Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: K.H on September 10, 2012, 07:35:25 PM
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Just out of interest what do people consider a pass when doing a 3/27 or 10/90.
Clear.cloudy some dropout?
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With me it's 90/10 and has to be clear . Although I'm sure the truck runs better on a few M/D/T's
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My common rail can be twin tanked, so I'm normally happy with 10% unconverted after the second stage. Thats a 90/10, my results seem to have been better when I used to do a 3/27.
Think the difference in accuracy between 3/27 or 10/90 has been mentioned before.
Nearly forgot, my wash waters normally still cloudy when I dry, but I only dry when theres no visible soap between the bio and water.
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That's a really good question and one to which I'd like to know the official answer.
In almost 100 batches, I've only twice had what I'd consider a clear result, and I mean clear as in colourless.
The rest of the time I get clear but coloured results.
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The "official" answer is anything but an instant clear is a fail!
A post on the VOD got me thinking about this,a guy said his result was cloudy-a good pass and was soon told it was a fail,so i was intrigued about other peoples opinions although i know peoples views will be dictated by the car it goes in
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Sorry I just realised my answer may be misleading when a day clear I mean not cloudy in any way but always colour , hope that clears things up
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I concider a pass to be light pee colour, but not cloudy.
If I have a small amount of dropout (0.5ml in a 90/10) I'm happy to put it in my cars, but they'll both run on veg so it's no biggy.
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Yes I'm with Mark, a pass is clear light yellow. With cloudyness, if left long enough invariably it clears but with a little bit of dropout at the bottom. That said, I'm happy to throw 10% unreacted into the car during the summer - it's only really winter that I want perfect passes to help with settling.
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If / when I go back to water washing in the winter a clear pass would be needed.
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I too consider a light yellow clear = a pass, but cloudy or even 0.25 drop out and I'll make that do.
Clear as in colourless? didn't know it was possible, never heard of it.
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Colourless is surely impossible? Bio is not colourless, and all you are doing is dissolving it in something, not removing the colour.
Some bio turns out lighter colour than other batches - i guess a very light batch may seem colourless when diluted, but im certain it wont actually *be* colourless.
The word 'pass' is surly subjective? 100% is objective.
I would consider 100% to be a clear solution with no cloudiness and no drop-out.
I would consider a 'pass' to be different things at different times of year, and with different feedstocks.
In winter, id want 100% conversion, as with solid feed stock at any time of year.
In the summer, with fluid feedstock, i wouldnt be that fussed (to the point of not bothering to test at the end of s2 at all)
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I'm happy with this....
(http://i471.photobucket.com/albums/rr79/julesandtash/Biodiesel/SAM_2767.jpg)
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If you can see through it then that's a pass, as far as I'm concerned. Colourless - not so sure about - non-opaque perhaps.
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A perfect pass is a clear 5/45. No haziness or dropout. My last batch was slightly hazy, which to me, was acceptable. I think we all have aspirations for the clear pass but we all know what will run in our own vehicles.
Both the Passat and the Golf we own will both run on veg so I don't tend to get too anal about it. If I owned something which was more fussy then I would put more effort in at the end of process in order to acheive perfection.
Nige
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I agree with JulianF, It cannot be clear AND COLOURLESS as the colour of the bio going in MUST colour the whole test.
I process untill I obtain a clear golden 5/45, summer or winter. makes no difference as far as I'm concerned.
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I like to process to a clear non hazy 10/90 but on those days I want to push on I will accept a hazy but no dropout 10/90, all our cars will run veg but that's not what it's about for me.
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I allow at least 30mins after mixing the meth and bio before judging the results of my 27/3 or 45/5 tests.
Gentle agitation of the test solution seems to speed up any fall out, and leaving the test mixture overnight leaves a clear test solution but with more fall out.
I use the two stage process and the titration calculator on this web-site to calculate how much more meth and potassium to add for a "third-stage". I often have to do a "fourth stage".
Been makin bio 4 years now. Realise what I used to make was only "mostly biodiesel".
Can't for the life of me get an honest straight clear 27/3 test pass with NO DROP-OUT!
Anybody else struggle with getting a clear honest 27/3 test pass?
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I would consider a light pee coloured, but not cloudy 5/45 a pass. But even if I get dropout the truck happily burns it. It's just the getting a clear pass gives me a nice warm feeling inside.
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I allow at least 30mins after mixing the meth and bio before judging the results of my 27/3 or 45/5 tests.
Gentle agitation of the test solution seems to speed up any fall out, and leaving the test mixture overnight leaves a clear test solution but with more fall out.
I use the two stage process and the titration calculator on this web-site to calculate how much more meth and potassium to add for a "third-stage". I often have to do a "fourth stage".
Been makin bio 4 years now. Realise what I used to make was only "mostly biodiesel".
Can't for the life of me get an honest straight clear 27/3 test pass with NO DROP-OUT!
Anybody else struggle with getting a clear honest 27/3 test pass?
Are you glyc drying your oil? if not it may be worth giving it a go as wet oil could be causing your problem
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I allow at least 30mins after mixing the meth and bio before judging the results of my 27/3 or 45/5 tests.
Gentle agitation of the test solution seems to speed up any fall out, and leaving the test mixture overnight leaves a clear test solution but with more fall out.
I use the two stage process and the titration calculator on this web-site to calculate how much more meth and potassium to add for a "third-stage". I often have to do a "fourth stage".
Been makin bio 4 years now. Realise what I used to make was only "mostly biodiesel".
Can't for the life of me get an honest straight clear 27/3 test pass with NO DROP-OUT!
Anybody else struggle with getting a clear honest 27/3 test pass?
Hi John
Can you give us some more details regarding your process as I think you should be getting better results from a 2stage. Needing to go more means that something is preventing a complete reaction , this could be something really simple to remedy or may need a rethink on your processor.
Also are you doing the 27/3 test at 20 degres , the test is also better done by doing a 90/10
If you get really stuck drop me a pm and we can have a chat and find out where it's going wrong
Paul
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Instantly clear and bright is a pass for me, but I will usually accept cloudy, or even a little fallout on occasion if I need to.
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Thanks everybody for your replies. More details on my set-up:
I extract the oil I get, direct from the fryers I clean as a business - usually at 175-185 deg C. It's filtered to 5 micron and is exclusively either rapeseed or GM Soya (no palm). I sometimes heat/settle it again, in my processor, to as hot as I can get it (70 deg+) for an hour or two and I don't get any water fall-out.
I titrate with either pheono or turmeric. The oil's been well used so it always titrates on the high side 4.0 to 6.5 using a potassium base are common. (I had some this week that titrated at nearly 10 - haven't dared try it yet.)
Batch processing sizes are 80 to 100 litres. Methanol is not virgin but is sold as 99% pure. The potassium hydroxide flake I buy is rated at 90%. I do a two stage process as described elsewhere on this site.
After the 2nd stage I sample 500ml of what's in the processor, allow the glyc to settle for 10-20mins, and do a 27/3 or 45/5 whilst the brew is still hot and roughly measure the amount of unreacted oil (often as much as 1ml of oil unreacted).
Erring on the high side I use the titration calculator on this site to calculate how much extra meth and potash to add for a third stage to try at getting a nil drop-out. I push it so far I sometimes end up with jelly but the reaction won't seem to go all the way.
I'm reading up on how to pre-treat the oil with an acid catalyst to esterificate it first before going on with a much less aggresive trans-esterification.
Three questions: Any advice on pre-treatment with sulphuric acid to esterificate oils with a high FFA? Could my process be making soap which in turn produces water which will stop the reaction going to 100% conversion? Has anybody else used the "extreme biodiesel" calculator - http://extremebiodiesel.com/titration-calculator.aspx?
Thank you
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I know nothing about acid pretreatment so can't tell you anything.
Read up on gly prewashing as this will reduce the titration value.
Also read up on non titration two stage, this will further reduce the amount of catalyst used and soap produced.
Leave about an hour for the gly to settle, 10- 20 mins is not long enough and will leave to much gly in the bio,
this will effect the second stage of the reaction and may be the reason why you get a failed 27/3.
Water courses soap not the other way around, water is produced when meths and catalyst are mixed.
If they're frying frozen chips you will have some palm oil in there as frozen chips are pre cooked on palm and this will end up on the fryer oil.
How long do you run the pump in each stage of the reaction ?
What reactor are you using ?
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Hi John
Your titration value isn't that high at 4-6.5 KOH it only works out to be 2.8-4.6 NaOH not that bad really. Also if you are getting jelly then you are probably ending up with too much catylist in the batch.
If you really want to go into esterification then I can help but I think you need to get the transeterification to work first otherwise you just have a much longer process with a lot more complications and it will be even herder to get a pass but much easer to get it all completely wrong
Have you tried the no titration method as I think this could help, with your oil I would use a base of 9g per litre for stage 1 with 15% meth and mix for 1 -1.5 hours
Let this settle overnight if you can before dropping the Glyc.
Then do a 90/10 test to workout the remaining un-reacted oil, this time use a base of 7g per litre and 15% of un-reacted oil in meth. Mix for 1-1.5 hour and test.
Reaction temp for both stages 65-70 deg
If you get a pass mix back in Glyc from stage 1 mix for few mins then leave to settle over night.
If you don't get a pass then we may need to get you a bigger stick to mix with.
Pm me your number if you want a chat about the process
Paul
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Methanol is not virgin but is sold as 99% pure.
might be worth testing how pure your meth is, poor meth will not help your reaction.
But more importantly using it for a 45/5 test could give you more drop out than you would get with virgin meth.
Mark
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Mmm that's true, do you have an alcohol hydrometer?
http://www.ebay.co.uk/itm/Spirit-Alcohol-Hydrometer-Alcoholometer-Vol-Homebrew-/170490844677
Or accurate scales and a 100ml measuring cylinder? 100ml should weigh 79.18g