Since you can use H2SO4 to reclaim the KOH from the glycerine reaction, why not use acid/methanol to reclaim your KOH from the raw biodiesel ester? Will the salts drop out and leave you with a good product? Of course I would reclaim the extra methanol, but if it does work, it sure would beat the heck out of water washing the ester. Granted you would have to titrate as not to add too much acid. Peace.
I haven't checked in lately to see if there is some kind of newfangled method for making biodiesel, but there should be extremely little if any KOH left in your raw biodiesel after the reaction. It is not consumed in the reaction and it settles out with the glycerine by-product.
The premise you are basing your question on is wrong. Furthermore I am not sure why you would want to reclaim the KOH from your glycerine byproduct. From what you described I think you would end up with Potassium Sulfate salts, water, purer glycerine and FFA's.
Adding Acid to the methyl esters will only make your biodiesel more acid. This is not good for the injectors and other parts of your engine.
Perhaps you are talking about filtering out the soap from the raw biodiesel. There are better methods for filtering soaps. Read up on wood shavings & resin towers.
Hope that helps.
The most efficient method is still he use of ion exchange resins. Once the biodiesel has been mostly demethed the resins take care of the rest in purification of the fuel. Adding a small micron fuel filter after the resins will offer a guarantee that no residuals remain.
** Biodiesel Glycerine Soap - The Guide
- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.
You are not reclaiming koh from anything with h2s04, you would be neutralizing it with the right amount of acid.
Thanks for all the posts. I'm now reading up on the ion exchange.