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Testing the Imisides method
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Yes I was calculating the theoretical maximum and did not refer to the results of the SB test at all. Initially we were talking about dissolving 50gm KOH, and then Dgs referred to getting 32gm water from 100gm KOH, so I doubled my numbers and got a little under 32gm which roughly appears to confirm what he was told.

I think it's reasonable to rely on theoretical calculations. You are quoted the makeup of the materials you buy and are entitled to rely upon them.

It's really important to understand that when you dissolve an ionic substance in a solvent, you no longer have that substance. If you put table salt in water, can you see the salt? No. It has separated into its consitutent parts - Na+ and Cl-, which are floating in solution.

So it's wrong to say in absolute terms that the KOH converts into potassium methoxide and water. It converts into the methoxide ion CH3O- and the potassium ion K+. If there is H+ and OH- ions present, the methoxide ion will give an electron to the H+ to form Ch3OH - methanol and the balance of ions K+ and OH- will form KOH - weakening the methoxide's potency.
 
Location: New Zealand | Registered: August 15, 2006Reply With QuoteReport This Post
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I can now report the results of the first stage of my testing, which was to react 1 litre of new cooking oil with methoxides that had been prepared and "dried" according to the Imisides method using quicklime and cement. A control solution of "undried" methoxide was also tested.

My first test after reacting the oil was to measure the amount of byproduct produced by each sample.

The result is that the amount of byproduct for each sample is exactly the same. The byproduct separated into two layers, with a dark band on top and a lighter layer below. The total amount of byproduct produced by the reaction was 120ml (I carefully calibrated my sample bottles prior to starting the experiment).

I will now test the samples using the 10/90 test and soap test and I will report back when I have the results.

I have attached a photo of the samples. The bio is crystal clear and each sample looks identical. Any differences you can see in the pic are down to my poor photography. They are the same.

On with the next stage of testing.

Imageimage.jpeg (32 Kb, 30 downloads)
 
Location: Leeds, UK | Registered: April 13, 2014Reply With QuoteReport This Post
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Sorry. Can't get my photo to attach. I've reduced the size but keep getting an error message.
 
Location: Leeds, UK | Registered: April 13, 2014Reply With QuoteReport This Post
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Very well done, David.

Not what I expected at all. I would have thought the 2x dried methoxide tests would have shown a reduced glycerol layer.

BTW your photo won't load.

Dave.

Ah, we were posting at the same time!
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi Paulus,

quote:
Originally posted by Paulus:
Yes I was calculating the theoretical maximum and did not refer to the results of the SB test at all. Initially we were talking about dissolving 50gm KOH, and then Dgs referred to getting 32gm water from 100gm KOH, so I doubled my numbers and got a little under 32gm which roughly appears to confirm what he was told.
Thank you for confirming that. I am not a chemist so it took a while to figure out what you were saying.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Hi Dgs,

quote:
Originally posted by Dgs:
I would have thought the 2x dried methoxide tests
Can you explain what you mean by "2x dried methoxide"






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post



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Hi Tilly,

I mean the two tests with the methoxide mixed with CaO and cement.
As said when I tried this full scale with methoxide dried with CaO
the glycerol amount was noticeably reduced.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi Dgs,

quote:
Originally posted by Dgs:
...I tried this full scale with methoxide dried with CaO
the glycerol amount was noticeably reduced.

Reduced from what?
I didn't think that you had done a side by side comparison test using identical oil that had not been glycerine prewashed like David is here.

As I recall you said something about 12% methanol for a full conversion which of course is not possible.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Hello Dave,

Thank you for your comments. Yes, I too was expecting the "dried" methoxide to produce less byproduct, as this certainly seemed to be the case with the larger batches we did over Christmas. I've been very careful when comparing the level of byproduct between the three samples and I can say with certainty that there is no difference between them.

So, not the result we were expecting but it is what it is!

Let's see what the next tests tell us.

David

Imageimage.jpg (28 Kb, 22 downloads)
 
Location: Leeds, UK | Registered: April 13, 2014Reply With QuoteReport This Post
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Tilly - have you any idea why the byproduct has split into two layers please?

Thanks

David
 
Location: Leeds, UK | Registered: April 13, 2014Reply With QuoteReport This Post
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This was virgin oil? Just how much reduction in the glycerol by-product were you expecting, considering the FFA in the oil was virtually nil?
 
Location: New Zealand | Registered: August 15, 2006Reply With QuoteReport This Post
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Hi David,

quote:
Originally posted by David Shinn:
Tilly - have you any idea why the byproduct has split into two layers please?

Thanks

David
No, I do not know why there are two layers.
I often got something similar to that when using "plenty" of NaOH with limited Methanol such as you are doing here with KOH but that was many years ago and I did not worry about it
If I were to guess I would say soap on top of glycerine.

Are you going to dry the biodiesel and measure the yield?

I too am finding your results interesting and look forward to your continuing testing results.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post



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quote:
Originally posted by Paulus:
This was virgin oil? Just how much reduction in the glycerol by-product were you expecting, considering the FFA in the oil was virtually nil?


Hi Paulus,

Yes, this was new oil.

I expected that the "dried" methoxide would produce a more efficient reaction due to it introducing less water into the process. My supposition was that a totally anhydrous process would not produce as much soap, and that this would be evidenced by a reduction in the amount of byproduct that settled out (I think I am correct in saying that in any reaction, a proportion of soap migrates to the byproduct layer).

The soap testing should tell us more.

Thanks for your interest

David
 
Location: Leeds, UK | Registered: April 13, 2014Reply With QuoteReport This Post
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[/QUOTE]No, I do not know why there are two layers.
I often got something similar to that when using "plenty" of NaOH with limited Methanol such as you are doing here with KOH but that was many years ago and I did not worry about it
If I were to guess I would say soap on top of glycerine.

Are you going to dry the biodiesel and measure the yield?

I too am finding your results interesting and look forward to your continuing testing results.[/QUOTE]

Thanks Tilly,

I will have another careful look at the samples tonight and see whether there is any difference in the thickness of the "soap layer" and "glycerol layer" from sample to sample.

David
 
Location: Leeds, UK | Registered: April 13, 2014Reply With QuoteReport This Post
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Hi David,

quote:
Originally posted by David Shinn:
I will have another careful look at the samples tonight and see whether there is any difference in the thickness of the "soap layer" and "glycerol layer" from sample to sample.

David
Of course it might not be a soap layer.
A quick test for soap would be to see if it is water soluble.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Morning David,

I would suspect the layer on top of the glycerol in the CaO test is probably due to calcium hydroxide.

Tilly, To measure the conversion %/yield it is the methanol that needs removing. As the water at this point in the process will be <1000ppm, it is not significant as regards yield.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi Dgs,
quote:
Originally posted by Dgs:
I would suspect the layer on top of the glycerol in the CaO test is probably due to calcium hydroxide.
Perhaps, but then it should not be in the test batch that was not CaO dried.


quote:
Tilly, To measure the conversion %/yield it is the methanol that needs removing.
I do not recall needing to remove methanol to use the 3/27 test to check conversion and of course we all know there is no current backyard test that accurately gives conversion percent.

I should have been more explicit and said "wash" and dry the biodiesel to measure the yield.
There will be glycerine and methanol in the biodiesel that requires removing to get an accurate measure of the yield Smile






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Here is a photograph of one of the sample bottles showing the two distinct layers of byproduct. The bio above is very light coloured and crystal clear.

Imageimage.jpg (10 Kb, 15 downloads)
 
Location: Leeds, UK | Registered: April 13, 2014Reply With QuoteReport This Post



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Here are the results of the 10/90 dropout test. Each test was allowed 12 hours settlement time.

The control sample had a total of 0.8ml of dropout. Of this, 0.6 ml was clear oil with a 0.2 ml lighter cloudy layer above.

The quicklime dried sample had a total of 0.5ml of dropout. Of this, 0.4ml was clear oil with a 0.1ml lighter cloudy layer above.

The cement dried sample had a total of 0.6ml of dropout. This was entirely clear oil.
 
Location: Leeds, UK | Registered: April 13, 2014Reply With QuoteReport This Post
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So to each 1 litre of new VO, you added 400ml of MeOH (40%) which contained 40gm of KOH when the usual amount for new VO would be 7.8gm?
 
Location: New Zealand | Registered: August 15, 2006Reply With QuoteReport This Post
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