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World Famous Dr Pepper Technique (Pat Pend)

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November 27, 2001, 07:11 AM
World Famous Dr Pepper Technique (Pat Pend)
as I remember it YOU were the one that posted that several persons had achieved OVER 100% conversion

I understand where I made my mistake in my original reply on this string.
November 27, 2001, 07:33 AM
Tilly SBC/IBA Cool Cool

"A person in love is incomplete, 'till he is married. Then he is finished."
November 27, 2001, 09:13 PM
Recovering more BD by weight than the starting material is possible, regardless of the conversion level. It is possible partly because you add caustic soda which converts free fatty acids to soaps and soap has a higher molecular weight than the free fatty acid. And the weight of combined methanol is ever so slightly heavier than the weight of glycerol removed.

But the main factor which can cause a rise in weight is the addition of methanol which must be added in substantial excess for the reaction to work.

Clearly there can never be a rise in weight if the BD is properly washed as washing removes both soaps and excess methanol. It also washes out some perfectly good BD.

In the initial separation a substantial amount of soap goes out with the glycerine layer. If a reaction produces anywhere near 100% yield it is proof that the amount of methanol remaining is also substantial.
November 28, 2001, 02:03 AM
On 2 August Michael (aus) posted on the "Making Biodiesel" forum in the topic "Comparing different production techniques" that it was possible to have a yield of 103%.

Tilly SBC/IBA High Yield Div Cool Cool

An egotist is a person of low taste- more interestedd in himself than in me.
November 29, 2001, 10:18 AM
I had to find another way of mixing my BioDiesel as my cement mixer has been away on site earning its keep.

The last 3x120lt batches of BD I made in an open top 200lt drum, that I stirred for less than 15 minutes with a length of 2x1 (flat stick).

I use the same stick for mixing the methanol with the sodium hydroxide which also takes less than 15 minutes.

Using this method I get a return of 120lts of BD +/- a couple of litres. I don’t wash so is that close enough to 100% or wot ?

My experience
Used cooking oil that starts off a dark black coffee colour,
Changes to a thicker white coffee colour when the methoxide (?) is added,
Goes back to the black coffee colour when it has been mixed enough,
Usually less than 1 minute with 1lt mini-batches, or 6-8 minutes with 120lt batches.
@ 100-15-5? With good oil, and 100-20-6+ if there is a high fat content

My Landrover is a TDI (Turbocharged Direct Injection),
Methanol varies with fat,
70,000+km on BD and blended BD.


Put a tap about 6 inches up from the bottom of the drum for draining off the BD.
Sucking the fumes up in a siphon hose is guaranteed to give you the worst trip ever.

[This message was edited by Dhill on 29 November 2001 at 10:57 AM.]
November 29, 2001, 05:04 PM
Now David, don't you feel a little guilty?

With all these other people investing hundreds of dollars on pumps that can move 20,000 litres of oil per minute at 3000psi and stainless steel reaction vessels that were origionally to be used for the pressure hull of a Thresher class submarine, You tell us that all you use is an empty 200 litre drum and mix for less than 15 minutes with a flat stick?


Next you will probably tell us that you no longer do the "Appeasing the Biodiesel Gods" Dance while you are heating the oil, and that you have stopped sing the "Happy Biodiesel Warrior's Transesterfying Chant" as you mix the oil and methoxide.

I am afraid that if this heresy continues you will be required to turn in your decoder ring with secret titrating eyedropper and pipette.

Tilly SBC/IBA Dogma div Cool Cool

"After I cook the vegetables, what do I do with the wheelchairs?"

[This message was edited by Tilly on 29 November 2001 at 10:31 PM.]
November 29, 2001, 08:59 PM

Great stuff. You're the one we've got to keep an eye on - lots of km on unwashed BD in a direct injection motor.

I have a theory that when the European and American standards were set they were based on what the big companies could achieve, not on what the engines needed. They were erring on the side of caution in order to have the best chance of getting the car manufacturers to agree on warranty.

Now that the warranty question has been largely settled it is time for the real research into what various motors really need.

The first question I would like an answer to is whether there is any harm in using BD which is alkaline and if so whether avoiding the use of aluminium and diecast alloys could avoid the harm.

Your BD is clearly alkaline Dhill. Is there any aluminium or diecast in your fuel line?

What is the ratio of BD to diesel that you have used?

Keep rolling.
November 30, 2001, 01:21 PM
Hi all,
Yesterday I made my first batch using the Dr Pepper technique. Picked up just discarded oil that was about 2 days old and hot 150F, I didn't worry about water, as I felt there should be none.
Filtered and Titration and came up using a total NaOH wt of 5.2gr. and 200ml of methanol. Blended the 2 and added 1liter oil that cooled to 130F and blended again. Poured off mix into a 2liter bottle and in a few hours looked well. I measured off in the pop bottle the 200ml and 1200ml as the should be fill lines.

In 8hr there was not to much glycerine in the bottom, was black and not thick or solid from what I have read. My % looks like 1050 to 1100ml of BD, Is this Possible and why is the glycerine not thicker even after Cooling oner night in the Frig? Did not turn to a gell and looked good.

Then UPS droped off the static mixer I ordered and rushed to set up the 44l mix.

I mixed 2gal of Methonal and had a hard time mixing in the NaOh (228gr) and the oil was cooling down to 120F fast. Some crystals ended up mixing in the oil and I ran the mix through a pump and 6in 1/2 6 tine static mixer pulling fron the bottom of the tank return line on top. Pumped for 45min..

Took a sample of about 3cups and added to a liter bottle. In about 4hrs was settling a bit different than the 1l test, in 8hrs looked like honey, but just slight cloudy, on a scale of 1-10, 9.5. I thought not bad for not having a good mix of sodium Methoxide. I could see only 2 layers of seperation.

After 8hr of settling I set in the freezer over night and was a light solid WVO color. Within min the solid turned to a liquid and I Drained off the oil and Glycerine, This was just like the test batch as in over 100% outcome BD.

I was hoping to distill the 2gal of methanol and reuse to keep cost down. where or what % is in the BD and in glycerine? How much methonal can I plan on distilling back when I have yields like this?

WASHING. I did a wash of the second batch test and this doesn't look to good!

Put the 3cups BD in a large 4cup container. Sprayed with a spray bottle untill ther was about 1/2cup of dark cloudy water in bottom of cup, poured off oil and took ph reading of wash water, 9.5ph. Read up on washing and added some vinegar and sprayed again. No need to read ph. The first wash was cloudy the second was worse, looked like honey butter, light tan in color, Like it went through a blender and the residual settling has a white layer and cloudy water layer after a good 3hrs of setting. Still no gell. Is this normal? I know I need to wait 24h till doing the next wash, But the color looks like I messed up some where?

Any ideas?

November 30, 2001, 03:43 PM
I will try to answer a few of your questions.

The length of time it takes for the glycerine to solidify depends on a lot of things, and particurlarly what type of oil you are using.
The glycerine from tallow goes solid MUCH quicker than the glycerine from canola. As a matter of fact, glycerine from canola may take days to go solid.

Lightly used oil will give you very close to the same amount of Biodiesel as WVO that you start with, and yes I have collected MORE Biodiesel than the starting WVO but I don't know how much is left after washing. Michael aus said it is possible to have a 103% yield, but 007 says not, so I will have to do more testing on this just to see what is what.

As for recovering methanol, most of the methanol is in the glycerine. I did some tests back in May and posted the results on the "General Biodiesel Discussion" forum on 9May.
If you distil the glycerine you should get back around 35ml-40ml methanol/litre WVO or about 20% of the original methanol used. If you stop collecting around 100 deg c the methonal should be around 98% pure which is good enough for making BD.

Washing has been talked about a lot on the forum. There are good reasons to NOT use vinegar in your wash. The important thing about washing is GENTLY, GENTLY GENTLY. Biodiesel always looks worse straight after you wash, but it does quickly clear.

Keep us posted as to the outcome.

Tilly SBC/IBA Paradise Div Cool Cool

"The only way to get rid of a temptation is to yield to it."
November 30, 2001, 05:22 PM
TL, sounds as though your washing is as yet incomplete. Use equal volumes of BD and washwater.
Although I have found that vinegar (especially small quantities in the form of glacial acetic acid added to the BD before wash) works wonders at reducing foaming, it has been suggested that other problems such as reformation of free fatty acids are introduced. Best to avoid using vinegar where possible and as Tilly says wash GENTLY.
My 1L test batches (Dr Pepper) can usually be washed, filtered and ready for use in 2 hours.
Most batches require three lots of wash water. The bubble washing is usually continuous with the exception of batches with low levels of NaOH which tend to foam badly when washed. These batches are washed intermittently to allow the foam to settle and usually require more than 3 washes. The endpoint for washing is a reasonably clear wash water with a pH of 8 measured using Universal Indicator. Phenolphthalein indicator could be used but it indicates alkalinity more than neutrality. Wash till wash water gives clear mix with phenolphthalein then give an extra wash.
The white layer sounds like tallow/tallow esters.
However since freezing the raw BD produced no deposit of tallow/tallowesters I wouldn't be sure of that one. This whitish material should be filtered out of the washed BD before drying. The heat involved in drying liquifies the whitish material. Whilst the warm dried BD will be clear, when it cools this material comes out of solution and clouds the BD. It can take weeks to settle out. I no longer dry my washed BD. Besides eliminating a stage and energy input I have found that the filtered washed BD is crystal clear and stable. The white material is retained by the filter paper (whatman No. 1, pore size retention 11 um ). Test drying has not produced any further separation of water.
You mention a suggestion to wait 24hrs before the next wash. What would be the purpose of this? If the BD is separating well from the wash water I see no reason for this.
Could you expand on your statement "still no gel"?.

Regards, Squarepeg.
December 03, 2001, 10:44 AM
HI Tilly

I still do the singing and dancing bit, but with a bigger smile now.

Hi Netural

I have no idea how alkaline my BD is, I have never checked it.

The fuel lift pump on my Landrover, seems to be aluminium and the injector pump seems to be cast iron.

I started using blended BD at around 42,000km mark, anywhere from 20% to 80% for around 48,000km.

Of the last 15,000km, 5,000 has been on 60%+BD, and the other 10,000 on 100% BD.

December 03, 2001, 09:20 PM
Paul and Tilly

I using good used vegetable oil, could have some chicken fat from those good fried wing? No tallow.

I started washing the larger batch of BD (12gal) This past Fri. Did one wash. Must not have had the BD warm enough, It seemed to glob together into two layers, white in color and the BD. I let it set over night and Sat AM Drained off a white liquid and then BD. I did 2 more washes that day. Used about 20gal of water and the wash started to get clear. Checked water PH and is about 8.2 and doesn't change. I thought I would do one more wash on Sun Am and try to get the PH close to 7.
Ran warm water through the BD and it globbed up again, Did some reading on temp and found the BD temp might be to low, 65F. Heated the BD mix up 160F till it seperated and the liquid turned white again. I must have ran over 40 gal of water through the BD and It will not change to clear.

Could it be that there is left over lye in the bottom of the tank and when the BD and water was heated it reacted and made soap?

I had a problem when mixing the methanol and Lye,
Not all mixed together but did get mixed in with the WVO when mixing.

I'll have that problem fixed on my next batch run for next week if the heater and pump are in.

I only have about 5 gal of BD with the white stuff left because of fustration.

I know one of the problems was the BD was not warm enough when I was washing. What is a good temp to wash? What I found was having the BD temp 90 to 105 and the wash above 85F. The water was ready to drain off in 20min of wash.

The question about gel, I put the Dr. Pepper batch the the Refrigator and I thought being below 40F it would thicken or gel up.

Also if I stopped washing at the point the BD wash water was close to clear and PH8.2 sound like it would have been ok to use. Dry, filter or what you suggest don't dry. How is this for use in winter climets? The snow should have been here by now and using the truck for plowing. It's going to be close to 60F tomorrow. I want to try this in our new chevy Durmax with a 20% blend. But don't want to rush it till it's write.

Any ideas?
December 03, 2001, 10:08 PM
TL, it has been my experience that the temp of the wash water does not make a great deal of difference, except I keep the temp above the temp that the BD solidifys at. In the case of tallow BD, 20 deg c (70 deg f) is sufficent. I think chicken fat would be considered tallow.
I have noticed that cool wash water seems to washe better/faster than warm.

If you had a layer of white and a layer of BD it sounds like the high temp tallow esters had started to solidify, and yes your wash water was TOO cold.

When washing the important thing is GENTLY GENTLY GENTLY.

My first wash is an equal amount of water as BD sprayed GENTLY over the top of the BD in a FINE spray, making NO ripples or splashes. This water quickly passes thru the BD and I immediatly remove this cloudy water and dispose of it.

The second and subsequent washes are also sprayed but a bit of GENTLE aggitation is allowed.

No your problem should NOT be left over NaOH, as the chemists on the board have advised that any residual NaOH and methanol will all be picked up by the first wash.

Tilly SBC/IBA Hand washing Div Cool Cool

The reason grandparents and grandchildren get along so well is because they have a common "Enemy".

[This message was edited by Tilly on 04 December 2001 at 09:43 AM.]
December 04, 2001, 01:54 AM
Originally posted by neutral:

Great stuff. You're the one we've got to keep an eye on - lots of km on unwashed BD in a direct injection motor.

I have a theory that when the European and American standards were set they were based on what the big companies could achieve, not on what the engines needed. They were erring on the side of caution in order to have the best chance of getting the car manufacturers to agree on warranty.

Now that the warranty question has been largely settled it is time for the real research into what various motors really need.

The first question I would like an answer to is whether there is any harm in using BD which is alkaline and if so whether avoiding the use of aluminium and diecast alloys could avoid the harm.

Your BD is clearly alkaline Dhill. Is there any aluminium or diecast in your fuel line?

What is the ratio of BD to diesel that you have used?

Keep rolling.

I too have been using unwashed BD in s pre-combustion engine 100 % and have done near 40000ks ,the injection pump is an inline piston and is all alloy as is the lift pump and filter houseing ,block and head are cast steel,I have noted no degeneration of any alloy parts except to note their clean state.I had been concerned the BD may have hassened the death of the motor so as to give me a chance to pull it down and note any internal defects caused by the use of BD unfortunately it just keeps on going better than ever,The motor is old and does use oil.but it seems to perform better now than when it was running on dino d.
December 04, 2001, 03:37 AM
Hi Hintertech

Another interesting story! 40,000km on unwashed biodiesel is a pretty fair test. The location of the aluminium in your fuel line is of interest. Does the fuel come into contact with the pump housings or is it completely contained in other internal components of steel, plastic etc?

It seems as though the fuel would be contacting aluminium in one place, the filter housing. Have you had a look inside that?
December 04, 2001, 03:57 AM
The fuel limes are rubber and steel the pump housing is alloy and in perfect ,all be it very clean (definately no pitting or discolouiration).The lift pump is steel with an alloy piston no rubber seal and steel flap valves,again very clean,the injector pump I have not dismantled ,however the housing is alloy,I would expect the interior to be a mix of high carbon steels and alloys,the performance of the engine sujests that their has been little degredation to tolerences internally in the pump.Just of interest I stored some BD (unwashed) in an alluminium pot for a few weeks ,the line at the level of the liquid was dicernable as "shiny below the BD line" not holey,mayby Im lucky and only have a slightly High PH,it does eat enamel paint ,but I dont quite know how to test its PH as Tilly has explained a straight PH test will be inacurate unless done in water not BD.Since Im using WVO oil in the sump I sort of figured the high acid content below the pistons would nutralise the high base levels being injected above...This of cause is in jest!
December 04, 2001, 04:29 AM
I know we are talking the wrong subject in this forum,but its the most interesting one
December 04, 2001, 08:56 AM

Thanks for the reply,

I know the washes I did on Sun were no way Gentle.

I'll try and wash and filter out the white gel with hope of clear water in 2 washes or less.

So it sounds like the chicken fat/tallow could be the white stuff? Using agressive last washing brought on this change? So I need to keep it gentle.

December 04, 2001, 09:17 AM

"An optimist thinks this is the best possible world. A pessimist fears that this is true".
December 04, 2001, 10:47 AM
I did a demonstration on washing bd using the MIST WASH SYSTEM today using tallow based BD as the test subject


no heating of the tallow was done at all nor was the water heated the tallow was decanted directly from the settling barrel and the glycerin was seperated at this time in a solid mass

the water was sorced direct from the house supply via an outside tap

the first wash went as expected and produced a layer of discoloured water and a cream layer that if seperated from the main body will eventually settle out to water and biodiesel

the second wash when as expected again with only two layers this time discoloured water and biodiesel

the third wash was left a little to long allowing the level to rise and the biodiesel to get to close to the misting nozzel this caused agitation on the surface and injected the water into the biodiesel a little to harshely, after turning off the water and allowing the bd to start settling large blobs of white stiff started to float to the surface

we took of two bottles of this stuff and did two tests

1 added a small amount of salt directly to the white stuff and shook this caused the white stuff to break up/disolve (or what ever) and reverted back to biodiesel

2 added heat only this caused the WS to again revert to biodiesel

we discussed these reactions for some time wondering if I had produced a problem I have had this happen before only when I allow the water to mist into the bd to aggressively this stuff can also be scooped of and just allowed to seperate on its own it seams to have no ill effect on the biodiesel and seams to be harmless

the moral I have to fit a ball valve to my wash barrel to restrict the level although this will not effect the 1:1 ratio of water to bd

NEUTRAL seeing as you are so knowledgable in this field maybe you could find the time to explain what I have produced here

to me it appears to be water,air,and biodiesel forced together, with the air causing it to float to the top of the bd layer

on testing the bd with new clear water the water and bd seperated well with the water very near clear but very slightly hazy although you could see through it easily

I do not BUBBLE wash as I have found that system to be a wast of time very slow and difficult to control

todays wash was done over a 4 hour period this included lots of stop starts (so my guest could have a look at the misting and emulsifying of the water and bd without using mechanicle assistance) the constant stop starts had no ill effect to the wash cycle