2 Stage process - dropout calculation

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

Can anyone clarify the directions in Steps 5 & 6 of the following please, specifically the "unprocessed oil volume x base" part.....I am unsure of the calculation.

As I am very new to the 2 stage process, I want to get this right.

(If i get say 3mL of dropout, does that mean 3mL of dropout x 5g KOH = 15g KOH/L of W.V.O.?) This seems very high to me.

Thanks in advance,

James
0447 761 717
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Do not titrate!

1) Make your first stage methoxide solution with base amounts 3.5g/l for NaOH or 5g/l KOH x full batch size + 80% of normal methanol amount.
2) Put this first stage methoxide mix into the processor at normal reaction temperature, and mix for an hour.
3) Stand for 20 minutes and drain off the glycerol into a clean container, and seal.
4) Do your 3/27, 5/45 or 10/90 test and measure the amount of drop out.
5) Determine the amount of unprocessed oil in your batch from the dropout.
6) Make up the second stage methoxide by mixing "remaining 20% of the methanol" with "unprocessed oil volume x base" catalyst.
7) Now mix as normal for second stage
8) Do another 3/27 test after 30 minutes to check conversion. If this does not give a clear pass continue mixing for another 30 minutes - it should give a clear pass. If not go to step 4 above and repeat but with minimal methanol.

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

Re: 2 Stage process - dropout calculation

Hi James,
I do not recommend using this procedure.
I have performed several tests with this method using NaOH and unless you have very low titration oil, it does not achieve separation in the first stage. This indicates they have never actually performed the procedure using NaOH before writing it up in such glowing terms.
It reminds me of the Foolproof Method in that regard.

As you point out the directions are vague and ambiguous.
What is the "Normal" amount of methanol and the "Normal" temperature they talk about? How do you determine what the un-reacted amount is?

I have asked the people who have posted this procedure to provide a link to the testing they performed comparing this method with the single stage method and the 80/ 20 2 stage method. They have always declined to provide any meaningful test information.
As far as I can tell there has never been any testing performed.

My recommendation is to start with the 80/ 20 method described if you scroll down the page. The 16% boost method looks interesting.

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

Re: 2 Stage process - dropout calculation

James,

To clarify for you (and it seems to work well although the science does not seem to support why !) Lets do a basic example

1) Lets say i have 100 litres of oil and i use KOH

2) You aim for using 20% methanol with this method - so we want 20l methanol total

3) now we are using out methanol in the 80/20 mode -so we want to seperate our methanol into 16L and 4 litres.

4) Now use the base amount of KOH that you would normally use - say 8 grams per litre - therefore add 800gms of KOH to the 16L of methanol and mix

5) Add this to your oil and mix using your method of choice - pump, agitator, paddle etc for your normal length of time - i mix for an hour because i know that works for me

6) Take a 1 litre sample in a soft drink bottle after 1 hour or so and let it sit to verify you are getting separation.

7) Once you have the glycerine drop out of this sample then take 90mls of methanol and add 10mls of the "semi processed" BIO from the bottle

8) Make sure you do this at close to 20c, shake this and let it settle - i support the jar i do this in on a tilted angle so all the drop out accumulates in one side

9) Now (i use a syringe) suck up this drop out and measure (the easiest way i find is to suck it all up with some extra liquid from the jar, then invert the syringe and expel the clear liquid)

10) Now as an example lets say we have 3mls of oil that has dropped out from our 90/10 above - the theory here says that we have 30% of unreacted oil, so this means do your new calculation as if you are reacting 30l of oil

11) Drain the Glycerine from your main batch (which should have settled out by now)

(It is upto you at this point and how confident you are with your oil - you can do another test batch before you do this step and verify that it will actually work) or if it needs tweaking (when i started doing this method i did this step - i do not bother any more)

11) So you would now add 240 grams (8 x 30) of KOH to your 4 litres of methanol and then add back to your batch

12) again mix for the required time, take a sample and ensure it separates, then perform a 90/10 on that to make sure there is no more dropout

As stated i only use KOH so can not comments on Tilly's results with NaOH. I can confirm that i have never had a problem with this method and that when i wash it at the end i seem to get a heap less soap and no emulsions.

If i do my batches with a normal single stage reaction i find that i need to use 16 grams KOH and 22 % of methanol to push the reaction to completion. Using this method i find that i use less methanol - i have it down to about 18% methanol and 12 grams KOH

Craig

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

Re: 2 Stage process - dropout calculation

do as craig says it will work I use naoh and do 3/27 then calculate the percentage dropout from that, 90/10 would be better for you. Something must work differently to titrated single or 2 stage reactions as craig says a lot less soap I can aggressively water wash and not get an emulsion, also I have never had the naoh glyc solidify any more I now use it to glyc pretreat and can leave it all in the processor with no fear of it going solid in the pipework, give it a try and then make up your own mind.

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

Re: 2 Stage process - dropout calculation

Hi Craig,
This is the problem with this method. It depends on the oil you are using.
The fellow who wrote this method up and posted it to Wikipedia was using oil that only requires 5g KOH per litre of WVO in the first stage.
You have found that your oil requires 8g KOH per litre in the first stage.
Without knowing the titration of the oil you are just guessing.

As far as I amm concerned, a procedure that starts out by saying "don't do a titration, just try to guess how much KOH to use in the first stage" is not going to be a reliable method. My Oil titrates less that 1, I could even get the posted method to work using NaOH (but just barely)

To take a trip back into history, A long time ago in another world Alek Kac posted to the JTF site his world shaking Base/base method called The two stage adaption of Mike Pelly's biodiesel recipe. It is still there if you want to have a look at it.
The amazing claim with this procedure was that no matter what oil you used you do NOT have to titrate and you use the same amount of methanol and NaOH no matter what. Just prepare the methoxide using 25% methanol and 6.25g NaOH no matter what the titration of the oil. Eventually, on another forum aleks said that his whole development of this procedure was with oil that had only been used to fry potatoes and titrated around 1..


QUOTE=craigcurtin;59306]James,
4) Now use the base amount of KOH that you would normally use - say 8 grams per litre - therefore add 800gms of KOH to the 16L of methanol and mix
Craig[/QUOTE]

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

Re: 2 Stage process - dropout calculation

Hi gilfish,

do as craig says it will work I use naoh and do 3/27 then calculate the percentage dropout from that...

Just so I am clear, you are saying that you perform this method using 3.5g NaOH per litre of WVO in the first stage and you achieve separation in the first stage? I can not recall the titration of the oil I tested it with but I am pretty sure it was less than 3 NaOH and I did not achieve separation in the first stage
What does your oil titrate?

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

Re: 2 Stage process - dropout calculation

Hi Craig,
This is the problem with this method. It depends on the oil you are using.
The fellow who wrote this method up and posted it to Wikipedia was using oil that only requires 5g KOH per litre of WVO in the first stage.
You have found that your oil requires 8g KOH per litre in the first stage.
Without knowing the titration of the oil you are just guessing.

As far as I amm concerned, a procedure that starts out by saying "don't do a titration, just try to guess how much KOH to use in the first stage" is not going to be a reliable method. My Oil titrates less that 1, I could even get the posted method to work using NaOH (but just barely)

To take a trip back into history, A long time ago in another world Alek Kac posted to the JTF site his world shaking Base/base method called The two stage adaption of Mike Pelly's biodiesel recipe. It is still there if you want to have a look at it.
The amazing claim with this procedure was that no matter what oil you used you do NOT have to titrate and you use the same amount of methanol and NaOH no matter what. Just prepare the methoxide using 25% methanol and 6.25g NaOH no matter what the titration of the oil. Eventually, on another forum aleks said that his whole development of this procedure was with oil that had only been used to fry potatoes and titrated around 1..


QUOTE=craigcurtin;59306]James,
4) Now use the base amount of KOH that you would normally use - say 8 grams per litre - therefore add 800gms of KOH to the 16L of methanol and mix
Craig

[/QUOTE]


Hey Tilly - i think they have refined the process further since i started using it about 18 months ago. The cut and paste i took of the wiki was using 8 gms KOH - next batch i make i will try it with the new amount and see if i can get a seperation.

Most of my oil does come from the one source and titrates consistently to 8. However i have used this method on a variety of other oils and never had to adjust it - i always assumed it was a bit of black magic but was happy.

Craig

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

Re: 2 Stage process - dropout calculation

Quote "Do not titrate!"

Huh? why not? Getting the amount of catylist right is fundamental to making bio without soap or unreacted oil, is it not?
Luckily most of my oil titrates between 0.2 and 1.5 plus the base 5.0 so I haven't had to resort to 2 stage methods. I have bumped the titration thread back up so any newbies can see how easy it is.

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

Re: 2 Stage process - dropout calculation

I aim for a 75-85% conversion on the first stage then the % of drop out for the second stage gives me a far more accurate amount of catalyst to use over the entire reaction cutting down on catalyst and methanol plus producing less soap at the end allowing for aggressive washes and no glyc solidification. The idea is not to cut out titrations altogether as I still titrate when i get crap oil so i can calculate catalyst to obtain 75-85% conversion.I have lost my best oil source which was 0.5 - 2 titration which allowed me to use between 500-650g naoh on the first stage and now use 750-850g to reach 75-85% this is on 165L batch size. Regardless of the flawed description or science behind it, it works well as it gives a more refined way of calculating the near exact amount of catalyst remember all the unknowns and variables are taken care of in the first stage of obtaining 75-85% conversion. I realise it may not be everybody's cup of tea but it still has merits.

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

Re: 2 Stage process - dropout calculation

I'm with you JJ, I dont see why anyone wouldnt titrate. using the metho and tumeric, the consumables are so cheap its definetely worth doing. It takes next to no time and is very simple.

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

Re: 2 Stage process - dropout calculation

Just to clear up a few misconceptions.
There is nothing magical about this method that goes against known chemistry rules.
If you process low titrating oil the method should work fine.
If you have higher titrating oil the method will not work fine.

I located a thread from Dec 2011 talking about this method. gilfish posted;
“I use normally use bases of 4 naoh and 8 koh @ 80% to obtain a conversion of around 60-70% but found i had to up this on my last batch which titrated at 4 naoh did it in 3 stages if you have oil that is consistent titration this method is very good but i reckon i will have to up or lower the base according to the quality of the oil.”
I think gilfish is correct.

I can not understand why, over and over, people will come up with the nugget of a good idea and then cloak it in mumbo jumbo magical nonsense. I do not understand what they think this will accomplish.


For instance, with this method, the “nugget” of a good idea is to determine the second stage amount of KOH/NaOH required by measuring the drop-out in a 3/27 test of the first stage. This part seems to work and if some real development and testing had been performed, a procedure would have probably been developed that would have been a useful addition to backyard biodiesel production.
Instead, the directions make the absolutely absurd statement “Do not titrate!” And then goes on to make the equally ridiculous claim that 3.5g NaOH is all that is required in the first stage for oil titrating up to 10 NaOH.
I just had to laugh when I read this. These two statements are total nonsense. All credibility is lost.

Just for the record, neither Craig or gilfish use the method posted on the Wiki.

I think gilfish has the right idea when he said: “The idea is not to cut out titrations altogether as I still titrate when i get crap oil so i can calculate catalyst to obtain 75-85% conversion.”
Just cut out the nonsense magical mumbo jumbo and do a titration to determine how much.

I think it would be very useful if gilfish would go on and do some more developmental work on his procedure that involves titrating the oil initially to determine the correct amount of caustic to use in the first stage and then use the results of the 3/27 test to determine the amount of caustic required for the second stage.

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

Re: 2 Stage process - dropout calculation

Hi All,

Thanks for all this information. I've looked all over the internet and I think this is the simplest description yet of the 2 stage method.
I tried making bio a few years ago but I got stranded interstate with black grit in the fuel strainer and was put off for awhile.

I generally use WVO in my truck and have been collecting the snotty dregs with a view to turning it into biodiesel sometime in the future. Well the future is here and I have 6 IBC's full of snot so it is time to bite the bullet and get biodieseling.

In particular I had 200L of oil that I put aside because as I was tipping it into the IBC it didn't smell right. It smelt like regurgitated blue cheese! This has been sitting around my factory for the last 2 years which was very unpleasant.

So I decided to start with that 200L. As it had been sitting for years I drained 30L of crap from the bottom which was mostly water which smelt putrid. Then I added some Glycerol from previous attempts at biodieseling made with NaOH. I cooked this for a few hours at 70C while stirring. I let this settle overnight and thought I could just drain away the Glycerol. No go. It seemed to emulsify but I drained away 40L anyway which was darker than the rest.

Now to start the biodiesel process properly. I bought a titration kit from Scintex on ebay and followed those instructions.
I have decided to use KOH now and the titration told me to use 20.5 g/L. I checked 2 more times and it all came back with the same figure. I had to extrapolate to get this as the titration table didn't go up high enough! Anyway, a test batch separated out OK so I pushed on.

Following Craig's instructions mostly to the letter, I got a good biodiesel separation with my 160L of crappy oil. The glycerin layer was 33% of the total volume. Then I did the 10/90 test which indicated 10% oil still needed reacting. So the next 20% of methoxide goes in and it all works beautifully.

I just did a mist and bubble wash and the bio was transparent and smelt right.
This time I will store it away for a few months before using it and maybe the grit problem won't come back. Or maybe it is just the fuel lines getting cleaned out.

Now I have to do some experiments with composting to get rid of the byproducts. I'll let you know how it goes if I have any success.

Anyway, thanks again to all the contributors on this forum for your useful information. Using your information I managed to successfully convert the most putrid oil I have into beautiful clear biodiesel.

Rob
1997 Ford Trader

[Bueff Biofuel Enthusiast Find all posts View Profile Close Bueff]

Re: 2 Stage process - dropout calculation

20.5g/l, and didn't convert in one go? holy dooly that's solid stuff

happy greasing

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

Re: 2 Stage process - dropout calculation

Hi RobW,
Was that the $139.00 high quality titration kit from Scintex?

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

Re: 2 Stage process - dropout calculation

That's correct. I bought it on ebay though for $149.