Hey, just tried my first batch using Dr. Pepper method the other day, using 4mg/NaOH in 250 ml of Methanol - everything seemed to settle out nicely, but never cleared stayed cloudy - washed it after a day til water was clear, BD remained cloudy, now after drying for a day there is a separation layer - cloudy BD on bottom and a thin layer of clear liquid on top - any suggestions on what this is?

Hello ACorder, congratulations on your success

The top layer is probably the meniscus of the biodiesel.
Are you drying it in the sun with the top off?
You could just pour the biodiesel into a sayce pan and heat it to around 100deg C and it should clear.

I did this this weekend and when I added the oil I saw a seperation-like activity. Shook it up and then shook it up again a few times.

I have 2 liters of brown liquid with some coagulant looking stuff at bottom of container but not completely seperated.

I think my lye "Rooto" 100% Lye which is the replacement to Red Devil may have been opened. Does this sound like my mixture of methanol and lye may not have been as full strength as it should have been ?

Is there anything I can do to re-attempt the process with the current solution ?

Thank you -robert

Hello rjr311, congratulations on your first successful batch of biodiesel

Can you be more specific as to what you mean by
"coagulant looking stuff at bottom of container but not completely seperated."

How do you know it was not complete seperation?

when I poke the bottom layer it seems to be like thin pudding. I can scrape the sides of the bottle like I was cleaning a dirty aquarium and the gunk on side of bottle drops to bottom ( it so think I can not tell ).

I had 2 sources - one unused cooking oil the other used asian restaurant oil.

The virgin oil seperated into
15-20% clear yellow/gold solution ( BioD
70% cloudy yellow/gold solution ( ???? BioD ????
< 10% darker gold on bottom ( glycerine

Looked great.

The used oil 2 days later is all dark-ish with a semi-solid layer on the bottom which can not be seen through and a possibly less denser layer on top. This seems to be about a 50/50 volume ratio.

Hi Tilly,
I am still a newbie. Working about 100 liters at a time. I just did a test shake in a small bottle of some dryed bio. 12 hours later it has separated but I have thin layer of what looks like emulsion between very clear colorless water and bio.
1. Appleseed processor, at 120 F, pump 2 hours.
2. Have 200L settling tank, let settle for more than 24 hours. Good separation of bio and glycerine.
3. Heated wash tank at 96 F. Mist wash 2 or 3 times depending on how clear the wash looks.
4. Bubble wash until wash is clear, what ever it takes. Have lots of water and easy disposal.
5. Bubble dried for 12 hours overnite.
6. Bio is crystal clear when I put sample in liter bottle and added 75 F tap water. I shook it hard for several seconds. More than 10 but not 30 seconds.
7. Separation was apparent in 10 minutes. 12 hours later I have crystal clear water with soapy emulsion like layer between water and bio. I guess the layer is 2mm thick. The water is clear with no disolved or suspended material.
8. Sorry I forgot. My oil is soy and comes from a chinese restaurant.

Does this appear to be acceptable bio? Am I being too much of a perfectionist? I wanted a perfect split.

One more data point. My house tap water pH is 7.4+, the water via hose to my wash tank is 8.3-8.4. The wash water when clear is 8.3. This is well water and what I get is what I get.

I am having a little frustration. I live in Maine and have about a 3 month window of warm weather to process my fuel. So far it has been pretty slow production.


Thanks again for your wisdom.

Hello penguy

What were the quantities of reactants per litre WVO?

Tilly,
Sorry to be slow to get back. We are building a home in the forest.

11g KOH and 220ml methanol per L of WVO. (In a 97.5 L batch of WVO I use 21.5 L of methanol, for this run I used 1073g KOH, and I also use 13.2 L of glycerol.)

From the forums I read where the use of 10% glycerol helped the production.


Once again thanks for your expertise. I must be on the back side of the clock for you. I'll check back in a couple of hours.

Hello Penguy

The glycerine should not be left in the oil when it is reacted.
The only reason for using glycerine before the reaction is to clear some of the crud out of the oil.
If you do use glycerine this way you need to remove it from the reactor before the reaction or some of your methoxide may become tied up with the glycerine and not used in the reaction.

If your oil titrated 3 or less KOH and you do not leave the glycerine in the reactor, you should get a very good reaction.

OK Tilly,
I will drop the glycerine out of the mix.

I do not have anything on hand to test for soap, that stuff is in the mail. I can wash some more or do I need to reprocess this current batch? Or should I just fuel up with the current batch? Now at almost 24 hours there is still some residual foam or emulsion still left at the bio water interface. Any feelings about this?

Should or can I send a picture as an attachment?

And then I will leave you in peace.

Thank you.

Hello penguy

I use my eyes to test for soap.
If the wash water is cloudy there is soap present.
If the wash water is clear there is not much soap present.

If the biodiesel is crystal clear at the lowest temp it will experience it is ready to use.
You can not visually determine the conversion of the biodiesel by looking at it.
What type of engine are you using the bidoesel in.
I would personally use the biodiesel but that is finally for you to decide.

Hi Tilly,

Done. I rewashed it overnite. Almost dry again. I will burn it (Oops, drive it). Several diesels, 2000 Jetta TDI, 97 Dodge Cummins, then generators, saws. etc.

Thanks again for all your help and advice.

Hi Tilly, thanks for all the BD info. I am a newbie and tried the Dr. Pepper processing technique. I am using waste restaurant oil. I titrated it at 4.5 Ml. I heated oil to 60 degrees C., added methoxide mix of 10G NAOH and 250 ML of yellow HEET. I shook mixture about 40 shakes. Then shook it again 10 minutes later and let it sit. I ended up with three layers. Top layer is golden yellow (Not clear) middle smallest layer is whitish jellow like, bottom layer is dark. I thought the top layer was the BD and the bottom layer the glycerol. I don't know what the middle jellow like layer is. Soap? Any ideas? How would I get rid of besides draining it away. Thanks for all the help!

Hello grandpa, welcome to the forum and congratulatios on your first successful batch of biodiesel.

Are you from Allentown Maryland? I used to go to the Tayac Elementary school in Allentown!

I suspect the middle layer is soap.
It may have some biodiesel tied up with it so you might try to wash it very gently.
Please keep us informed.

tried my first small batch after four hours no seperation yet. when I put in the methoxide it boiled. should it have done that? I used new oil. heated it to 140 F. I did not see any color change.

Hello Keith

If the methanol boiled you have lost at least some of it. this is not a good thing.
140f= 60C which should not boil the methanol. Possibly your thermometer is inaccurate.

I will get a new thermometer also when i put the hot oil into the plastic bottle it melted the bottle. I then went and bought a glass bottle. but now i would like to make a batch about 4 X as big. do i just multiply by how much more i want to make. the amount needed for the dr. pepper one ltr thanks for the help one day i hope to be makeing enough for my tank
Keith

Hello Keith

Did you go to 140deg F or C?

Yes, just multiply everything by 4.

Hey Tilly, just been browsing a Lister engine group on Yahoo and noticed that recent threads are questioning the Dr Pepper method (and you personally).

quote:

posted on http://groups.yahoo.com/group/Lister_CSOG/message/1524 27 July 06
RE: [Lister_CSOG] Dr Pepper method for biodiesel?


It's a hokey soda bottle shaker method that doesn't make very good
biodiesel. It's cool for doing demonstrations. We were using it in classes
long before the "inventor" heard about our demonstrations and decided to
claim the process, without understanding the caveats..

Steve Spence

Director, Green Trust

http://www.green-trust.org

Any body else find "it doesn't make very good
biodiesel" I have never had a problem with quality.

Reading a bit further it seems like Steve Spence holds Keith Addison in high regard so that probably says enough about him so should be ignored.

Just thought you may be interested in what was being said in other places, I guess others may have seen it.

yeah, that's what I thought