3 Biodiesel Titrations

[oldskoolhead0]

is mixing the caustic with the methanol before adding to the oil nescessary or can you add the methanol to the oil then add the caustic to the mixture? as just a thought, instead of titrating the oil could you not just add caustic to the whole batch of oil/methanol mixture untill you reach a desired ph? as i think if you went this method you would get a far more accurate result providing you mixed it well enough and added caustic slow enough and save a lot of messing about

[darrendaz6969]

Disagree with you adding a "few more drops" of titrate, an accurate titration is the momment the colour change is constant for 20-30 seconds, and the colour change should be pink and no more. even if that batch of biodiesel was ok to use in a car engine it would cost more to produce then was needed. just an observation bud.

[BigTW707]

Would biodiesel be safe in a 2005 chevy duramax I've heard it's not good for 2002 & up diesels

[nickdicks]

You couldnt just use swimming pool test for the acid content?

[01840146]

why 30 seconds?

[davolikes2fight]

would someone please, please, please explain where the 7.5 for KOH, or alternatively the 5.5ml for NaOH comes from???

it takes on average approx 4 ml of catalyst solution to nuetralise the oil right, so why is it approx 4g PLUS 7.5 grams that needs to be added per litre of oil???

if someone could explain this it would b greatly appreciated

cheers

[trapperjohn80]

You don't want to bulldoze over the endpoint so that the solution is that pink. You want it only very slightly pink. Also, try not to slop your analyte because your calculations of FFA will be too low. Perhaps that is why he added too much titrant ...

[garvintimmann]

Engine damage of a car using the BioCar SVO system was traced to a supply of soy oil which was not the usual food-grade oil and had a high acid content. "An examination of the defective sections found substantial surface erosion of the hardened steel high pressure parts, which are not acid-proof."

[ttttonyyyy]

Getting exactly 10ml of IPA isn't critical to the titration - also because IPA goes acid as it ages it should be blanked with the titration solution (with indicator solution present) before adding the oil to it. And you can get 1ml syringes for measuring out the oil, which IS critical to accurate titration. It's all good fun :)

[samuel199166]

haha... I feel bad that i felt asleep in my chemistry class now, Totally fogot how to do titration. :(

[adrianb23]

To follow up on my previous post (which isn't appearing yet because it has to be approved), i figured out the math at the end.

I forgot to figure in the 7.5 ml (for KOH) or 5.5 ml (for NaOH).

So, from the 3 titrations:

1st: 3 ml titration solution used

2nd: 4 ml used

3rd: 4 ml used

3 + 4 + 4 = 11 ml, average would be about 3.67 ml.

7.5 + 3.67 = 11.17 ml <-- the amount of base to add per liter of oil would be closer to this, rather than 12.

[adrianb23]

Hi Graydon, i'm a little unclear on the math at the end. Can you please clarify?

Basically what's not so clear is if i should base the final amount of titration solution on the remaining solution in the syringe, OR the actual solution that was used to neutralize the acid.

1st titration: 3 ml titration solution used / 7 ml solution remaining

2nd titration: 4 ml used / 6 ml remaining

3rd titration: 4 ml used / 6 ml remaining

How did you arrive at 12 grams?

[cedartree696]

How come you don't blank your solutions?

[vernifort]

very informative and helpful specially for laymen like me

[jarp87]

what do you recommend for example lets say:

i got oil from kfc and oil from bk, mix them and take the sample of oil from the mix? is it ok(to mix oil in order to have the sample)?

[graydonblair]

I recommend oils from Chinese restaurants or from upscale restaurants. I don't care much for KFC or BK oil. It's usually really nasty...

But, yes, you can mix the oils. Just as long as they're really mixed well before you do the titration.

-Graydon, Utah Biodiesel Supply

[winverawin]

no it will be different because you wont add 7 to it you will add 5 instead

[jarp87]

what do you mean by that? i got confuse last minute how do u calculate it?

how do u get 12 grs of catalys?

7.5 + 4 = aprox 12 but the 7.5 ? the 4 is what u used of titration solution, 7.5 ?

[matteo240z]

same with NaOH?

if you need 4 ml of titration you will use 9.5 g/l catalyst?