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Thread: Glycerol composition.

  1. #11
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    Re: Glycerol composition.

    Well I suppose it is good to have a forum with entertainment, there is little to nothing happening on the other bio forums.

  2. #12
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    Re: Glycerol composition.

    Hi smithy,

    Quote Originally Posted by smithy View Post
    Question, Does the glycerol pre-treatment produce glycerol.
    smithy; Not usually unless the glycerol is enhanced. A normal glycerol pre-treatment using glycerol from the previous reaction usually only serves to reduce the titration value...
    This is total Incorrect.
    If there is methoxide in the glycerol then a partial reaction of the WVO occurs when you mix the glycerol with the WVO and perform this first stage reaction.
    This includes both neutralizing the FFA's and performing a partial transesterfication.
    Neutralizing FFA's and Transesterification of the oil occurs simultaneously.
    The more methoxide present in this first stage reaction the further the reaction goes.

    By "enhancing" the glycerol (adding extra methoxide to the glycerol) you make this first stage reaction go further.




    ...for instance when my oil shows a 20% conversion before the 1st reaction...
    That statement makes no sense. You can not have conversion before the first reaction. If you claim there is conversion then it is because there has been a reaction.




    Most of the water unintentionally added to the process is in the methoxide.
    "Unwanted water" would be a better choice of words

    Water usually enters the standard base biodiesel reaction in three main ways.
    1. If you are using KOH in the reaction there will usually be water in the KOH. Typically about 10% of the weight of the KOH is water.
    2. There is a tiny amount of water produced when you mix the methanol and KOH to produce the methoxide.
    3. Neutralization of FFA's. The largest amount of water present in the reaction is often the result of neutralizing FFA's

    Additionally, if the oil has not been dried properly there may be water in the oil.
    If you are using new methanol which virtually everyone in Australia uses then it is over 99% pure and water is not a concern.
    If you are using NaOH instead of KOH it is usually over 99% purity and water is not a concern.




    If using KOH in an average concentration this water level is in the order of 2.6%...
    What do you mean by an average concentration
    ?
    2.6% of what?




    Question, Even though only 2 members of this forum are posting to this thread I have heared there are a number of members interested in your work, so why are they not contributing.
    smithy; It may well be that they prefer to contact me by PM to avoid the belittlement and hassle that would result.

    Question, if that is the case then surely it is counter productive to the forum?
    smithy; Indeed it is, all subjects regarding this thread need to be discussed in public, if some members are reluctant to do so because of humiliation it is indeed a sad state of affairs





    Smithy, you have still not explained how you achieve a full conversion in a single stage reaction on WVO using just 12% methanol.
    I am sure all the people who you claim are reluctant to join in this discussion for fear of being humiliated are desperate to know how you achieve this seemingly impossible feat.
    Please tell us how you do this.


    "I appreciate your effort here but you consistently get results that no one else can achieve due to unknown circumstances, because of this your results dont hold much weight."
    Last edited by tillyfromparadise; 3rd December 2017 at 04:20 AM.

  3. #13
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    Re: Glycerol composition.

    Ive just started a 420L batch of "cement biodiesel" and Ive now got to wait a couple of days for the fines to drop out before I continue.
    The only thing I changed was adding the cement to the methoxide.
    My WVO has a high fat content so i use Paul Martins two stage process. The WVO is heat to 55C before anything is added
    Glycerol pre-wash, Around 120L from previous reaction which brings the Titration down to 3-4
    Caustic striping which brings the Titration down to 1-2 there is about 380L WVO left.
    20% methanol with 5-6kgs of KOH. T WVO is then down to about 380L (this time I added about 5kgs of cement also)
    add 75% of the methoxide, Mix and drain off the Glycerol
    Add the remainder and Mix add 4 L of water at the last 5 seconds of mixing and drain again.
    Bubble dry for a week or 2.
    I end up with around 300L or so of bio, so I will post the results in a couple of days.

  4. #14
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    Re: Glycerol composition.

    Hi smithw,

    It sounds like you are reaction 420 litres of WVO in a single batch.
    Do you mean that when you do these types of reaction you typically start with about 420 litres of WVO and end up with around 300 litres of biodiesel
    ?
    That would represent a yield of only about 71% by volume.

    What is the starting titration of the WVO?
    Last edited by tillyfromparadise; 4th December 2017 at 12:22 AM.

  5. #15
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    Re: Glycerol composition.

    Seems you are getting confused again Tilly or do you think smithw and myself are the same person?

    smithw, interesting stuff, please keep us informed.
    Last edited by smithy; 3rd December 2017 at 08:50 PM.

  6. #16
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    Re: Glycerol composition.

    Hi smithy,

    You are correct!
    It did puzzle me that you would admit to having a yield under 100% when performing a reaction


    Thank you for pointing out my mistake.
    Last edited by tillyfromparadise; 4th December 2017 at 12:19 AM.

  7. #17
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    Re: Glycerol composition.

    Around 300L sometimes 330L sometimes 280L Just depends on how fatty the oil is. I generally don't titrate the oil before I start, as what would I do with this information?
    Last time I did it I think it was around 7-8, so the WVO is pretty filthy.

  8. #18
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    Re: Glycerol composition.

    Hi smithw,

    I used to make a lot of my biodiesel from animal fat/ tallow. The main brands I used were "frytol" and "red band"
    I found that animal fat requires the same reaction procedures and the same chemical amounts as you use reacting vegetable oil and would produce similar yields.

    The "rule of thumb" is that in a normal single stage base reaction, for every 1% FFA's present in the oil you will will lose 1% yield as the soap produced and 2% yield because of the biodiesel bound with the soap.
    A KOH titration of 1= about 1/2% FFA
    WVO with a KOH titration of 8= about 4% FFA which should result in a loss of yield of about 4% as the soap produced along with about 8% loss of yield due to the biodiesel bound with the soap.

    That means that if you were doing a single stage reaction on WVO titrating 8 KOH you would expect a total loss of yield of around 12% so you should expect a yield in the order of 88%.
    I do know that on the occasions when I actually checked the results I achieved, my yields were pretty much in line with these numbers or possibly a slightly less yield.

    However, because your first stage reaction is a glycerol pre-wash these numbers change and that depends on a number of things including, but not limited to, the amount of methoxide and the amount of glycerin contained in the glycerol that is used to do the pre-wash reaction.
    Many people find that after they perform the pre- wash reaction stage and drain the glycerol, besides a partial reaction occurring, there is actually an increase in volume of the contents in the reactor.
    This increase in volume in the reactor is due to some of the biodiesel bound in the glycerol that was added to the reactor to perform the pre-wash reaction had been released into the reactor.

    Your yield seems to be considerably less than I would expect you to achieve
    Last edited by tillyfromparadise; 4th December 2017 at 08:47 AM.

  9. #19
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    Re: Glycerol composition.

    Tilly I also do a caustic striping, and I lose about 40-50 L with that. If I don't do a caustic strip my bio gels in winter.

  10. #20
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    Re: Glycerol composition.

    Hi smithw,
    Quote Originally Posted by smithw View Post
    Tilly I also do a caustic striping, and I lose about 40-50 L with that. If I don't do a caustic strip my bio gels in winter.
    That is an awful lot to lose in caustic stripping


    I personally have never performed caustic stripping, however the articles I have read about caustic stripping seemed to suggest that the only loss is the FFA's converted into soap which is a loss of 1% yield for every KOH titration of 2.

    The things that normally affect the gel qualities of your biodiesel is the oil the biodiesel is made from and the amount of conversion of the biodiesel.
    I understand that if you use ethanol in the reaction that will affect the gel qualities of the biodiesel produced but I do not know anyone who produces backyard biodiesel who uses ethanol

    I doubt that converting your FFA's into soap by caustic stripping would have any significant affect on the gel properties of the biodiesel when compared to biodiesel where the FFA's are neutralized in the normal way using methoxide. In either case you are converting the FFA's into soap and water and removing the soap and water

    What chemical are you using to do the caustic stripping
    ?
    If it were me, I would do a few 1 litre test samples just to make sure there really was an increase in jel temperature when performing the standard reaction.
    I do not think there will be.

    In the mean-time I will do a little research and see what I can find on caustic stripping.
    I do know that Keith Addison was one of the first backyard biodiesel producers to do some testing with caustic stripping and he posted his results on his JTF site.
    I'll go have a look
    Last edited by tillyfromparadise; 5th December 2017 at 02:01 AM.

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