in
connection with biodiesel) and fatty acids. These are formed as a by-reaction
in the trans-esterification process, often encouraged by the water content.
Salt in every-day talk is NaCl sodium chloride , where in this case the
chlorine is fetched from HCl, hydrochloric acid. Does this spread any light to
you ?
You are using acetic acid to break the emulsion. This will create the salts
potassium or sodium acetate and water.
Best regards
Jan
----- Original Message -----
From: Roderick Roth
To: biofuel@sustainablelists.org
Sent: Sunday, August 12, 2007 6:03 PM
Subject: Re: [Biofuel] (was Glycerine Settling Time) removing salt/dirt
fromwvo
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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