[Biodiesel In Utah] Acid-catalyzed esterification

[eastmanassociates at comcast.net]

Derek -

A few quick comments, as a chemist.  First, the acid-catalyzed method is relatively new; the traditional method of making biodiesel uses caustic, i.e., base catalysis.  Virtually all home-brewers use the base-catalyzed method.  

Here's a quick comparison of the two:

Base catalysis - sensitive to water, free fatty acids (FFA), catalyst concentration ~1%; can be either batch or continuous, most common method

Acid catalysis - used when high FFA is a problem, but water must be continuously removed in that case, requires more catalyst (5-25%), used for about 10% of commercial capacity.

For a little more information, try this link:  http://www.biofuels.coop/pdfs/4_commercial.pdf

Now let's answer some of your questions:

1 - is an acid-base reaction how biodiesel is produced?  No.  It's a transesterification, and the acid or base that you add is simply a catalyst.  See the link above for the details.

2 - is mL a standard measure of sulfuric measure?   Well, yes, but it's more complicated than that.  You also have to consider the concentration of the acid.  I suspect that you're being asked to add commercial "concentrated sulfuric acid."  The amount of sulfuric acid that you add is determined by how well the catalyst works; no specific amount is required by the reaction itself, since the catalyst is not consumed during the reaction.

3 - is this how the 'big boys' produce biodiesel?  Usually, the big boys use base catalysis, but there is a trend toward more acid catalyzed processes, and especially toward solid acid catalysis, since solid acids are more convenient for large-volume continuous processes.

Hope this helps.

--
Alan D. Eastman, PhD 
Eastman Associates LLC 
801-278-9560

-------------- Original message -------------- 
From: dgkemp1 at comcast.net 

Hi all 

I have been lightly reading over the Biopro 190 tech sheet 
and had a few questions 

is a acid - base reaction method, the prefered way to produce Bio ?

In reading  You use 190 mL of Sulfuric acid, is  1mL a standard quantity  for the acid used, now matter what the oil titrates at ?

is this how the big boys produce Bio ?  

Thanks 

Derek   
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