not reacting

[fourtrak Biofuels Forum Newbie Find all posts View Profile Close fourtrak]

hello, ive just join and was wanting to pick someones brains, i made a batch of bio yesterday, and i did everything as normal, i get my oil from the same place and it generally titrates between 0.8 and 1.8, but yesterday it titrated at 3.6, i thought that strange so done another titration and it came to 3.6, so i added the pottasium to the mathanol, i always do a 2 stage reaction so i added two 3rds of the methoxide to the oil and left it to mix for 1hr, as i always do, i returned to the shed 2hrs later to drain of the glycerine but it hadnt seperated, so my question is "why hasnt it seperated"
i rang the bloke who i get my methanol of and he said my sodium hydroxide will be out of date and given me a wrong titration, now initially i thought that was fesable because the titration was high at 3.6, but surely something would react wouldnt it? my next thought was, could it be the methanol as it was a new batch and i thought it smelled different from normal, abit harsher on the nose when smelling it,
so basically i want to know
1) could my sodium hydroxide be at fault?
2)could the methanol be at fault?
3)and how do i find out which is at fault?
4) what can i do to salvage the batch?
sorry for the questions guys its just im at a loss at what to do next

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: not reacting

How much KOH did you use per litre of oil?
The most likely cause of your problem was that you did not have enough KOH in the first stage.
I would add the rest of the methanol/KOH and see what happens.

[fourtrak Biofuels Forum Newbie Find all posts View Profile Close fourtrak]

Re: not reacting

when you say KOH i assume you mean pottasium, is that right?
i had 60litres of oil in the reactor and 12litres of meth in the side tank, the titration was 3.6 so i added the 3.6 to 3.5 =7.1, 7.1 x 1.7 =12.07, 12.07 x 60 = 724.3gs of potassium, mixed with 12litres of meth i then mixed 2, 3rds of the methoxide with the oil,
i assumed if the titration was wrong due to the sodium hydroxide being out of date and it gave me a high titration would that not mean i'd put too much pottasium into the methanol, making the methoxide a higher concentrate than i needed

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: not reacting

Yes, KOH= Potassium hydroxide
NaOH= Sodium hydroxide

when you say KOH i assume you mean pottasium, is that right?
i had 60litres of oil in the reactor and 12litres of meth in the side tank, the titration was 3.6 so i added the 3.6 to 3.5 =7.1,

That is your problem. When you use KOH as the catalyst you should use a base of 7g KOH per litre of WVO reacted, not 3.5. Considering most KOH is 90% purity that increases the Base amount of KOH to 7.7g per litre of oil reacted.
If you were actually using NaOH/sodium hydroxide in the titration you will need to multiply the titration number by about 1.5 which will take into account the difference in molecular weight between NaOH and KOH as well as the 90% purity of the KOH
That would make it about 5.4+ 7.7= 13.1g KOH per litre of oil reacted, not the the 7.1g you used.

If you were titrating with KOH and not NaOH that works out to about 3.6+ 7.7= 11.3g KOH per litre of oil reacted

[joe Moderator Find all posts View Profile Close joe]

Re: not reacting

there could be water in the oil.

[WesleyB Donating Member Find all posts View Profile Close WesleyB]

Re: not reacting

If the titrating NaOH fluid is at fault the titration number might be higher. With a NaOH titration number of 3.6 I figure you've made at least 3 3/4 pounds of potassium soap in your reaction mixture. The ffa's react quickly to make soap. If your oil has water in it then even more soap is produced. I buy factory made titrating fluid. Getting it exactly right is a big problem for me, so I just buy it ready made.

[fourtrak Biofuels Forum Newbie Find all posts View Profile Close fourtrak]

Re: not reacting

Yes, KOH= Potassium hydroxide
NaOH= Sodium hydroxide
That is your problem. When you use KOH as the catalyst you should use a base of 7g KOH per litre of WVO reacted, not 3.5. Considering most KOH is 90% purity that increases the Base amount of KOH to 7.7g per litre of oil reacted.
If you were actually using NaOH/sodium hydroxide in the titration you will need to multiply the titration number by about 1.5 which will take into account the difference in molecular weight between NaOH and KOH as well as the 90% purity of the KOH
That would make it about 5.4+ 7.7= 13.1g KOH per litre of oil reacted, not the the 7.1g you used.

If you were titrating with KOH and not NaOH that works out to about 3.6+ 7.7= 11.3g KOH per litre of oil reacted

when i started out i was using NaOH and i was told new oil titrates at 3.5 so if the wvo titrated at say 2.5, i had to add the 2.5 to the 3.5 =6. so that was 6g of NaOH per litre of wvo, but then i went onto using KOH, and was told once i had titrated it, i had to times it by 1.7 eg 2.5 + 3.5 =6, (then times the 6 by 1.7) 6 x 1.7= 10.2 so that was 10.2g of KOH per litre of the same wvo
could it be possible that the methanol isnt right, as everything i used except the meth was used last week and that reaction worked perfectly, im wanting to lean towards the meth as the problem but i could be wrong as i often am,

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: not reacting

Hi Fourtrack,
I missed the part where you multiplied by 1.7. I have never seen that before, but it comes pretty close.
Right now your problem is no seperation. If you make some excess soap you usually still get seperation.
If you have made lots of soap there is no solution to your problem.

I would still add the remaining 1/3 methanol/KOH and see what happens.
The worse that can happen is that you will not get seperation and you will have to throw everything away.

[WesleyB Donating Member Find all posts View Profile Close WesleyB]

Re: not reacting

I titrated new corn oil at 0.66 NaOH (Sodium Hydroxide).

[fourtrak Biofuels Forum Newbie Find all posts View Profile Close fourtrak]

Re: not reacting

i havnt made any soap, my only problem is,it hasnt seperated, it still looks like it did after the 1hr mixing period, could it be possible that the methanol is dodgey as i was talking to a bloke today that said, if ive been sold reclaimed methanol instead of 99.5% pure methanol there is a chance that it wouldnt seperate, the guy ive got to ask for advise is the guy who sells me the methanol so he probably wont want to admit the methanol is reclaimed if it is reclaimed, everything worked as it should last week when i used the remaining methanol from the last batch, im gonna ring him now to see what he says, cheers

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: not reacting

i havnt made any soap, my only problem is,it hasnt seperated

When you use KOH you do not see the soap. You see the no seperation

[fourtrak Biofuels Forum Newbie Find all posts View Profile Close fourtrak]

Re: not reacting

ive spoke to the guy and he said the mix probably wasnt strong enough, so he's advised me on putting another 300gms of KOH into the remaining amount of methoxide and mixing it up, which it is doing now, ill report back later, cheers

[fourtrak Biofuels Forum Newbie Find all posts View Profile Close fourtrak]

Re: not reacting

right folks this is what ive done
1 heated the mixture for 1hr
2 ph tested it, it was 10
3 added 300gms of KOH to the remaining 3rd of methoxide
4 mixed it with the diesel for 20mins
5 27/3 test, went cloudy, then clear with a rice crispy sized drop of oil
6 drained the glycerine out the bottom, of with there was 15 litres
7 ph tested again, was 10 again
8 added 150gms of KOH to 1.5litres of methanol and mixed it up
9 added this to the diesel and mixed for 15 mins
10 27/3 test again it was clear like whiskey with no droplet of oil
11 added 1.5litres of water to diesl and mixed for 2mins
12 left the heater on and of to bed, been told yhe water and the rest of the glycerine will drop out over night, so fingers crossed, and good night chaps or should i say good morning,lol, cheers steven

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: not reacting

Hi Steven, I am glad you have solved the problem I see there was not enough KOH in the first stage. As I recall someone had mentioned that as the most likely problem earlier in the thread.

right folks this is what ive done
1 heated the mixture for 1hr
2 ph tested it, it was 10

pH testing tells you nothing important here.

3 added 300gms of KOH to the remaining 3rd of methoxide
4 mixed it with the diesel for 20mins

Personally I would have just added the remaining Methoxide and observed what happened.
20 min mixing is not nearly enough time for most reactors. A minimum mixing of at least an hour is my recommendation if you are trying to pass 3/27.

12 left the heater on and of to bed, been told yhe water and the rest of the glycerine will drop out over night, so fingers crossed, and good night chaps or should i say good morning,lol, cheers steven

Leaving the heater on overnight is not a good idea.

[fourtrak Biofuels Forum Newbie Find all posts View Profile Close fourtrak]

Re: not reacting

Hi Steven, I am glad you have solved the problem I see there was not enough KOH in the first stage. As I recall someone had mentioned that as the most likely problem earlier in the thread.pH testing tells you nothing important here.
Personally I would have just added the remaining Methoxide and observed what happened.
20 min mixing is not nearly enough time for most reactors. A minimum mixing of at least an hour is my recommendation if you are trying to pass 3/27.
Leaving the heater on overnight is not a good idea.

hi tilly
1 i was told to ph it and if it the ph was 10 it ment all the KOH had been used up,
2 i agree, i thought mixing for 1 hr wouldve been better than 20mins
3.i thought leaving the heater on would help the glycerine to drop out thats why i left it on
anyhow i drain the remaining glycerine off this morning, neutralised it and washed it, gonna dry it later after work, cheers
also, do i need to change my sodium hydroxide solution for titration, is that whats been the cause of this, thanks steven