BIODIESEL & SVO DISCUSSION FORUMS





Sponsors    Biodiesel and SVO Forums Home    Forums  Hop To Forum Categories  Biodiesel  Hop To Forums  Acid Esterification    acid base questions
Page 1 2 3 

Moderators: Shaun, The Trouts
Go
New
Find
Notify
Tools
Reply
  
acid base questions
 Login/Join
 
Member
posted
I startedwith 25 gallons. 94 l, andbrought it up to temptode-water, once color was good I mixxed 10% methanol with 535 ml of Sulfuric acid. At 140 degrees I added the acidto my oil that titrated at 35. I mixed for one hour then let sit over night. This morning it had not really seperated, what I drained was like mocha colored, the oil was redish and cloudy. This is my first attempt with the acid base because this is my first oil that titrated so poorly. SO, where did I go wrong, what is it supposed to look like, how do I get this working. I am rather distressed, i had to put diesel in my car yesterday because of this crappy oil for the first time in over a year. Call me or post or email, but please help me. 772 215 4495, I would lve to talk to someone about how to get this working.
 
Location: Florida | Registered: March 05, 2012Reply With QuoteReport This Post
Member
posted Hide Post
Well the stuff you drain from the bottom is generally going to look pretty gunky. The acid stage is WAY more sensetive to water than base though.

Did you ever do a titration after you drained to see what your new titration # was?

From the sound of it I would recommend reading up on the acid stage both here (the big 70 page acid stage thread) and here

http://www.make-biodiesel.org/...id-base-recipes.html

The acid stage doesn't actually completely react your oil, it is simply a pre-treatment for the base stage.

There are plenty of people here that can guide you through it though.
 
Registered: February 25, 2010Reply With QuoteReport This Post
Member
posted Hide Post
wow that's crazy oil! how did you dry the oil and what test did you do to check for dryness? the color of the drainage indicates that the oil was slightly wet. The higher the titration of the oil the more bound water that will be present and therefore dryness is even more important!, as the chemical reaction moves forward this bound water is released and eventually stops the reaction.
What was the morning titration? t35 oil + t12.45 from the acid = T47.45 from this you can figure out how well the reaction worked. How did you determine this acid amount? The fact that you had mocha junk and redish oil shows the seperation did work. no gycerol byproduct is produced during AE, this process only esterfies the free fatty acids.


" 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
Member
posted Hide Post
quote:
Originally posted by Biotom:
... The higher the titration of the oil the more bound water that will be present and therefore dryness is even more important!, as the chemical reaction moves forward this bound water is released and eventually stops the reaction... no gycerol byproduct is produced during AE, this process only esterfies the free fatty acids.
It is not bound water. In acid esterfication, FFA+ methanol produces methyl ester + water.
At the same time a little of the following reaction occurs, which is transesterification: triglyceride plus methanol gives methyl ester plus diglyceride,
then diglyceride plus methanol gives monoglyceride plus methyl ester,
then monoglyceride plus methanol gives methyl ester plus glycerol.
This series of reactions is very much slower than the esterificaion reaction with FFA and very much slower than base catalysed transesterification.
Glycerine is produced.

HTH
 
Registered: October 04, 2010Reply With QuoteReport This Post
Member
posted Hide Post
transesterfication using acid is possable, but so slow it is not practical so why complicate the process instruction? and it is a fact that the higher the ffa content the higher the bound water content can be. lot of work has been done on this fact in the svo section.


" 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
Member
posted Hide Post
Biotom,
transesterfication of triglycerides is happening at the same time as you esterfy the FFA's. You can not stop it from happening. I am sorry if you find that a distressing or complicated idea but there is not much you can do about it.

I am not sure what you mean when you say the higher the FFA's the higher the bound water can be. Do you mean the bound water has to be higher or do you mean if you work sloppily it can be high.
I know of a person who work with very high FFA oil and he has never mentioned this bound water that you are talking about.

I stand by the chemistry in my above post
quote:
Originally posted by Biotom:
transesterfication using acid is possable, but so slow it is not practical so why complicate the process instruction? and it is a fact that the higher the ffa content the higher the bound water content can be. lot of work has been done on this fact in the svo section.
 
Registered: October 04, 2010Reply With QuoteReport This Post



Member
posted Hide Post
Well this thread seems to have attracted a rather unsavory crowd. Biotom is one of the better/more experienced acid stage folks in here if you are looking for info.

What he is getting at is that the higher the FFA or titration the more water will be dissolved (and not drop out) in your oil. So high titrating oil will be harder to dry, and thus harder to do an acid stage on which rather complicates matters. The acid stage WILL perform some transesterification yes, but in such a small amount for most people it almost isn't worth mentioning.

and well brittanycruise just looks like spam
 
Registered: February 25, 2010Reply With QuoteReport This Post
Member
posted Hide Post
Yes, I agree with you.
quote:
Originally posted by BWilder:
Well this thread seems to have attracted a rather unsavory crowd.
 
Registered: October 04, 2010Reply With QuoteReport This Post
Member
posted Hide Post
You can stand behind anything you want, even in front of if you choose, I don’t have a problem with that! Acid transesterfication of vegy oil is a very slow process and requires temperatures in excess of 100C, at 117C it takes about 3 hr and at 72C it takes 18+ hrs. I don’t see those kinds of temperatures being used in AE. (can you say special equipment)
I recommend you read the Report on AE by J Van Gerpen, in that report you will find that initially they mixed new oil and palmitic acid to create high ffa oil. Then they go through the AE process, adjusting the molar ratios, and it works. Next they use high ffa used vegy oil and the same methodology and the process doesn’t work? What is the difference between the two oils? The new oil and palmitic acid have no bound water, no mono or diglycerides, where as the used fryer oil with high ffa does. Used oil containing mono and diglycerides also contains bound water, the higher the ffa the higher the bound water count. Also in that report you will find a chart that shows the effect of water on the AE process.
Tilly give it up already !


" 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
Member
posted Hide Post
ckammel if you wish, you can PM me, I'd be more than happy to lend a hand. 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
Member
posted Hide Post
Do you mean that AE does not work if you have high titration WVO?
quote:
Originally posted by Biotom:
I recommend you read the Report on AE by J Van Gerpen, in that report you will find that initially they mixed new oil and palmitic acid to create high ffa oil. Then they go through the AE process, adjusting the molar ratios, and it works. Next they use high ffa used vegy oil and the same methodology and the process doesn’t work? What is the difference between the two oils? The new oil and palmitic acid have no bound water, no mono or diglycerides, where as the used fryer oil with high ffa does.
 
Registered: January 07, 2012Reply With QuoteReport This Post
Member
posted Hide Post
No, I didn't say that, but with higher titrating oils the chemical process will be stopped by the water produced during the reaction. This means that for T's higher than 20 you will need to do more than one AE
In the exerpt from the VanGerpen report you can see the effect of water, Water is a mojor obsticle to AE reactions so we have to get to know what is required for the varying ffa levals in the oils we collect.


" 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



Member
posted Hide Post
Biotom, I have copied this from The Biodiesel Handbook
Editors Gerhard Goeth Joh Van Gerpen, jurgen Krahl

R-COOH (Fatty Acid) + CH3OH (methanol)→ R-COOCH3 (methyl Ester)+ H2O (water)

Due to it's low cost, sulfuric acid is the typical acid used in the FFA esterfication step of the two step process. Water, a byproduct of esterfication prevents quantitive ester synthesis. By conducting two sequential acid catalyzed esterfications, with the removal of accumulated water after the first of these, acceptably high esterfication of FA can be achieved...It also should be mentioned that the oil or fat substrate is partially converted to partial glycerides and FAME during the esterfication step which facilitates final conversion to FAME in the Transesterfication Step

If you go back and read my first post you will see that is what I posted.
I can not find any mention of the bound water you say is in high FFA oil.
Can you tell me the location of your source for this.

I am disappointed that you seem so upset about this. I can not change the chemistry of the reaction
 
Registered: October 04, 2010Reply With QuoteReport This Post
Member
posted Hide Post
Why do you think I am upset? Did I say that acid was not a good way to esterfy FFA prior to transesterfication? If you are disappointed, so be it!!


" 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
member
2013 Sponsor
posted Hide Post
Maybe the issue is definitions. When Biotom is talking about "bound" water, I'm sure he is talking about water that is either dissolved into or emulisfied with the freshely collected oil. This type of oil can be hard to detect with the hot pan test. In fact some water can only be detected with a chemical test like the carbide manometer, sandy brae, or the karl fisher titration.

Yes the reaction also produces water. It is the sum of the two sources of water that eventually poisions the reaction. So if the oil starts off with more water, it will have less reduction in the FFA per draining/drying cycle.

Before anyone gets their panties in a wad, ckammel didn't put enough information to help him out without making some assumptions. It looks like you guys made different starting assumptions.
 
Location: Cowboy Country | Registered: December 06, 2004Reply With QuoteReport This Post
member
posted Hide Post
Thanks Biotom for giving an approximation of how long AE takes to reach equilibrium. But if you increase the amount of catalyst or methanol, I expect it is quicker. Is your 3 hour reaction time at above 100 degrees centigrade based on 10% methanol and how much H2SO4 per litre? Thanks again
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post
Member
posted Hide Post
WB the process at 100C was NOT AE, but transesterfication using acid insted of caustic.
just to be clear, when we have oil that has high levels of ffa then you can expect higher levels of mono and dyglicerids. One end of the mono or dygyceride (the fatty acid) is soluable in oil, the other end (glycerol)is soluable in water and that makes the mono and dyglycerids good emulcifiers binding oil to water. This bound water is very difficult to remove and is not detected by the sandy brae water tester or Imake manometer.


" 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
member
posted Hide Post
Biotom; Good to see a reply. I did esterfication/transesterfication of new corn oil for 28 hours at 75 to 79 degrees centigrade using new corn oil, magnetic stirring, 99.5% ethanol, and concentrated sulfuric acid catalyst. There was a chemical change that I think was not only esterification but transesterification. After the reaction the alcohol did not float to the top and form a separate phase as it did when the reactants were first mixed. My point is that esterfication and transesterfication proceed simultaneously. I followed my acid catalysed reaction with a KOH catalysed reaction. It is working well. I've got two phases of ethyl biodiesel and a glycerine phase.
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post



Member
posted Hide Post
quote:
Originally posted by WesleyB:
My point is that esterfication and transesterfication proceed simultaneously.
You are correct.
 
Registered: October 04, 2010Reply With QuoteReport This Post
Member
posted Hide Post
WB why did you have to proceed with a base stage after acid transesterfication? did you do a 3/27 at the end of the acid stage to determine how well the process worked? how much acid did you use, how much ethanol? the reason I ask is I would like to experament with this process. At the temp/time you used the process should have been complete. I read that new oil should yied 99+% where as new oil and base process yield is normally 98%. I will also carry out this rest proceedure at NORMAL ae temps just to see what happens in the amount of time that we normally take for AE.


" 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
  Powered by Social Strata Page 1 2 3  
 

Sponsors    Biodiesel and SVO Forums Home    Forums  Hop To Forum Categories  Biodiesel  Hop To Forums  Acid Esterification    acid base questions

© Maui Green Energy 2000 - 2014