first batch , need advice,
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The only thing that gets adjusted for purity is the base amount.. For 90% Purity KOH your base amount should be 8. (7.8 actually but just round up.. in this case, more is better)
You DO NOT factor in the 90% when titrating.. The titration solution you make from the same catalyst will factor itself.. No need for more factoring..
Just titrate as normal, use 8g/l as your base and you'll be fine.
This is the CORRECT way to do it.
You DO NOT factor in the 90% when titrating.. The titration solution you make from the same catalyst will factor itself.. No need for more factoring..
Just titrate as normal, use 8g/l as your base and you'll be fine.
This is the CORRECT way to do it.
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The method Murphy2000 posted is certainly the easiest way to set up a batch. There are a couple handy calculators at http://www.biodieselcommunity.org/recipecalculator/ that make calculations quick
It is possible the small amount of KOH removed to make the titration solution may not be at the same purity as the bulk of that batch of KOH, so you could get a solution that does not give the best titration results. Probably not something to worry about, but a factor to consider if you start having trouble with batches after making a new titration solution
I go a different route as I prefer to have all my titrations accurately relate to the oil for record keeping and later comparison. Using KOH with a variable purity would give me a different titration of the same oil every time I get a new batch of catalyst. Of course after determining the purity of the catalyst I could adjust the titration value too, it just isn't the way I like to do it.
It is possible the small amount of KOH removed to make the titration solution may not be at the same purity as the bulk of that batch of KOH, so you could get a solution that does not give the best titration results. Probably not something to worry about, but a factor to consider if you start having trouble with batches after making a new titration solution
I go a different route as I prefer to have all my titrations accurately relate to the oil for record keeping and later comparison. Using KOH with a variable purity would give me a different titration of the same oil every time I get a new batch of catalyst. Of course after determining the purity of the catalyst I could adjust the titration value too, it just isn't the way I like to do it.
Last edited by JOAT; Apr 21, 2007 at 06:41 PM.
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Originally Posted by JOAT
The method Murphy2000 posted is certainly the easiest way to set up a batch. There are a couple handy calculators at http://www.biodieselcommunity.org/recipecalculator/ that make calculations quick
It is possible the small amount of KOH removed to make the titration solution may not be at the same purity as the bulk of that batch of KOH, so you could get a solution that does not give the best titration results. Probably not something to worry about, but a factor to consider if you start having trouble with batches after making a new titration solution
I go a different route as I prefer to have all my titrations accurately relate to the oil for record keeping and later comparison. Using KOH with a variable purity would give me a different titration of the same oil every time I get a new batch of catalyst. Of course after determining the purity of the catalyst I could adjust the titration value too, it just isn't the way I like to do it.
You can forget all about anything having to do with purity.. don't even think about it.. Just remember that base is 7 grams KOH @ 100% or 8 grams @90% and forget about the rest.
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Originally Posted by Murphy2000
You can forget all about anything having to do with purity.. don't even think about it.. Just remember that base is 7 grams KOH @ 100% or 8 grams @90% and forget about the rest.
And do you have a recommended method for determining that it's really 90%?
KOH usually is sold in a range, not a specific purity. At least the stuff most of us buys is. The KOH from hill chemical can range from 84.5% to 90.5% from the factory per the MSDS, with the rest being water.
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Originally Posted by JOAT
If you recommend forgetting about anything having to do with purity then why would you say adjust the base to 8 grams for 90% purity? Just curious.
And do you have a recommended method for determining that it's really 90%?
KOH usually is sold in a range, not a specific purity. At least the stuff most of us buys is. The KOH from hill chemical can range from 84.5% to 90.5% from the factory per the MSDS, with the rest being water.
And do you have a recommended method for determining that it's really 90%?
KOH usually is sold in a range, not a specific purity. At least the stuff most of us buys is. The KOH from hill chemical can range from 84.5% to 90.5% from the factory per the MSDS, with the rest being water.
As for the purity.. I buy a bag a week and i've never seen anything other than 90%.. or 90.4 or something like that.. My msds sheets say the same thing about the range.
Some koh is sold at 100%.. (or something like 98 or 99) very high purity.. Its used for some common purpose but I can't remember what.. Leather or something..
As for titrating, there is no need to adjust for purity at all.. your titration number will already be adjusted on its own.
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No real necessity, but I would like to see an easy test of purity just so when someone posts they cant get any batches to work, there would be a way to be sure they didn't have low purity KOH messing things up.
Leather tanning uses a fairly high purity, but they charge extra for it. Braintan has an online store with it. You can use high purity lab grade stuff to titrate, then use your process stuff for titration, and compare the results to get a percentage. I'd like to find a more scientific way that is easy to set up and explain. It can be done by neutralizing a KOH water mix with sulfuric acid of known purity. But the chemistry of that is a bit difficult to explain, (or at least for me anyway
. And being sure your acid is pure enough, and way to test PH is accurate enough, and were back to confusing everyone.
Leather tanning uses a fairly high purity, but they charge extra for it. Braintan has an online store with it. You can use high purity lab grade stuff to titrate, then use your process stuff for titration, and compare the results to get a percentage. I'd like to find a more scientific way that is easy to set up and explain. It can be done by neutralizing a KOH water mix with sulfuric acid of known purity. But the chemistry of that is a bit difficult to explain, (or at least for me anyway
. And being sure your acid is pure enough, and way to test PH is accurate enough, and were back to confusing everyone.
Last edited by JOAT; Apr 22, 2007 at 09:13 PM.
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Originally Posted by JOAT
No real necessity, but I would like to see an easy test of purity just so when someone posts they cant get any batches to work, there would be a way to be sure they didn't have low purity KOH messing things up.
Leather tanning uses a fairly high purity, but they charge extra for it. Braintan has an online store with it. You can use high purity lab grade stuff to titrate, then use your process stuff for titration, and compare the results to get a percentage. I'd like to find a more scientific way that is easy to set up and explain. It can be done by neutralizing a KOH water mix with sulfuric acid of known purity. But the chemistry of that is a bit difficult to explain, (or at least for me anyway. And being sure your acid is pure enough, and way to test PH is accurate enough, and were back to confusing everyone.
Leather tanning uses a fairly high purity, but they charge extra for it. Braintan has an online store with it. You can use high purity lab grade stuff to titrate, then use your process stuff for titration, and compare the results to get a percentage. I'd like to find a more scientific way that is easy to set up and explain. It can be done by neutralizing a KOH water mix with sulfuric acid of known purity. But the chemistry of that is a bit difficult to explain, (or at least for me anyway
. And being sure your acid is pure enough, and way to test PH is accurate enough, and were back to confusing everyone.Another way to check your catalyst is to make a 1 Liter test batch using brand new oil.
Its like algebra ! Just eliminate the "other" side to get the answer..
90% of the beginner confusion or problems I see are related to the basic titration.
It always comes down to Time, Temperature, and Concentration in almost all chemical processing. Its like the three "L's" of realestate.
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