Hi Michael et al
I’m wondering if anyone has looked at calcium oxide as
a reactant/catalysis. CaO is very hydroscopic and
should(?) suck up all the H2O and ffa’s. I’m thinking
about this in order to use hydrated rice straw derived
ethanol directly from fermentation rather than going
through laborious distillation and drying procedures.
CaO is used in cement and available at low cost
(mountains of limestone and five cement factories in
West Java). Can make concrete things as well as
biodiesel and glycerol.
Probably a crazy of the top of my head idea and just
wondering if anyone has tried it.
Ken
PS The p function is defined as –log (base 10) of the
thing being measured. This must be a dimensionless
quantity. The concentration of water is defined as
one. [H2O] = 1. The [] mean concentration.
[H+][OH-]/[H2O] = 10 to the minus 14. I.e.
[H+][OH-](dimensionless quantities) = 10 to the -14
and p(H+) + p(OH-) = 14. Agreeing with Michael, p(H+)
in something other than water has a different
meaning(?) and the rate of dissociation will be
different than in water.
--- Michael Allen <[EMAIL PROTECTED]> wrote:
> 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
> >> =>
> >> =>
> >> =>summa scientia nihil scire
> >> =>Help the planet each day! It's free and easy:
> >> =>http://www.Care2.com/dailyaction/
> >> =>
> >> =>
> >> =>
> >> =>Biofuels at Journey to Forever
> >> =>http://journeytoforever.org/biofuel.html
> >> =>Biofuel at WebConX
> >
> >>
>
=>http://webconx.green-trust.org/2000/biofuel/biofuel.htm
> >> =>List messages are archived at the Info-Archive
> at NNYTech:
> >> =>http://archive.nnytech.net/
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> to:
> >> =>[EMAIL PROTECTED]
> >> =>
> >> =>
> >> =>
> >> =>Your use of Yahoo! Groups is subject to
> >> http://docs.yahoo.com/info/terms/
> >> =>
> >> =>
> >>
> >>
> >>
> >>
> >> Biofuels at Journey to Forever
> >> http://journeytoforever.org/biofuel.html
> >> Biofuel at WebConX
> >>
>
http://webconx.green-trust.org/2000/biofuel/biofuel.htm
> >> List messages are archived at the Info-Archive at
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> >
> >
> >
> >
> > Biofuels at Journey to Forever
> > http://journeytoforever.org/biofuel.html
> > Biofuel at WebConX
> >
>
http://webconx.green-trust.org/2000/biofuel/biofuel.htm
> > List messages are archived at the Info-Archive at
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