Hello Emre, Rafal et al.
I have to say that I partially disagree with some of your statements. The
limit of FFA for a flawless trans-esterification is drawn at 5mg KOH/g of
oil. Any value above will demand pre-treatment of the oil. It is always
important to check the water content, which should be below 0,5%. Try to get
hold of a water-in-oil test kit for quick determination.
If we are talking about the EN standard, it is always necessary to process
the oil/catalyst/methanol mix for 90 minutes to obtain the right values for
tri- di- and monoglycerides. And - this assumes that you have correct
stochiometric conditions and no methanol losses during processing.
As for the phophatides and the chlorophyll compounds, my experience is that
these are not very important for the processing result, unless the values of
these are extremely high (thousands of ppms). If so, the oil is usually very
dark. Totally refined oil, on the other hand, may have preservatives added,
and some of these will eat catalyst. So, good oil quality is a tricky thing.
Best of luck to you !
Jan Warnqvist
AGERATEC AB
+ 46 554 201 89
+46 70 499 38 45
----- Original Message -----
From: "EMRE ELMAS" <[EMAIL PROTECTED]>
To: <biofuel@sustainablelists.org>
Sent: Sunday, August 20, 2006 10:15 PM
Subject: Re: [Biofuel] tirating a virgin oil
Dear Rafal,
First of all, as long as you use cheap oil you should always be prepared
to
deal with much more FFA and water than it should normally contain. I think
your emulsion problem occurs as a result of highly contained water. If
that
is the problem you should first dry the oil then process the reaction.
Also if you use crude oil you should be very careful about the chemicals,
such as lesitine, in the oil. So always try to use degummed oil, if you
have
to process crude oil.
Another thing is, as you probably know, approximately 95 - 97 % of the
reaction is completed in the first 35 minutes, so you do not have to wait
for 2 hours. Also the alcohol boils at 65 C and the closer you get to that
point, the more alcohol you will lose at the time you need it the most for
the reaction. This prevents you to complete the reaction 100 %.
As I mentioned above if you just watch the content of water and the other
impurities in the oil you will be fine.
Hopefully the information works for you. I am looking forward to hear from
you soon.
Best wishes,
Emre ELMAS
Mobile: +90 533 517 72 45
From: Rafal Szczesniak <[EMAIL PROTECTED]>
Reply-To: biofuel@sustainablelists.org
To: biofuel@sustainablelists.org
Subject: [Biofuel] tirating a virgin oil
Date: Sun, 20 Aug 2006 19:31:26 +0200
Hi,
Recently I've came through problems with testing a cheap virgin oil
in my test processor which every time ended up with incomplete reactions
(emulsion problems). I did make the process longer (2 hours) and at
higher temperature (60-63 degC) - still nothing, though by product
separation is very nice.
Today, I tried to titrate the oil and - to my surprise - it took 0.925ml
of KOH solution. This was my first experience with titration, so I can
also tell that the phenolophtalein solution turned pale (but noticable)
magenta for about 15 secs (as described at JtF) after 0.925ml. After
adding 1.05ml the colour got more intensive for longer time.
My main question is - is it normal in case of cheap oils ?
I suppose they contain (as other oils) some amount of FFAs, but so much ?
Additional matter is whether I got titration right. I mean, interpreting
the colours.
I'm running out of ideas what could be wrong in the process, so any
help is appreciated.
--
cheers,
Rafal Szczesniak **mir[at]diament.iit.pwr.wroc.pl
Samba Team member mi***[at]samba.org
+---------------------------------------------------------+
*BSD, GNU/Linux and Samba http://www.samba.org
+---------------------------------------------------------+
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