First time -no separation

[Blacksmith Junior Member Find all posts View Profile Close Blacksmith]

Tried my first mix, 200 litres of oil. titration worked out to 1600 gms koh in 40 litres methanol. mixed it for an hour at 50 degrees but no separation.
Did another test on the mixture in processor and it looks like I was to hasty with the first titration.
The new titration calls for 1800 gms koh.
Question is -- can I restart the reaction?
A friend suggestion I just treat it as a new mix but do I need to add another 40 litres of methanol or do I use a small amount of methanol with 1800 grams of koh?
Any help would be much appreciated.

[Geoff Junior Member Find all posts View Profile Close Geoff]

Re: First time -no separation

The "Standard" Reprocess is 1g NaOH/ 1.4g KOH mixed into 50ml methanol for each litre of washed and dried biodiesel in the reaction and 1g NaOH/ 1.4g KOH mixed into 35ml methanol if the biodiesel is unwashed. I've used this formula and it has worked for me. If you search under REPROCESSING you should find enough advice to work thru you problems.
Geoff

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

Re: First time -no separation

Before you rush out and start reprocessing it would be a good idea to draw off a quantity of the processed oil to work with.

Do 1 litre test batches with increasing quantities of NaOH/KOH until you get seperation.

We might be able to be more helpful if you gave more information, like what number your oil titrated to.

Titrating your oil now WILL NOT give you any useful information. You have added KOH to it so the titration point has been changed. If you had more of the same oil that has not been used in this reaction you can try titrating that.

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: First time -no separation

What was the actual titration in mL was and what was the catalyst amount (base amount for some), in g/L

This may help us find out why it did not work.

You are very foolhardy doing your first batch on 200L of oil.
It would have been prudent to do several test batches first, to verify your amounts of KOH.

Was the oil dried?
Have you done a HPT on the oil to verify it is dry?

I support the suggestion that you take several 1L batches and trial your reprocessing on them.

You can titrate the batch and see if you need any titrating fluid to neutralise any remaining FFA.
If you do, then you need to add the titration amount plus the catalyst amount times 1 (for 1L batch). If this batch works fine, you should be able to upscale the process.

If your titration indicator changes colour at the first drop of titrating fluid then you should reprocess as per the recipe given above.

As before, use a 1 L batch to verify the reprocessing quantities. It would be no good if you added the KOH and turned it all into Soap, would it?

It would be useful for you to do a number of 1L batches in either case, using slightly more and less (+/- 1 & 2g/L) catalyst than indicated, to verify the optimal amount to use.

Good luck with your recovery.

Tony

[Blacksmith Junior Member Find all posts View Profile Close Blacksmith]

Re: First time -no separation

Before you rush out and start reprocessing it would be a good idea to draw off a quantity of the processed oil to work with.

Do 1 litre test batches with increasing quantities of NaOH/KOH until you get seperation.

We might be able to be more helpful if you gave more information, like what number your oil titrated to.

Titrating your oil now WILL NOT give you any useful information. You have added KOH to it so the titration point has been changed. If you had more of the same oil that has not been used in this reaction you can try titrating that.

Thank you Qwarla

Titrated at 1ml.
I still have some of the same oil. I'll do a titration tomorrow and post it on the forum.
I'll try a test batch and see what results I get with that.
As there is already the correct amount of methanol in the mixture not sure how much more to add.

Just as a matter of interest, what does happen if you mix in too much methanol, say 50 litres when it should be 40 ?

[Blacksmith Junior Member Find all posts View Profile Close Blacksmith]

Re: First time -no separation

Tony. Changed colour with 1 ml of titrating fluid. I used a base of 7 g/L

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: First time -no separation

Has the batch remained sealed to prevent methanol evaporation?
Please give more information on your technique,
Oil temperature,
Mixing method ,
Mixing Duration.

Was oil tested for water? Even a little bit of water can increase the amount of caustic needed for a good reaction.

Reprocess using a 1L sample with 1g/50mL per litre of batch, to verify the reprocessing works.
You could also do it with 1.5 and 2g/L/50 mL methanol to give an idea where the best conversion happens.

Keep up the good work,

Tony

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

Re: First time -no separation

Just as a matter of interest, what does happen if you mix in too much methanol, say 50 litres when it should be 40 ?

If you add extra mathonal that is not a problem except for the fact it is wasted. It will not hurt the reaction.

To reprocess test batches you will need a small quantity of methanol to dissolve the KOH. 50 ml or so will do the trick.

Provide your titration was correct, the quantities you stated in your first post seem correct. Titration is one area of great debate.

Here is a site that should give you some more insight into making bio. I suggest you bookmark it and spend some time reading through it.
It gives info on using tumeric as the indicator.

What are you using for your indicator? The other problem area is the mixing of the titration fluid. Measuring out 1 gram of KOH to add to 1 litre of water is almost impossible without a very good set of scales that read to one or two decimal places.

[Blacksmith Junior Member Find all posts View Profile Close Blacksmith]

Success __ then disaster.

Mixed a test batch of the original oil using 9 gms of koh instead of 8.
Separated beautifully.
Then heated oil in processor and started pump to mix oil.
After 15 mins pump changed note turned it off as it was hot then noticed the oil had turned black.
I'm 99.9% sure the impellers in the pump are rubber which have partially dissolved and jammed the pump, instead of the stainless steel they are meant to be.
On the plus side I've finally made some biodiesel (even if only 1L) and I will not be making the next batch until I've done a trial mix.

Thank you all for your help