Anyone tried using any anhydrous salt like sodium
sulfate to dry the oil/biodiesel, or the reaction mix?
JB
--- Tim Desson <[EMAIL PROTECTED]> wrote:
> the reaction between FFA and methanol is an
> equlibrium when catalysed by an
> acid
>
> FFA + methanol <==> Me ester + water
>
> so the reaction is driven to the right by an excess
> of methanol (the
> reaction you want) but is driven to the left by an
> excess of water, so my
> guess is that you need to get rid of water in your
> oil to make the FFA go to
> Me ester, and more methanol will help push the
> reaction the way you want.
>
> cheers, Tim
>
>
>
>
>
>
> >From: Keith Addison <[EMAIL PROTECTED]>
> >Reply-To: biofuel@yahoogroups.com
> >To: biofuel@yahoogroups.com
> >Subject: [biofuel] Fwd: Re: reducing ffa's
> >Date: Mon, 11 Aug 2003 19:50:13 +0900
> >
> >Fwd from Biofuels-biz.
> >
> >
> > >To: biofuels-biz@yahoogroups.com
> > >From: Michael Allen <[EMAIL PROTECTED]>
> > >Date: Mon, 11 Aug 2003 14:19:24 +0700
> > >Subject: Re: [biofuels-biz] reducing ffa's
> > >
> > >Dear Colton (and indirectly Girl Mark),
> > >
> > >I think pH meters are very stable and reliable
> instruments these days.
> >But
> > >you have to rememebr that they measure the
> hydrogen ion concentration in
> >a
> > >solvent that allows ionisation such as water.
> (Indeed, the pH scale is
> > >devised so that pH 7 is as neutral as water is
> supposed to be). Methyl
> > >ester and vegetable oils are not such solvents.
> If you put the electrodes
> > >of a pH meter into oil or an oil/water mix, the
> lack of an ionisable
> > >solvent between them causes the apparent pH value
> to wander all over the
> > >place. You can even damage some pH meters.
> > >
> > >I think that is also part of the answer for Girl
> Mark too: You can soon
> > >test what Todd is saying by dropping some sodium
> hydroxide pellets or
> > >flakes into some vegetable oil. You will see that
> it slowly reacts with
> >the
> > >glycerides to give sodium soaps which encase the
> pellets. This would make
> > >ppoor hand-soap because the unreacted pellets
> would be quite dangerous.
> >But
> > >add some water and a little heat and the reaction
> is much faster and more
> > >complete. The sodium salt of the fatty acid so
> formed can be skimmed off
> >or
> > >separated out with a strong brine solution
> (including calcium chloride
> > >solutions just like emulsion breaking mentioned
> elsewhere). It may then
> >be
> > >washed with fresh brine at this time to remove
> unreacted sodium
> >hudroxide.
> > >The pH of the soap made in this way is usually
> then lowered by adding
> >resin
> > >(wood resins such as pine and kauri have been
> used for yonks) and
> >buffered
> > >by adding something like borax (sodium
> tetraborate) or a phosphate (which
> > >also counters scum-formation in
> calcium-containing "hard" waters). The
> >soap
> > >is then left to harden ("aging") so that water
> evaporates and any sodium
> > >hydroxide (lye) left gets a chance to react with
> carbon dioxide in the
> >air
> > >to make the less skin-aggressive sodium
> carbonate. (This is basically how
> > >laundry soaps and soap powders were once made --
> and still are in some
> > >sustainable-technology countries). Some of these
> crude soaps are then re-
> > >milled, heated with colouring, perfumes, resin,
> buffers, glycerol etc. to
> > >make toilet soaps. (Incidentally, I think there
> are many more good
> >recipes
> > >on the net for soap-making than there are for
> ester-making. Here are just
> > >three of the thousands presented by google:
> > >http://candleandsoap.about.com/mbody.htm,
> > >http://waltonfeed.com/old/soaphome.html,
> > >http://members.aol.com/oelaineo/soapmaking.html)
> > >
> > >I'm sure you can see the similarities of this
> saponification reaction to
> > >the transesterification reaction. And you can
> also see how the presence
> >of
> > >water can quickly turn one into the other!
> > >
> > >But to return to Colton's enquiry:
> > >For the reasons given in the first paragraph, we
> measure the pH of the
> > >wash-water in contact with the methyl ester. Of
> course it takes some time
> > >for the two phases to come to equilibrium
> depending on how much mixing is
> > >going on, surface area exposed etc. Strictly
> speaking, we are not trying
> >to
> > >make the oil pH neutral by washing so much as
> trying to remove sodium
> >soaps
> > >and methoxide. If these remain in the ester, they
> could be deposited in
> >the
> > >engine and may cause damage. (Whether such damage
> is more dangerous to a
> > >diesel engine that a long drive down a
> spume-covered coast road I cannot
> > >say ..... but it's an interesting thought!)
> > >
> > >Hope this is some help
> > >
> > >Michael Allen
> > >Thailand
> > >
> > >On Thu, 07 Aug 2003 03:01:07 +0000,
> <[EMAIL PROTECTED]> wrote:
> > >
> > > > We are using a pH meter (& visual) methods
> during our titration to
> > > > determine the ffa%. It is very frustrating
> since the pH meter readings
> > > > are very inconsistant. Our current ffa% is
> 1.6% and we are trying to
> > > > reduce it to .5% by acidification. Any
> comments on methods for
> >determing
> > > > the ffa%?
> > > > Thanks
> > > > Colton
> > > >> How were you able to know that your ffa's
> increase?
> > > >> If you are just using a pH meter, it is but
> natural that the pH will
> > > >> fall
> > > >> since you are using a strong acid H2SO4.
> > > >> If you are titrating with NaOH, H2SO4 will
> eat up a considerable
> >amount
> > > >> of
> > > >> lye.
> > > >>
> > > >> Christopher
> > > >>
> > > >> =>-----Original Message-----
> > > >> =>From: Orion Polinsky
> [mailto:[EMAIL PROTECTED]
> > > >> =>Sent: Tuesday, August 05, 2003 8:53 AM
> > > >> =>To: biofuels-biz@yahoogroups.com
> > > >> =>Subject: [biofuels-biz] reducing ffa's
> > > >> =>
> > > >> =>
> > > >> =>hi all,
> > > >> =>
> > > >> =>I am trying to convert my free fatty acids
> to
> > > >> =>esters by acidification using methanol and
> > > >> =>H2SO4. Unfortunately, each time I try it,
> my
> > > >> =>ffa level increases.
> > > >> =>Is there anyone out there with a good
> > > >> =>acidification recipe?
> > > >> =>thanks,
> > > >> =>Orion
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