You prepared a 4 liter batch from which you pulled both wash samples. Yes?
Your only variable was temperature of the wash water. Yes?
You point out that the warmer sample separated well and the colder one not.
Yes?
So why did you "dispose" of the cooler sample prior to letting your
experiment go one step further by allowing it to warm to the same degree as
your warm sample was and then observe? In theory the end result would be the
same, with the emulsion breaking and a quick settling time after
re-agitating.
If your sampling was conducted to determine the effects of different wash
temperatures, then you're asking the wrong questions.
But to answer them:
Testing for triglycerides would be rather unneccessary. If they are present
there would also be mono- and di-glycerides and you'd know something was
quite amiss when you achieved heavy emulsion in a wash. As well,
triglycerides don't appreciably emulsify as do mono- and di-glycerides.
Best method to reduce any concerns of soap formation is an acid
esterification, followed by transesterification. The esterification converts
to biodiesel what normally would become soap, in turn putting an end to
concerns about "excess soap." Once soap is almost completely eliminated from
the equation through esterification and sufficient settling, unconverted
glycerides by and large become the only emulsification variable.
Yes. "4m fuel" is better than "10m fuel" if everything else is perfectly
equal. But you can't say the same thing when you throw in variables.
Todd Swearingen
----- Original Message -----
From: "John Guttridge" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, December 29, 2004 1:37 AM
Subject: [Biofuel] more on the quality test
I have completed my testing with 150mL from my 4L batch.
before testing my fuel was settled for 7 days until it was crystal clear
and light yellow in color. after 24-48 hours it seemed to settle
completely but it was still hazy, this went away entirely after the full 7
days. there was no appreciable increase in the volume of the glyc layer
after the initial settling period.
ambient temp is 55 degrees. all samples were prepared with normal city
water from my tap (I don't think it is hard but there is certainly stuff
in it from treatment, like chlorine for example).
glassware used in measuring the samples is accurate to .24mL at 150mL (per
labeling etched in the glassware). all measurements are read from the
bottom of the meniscus.
samples were added to a small ball jar (about 450mL volume) and then
shaken for 10 seconds fairly violently.
at 70 degrees F 150mL sample separated in 4m 10s, it was a celan
seperation with absolutly no emulsion. there was some haze in the
biodiesel like it looks when I start to wash, it goes sort of milky yellow
with lots of tiny little bubbles, this will become crystal clear and even
lighter yellow than it began if allowed to settle for a while (usually a
day or two).
at 40 degrees F 150mL sample separated in 12m 4s, there was gunk in
emulsion in the FAME on top that never settled out, after about seven
minutes it had separated into 60/40 (the 60 being BD) with lots of
emulsion in the biodiesel layer, this emulsion never really broke but it
reached about 55/45 by the 12m 4s point at which point it was as complete
as it got within the 40m before I disposed of it. I don't think that I
would say this "passed" because of the junk in the top layer and also
because it never really came back to 50/50.
some questions remain:
this test clearly tests for three things: soap, monoglycerides, and
diglycerides. how can we test for triglycerides (really incomplete
reaction)?
if we look at the results and say "this didn't pass" we should have some
path for figuring out why. what methods can be used to tell the difference
between excess soap and unreacted mono and di glycerides?
do we learn anything from the separation time itself on a "passing" batch?
is 4m fuel better than 10m fuel?
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