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Questions on glycerol pretreatment and 5% water prewash
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I have been making biodiesel for about two years now starting with the single stage and progressing to two stage with no titration with pretty reasonable outcomes. My goal is to make the best quality biodiesel with good yield in the least possible time.I have used the glycerol pre treatment and the 5% water prewash but not both on the same batch.If I do this will I be able to use the resultant glycerine in subsequent batches.As I see it the glycerol attracts water so will it get to a point where it has too much water and be unable to be used in the subsequent batches.The point is to cut down on water washes which are time consuming.Input from experienced bio makers would be greatly appreciated.
 
Location: Kokstad.Kwazulu Natal.South Africa | Registered: June 23, 2012Reply With QuoteReport This Post
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Jock, you can't use glycerol that has had the 5% prewash water mixed in to pre-treat your next batch.

The 'norm' is to use stage 1 glycerol for pre-treatment and stage 2 glycerol for the 5% wash.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi Jock,

quote:
Originally posted by Jock:
My goal is to make the best quality biodiesel with good yield in the least possible time.
If this is your goal then you should change to a single stage reaction with titration and bump your KOH up to 9g KOH + titration per litre of 50 deg C WVO.
As long as your reactor is an adequate design the reaction will be finished in about an hour.
As long as the titration of your oil is not too high this should result in biodiesel that passes the Warnqvest/ 3-27 test with a yield well over 90%






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Hi Jock, We found out that when you water wash just after the last bit of water being removed, there is always an amount of 'curdled' or emulsion left, drop that out as well, keep it aside, this seems to contain a large amount of soaps, and if not dropped out, you end up keeping on washing through this and end up doing multiple washes before the bio is clear. The 'curdled' liquid will eventually settle out with Biodiesel floating on top of water. Sorry not my best effort, but I think you should be able to follow what I mean. Jim.
 
Location: Cape Town | Registered: May 17, 2006Reply With QuoteReport This Post
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Jim, the curdled/emulsified layer is a monoglyceride layer.It can be avoided/kept to a minimum by either mixing the last reaction for longer or even when you get a clear 3/27 perform another small reaction using @ 0.2gm catalyst/litre.

Jock, my goal is similar to yours but I have bags of time (as far as bio is concerned) so prefer to do 2 or 3 stages. I water wash, dry and centrifuge and end up very close to 100% yield.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Thanks DGS. Jim.
 
Location: Cape Town | Registered: May 17, 2006Reply With QuoteReport This Post



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Hi All,Jim thanks for that it will be quite simple to have a 25 or 50 litre container with a tap on to drain off the separated bio diesel in the emulsion.
Thanks Tilly
I thought that the 2 stage gave better yield and better quality than the single stage.Is it just a chemical saving without the hassle of titrating that is the advantage with a 2 stage.
Thanks Dgs
Does anyone do a glycerol pre treatment and a water wash using the 2nd stage glycerol for the water wash or is it counter productive.How much Methanol is added to the .2gm/ltr KOH and how long is it reacted.
 
Location: Kokstad.Kwazulu Natal.South Africa | Registered: June 23, 2012Reply With QuoteReport This Post
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Just use a minimum of methanol to dissolve the 0.2gms.
If you are up to reaction temperature then just leave it to mix for as long as you can (30 to 90 mins)

A while ago I tried a method from one of the guys on VOD. After glycerol pre-treating the oil 7gms KOH/litre were added with 15% methanol and mixed for 4 hours. (OK, I know not a practical mixing time, but thought I would give it a go)

I never did achieve 100% conversion but very close (this was with my old, less efficient processor)

The significant observation with this method was that during the aggressive water wash I never got the small layer of Mono's, not even a hint.
My thinking is that the long mixing time although not converting all the triglycerides, did convert all the monoglycerides.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Just use a minimum of methanol to dissolve the 0.2gms.
If you are up to reaction temperature then just leave it to mix for as long as you can (30 to 90 mins)

A while ago I tried a method from one of the guys on VOD. After glycerol pre-treating the oil 7gms KOH/litre were added with 15% methanol and mixed for 4 hours. (OK, I know not a practical mixing time, but thought I would give it a go)

I never did achieve 100% conversion but very close (this was with my old, less efficient processor)

The significant observation with this method was that during the aggressive water wash I never got the small layer of Mono's.
My thinking is that the long mixing time although not converting all the triglycerides, did convert all the monoglycerides.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi Dgs,

quote:
Originally posted by Dgs:
I never did achieve 100% conversion but very close (this was with my old, less efficient processor
The reaction we use to make biodiesel is an equilibrium reaction and will never achieve 100% conversion.
You have me curious, what test are you using to determine conversion






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Hi Jock,

quote:
Originally posted by Jock:
Thanks Tilly
I thought that the 2 stage gave better yield and better quality than the single stage.Is it just a chemical saving without the hassle of titrating that is the advantage with a 2 stage.
Let us first talk about the normal 2 stage Base/Base method using titration.
If performed properly, a two stage Base/ Base procedure using titration and a single stage base procedure using titration can achieve virtual identical results as long as the oil is not too high a titration.
The trade off is in time and and chemicals used.
A single stage procedure is quicker to perform but uses more chemicals than the 2 stage procedure.

The no titration two stage procedure is always a question mark which may or may not work. I can see no value with using it other than not having to titrate.

Also the glycerine prewash is a stage of reaction.

It depends on how much time and chemicals you want to spend.
Your stated goal is to "to make the best quality biodiesel with good yield in the least possible time."
Least possible time and best quality = single stage reaction with plenty of Chemicals.

How do you test for "best Quqality"






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Originally posted by Tilly.

How do you test for "best quality"
-----------------------------------------------------------------------------

By performing all the tests we have at our disposal as accurately as possible.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post



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Hi Dgs,

quote:
Originally posted by Dgs:
By performing all the tests we have at our disposal as accurately as possible.
Please provide a link to all the tests you are referring to that you routinely use to arrive at "best quality" and the results for each test that you consider necessary to indicate "best quality" for that particular test has been achieved.

I am particularly keen to know what test you are using that seems to be giving you an accurate reading on percent conversion. You seem to be reluctant to share this with us Wink






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Hi Tilly,
You have posted before on here that you do not test your biodiesel.
If you are now worried about the quality of the product you make I will happily provide you with links for the various tests which would explain the details far better than I could.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi Dgs,

quote:
Originally posted by Dgs;
You have posted before on here that you do not test your biodiesel.
If you are now worried about the quality of the product you make...
Goodness me, where ever did you read that???
Put your mind at ease, I have a very STRICT quality control program that every ml of biodiesel I make has to pass before I use it.
I never put biodiesel into my vehicles until it has passed my quality assurance programme and has earned the much coveted “Seal of approval”



SEAL OF Approval

It is without a doubt that my strict adherence to quality control and thorough testing in every step of manufacturing, storage and dispensing has played a very large part in my present vehicle having run perfectly for more than 9 years and 260,000km exclusively on “Tillys Finest home made B100”






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Hi Dgs,

quote:
Originally posted by Dgs,
I will happily provide you with links for the various tests which would explain the details far better than I could.
I am sure there are any number of sites and people who could explain the tests far better than you can.
However I noticed how you jumped right in and attempt to answer a question I had asked Jock. I could tell you were eager to share with us and that is also important.


quote:
By performing all the tests we have at our disposal as accurately as possible.
I think I can safely say that you would be the only person on this forum who routinelly performs all the tests at their disposal to check the quality of their biodiesel.

There is one test I have always wondered about.
Please describe the procedure you use when performing the “JG Shiny Penny Test”, how you interpret the results and what important information you feel you gain from using it when testing your biodiesel.
Curious if it makes a difference whether you use a Canadian, US or UK penny







 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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quote:
I think I can safely say that you would be the only person on this forum who routinelly performs all the tests at their disposal to check the quality of their biodiesel.

There is one test I have always wondered about.
Please describe the procedure you use when performing the “JG Shiny Penny Test”, how you interpret the results and what important information you feel you gain from using it when testing your biodiesel.
Curious if it makes a difference whether you use a Canadian, US or UK penny




That's it I'm out of here, I thought the troll might have quit by now, but as you can all see he keeps on posting inane drivel.
In the past he chased away some of the best and then suddenly quit, thank goodness, but he came back and it appears he's here to stay now.
I have enjoyed this site and it has helped me in the past no end, but look around at who is left and you will see that it coincides with the re-appearance of one self opinionated and I believe, lonely person.
Thanks everyone I have enjoyed reading your posts and learned much from most of you. 'Over and out'. Jim.
 
Location: Cape Town | Registered: May 17, 2006Reply With QuoteReport This Post
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