Poor conversion

[willbuild]

Did a100ltr batch on Wednesday, High tit around 10, dried for 30 mins at 90c only half a ltr of water.
added glyc for pre wash and had to take off some oil after a few mins of washing because of foam coming out of vent. I put it down to having filled very close to its capacity and the temp was still high due to de watering. from then on i noticed a thin skin on the tops of the samples all the way through the process. left to cool then finshed the wash then drained.
Then 17ltrs meth and 1100grs of Noah 1st stage. 2nd stage 8ltrs of meth 400grs of Noah, 90 mins later i did a 10/90 testand had a 0.4 fall out so added 2ltr of meth and 150grs Noah 40 mins later a clear 3/27 pass.
added back the first stage glyc and dicided to de meth as i had used 27ltrs of which 7 was reclaimed.
I stopped de mething when i had recouped10ltrs did a 75 water wash, drained off the pipework and left overnight.
the next morning i drained of 70 ltrs of glyc leaving 45 litres of bio. was going away for a fewdays so left glyc in 20 ltr cubbies to see if any bio would separate.
Got back this afternoon (3 whole days)and took just under 10 litres of bio of the tops of the cubbies.
so at best am looking at 50% conversion.
Can wvo convert that low? or is there some trapped in glyc?

[Head Womble]

16.5g per liter is a hell of a lot of catalyst.
I'd say the oil was still wet (skin on samples) adding to the high titration this would reduce yield,
but 50% yield is still low.

[willbuild]

it is possible that i mistakenly used glyc that was wet instead of dry for the pre wash.

[Head Womble]

May be, may be not. Even dry gly is limited as to the amount of water it will remove.

[willbuild]

will leave the glyc aside for a few days and see if any bio separates.
but i have 45 lts of bio in processor, not enough to cover element so will remove do a small batch of around 70 lts, get it to around 90% conversion drain off the glyc then add in the 45lts +the 10 lts of bio that was on top of glyc., do a 10/90 test and dose according to result.
would it be a problem if i used potasium to process?
I have 40 lts of the same oil to which i will add 30 lts of a good oil. have used potasium on the same wvo on a previous batch with much better results in the past.

[Head Womble]

I see no problem in your plan, you can use whatever catalyst you like regardless of what has been used in the previous reaction.

[Rossey]

Is drying for 30mins at 90c long enough?

[willbuild]

Is drying for 30mins at 90c long enough?

Depends on how wet the wvo is.
Started a batch yesterday afternoon heated to 85c and left running till water stopped 2hours and 7lts of water. left overnght. when i got back from work drained 2ltrs offthe bottom (very thick and dark brown) and then did a hot pan test to be sure it was dry.
then heated to 55c and did a 1 hour glyc wash. I will now leave overnite, drain in the morning and do my first stage.

[BANDIT2]

I've always heated to 90 and dewatered overnight if I'm using wet oil.
Turn off heater when at 90 and just run the pump.
Doing this has never ever given me a crappy batch.
Did you do a HPT? [on the dried oil].
There are quicker ways I believe but I'm a fearful creature and like to play safe

[willbuild]

I see no problem in your plan, you can use whatever catalyst you like regardless of what has been used in the previous reaction.

after my first stage when i add in the bio from last batch, i will mix for 40 mins 1hour then do another 10/90 test. I'm thinking that there will be quite a bit of residue catalyst and meths in the bio

[willbuild]

I've always heated to 90 and dewatered overnight if I'm using wet oil.
Turn off heater when at 90 and just run the pump.
Doing this has never ever given me a crappy batch.
Did you do a HPT? [on the dried oil].
There are quicker ways I believe but I'm a fearful creature and like to play safe

Yes. after what happened on last batch I'm also taking the play safe approach