Joe,
I've been wondering about this myself.
This was, in part, what I was asking. Do we simply have to neutralize
the mix or do we have to achieve a particular pH?
Would it be possible to measure the amount of acid needed to bring a
known volume of the glycerine mix to the desired pH and then extrapolate to
the volume of cocktail we have at hand?
Todd S. describes (at JTF: "Separating Glycerine") how to calculate the
amount of acid needed for glyc. cocktail of unknown history. It is
effective, but one must have patience.
I suspect that many people do not split the mix because it's a bit
confusing or sounds difficult.
Tom
----- Original Message -----
From: "Joe Street" <[EMAIL PROTECTED]>
To: <Biofuel@sustainablelists.org>
Sent: Monday, May 15, 2006 2:49 PM
Subject: Re: [Biofuel] Separating Glycerine
> Further to Tom's inquiry;
>
> My issue is that I have a small reactor and so I only produce a small
> amount of the glycerine cocktail. By the time I have a cubie full of
> cocktail it is the remains of several batches of fuel which makes it
> difficult to guage the amount of caustic it contains. Is there a way to
> titrate the cocktail? If you don't want to answer just say bat guanno
> and I'll get the hint. LOL
>
> Joe
>
> Thomas Kelly wrote:
>
>> Hello to all,
>> The short version:
>> 1. To split the glycerine cocktail must one merely neutralize the
>> NaOH/KOH used to produce it or is it necessary to go beyond neutral, to
>> acid?
>> 2. If it must be acidic,
>> if one knows how much H3PO4 it takes to neutralize the mix, can one
>> predict how much more H3PO4 it will take, to get the split?
>>
>> The long version:
>> On 4/10/06 Todd Swearingen, in a post entitled "Re: Separating
>> Glycerine" suggested that I would need to add 510 - 590 ml of 85%
>> phosphoric acid to each cubie (4.5 gal/17.7L plastic container) of
>> glycerine cocktail to achieve a split.
>> Sure enough, when I added 540 ml (lowest) - 580ml (highest) of 85%
>> H3PO4 to the next cubies of glycerine mix I got separation into mineral
>> precip, crude glycerine, & free fatty acids.
>> I've been wondering ever since how he was able to make the
>> calculation/prediction .... or is he just a good guesser?
>>
>> On 12/02/05 Bioclaire Nederland described how to calculate the
>> amount of H3PO4 to add for separation if one knew the amount of NaOH
>> used to process the WVO that yielded the Glycerine cocktail. (See
>> "separating Glycerine" & "separating Glycerine Mistake!").
>> The explanation is based on the equation for neutralizing NaOH
>> using H3PO4.
>> H3PO4 + 3NaOH ------> Na3PO4 + 3H2O
>> 1 Mole (98g) of H3PO4 will neutralize 3Moles (120g) NaOH
>>
>> If one knows how much NaOH (or KOH) was used in the batch(es) that
>> produced the Glycerine cocktail it should be possible to calculate how
>> much H3PO4 it would take to neutralize (and split?) the mix.
>>
>> Here is where the problem, and questions come in:
>> The Glycerine mix I was using (4.5 gal/17.7L) containers each came
>> from two 76L batches (152 L WVO, total).
>> The oil I used for these batches titrated at 1.0 - 1.5 g NaOH/L of
>> WVO. (684 - 760 g of NaOH)
>> Adjusting for 85% H3PO4 (115g of 85% H3PO4 would contain the 98g -
>> i.e. 1M.- of H3PO4) and using the density of 85% H3PO4 (~ 1.59g/ml),
>> that I should only need 460ml of the 85% H3PO4 to neutralize the lye
>> used to process the oil.
>> Not all of the lye is in the glycerine cocktail. Some is in the BD.
>> I use 0.20 ml H3PO4/L of oil processed when I do my first wash (15ml/76L
>> batch or 30ml for two batches). This results in wash water very close to
>> neutral suggesting to me that approximately 50 g of the lye used to
>> process the WVO comes out in the BD, not in the Glyc. mix. The 710g of
>> lye that is in the glyc. mix should only take about 430 ml of the 85%
>> H3PO4 to be neutralized.
>>
>> None of the cubies would separate w less than 540ml of the 85%
>> H3PO4. This suggests that it takes more than merely neutralizing the
>> glycerine mix to get it to split.
>> (Answer to Ques #1?)
>> Note: I'm doing a lot of this in my basement or in a shed out back,
>> not a lab.
>> So how did you do it Todd? Neutralize + 20%?
>> If it's a secret, include the word iguana anywhere in your response
>> and I'll drop the subject.
>> Still puzzled
>> Tom
>>
>>
>>
>>
>>
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>>
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>
>
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