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Need 1 oz of KOH for Titration.
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I am just getting started into Biodiesel production after 2 successful test batches. I have decided to establish and perform as many of the ASTM tests as practical to ensure passable quality fuel for my vehicle. Built the manometer for water content, conducted process completion, (3/27 test) residual catalyst and soap content. Now the reason for this post, I want to test for total acid. To do so requires a 0.10% solution of KOH. Since I use NaOH, I do not have ant KOH and do not want to purchase 2 lbs for this purpose. Anyone using KOH in their process that would be willing to send me 1 oz., I will pay you material cost and postage thru PayPal. Interested parties, send me an email at retired62441@yahoo.com and I will send you my mailing address.

Thanks Jeff
 
Location: Casa Grande, AZ | Registered: January 28, 2013Reply With QuoteReport This Post
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You want to test for total acid? Can't you use NaOH instead of KOH in the proceedure? They're similar strong bases. Are you talking about titrating the starting vegetable oil for free fatty acid content? Thanks
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post
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0.1% KOH Aqueous solution? I guess this is 1 gram KOH dissolved in 1 litre of (distilled) water solution. Well there are ways to get it and make it that way, if NaOH won't do. There is a business called Hach Company, telephone in USA (800)227-4224. Hach is in Colorado and does mail order for water testing supplies. I never had any problem with them. Hach sells 1 Normal KOH Aqueous solution in a quantity of 50 milliliters for $10.15 (American dollars). For KOH a 1 Normal standardised solution equals a 1 Molar solution. That's 1 mole of KOH dissolved in 1 litre of water. 1 Mole of KOH weighs 56.11 grams. So 50 millilitres of 1 Normal KOH aqueous solution has 2.8055 grams of KOH in it. So to get a strength of 1 gram per litre, dilute 50 millilitres of 1 Normal KOH aqueous solution with distilled water until it makes up 2805.5 millilitres. Hach Company also sells Potassium Hydroxide pellets, 500 grams for $35.99. The pellets are approximately 85% pure. When measuring accurately it is kind of hard to weigh out one gram perfectly because the pellets probably weigh 1/10th of a gram each. And while you're weighing out the potassium hydroxide its absorbing water and carbon dioxide from the air, constantly changing weight a little. 50 milliliters of KOH 1 Normal aqueous solution might be small enough that you don't have to pay a hazardous material shipping fee in addition to postage. Where mail order is expensive is if they charge a lot for shipping.
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post
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To test the acidity of your biodiesel you can simply titrate it with the same NaOH solution and method you used to titrate the WVO in the first place. There is no need for koh.
Cheers,
Jon
 
Location: Wellington County, Ontario Canada | Registered: February 07, 2008Reply With QuoteReport This Post
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quote:
Originally posted by Jon Heron:
To test the acidity of your biodiesel you can simply titrate it with the same NaOH solution and method you used to titrate the WVO in the first place. There is no need for koh.
Cheers,
Jon


Which tell me nothing about where I am relative to the ASDM D644 Acid Number specification which is 0.5 max mg KOH/g.
Guess I will just bite the bullet an buy 2 lbs. KOH and have it occupy space on my shelf.
 
Location: Casa Grande, AZ | Registered: January 28, 2013Reply With QuoteReport This Post
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Originally posted by WesleyB:
0.1% KOH Aqueous solution? I guess this is 1 gram KOH dissolved in 1 litre of (distilled) water solution. Well there are ways to get it and make it that way, if NaOH won't do. There is a business called Hach Company, telephone in USA (800)227-4224. Hach is in Colorado and does mail order for water testing supplies. I never had any problem with them. Hach sells 1 Normal KOH Aqueous solution in a quantity of 50 milliliters for $10.15 (American dollars). For KOH a 1 Normal standardised solution equals a 1 Molar solution. That's 1 mole of KOH dissolved in 1 litre of water. 1 Mole of KOH weighs 56.11 grams. So 50 millilitres of 1 Normal KOH aqueous solution has 2.8055 grams of KOH in it. So to get a strength of 1 gram per litre, dilute 50 millilitres of 1 Normal KOH aqueous solution with distilled water until it makes up 2805.5 millilitres. Hach Company also sells Potassium Hydroxide pellets, 500 grams for $35.99. The pellets are approximately 85% pure. When measuring accurately it is kind of hard to weigh out one gram perfectly because the pellets probably weigh 1/10th of a gram each. And while you're weighing out the potassium hydroxide its absorbing water and carbon dioxide from the air, constantly changing weight a little. 50 milliliters of KOH 1 Normal aqueous solution might be small enough that you don't have to pay a hazardous material shipping fee in addition to postage. Where mail order is expensive is if they charge a lot for shipping.


You seem to have missed the point to my original post. My objective was to obtain a small amount to conduct the ASDM test and avoid having a 2 lb bottle sitting on my shelf which I will likely never use. It doesn't make much sense to me to spend $36 when I can buy the KOH for $16
 
Location: Casa Grande, AZ | Registered: January 28, 2013Reply With QuoteReport This Post



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I don't know how accurate you want to be in your testing. NaOH has 40.00 grams/mole , KOH has 56.11 grams/mole. To convert to an equivalent molar amount of KOH from the mass of NaOH used in the test multiply by 0.712885404. So the 0.5 milligram max of KOH/gram would equal 0.356442702 milligrams max of NaOH. At some point the number is rounded off. You might read the listing "standard solution" on Wikipedia. All the best. To convert from NaOH to KOH multiply by 1.40275.
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post
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Which tell me nothing about where I am relative to the ASDM D644 Acid Number specification which is 0.5 max mg KOH/g.
Guess I will just bite the bullet an buy 2 lbs. KOH and have it occupy space on my shelf.

Its ASTM, not ASDM. May I ask why you would care about the ASTM spec for biodiesel acid number? It is irrelevant in the real world as is much of the ASTM standard for biodiesel.
In any event, titrating with your NaOh will give you an acid number that can be converted as suggested by Wesley.
quote:
It doesn't make much sense to me to spend $36 when I can buy the KOH for $16
IMO buying koh to test the acidity of your biodiesel when you have NaOH on hand makes zero sense to me...
If your trying to test to see if your biodiesel is suitable to burn in your diesel engine, as I suspect, I would recommend looking into the phlip test as it is quite comprehensive.
If you decide for some reason to purchase the koh to do this test, please do me a favour and let me know how it compares to a simple titration as I suggested above, I would suggest the 2 numbers will be quite close...
Good luck!
Jon
 
Location: Wellington County, Ontario Canada | Registered: February 07, 2008Reply With QuoteReport This Post
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quote:
Originally posted by WesleyB:
I don't know how accurate you want to be in your testing. NaOH has 40.00 grams/mole , KOH has 56.11 grams/mole. To convert to an equivalent molar amount of KOH from the mass of NaOH used in the test multiply by 0.712885404. So the 0.5 milligram max of KOH/gram would equal 0.356442702 milligrams max of NaOH. At some point the number is rounded off. You might read the listing "standard solution" on Wikipedia. All the best. To convert from NaOH to KOH multiply by 1.40275.


Thank You very much. This is what I needed to know. I do appreciate your input.
Regards Jeff
 
Location: Casa Grande, AZ | Registered: January 28, 2013Reply With QuoteReport This Post
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Here is some discussion's I had about testing for acid back when I was using muriatic acid to neutralize the caustic before starting WBD, you may find it interesting. http://biodiesel.infopop.cc/ev...311057172#4311057172
Cheers,
Jon
 
Location: Wellington County, Ontario Canada | Registered: February 07, 2008Reply With QuoteReport This Post
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Thank you Jon. Read through the posts once and will read them again. Lots of interesting discussion. What does WBD mean?
Jeff
 
Location: Casa Grande, AZ | Registered: January 28, 2013Reply With QuoteReport This Post
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WBD- Whole Batch Demeth. That's removing excess methanol from the Biodiesel reaction product with the lower glycerine layer still present. Rather than removing the glycerine layer and removing the excess methanol from only the upper biodiesel layer by evaporation or boiling it off (distil it away from the biodiesel). It is partly an effort at efficiency improvement. Recovers methanol for use later, but there may be some water in the methanol. Can be done while a big batch is still warm so it doesn't have to be reheated. After the biodiesel has excess methanol removed more soap and probably glycerine settles out of it. I'm probably not mentioning everything about WBD (whole batch demething) but there's a lot of factors to consider. Thanks
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post



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Yep, Wesley pretty much summed it up. Its removing the methanol from the entire batch glycerin included in one shot.
It provides a huge increase in efficiency and savings and is the only way to go IMO.
Here is a very long thread with lots of good info about WBD if your interested. You will see in it many questions and concerns about the fuel quality after a WBD but they have all been answered by the test of time. Using the WBD method makes top quality fuel very efficiently.http://biodiesel.infopop.cc/ev...5551/m/989100721/p/1
Cheers,
Jon
 
Location: Wellington County, Ontario Canada | Registered: February 07, 2008Reply With QuoteReport This Post
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