Hello HH

I will review this over the next two weeKs and post my thoughts when I am finished.

quote:

Originally posted by Tilly:
Hello Hans
Also, The stoichiometric quantity of methanol is usually said to be 12.5% by volume, that is, 125 millilitres of methanol per litre of oil reacted, not 150ml.
However, this will vary slightly depending on the oil used.
Rape/canola oil is 11.3% (113ml),
Mustard oil is 11.8% (118m),
Cod liver oil is 12.1% (121ml),
Peanut oil is 12.3% (123ml),
tallow is 12.4% (124ml),
soy oil is 12.5% (125ml),
Cottonseed and corn oil is 12.6% (126ml), and
palm oil is 13% (130ml).
The only oils I can find that are above 13% (130ml methanol) are Palm Kernel at 15.4% (154ml)and Coconut oil at 16% (160ml)

Tilly,
Do you have a link to this information? I find it fascinating (but 100% logical) that different oils require different amounts of alcohol for conversion.

Your help would be appreciated.

Dusty

Hello Dusty

I got the information from Here

quote:

I got the information from Here

Hmmm...JTF?

Tilly...are you going to the dark side???

Tilly,
My interest was from the producer standpoint. Lowest dollar amount of supplies = lowest cost to produce?
11.3% methanol for one oil, 15% or more for another oil... price of one oil vs the other and so on.

JTF information regarding yields, contents, percentages, etc. seem to be somewhat in the ballpark - but not to be taken as the gospel truth. I followed the JTF link to the supplier of some oils and the numbers were along the same lines but certainly not identical.

I suspect you are very close to being right, and I have read many discussions about the max and min amounts of methanol here and have not been convinced as to the absolute percentage required.... Sure, there have been many recommendations that will work but no absolute upper or lower limits that I have been able to find here.

Hans, don't be discouraged over one little correction (complaint?). The merits of your production far outweigh your current (apparent) feelings of frustration. Your labor is appreciated, your disclaimers should answer most complaints - especially since you stated from day one that this project is a work in progress.

Dusty

quote:

Originally posted by DustyDame:
My interest was from the producer standpoint. Lowest dollar amount of supplies = lowest cost to produce?

The oil, if purchased new, is the single largest expense in producing biodiesel. The value of oil is so great compared to the costs of methanol, catalyst, and processing, that saving a few cents/pound on the oil will more than offset any differences in methanol percentages.

If you get your oil for free, then the overall cost of the biodiesel you produce will be so much less than the cost of petroleum diesel that it replaces, that the small percentage differences in methanol and catalyst will not be too significant.

That's a really good start there Hans! I've been working on one for about three years now and there is always something to update or correct. You've got a lot of good information there.

It's a whole lot better than most of those "biodiesel books" on ebay. For the most part, they are just copying biodiesel information at random off various internet sites.

Keep up the good work!

On page 51,, the tool is called a Nipple Extractor,, I went and bought that tool and That tool is only for Extracitng. The tool in Your photo is a Internal pipe wrench. Found one at a plumbing supply store, for 4 and 5 bucks for 1/2 and 3/4. Now I will be returning the Extractors,,,( they twist in oneway, like an Easy-Out for broken bolts. ) I have to say I just bought that same water heater,, and I've been in the garage for a few hours the last few nights,, with this manual on my laptop, looking at pics. I have the dry fit done. If I see anything else, I'll bug ya somemore. Great Job on all the work. It sure has helped me!

All though my neice's husband made the comment the other night, when I said I was gonna start brewing, "Hey man, didn't you know that rednecks and Science don't mix?"
I just smiled and said,, yep bout $45 bucks to fill my tank, instead of $165. Redneck that!

Hello Hans.
In this post I have only really looked at the "Chemistry" involved with biodiesel production.
The following are the concerns I have found with the information in your manual.


PAGE 24- You are discussing rubber fuel lines and you say:"Note that newer cars have abandoned natural rubber and now use synthetic rubbers..."
Rubber fuel lines have never been made from natural rubber. Petroleum products attack natural rubber just the same as biodiesel does.

PAGE 39 says: "Stoichiometrically, the reaction requires 5 grams of NaOH and 150 ml of methanol per liter of waste oil (triglyceride) used."
Stoichiometric is not the correct word to use to describe the amount of NaOH used because the NaOH is a catalyst in the reaction making biodiesel not a reactant.
The Stoichiometric amount of methanol is around 125ml per litre of oil reacted for most oil types likely to be used by Biodiesel producers in the USA, not 150ml.
I know of no oil that stoichiometrically requires 150ml methanol per litre of oil reacted

PAGE 39- says; "The volume of biodiesel produced will equal the volume of triglycerides reacted, and the volume of glycerin byproduct will equal the volume of methanol reacted."
This is an incorrect generalization. There are many things that will determine the amount of biodiesel and "glycerine" produced during the reaction.
I can not recall anyone claim a yield of 100% for normal backyard production.

Page 40 says;"Soaps will be suspended in the biodiesel phase, and require washing with water."
There are other ways to remove the soap besides washing with water.

PAGE 40- says; "Stoichiometrically, 1 liter of waste vegetable oil (triglycerides) requires
150 ml of methanol."
See my post above about this.

PAGE 41- says; "If reactants are not heated and/or mixed appropriately, the reaction may not go to completion."
This is not correct. testing has clearly shown that as long as everything is liquid, temperature is not a limiting factor in the reaction.

PAGE 43- says "Acid-esterification should be employed on oils that contain more than 6% acidity as determined by a base titration. Oil acidity is determined through a simple titration with a 0.1% solution of sodium hydroxide, the details of which are discussed in the source-oil characterization phase of this document."
The Titration does not directly tell you the % acidity of the WVO

PAGE 43- says; "Water may be formed as a byproduct of the acid esterification, and needs to be separated before executing a base-transesterification on the products of the reaction."
I am not up on the latest Acid/Base thinking, but I know when I was experimenting with Acid/Base I never removed the water produced in the acid stage.
Could you verify that the water produced by the acid stage needs to be removed before performing the Base stage and more importantly how do you remove the water.

PAGE43- says; "As such, producers must recalculate the acidity of the acid transesterification products and adjust the catalyst for base-base transesterification accordingly."
Are you recommending a Base/Base procedure after the Acid stage?
If this is the case, what are the quantities of catalysts/reactants you recommend for each of the three stages?

PAGE 109- says; "The milliliters of solution added to the oil for the color change equates to the percent acidity of the oil sample."
This is incorrect. The titration number is not the percent acidity of the oil sample.

PAGE 154- says; "Cloud point is defined as the lowest temperature at which wax crystals
begin to form in the fuel."
I think you mean to say Highest temperature instead of lowest temperature

Thanks everyone for your review and comments. I took a peek tonight to see if there was something I could get started on, and sure enough, you've all provide me with plenty to work with.

I'll take all of your comments seriously and consult with others in the Tucson biodiesel community on edits. I promise to have a new revision posted by COB Sunday so stay tuned.

Tilly; in order to avoid trying to hit a moving target, please hold off on further suggestions/corrections until I get the latest addressed. Once version 1.03 is posted, you are welcome help me improve once again.

I think with the support of this forum, we can generate a quality document which addresses everyone's needs and concerns.

More to come -

Hans Huth

Hans,

Where were you 6 months ago?!?! I certainly could have hacked a huge amount of time out of my learning curve. I see you're taking a few hits here and there, but that's expected when you choose to bare your soul on a forum. I hope this only helps to improve your final product.

I can only praise you for being so diligent in your pursuit and for taking some much of your personal time and effort to produce this "living" document. Your parents obviously did a great job teaching you how share at an early age...

You have all of my support.

Jim...

Many thanks to all of you who’ve taken the time to review and submit much needed edits to this document. Below, I’ve summarized your comments and noted my response and action taken.

PAGE 24- You are discussing rubber fuel lines and you say:"Note that newer cars have abandoned natural rubber and now use synthetic rubbers..." Rubber fuel lines have never been made from natural rubber. Petroleum products attack natural rubber just the same as biodiesel does.

RESPONSE: Correction addressed, line now reads: “Note that newer cars have abandoned rubber and now use alternative materials such as viton for their seals and fuel lines.”

PAGE 39 says: "Stoichiometrically, the reaction requires 5 grams of NaOH and 150 ml of methanol per liter of waste oil (triglyceride) used." Stoichiometric is not the correct word to use to describe the amount of NaOH used because the NaOH is a catalyst in the reaction making biodiesel not a reactant. The Stoichiometric amount of methanol is around 125ml per litre of oil reacted for most oil types likely to be used by Biodiesel producers in the USA, not 150ml. I know of no oil that stoichiometrically requires 150ml methanol per litre of oil reacted

RESPONSE: Regarding the use of the word stoichiometrically, I agree – NaOH should not be referenced as part of the stoichiometry of the reaction. I’ve removed all references to this word since it is really not necessary for the purposes of the introduction I am presenting here.

PAGE 39- says; "The volume of biodiesel produced will equal the volume of triglycerides reacted, and the volume of glycerin byproduct will equal the volume of methanol reacted." This is an incorrect generalization. There are many things that will determine the amount of biodiesel and "glycerine" produced during the reaction. I can not recall anyone claim a yield of 100% for normal backyard production.

RESPONSE: I was referring to a perfect ideal reaction. When I have high quality oil and methanol, I generally get yields in the mid 90s. Note that I go on to say that realistically, the reaction is more complicated, and discuss things that can impact the overall process and yields such as poor quality oil. Regardless, I have removed the text since it is not necessary for the introductory nature of these six pages.

Page 40 says;"Soaps will be suspended in the biodiesel phase, and require washing with water." There are other ways to remove the soap besides washing with water.

RESPONSE: Of course, but most homebrewers are going to use water. Regardless, I’ve rephrased as “may be eliminated through washing with water.”

PAGE 40- says; "Stoichiometrically, 1 liter of waste vegetable oil (triglycerides) requires
150 ml of methanol." See my post above about this.

RESPONSE: … and mine.

PAGE 41- says; "If reactants are not heated and/or mixed appropriately, the reaction may not go to completion." This is not correct. Testing has clearly shown that as long as everything is liquid, temperature is not a limiting factor in the reaction.

RESPONSE: I’m not sure of what testing you are referring to; can you give me a source? I’ll admit I’m not a chemist, but I do remember a few things from college chemistry, specifically, that the equilibrium ratio of reactants to products in a chemical reaction is guided by temperature and pressure. In addition, there’s probably some hysterisis involved in the conversion of waste vegetable oil to biodiesel (i.e. there’s resistance to the reaction moving backwards as temperature falls). At a minimum, heating helps with the kinetics of the mixing, so I find it difficult to believe that temperature will not have an impact on the reaction (all else equal).

For the time being, I have addressed as follows: “Mixing is required to ensure reactants overcome kinetic barriers for transesterification. If reactants are not mixed appropriately, the reaction may not go to completion. This will result in a smaller yields of biodiesel coupled with the formation of mono and diglycerides, as well as unreacted triglycerides. The presence of unreacted or partially-reacted triglycerides is addressed through reprocessing. Introducing heat helps with the mixing process.

PAGE 43- says "Acid-esterification should be employed on oils that contain more than 6% acidity as determined by a base titration. Oil acidity is determined through a simple titration with a 0.1% solution of sodium hydroxide, the details of which are discussed in the source-oil characterization phase of this document." The Titration does not directly tell you the % acidity of the WVO

RESPONSE: To be honest, I suspect you are right. However, my use of the phrase “percent acidity” in this context results from my conversations with a friend and owner/operator of a tallow plant here in Tucson. Percent acidity is how he reports the quality of recycled grease which he sells as a commodity. He uses the same titration method to calculate this acidity. Can you please shed additional light on this or provide me with a source on the difference? I wouldn’t be surprised if this needs correction, but I’d like to know more on this front before doing so.

In the event that there is a mistake here, I’ve added the following text to all references regarding percent acidity of oil: “Note: In this document, percent acidity refers to the number of ml of 0.1% solution of sodium hydroxide added to neutralize acid in oil. This definition was provided to me by Mr. Balvino Hurtado of Tucson Tallow who reports percent acidity to customers who purchase recycled grease from his firm.”

PAGE 43- says; "Water may be formed as a byproduct of the acid esterification, and needs to be separated before executing a base-transesterification on the products of the reaction." I am not up on the latest Acid/Base thinking, but I know when I was experimenting with Acid/Base I never removed the water produced in the acid stage. Could you verify that the water produced by the acid stage needs to be removed before performing the Base stage and more importantly how do you remove the water.

RESPONSE: I do not pursue acid esterification, but I have friends who do. Most of my information on acid esterification for the document came from a recorded interview with Steve Fischer on November 17, 2006. For you convenience, I will provide you with a transcript of that portion of the conversation in a posting soon to follow this one.

PAGE43- says; "As such, producers must recalculate the acidity of the acid transesterification products and adjust the catalyst for base-base transesterification accordingly." Are you recommending a Base/Base procedure after the Acid stage? If this is the case, what are the quantities of catalysts/reactants you recommend for each of the three stages?

RESPONSE: First, please read the posting I’m about to place in this thread regarding the mentioned interview. Steve recalculates the acidity of the resulting solution from the acid esterification, and then diverts the entire mix to his appleseed for reprocessing using simple base-transesterification methods. The biodiesel generated from the acid-esterification is not separated out prior to base transesterification and does not interfere with that reaction; he just processes the entire thing as if it were waste vegetable oil. The only difference is that when he does the titration on the (acid-esterified) mix, the acid number is much lower and thus requires much less catalyst and all the headaches that accompany highly acidic oils. Unlike myself, Steve is a professional engineer. He generates beautiful biodiesel and has logged over 30K on B100 homebrew used in his jetta.

PAGE 109- says; "The milliliters of solution added to the oil for the color change equates to the percent acidity of the oil sample." This is incorrect. The titration number is not the percent acidity of the oil sample.

RESPONSE: Comment addressed as stated above and is based on definition provided to me from someone who does this for a living. Regardless, I’ll be glad to make further adjustments if you can provide me with more information.

PAGE 154- says; "Cloud point is defined as the lowest temperature at which wax crystals begin to form in the fuel." I think you mean to say Highest temperature instead of lowest temperature.

RESPONSE: You are absolutely right, there is an error here. Actually, it should just read temperature (not highest or lowest): “Cloud point is defined as the temperature at which wax crystals begin to form in the fuel.”

-------

That does it for the modifications related to the postings to this blog thus far. There are other modifications to the document which will be included in version 1.03 to be posted this Sunday. The modifications include some of the missing pictures.

Let me acknowledge Saint Tilly in particular for helping me address some obvious errors in the chemistry section of this document. Along those lines, I’ve added the following text to the chemistry section in the event that readers have not read my disclaimer

“The following overview is principally sourced to Maria Mark Alovert’s Homebrew Manual and consultations with homebrewers in the Tucson biodiesel community. I must also acknowledge those of you who have provided valuable input via the http://biodiesel.infopop.cc/ information coop in this thread:

http://biodiesel.infopop.cc/eve/forums/a/tpc/f/719605551/m/2841034642

Please keep in mind that this section has not been compiled or peer reviewed by a credentialed chemist; I’m just a home brewer trying to get my head around what’s taking place in my processor, so please put this summary in its proper context. For those of you with a broad background in biodiesel chemistry, I’ll admit this section will not broaden your horizons significantly. Instead, you are better served reviewing the archives of the American Oil Chemist Society (http://www.aocs.org/archives/icb/ ) and the published literature.”

I mean no disrespect to Saint Tilly with that last paragraph. I sincerely appreciate his input and will continue to take his and other’s comments seriously, but I would like expectations of future readers to be somewhat in line with what I’m trying to do here: provide a very basic overview of the chemistry involved in rendering biodiesel from waste vegetable oil. Having said that, any errors identified by reviewers who take the time to post to this blog will be investigated and addressed in as timely a manner as I can muster.

Regards –

Hans Huth

quote:

Most of my information on acid esterification for the document came from a recorded interview with Steve Fischer on November 17, 2006. For you convenience, I will provide you with a transcript of that portion of the conversation in a posting soon to follow

And here is the transcript from my handwritten notes:

---->

Acid Esterification

STEVE: Oil you collected required 14+ ml to neutralize acid - brought it down to 8 via acid esterification. 93% sulfuric acid: 9$ / gallon ; 99.9 sulfuric acid: 90$ liter; frequency of collection helps offset acidity. Submersion pump – rigged up with a valve – heating up high-acidity shortening up to 105-110 degrees. Use a small hand mixer on a drill.

Heat oil to 110 degrees. Add 2.8 gallons of alcohol (or better said, 8%) in 35 gallons of acidic oil for acid esterification. Mix up oil/alcohol for 5 minutes initially with hand pump, and then add 1ml per liter sulfuric acid, and then mix 4 hours (at 95 to 100 degrees F) with submersible pump, and then let sit for 24 hours.

HANS: Do I have to keep solution heated for esterification to take place?

STEVE: Yes

Within two days, esterification will reduce titrations of 9-12 mls down to 3-6 mls. In addition, out of 35 gallon batch where normally you’d get 80% return, you’ve been getting close to 100% return (not to mention less formation of soaps).

HANS: Does all the acid get consumed in the acid esterification? Isn’t there a chance it will impact your titration?

STEVE: Only if you use too much – if you use too much acid, reaction will go backwards, so less is better than more.

HANS: You purchased a 1/2 hp submersible pump for mixing. What did you pay for that pump at Harbor Freight?

STEVE: Cheapest is $39. Also, the byproduct of acid esterification is water which can be siphoned off of the top of the barrel with the submersible pump. You can also use the appelseed to separate water – heat it up to 130 and let it settle for 30-60 minutes. Separation results in draining off about a gallon.

HANS: Can you acid esterify the FFAs in your glycerin byproduct?

STEVE: Yes. Regarding glycerin/FFA: 4 gallons usually takes 1 liter sulfuric acid ( l liter H2SO4 for 15 liters or 6.67% or 67 ml acid / liter glycerin).

When you collect oil, try to filter down to 600 microns at the pickup place. This helps helps remove the water – food particals holds about 70% of the water. Then, filter glycerin down to 200 micron prior to acidifying.

<---

That's all I have in my notes regarding my acid esterification convesation with Steve; other items come from memory. I am scheduled to lead a community college on a field trip to some biodiesel rendering facilities in Tucson during the last week in May. If you have some questions you'd like me to ask Steve, I'd be glad to query him on your behalf.

HH

Hello Hans
It is good to see that you are willing to correct your information.
I will endeavour to to provide you with the additional information you require.

quote:

Originally posted by thegreenbeat:
RESPONSE: Correction addressed, line now reads: “Note that newer cars have abandoned rubber and now use alternative materials such as viton for their seals and fuel lines.”

This is still an incorrect statement. Rubber fuel lines have not been abandoned.
Synthetic rubber has always been and continues to be used for fuel lines and seals in many of the newest diesel fuel system.
I have an aquantance who is having problems with his 2005 Peugeot 307 station wagon diesel injector leaking because Bosch is using nitrile rubber in the IP that is not compatable with Biodiesel and the replacement seal kit from Bosch in Germany is made from same Nitrle rubber.

quote:

RESPONSE: Of course, but most homebrewers are going to use water.

I don't know, there seem to be a lot of people using dry wash systems containing magnasol and other things I am not current on.
And still others who just allow the biodiesel to sit for a month or two to de-meth.
These systems seem to work at least as well as water to clean the biodiesel.

quote:

RESPONSE: I’m not sure of what testing you are referring to; can you give me a source?

If you have read the tests performed by chemists you will notice that is common practice to leave the reactor run all day at "Room" Temperature rather than continually heat.
This Thesis by Rothermel "Investigation of transesterification reaction rates and engine exhaust emissions of biodiesel fuels." on the Iowa State University biodiesel site Is a good paper.
The Results
The ASTM standard for glycerol content is 0.24%

This test was run to a stricter 0.15% glycerol content
The following are the time/temperature to achieve 0.15% glycerol.
80deg F took about 4.5 hours in the reactor
100deg f took a bit less that 2 hours
120deg F about 45 min
140deg F about 22 minutes.
Introducing heat reduces the time required to mix. Increasing temperature increases the speed at which a chemical reaction progresses.

If you look at the graph on page three you will notice thet after 8 hours the % glycerol was still falling in the batch made at 80deg C

quote:

RESPONSE: To be honest, I suspect you are right. However, my use of the phrase “percent acidity” in this context results from my conversations with a friend and owner/operator of a tallow plant here in Tucson. Percent acidity is how he reports the quality of recycled grease which he sells as a commodity. He uses the same titration method to calculate this acidity. Can you please shed additional light on this or provide me with a source on the difference? I wouldn’t be surprised if this needs correction, but I’d like to know more on this front before doing so.

Titrate with NaOH or KOH will give you different numbers. They can not both be the Acid percent, and in fact neither number is.
"Neutral (Industrial Research Chemist PHd and over 20 years Biofuels/Biodiesel R&D) posted on this forum
To calculate the FFA from a homebrew titration use the following with a 1ml sample of oil:
FFA% = 0.766 x t for titration with 1g NaOH per litre where t is the volume of solution in ml for 1ml oil
FFA% = 0.546 x t for titration with 1g KOH per litre"
In simpler terms, for the FFA percent of the oil, if you titrate with NaOH multiply the titration number by 0.766 and if you titrate with KOH multiply the titration number by 0.546

Thank you,

These are relatively easy fixes and appear to be legitimate. On the rubber, I'll suggest that "many" new cars are using alternatives to synthetic rubber since I don't have statistics suggesting "all" newer cars are using altneratives. The original phrasing was based on my experience and conversations with others in this realm.

On the percent acidity, I'll just rephrase as "acid number" and share the information you provided with Balvino for his input. "Acid number" does appear to be an adopted phrasing, so there is no need to complicate matters further.

Although the heating does not appear to be a requirement, I do think it helps with the mixing purely from a kinetic point of view. I believe you confirm the same since you note that it lowers mixing times. As version 1.03 is rephrased, I believe it currently addresses your original concern. As far as my own operation is concerned, I'll continue to heat since I feel it is a better alternative then increasing the wear and tear on my pump via extended mixing times.

Regarding the washing with water, the rephrasing for version 1.03 leaves the topic open for anyone who wants to invest time in researching alternatives.

I think my introduction makes it clear that my goal is not to address every angle of home brewing and respective methodologies (at least not in version 1.03). As I state in the document, I present what works for me, but note that the experience of the reader may take him/her down a different path. Of course, in addition to the corrections, I could add another 10-12 pages of details that reflect many of the interesting observations you've shared. Since I am not well versed in such matters, I'd prefer to keep it as simple as possible and will limit what I write to my experiences and current understanding of things.

Version 1.03 will reflect new edits in this post.

Thank You -

HH

Hans,

Your efforts in writing and assembling this collection of material is exceptional and deserving of praise. Offering it to anyone for free is extremely generous, too.

Many of the points raised by others make me, an organic chemist, chuckle a bit. I think your point that newer "rubbers" are more impervious to biodiesel is certainly understood. And being fixated on "stoichiometric" measurements and the exacting use of it as a term is a bit overkill, even to a chemist. Especially when one considers that the oils are biological compounds with tremendously variable molecular formulas in their mixture, varying from plant sources, and even among samples. Vegatable oil is not a pure substance. Also, the reaction isn't even being done in a pure stoichiometric fashion. It is, afterall, being driven by a shift in equilibrium toward the desired end products through the use of excess reagent (MeOH) and the removal of methylesters via phase separation due to their immiscibility.

One could take issue with someone calling the KOH or NaOH a catalyst. Although most of it is, some is acting as a reagent neutralizing any free fatty acids. My point is that picking on these little issues overlooks the masterful job you have done in this work.


This is a job well done and one for which I would give any of my college students and outstanding grade. A+

Thanks Foxden,

As much as I'm open to constructive criticism, it's also nice to hear some encouragment from yourself and others who have posted to this forum.

Regards -

Hans Huth

Hello Foxden, welcome to the forum!

quote:

Originally posted by Foxden:
Many of the points raised by others make me, an organic chemist, chuckle a bit.

And as a teacher, I find that a chemist who is suggesting that incorrect information given in "Good Faith" should not be corrected, is disappointing.

quote:

I think your point that newer "rubbers" are more impervious to biodiesel is certainly understood.

As I recall, I only challenged Hans' incorrect statement about natural rubber having been being used in fuel lines and fuel systems and that now there is no rubber of any type used in fuel lines and fuel systems.
If you were to google biodiesel natural rubber
you would find in excess of 40,000 websites inaccuratly warning about the dangers of the Natural Rubber fuel lines that used to be used on cars.
We do not need another one.

quote:

And being fixated on "stoichiometric" measurements and the exacting use of it as a term is a bit overkill, even to a chemist.

Do you actually feel that correcting the inaccurate use of the term Stoichiometric is over kill?

quote:

Especially when one considers that the oils are biological compounds with tremendously variable molecular formulas in their mixture, varying from plant sources, and even among samples. Vegatable oil is not a pure substance. Also, the reaction isn't even being done in a pure stoichiometric fashion. It is, afterall, being driven by a shift in equilibrium toward the desired end products through the use of excess reagent (MeOH) and the removal of methylesters via phase separation due to their immiscibility.

When I started making biodiesel it was generally accepted that the reaction used 8%/80ml methanol per litre of WVO in the reaction.
Then a chemist on this forum and another forum both figured it out independantly to be around 12.5%/125ml methanol and that has been the accepted number for the last 7 years or so.
Now Hans has just posted in this manual that it is 15%/150ml methanol.
I invite you to post your thoughts as to the correct number.

quote:

One could take issue with someone calling the KOH or NaOH a catalyst. Although most of it is, some is acting as a reagent neutralizing any free fatty acids.

You forgot to mention the side reaction that is also making soap out of the oil/biodiesel and the NAOH/KOH that is catalyzing the main reaction that makes biodiesel.
This side reaction that uses the NaOH/KOH that is catalyzing the reaction making boidiesel as a reagent to make soap is the reason the main reaction making biodiesel eventually stops whether the reaction is finished or not.
This is a biodiesel forum and not a soap making forum.
We normally talk about the NaOH/KOH catalyzing the reaction that is making biodiesel and being consumed in a side reaction as a reagent making soap.
All "Common Knowledge"

quote:

This is a job well done and one for which I would give any of my college students and outstanding grade. A+

And I would not. There were too many inaccuracies.

Perhaps you would care to share your biodiesel experience with us.

quote:

One could take issue with someone calling the KOH or NaOH a catalyst.

One could, but they would be wrong. In the reaction whereby FAME is made through transesterification of triglyceride, KOH or NaOH are used catalysts.

quote:

Perhaps you would care to share your biodiesel experience with us.

Tilly I don't see your biodiesel manual. These days you can get a URL for under $10 and web hosting for free.

I'm sure Hans will address your nit picking in his own time. He is not getting paid for either writing or posting this document. From someone that's done a bit of writing, what he has put together has taken a good chunk of his life's energy and time. There's doers like Hans, and then there's those that whine and complain that the doers are not doing their way. Like I said, where is your how to manual?