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It is agreed that everyone's oil should be as dry as possible... especially if one is using the HTAE process or using NaOH. If you watch the video which is 28 minutes long the process seems to be complete with no foaming/scum at the top. I do not know how a magnetic stirrer compares to eductors/paddles but I am significantly intrigued.
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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Paddygoat

Rather than titrating the oil with 1 molar KaOH solution and using an indicater solution, I started titrating with a known concentration of potassium methoxide, in this case 35g KaOH per litre of methanol as I thought this would be more accurate and take account of impurities such as water etc. This KOH is put in the burrette and added to the hot oil on a magnetic stirrer until the colour turns dark orange, indicating that the reaction has taken place (only works with WVO). In the above case it titrated to exactly 20% of the volume of the oil. It's a really nice method and the end point of the titration is quite precise.

Paddygoat

adding methoxide to hot oil does not seem to get a reaction until it reaches a critical concentration, whereas adding the oil to the methoxide achieves critical concentration straight away.

Paddygoat

The titration is done with methoxide in the burette and the reaction in the processor is done backwards with respect to the titration. Had another go this morning and got it to work nicely adding an extra 50% veg oil and a bit of methanol to keep the overall methanol level to 20%. Will try it with new sunflower oil next.
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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Paddygoat

In my 2008 recipe the catalyst is added to the methanol in the reactor and mixed using stale air from the top of the processor through a diaphragm pump operated by hand or by pressurised air. The temp of the methanol does increase slightly, but htere is no further heating. The oil is heated in a separate vessel to between 65 and 75 degrees C depending on the ambient temp and what size processor is being used (150, 400 or 700 litres per batch). The hot oil is pumped over on top of the cold/warm methanol and the end temperature is between 60 and 65 degrees C once all the oil has pumped over.

The interesting bit is that the reaction gets going as soon as about 50 % of the oil has been transferred, with a bit of paddle mixing operated by hand or by air cylinders. This means that biodiesel is being produced so the methanol mixes in much more easily and the temp of the brew can be hotter. Also,by the time all the oil has been pumped across, the brew is about 40% biodiesel already, before any glycerol has settled out (this is my estimation, but I do remember reading somewhere that this had been measured, but cant remember where!).

Next, whilst the brew is left to stand, the rest of the 60% of the reaction takes place, because the EQUILIBRIUM goes to the right as glycerol settles out. 3 days later and it's about 95 to 98% pure.

All of the above is fairly standard biodiesel stuff, but what I'm trying to do now is add another 50% hot vegetable oil and another 10% methanol, but no extra catalyst, to the brew before removing any gycerol. If I could prove that it does actually work then this would be the upgrade to the 2008 recipe, ie 2009!

Paddygoat

The oil is added slowly and the mixer is turned on every now and again. If you only had one pump, you could use a diverter valve to use the same pump for pumping in and mixing.

NaOH can be used. Dissolve 30 g of caustic in 1 litre of methanol and use this solution in the burrette. Titrate into 250 ml of veg oil. The formula is:
((burrette reading) divided by 50) x 30 ..... gives you the methoxide strength in g caustic per litre methanol

Drain off glycerol 1 hour after the start of the settling time.

Let the brew cool down. Glycerol is less soluble in the brew at lower temperatures so cooling is not really a problem.

There's no ACTIVE de-mething in the process ie it is not driven off by heat. I have always considered this far too hazardous for home brew. So, to minimise hazards, it's not done.
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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quote:
Originally posted by dennislarock:
Paddygoat

Rather than titrating the oil with 1 molar KaOH solution and using an indicater solution, I started titrating with a known concentration of potassium methoxide, in this case 35g KaOH per litre of methanol as I thought this would be more accurate and take account of impurities such as water etc. This KOH is put in the burrette and added to the hot oil on a magnetic stirrer until the colour turns dark orange, indicating that the reaction has taken place (only works with WVO). In the above case it titrated to exactly 20% of the volume of the oil. It's a really nice method and the end point of the titration is quite precise.

Paddygoat

adding methoxide to hot oil does not seem to get a reaction until it reaches a critical concentration, whereas adding the oil to the methoxide achieves critical concentration straight away.

Paddygoat

The titration is done with methoxide in the burette and the reaction in the processor is done backwards with respect to the titration. Had another go this morning and got it to work nicely adding an extra 50% veg oil and a bit of methanol to keep the overall methanol level to 20%. Will try it with new sunflower oil next.


I wonder about this explanation. At what point did he decide upon 35g per litre of potassium methoxide. I would figure a pre-titration would be needed. This is based upon the KOH being the reagent and would need to be a specific concentration for the oil being processed.

If that is the case, I do not see a need for this step, unless you want to insure an accurate reaction. But at this point, I am definitely shooting from the hip (read as....having no clue).

James L
 
Location: Central Alabama (Marion Junction) | Registered: February 20, 2010Reply With QuoteReport This Post
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quote:
I wonder about this explanation. At what point did he decide upon 35g per litre of potassium methoxide. I would figure a pre-titration would be needed. This is based upon the KOH being the reagent and would need to be a specific concentration for the oil being processed.

If that is the case, I do not see a need for this step, unless you want to insure an accurate reaction. But at this point, I am definitely shooting from the hip (read as....having no clue).

James L


As I read it 35 was his starting T...

"The waste oil that I am using titrated at 35g potassium hydroxide per litre methanol"
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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Rick,

from the pictures I have seen here and on the other site jamesrl's setup does not appear to be that elaborate... other than his mastery as a copper-smith. Its a GL setup with his venturi's, condenser's etc., which are beautiful
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post



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quote:
Originally posted by dennislarock:

As I read it 35 was his starting T...

"The waste oil that I am using titrated at 35g potassium hydroxide per litre methanol"


So is the whole video about double checking his titration, or is he actually titrating that way. I don't see that it's a better method.

For example.....by his method his oil titrates at around 2.82. If the oil was actually around a 6 there would need to be 46.35 grams of KOH per liter. Now if you started with a 35 g per litre batch and was titrating, how much more methoxide would be needed? That doesn't sound like a very logical approach to me (especially if you are not reclaiming the methanol). I guess there would be little waste due to the testing size.

Now if the oil titrated to 6 and you had a 46.35g batch of methoxide, to insure the reaction would start where you wanted, that is different. Maybe I'm missing something.

Am I lost??

James L
 
Location: Central Alabama (Marion Junction) | Registered: February 20, 2010Reply With QuoteReport This Post
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I'm a little lost as well. However, like biotom I have been following this method for a while as it is becoming the standard across the pond. I got serious about it this morning and really started to dig. I am hopeful that some of our friends with a better understanding of chemistry than I can join in this discussion.
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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-I will Pm paddy this evening and see if we can get a step by step procedure along with further explanations. (I am also a member of that forum)
-I wasn’t able to get that video to work anyone else having problems with that ?
also confused Confused Confused Big Grin Tom


" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
 
Location: Manitoba Canada | Registered: March 24, 2009Reply With QuoteReport This Post
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biotom,

I am downloading it now

copy and paste the following into Google search

Google videos A biodiesel from waste vegetable oil titration method
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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Got it... 104MB Mp4

I can set up an ftp site if anyone needs it. However, it should play straight away from Google videos and you can download it from Google as well
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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I too watched the video (took up 1/4 of my daily bandwidth), but still it created more questions than it answered.

I truly think he is pre-titrating, and is using that step to insure a proper reaction. It is the only feasible reason I can see for it. I may be wrong though....only an answer from him will solve the equation.

James L
 
Location: Central Alabama (Marion Junction) | Registered: February 20, 2010Reply With QuoteReport This Post



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James,

My understanding (which may be wrong) is that this evolved and is in 2 parts i.e., part 1, 2008 titration method and part 2, 2009 processing method. I think part 2 was discovered while dicking around with part 1.

A quicker reaction time is not the only benefit, yields seem to improve, less chance of emulsification, the reaction can continue and one may be able to use less catalyst.
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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Lastly... for the moment

If this looks promising there are some very, very good minds here. If attacked as acid esterification was then this could go a long way. I only wish I had one of those good minds
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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Dennis,

I already understand the Acid/base reaction. I was going to not use is because of the damage it can do to the processor (my belief's....not any proof). It is said that with an acid/base reaction the resulting reaction has a better yield, especially with high FFA oil.

What I need now is a better diagram of what I think they are doing. I believe I have figure it out, but would like to have it confirmed.

They are using eductors for a higher mixing rate (in the tank and with the pump), along with using a venturi to introduce the methoxide to the processor/reactor. That is one reason they are using 10% oil first....to be able to use the injector venturi.

They are also using the eductor (or injector.....don't know at this point) to raise the pressure in the circulatory pipe. This allows them to raise the temperature of the mixture, and have the methanol "flash" off. The differential between the pipe pressure and ambient tank pressure would allow this to happen if the temp and pressure ratio was just perfect. Then the venturi would pull the vapor out quickly to be condensed back into the receiving container.

I'm close to understanding it all, but the pressure temp balance for flash recovery is very critical.

James L
 
Location: Central Alabama (Marion Junction) | Registered: February 20, 2010Reply With QuoteReport This Post
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James,

Yes, the rule of thumb is for every 1% of FFA you lose 3% of yield. So if titrating at 5 you get about 85% yield T1 = 97% yield or therein about.

I believe that you are correct in that he pre T'd the oil in his experiments.

Good mixing is essential, an eductor is a cheap way to gain extremely good micro mixing, and paddles are extremely good at macro mixing. Murphy's pumps would be very good at macro mixing as well.

I would suggest flash evaporating water first to dry the used veggie oil... less volatile than methanol. look up tim c cook who did some exhaustive work on flash evaporation
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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James
-let me allay your fears of causing degradation to your processor by using acid esterfication. The sulfuric acid is not resident long enough to cause ANY problems. Last year I decommissioned my old processor that had processed 5 days a week for 3.5 years, and other than a build up of crude on the internal water heating coil it was in perfect condition, just too small.( I don’t want this thread to turn into a debate on AE so if anyone has further questions on this, ask on the acid thread, or just PM me)
-I’m going to down load the video, but from what I understand, first paddy t’s his wvo, and from that mixes a methoxide solution using 1 gram of caustic for each point of T ei T 10 would be 10 grams of caustic in 1 ltr of methanol. Then he uses this to titrate 1 ltr of wvo directly, looking for the colour of the wvo to change to orange he then adds the amount of caustic it took to make the change to the total he has mixed to make that titrant.
-I will have to do some test batches in the next few days to see if this is right.
-they use eductors so they can process with the small pump, I forget the pump name but is is similar to our NT pump.If you have a half decent pump or mechanical stir system edutors are not required. Tom


" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
 
Location: Manitoba Canada | Registered: March 24, 2009Reply With QuoteReport This Post
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Have the Brits stumbled onto something... remember this is land of Benny Hill!

What does AAF stand for?

AAF method, (ar$e about face)

Shouldn't methoxide be introduced slowly?

Why do you think methoxide has to be feed in slowly? A very old theory that's been proved to be wrong. Dump it as fast as possible. Infact you can put 100% of the methoxide in first, Paddy's AAF method.

Mixing? No eductor or paddles just a pump that turns it over once a minute

10 Mins Pass!
Hi Guy's, Did a batch this morning.
90 Oil
19 Meth
800 Naoh
Titration total 9g
Temp 58 deg
120 ltr pump, no eductor, 22mm pipe work, so know it's not 120 ltr a minute, but can't be far off at that reacton time.
Tested at 10 Mins
Methanol 20 deg, 27/3 Pass
Tested at 30 Mins
Methanol 20 deg, 15/15 Pass
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post



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This is the first response I received from the question what does AAF stand for, ARSE about face/back to the front (there is an accent over the A)


" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
 
Location: Manitoba Canada | Registered: March 24, 2009Reply With QuoteReport This Post
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Biotom,

if this works... I wonder if one could knock HTAE down to 15 to 20 min ... almost continuous flow?
 
Location: New Orleans | Registered: December 31, 2007Reply With QuoteReport This Post
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