Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: Tony on April 18, 2012, 05:51:41 PM
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Edit: Topic split for discussion
You could hive out part of the titration calculator and use it for a "No titration" page.
That's a good plan - might need some help with it though, I tried no-tit once but it was more hassle than titration for me. So not completely familiar with it.
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You could hive out part of the titration calculator and use it for a "No titration" page.
That's a good plan - might need some help with it though, I tried no-tit once but it was more hassle than titration for me. So not completely familiar with it.
I'm in the same boat, so not much help I'm afraid ... I'm sure Vince will jump in if he reads this post.
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Im not doing it either
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OK, added no-titration calculator to the menu bar, following the advice on the wiki page for how to do it. I'll ask Vince to check it out.
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Vince says he thinks the option to put in a %age methanol should be removed and first stage should be 3.5g base for NaOH and 5g base for KOH to encourage less of a reaction in that first stage.
I've asked for base amounts to use for second stage (IE after measuring dropout).
This doesn't currently tally with the wiki page on how to do it so I think we'll have to update that when the calculator is figured out.
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Vince says he thinks the option to put in a %age methanol should be removed and first stage should be 3.5g base for NaOH and 5g base for KOH to encourage less of a reaction in that first stage.
I've asked for base amounts to use for second stage (IE after measuring dropout).
This doesn't currently tally with the wiki page on how to do it so I think we'll have to update that when the calculator is figured out.
sorry i ment % purity caustic
i use 3.5 base stage 1 naoh & 5 base for stage 2, & 4.5 base stage 1 koh and 7 for stage 2.
other do other things so it may be best not to default to a g/l and let people put in what they want.
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Ah gotcha.
The purity bit was because it was adapted from the titration calculator.
What I'll do is put in an entry box for second stage base amount and reduce the defaults for first stage base accordingly. And remove the purity options, keep it simple.
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Are we happy with an assumed purity of 99% for NaOH and 90% for KOH?
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I've rewritten the no-titration calculator - how does it look now Vince?
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I've rewritten the no-titration calculator - how does it look now Vince?
i really don't think the purity has any need to be involved at all, we use a figure for stage one and another figure for stage 2, its done on a try and see basis and the next batch is changed slightly according to how the last batch went.
if we give accurate figures to people we will just get told it don't work, when what they should be doing is learning what works for them and understanding the process for them selves not just blindly following a list done by others.
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Sounds reasonable. I suppose the trouble is I like to quantify things :)
For the purpose of the calculations then, should it ignore purity and assume 100% for both, leaving the rest up to the brewer's experience to tweek? It would certainly make the calculations a bit simpler.
If nothing else it gives a double check to make sure people's workings aren't far out, when brewing a batch.
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the problem is its not an exact science and every ones oil is differant,
i think we should just supply then empty boxes for base amounts and let them put what they want in them.
i see the calculator as just something to save getting a pen and paper out.
I have just printed out a spreadsheet with stage 2 qty per 0.1ml of drop out.
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in fact i am not sure we even need a koh/naoh button at all
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I see what you mean. Don't specify the catalyst, user chooses the base, everything falls out of that.
I'll get right on it!
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OK, how about now?
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ok i think it now has all the boxes that are needed and the maths seems correct.
i would think about changing some of the text, "3/27" i would change to "drop out test" and have a link to the page on the wiki about doing the test, as at present it says 3/27 and then askes you to put in your sample size, i can see some getting confused by this.
it would also be nice to have a bit text for each stage such as.
First stage, start with a base of 5g/l naoh, 7g/l koh, adjust this up or down on following batches to try and achive a 60 to 80% completed reaction from this stage. This will depend on the quality of your oil and will take a few batches for you to get a feel for the oil you use. Currently people are using as little as 3g/l naoh & 4.5g/l koh.
second stage, the base you use for the second stage dose not have to be the same as for stage one, as with the first stage start with 5g/l naoh & 7g/l koh, if you get a quick clear result from the drop out test consider reducing the second stage base on your next batch by 0.5g/l
what do you think?
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Happy to make it whatever you want of it Vince
But, I've had a few jars (not your infamous rocketfuel though!) so should be kept away from coding for at least this evening :)
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OK I've changed the 3/27 bit (on both titration and no-titration calculators) - is that easier to understand?
Will add text later.
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Link from wiki page to calculator added.
Just a thought ... could the calculator page loose the forum heading and have a "Back to wiki" button at the bottom? Might make it look more part of the wiki.
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Those pages are generated by the forum software so I think the forumy stuff is mandated by that. I'm sure there is a way but it won't be easy.
On the page itself the line in the description is clickable - though it doesn't show up any differently to normal text. I'll have a look at changing the link style so it stands out a bit more.
Edit: tweaked - the link is a little more obvious now.
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People seem to be ignoring the "adjust the amount" idea,a bit unfair saying the wiki is out of date
http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=32695
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Maybe rather than 80/20 split on the Meth the second stage should be 20% (or whatever the user configured) of the dropout amount?
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Made it down under
http://www.biofuelsforum.com/making_biodiesel/10461-no_titration_method_sodium_mehylate.html
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Famous worldwide, I'll roll out the red carpet 8)
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These comments have come up,is this something we (you Tony/Julian :) ) can do?
"Thanks for the great info. Will definitely try this when i get the chemicals. For anyone using methylates though what do you put in as the base on the site http://www.biopowered.co.uk/forum/tools/notitration.php shown earlier? Do you also leave the methoxide % at 20%?"
"in fact what we need is a calculator for the wiki where you put in your naoh or koh base you want to use and it gives you the methylate equivilant"
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Evening all do you have the methylate calc's or would you like me to send some over
Paul
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Would you mind Paul? If it's wanted we should add it.
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with 30% sodium methylate you times the base amount by 5
So First stage base of 4.5 = 22.5ml x volume , allow 70% of that to be meth so reduce you meth accordingly.
Second stage you can use a base of 4 = 20ml x un reacted oil
I will try and find info for other strength but 30% was the most common
Paul
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Presumably Methanol quantity is reduced accordingly, so for higher base amounts less pure Meth is required, as it comes for free with the Methylate?
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with 30% sodium methylate you times the base amount by 5
So First stage base of 4.5 = 22.5ml x volume , allow 70% of that to be meth so reduce you meth accordingly.
Second stage you can use a base of 4 = 20ml x un reacted oil
I will try and find info for other strength but 30% was the most common
Paul
According to a post by CountryPaul on VOD:
If you titrate it with 0.1% NaOH solution, the calculation is:
(((titration +base) x litres)/40*54)/30*100)/0.95
Given MW of NaoH = 40, NW of MeONa = 54, density of 30% sodium methylate = 0.95 http://www.kitchen-biodiesel.com/Methoxide_MSDS.pdf).
So using 100L at 1.5 titration as per James gives
((1.5+5) x 100)/40*54 = 2925g of 30% solution
2925g/0.95 = 3080ml (rounded)
Each litre of methylate also gives you only about 830ml of methanol.
The 30*100 term must be for 30% Methylate. Trouble is I guess the density changes with Methyate percentage so that would also need to be factored in somehow.
I can add it to the calculators but it may be slightly out for anything other than 30% as a result.
I'm not clear on how the 830ml of Methanol is derived either.
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I had that formulae on a big white board for a good few years. For the methanol I just alowed 70% of the methylate to be methanol. This isn't right but always worked ( I'm not a chemist I'm a bricklayer).
My moto keep it simple.
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Ah yes of course, sound pretty reasonable to me :)
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I use the same formula but with a base figure of 4.0 for both stages and 12% (of batch volume) methanol for each stage.
That is a figure I have arrived at empirically but it works very well (especially when using glyc wash first).
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On the second stage do you could do unreacted percentage of batch * 20% Meth?
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You could use 20% of the unreacted litres as methanol but that will leave quite an excess in the glycerol and biodiesel.
I have successfully used 12% on each stage though.
On a 300 litre batch it generally goes like...
Glyc wash with 45 litres of glyc from last batch. Stop, drain glyc, add 30 litres of methanol + 6 litres of methylate, mix for 45mins, take sample, stop and wait for an hour.
Then I measure dropout of the nicely settled sample (normally is around the 2.0l mark) and drain the first stage glycerol.
Then multiply the dropout ratio (ie 20% normally) by the remaining batch size once first stage is drained.
It is important to do it that way I feel rather than just assume the batch size remains unchanged since, depending on moisture content etc, the batch size at the start of stage 2 could vary up or down.
Assuming it was 2.0ml dropout and remains at 300 litres batch size, the unconverted litres value is 60. Therefore I would mix up 4.0X60X5 = 1200ml of methylate with 12% of 60 = 7.2 litres of methanol and suck that in with the venturi.
I then start taking 10/90 samples from around 20mins mixing onwards and keep going until I get a perfect pass. If it's not perfect after an hour of second stage mixing I know I have messed up somewhere so just stop, drain second stage glyc and do a third stage. It is very rare that I have had to do this though (generally it has been down to me being in a hurry and having wet oil or not letting the glyc wash separate for long enough)