[Bioconversion] Re: [Gasification] Biodiesel in Belize

[AJH]

On Sun, 23 Apr 2006 09:47:57 -0500, Harmon Seaver wrote:

>> I don't know either but it looks like 10% of the bio diesel is
>> contribution from the alcohol so there should be every incentive to
>> make this fossil free, if indeed there is real need to use the trans
>> esterised product rather than straight oil.
>>
>         No, there should be zero alcohol left in the biodiesel.

That bit's true because the bit of the alcohol that's attached to the
fatty chain is just the methyl or ethyl group.


> It is
>only a catalyst and you should be able to recover all of it, although
>some people do just heat the oil and evaporate the alcohol off into
>the air, but since the methanol is the major cost (if you are using
>free WVO) then that's pretty dumb.

I think you are mistaking the methanol with the caustic soda, the
caustic soda reacts with the methanol to make methoxide which then
splits the triglyceride into three chains and sticks a methyl group
onto each one. The glycererine which is formed is then a by product of
the operation. Any un reacted methanol remains in the fuel and I think
this is why some poorly made biodiesel causes trouble with fuel system
seals.

Follow this up to bioconversion if you like, whilst I have a friend
who makes the stuff and gives me his glycerol for experiments I've
only seen the process as a bystander.

AJH