PH of glycerin by-product

[Fowlchick Biofuels Forum Newbie Find all posts View Profile Close Fowlchick]

Would anyone know what the pH of their glycerin by-product is? The couple of batches I'm playing with indicate pH 10.9 and 10.1. Assume many wouldn't know this information for any particular reason, but would greatly appreciate an idea of the range it can fall within. Thanks in advance.
Regards,
fowlchick

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: PH of glycerin by-product

Fowlchick,
The byproduct will have in it all of the unused caustic (the catalyst), most of the methanol and most of the soaps made in neutralising the FFAs in the oil.

Why do you need to know the pH of the byproduct?

If you need to know how much acid is needed to neutralise it, then you can do a titration to pH 6.5 or so to let you know how much acid to add to the byproduct.

If you are trying to release the FFA from the soaps, then titrate to around pH 5 or so, using Bromophenol Blue (I am not positive about the pH or the spelling of the indicator). This will tell you how much acid to add, to convert the soaps to FFA.

[Fowlchick Biofuels Forum Newbie Find all posts View Profile Close Fowlchick]

Re: pH of glycerin by-product

Tony,
Appreciate alot of your posts. Really don't want to sound smarmy, but I know that already. Ahh, except of course that pH level?
Basically, I'd like to know as it's an assumption that a particular stockpile falls within the norm without a comparison to others. Wondering as I'm playing.
Thankyou,
Fowlchick

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: PH of glycerin by-product

Hello Fowlchick,

The pH of Caustic Soda (NaOH) is between 13- 14.
Soap is the salt of a weak acid and a strong base and typically has a pH not greater than 10.
As both NaOH and soap are present in your glycerine layer in varying quantities depending on a number of variables, I would expect the pH of your "Glycerine Layer" to be greater than 7.

I would be concerned if the pH of your "glycerine layer" exceeded 14.

Tilly

[duschl Biofuels Forum Newbie Find all posts View Profile Close duschl]

Re: PH of glycerin by-product

hi,
i just checked the glycerin byproduct of a 250 mL used vegetable oil test batch. the litmus paper only goes from 2.0 to 9.0 and the pH i measured is either 9.0 or greater...
cheers,
duschl

[Bill Biofuels Forum Newbie Find all posts View Profile Close Bill]

Re: PH of glycerin by-product

Tilly is right in many respects.

The caustic and the soap would form a pH mix around the 10 to 11 mark.

If the pH exceeded 14, however, I believe (and probably so does Tilly) the universe would cease to exist.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: PH of glycerin by-product

Hello Bill,
Three months ago, when I wrote the reply above, I would have agreed with you,

But now, Since learning about the Flitch Fuel Catteliser, I have come to the conclusion that it is probably not a concern until the pH reaches 17.

Tilly

[Bill Biofuels Forum Newbie Find all posts View Profile Close Bill]

Re: PH of glycerin by-product

Hello Bill,
Since learning about the Flitch Fuel Catteliser,

I had better learn about this device that allows a pH above 14. I guess in an infinite universe all things are possible, especially if there is a different definition of pH out there.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: PH of glycerin by-product

Yes, the world is an amazing place!

If using the Flitch Catteliszer can make this massive of difference to a Dyno test, anything is possible!



Tilly

[farmer puddles Junior Member Find all posts View Profile Close farmer puddles]

Re: PH of glycerin by-product

Just remembering some uni chemistry, i think pH = -log(Hydrogen conc)?? can't remenber formula?? , it is possible to have pH less than zero and greater than 14 depending on concentration of acid or alkali

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: PH of glycerin by-product

Only with a filch catteliser.
For the rest of the real world where the rules of chemistry and physic apply, 0- 14 pretty well covers it.

Tilly

[Bill Biofuels Forum Newbie Find all posts View Profile Close Bill]

Re: PH of glycerin by-product

This reminds me of the NSW Environment Minister (about 10 years ago) who thought that pH7 was too high for streams and lakes and wanted the pH regulation limits set at a much lower value, say 1 or 2, nay zero even.

[Sauman Senior Member Find all posts View Profile Close Sauman]

Re: PH of glycerin by-product

Only with a filch catteliser.
For the rest of the real world where the rules of chemistry and physic apply, 0- 14 pretty well covers it.

Tilly

good one Tilly

And leong please do hang around.Lots of action to come.Remember more the merrier bigger the party.

Have a good weekend

Cheers
Sauman