Loads of foam never had this before

[Dickjotec]

A new experience today
Normal no tit two stage
150l.  25l 900g NaOH. - 5l and 200g
Normal pass
Demeth bio only

Transferred some nice looking bio to the settling tank then the pump started pumping white foam! There was loads of very small bubble white foam. It is in a cubie and seems to be turning back to bio. Never had that before.

[Tony]

Maybe a detergent in with the oil?  Is it from a usual source?

[Dickjotec]

Maybe a detergent in with the oil?  Is it from a usual source?

It was not my normal source and it was fairly manky so it could have had anything in it. Be interesting to see what the foam looks like tomorrow.

[Head Womble]

In the past I found that I got foam on top of the settling drum if the batch was quite soapy and there wasn't much meths left in the bio.

[Julian]

I used to get foam every so often whilst processing in my early days of making bio.  Usually when demething.  Some times it was so bad that I had foam coming out of the vent!  I've no idea what caused it and even commercial anti foam agents wouldn't prevent it.

Luckily I haven't experienced it for years now.

[Glycer-rides]

6 g/l on stage one?
Is that normal for you?

[Dickjotec]

6 g/l on stage one?
Is that normal for you?

That is what I usually use with no problems, it is old NaOH though.

Most of the foam had gone this am the rest had coalesced into soap. Still floating so I fished it out with a sieve.

[Jamesrl]

6 g/l on stage one?
Is that normal for you?

I'm with you on that one Glyc, that's an awful lot of NaOH & meth for a 150ltr batch 1st stage.

I'd be looking at a max of 4g/ltr and no more than 22.5lt of meth. and would expect around an 85% conversion.

I never use more than 3g/ltr and 15% meth for stage 2.

The more catalyst you use the more water you generate the more soap you get.

[Glycer-rides]

I've just half done a batch @ 3.5 g/l and 16%.
Usually works OK. Until one uses watery meth and leaves over night = solid caramel soap in pipework.
Feeling non-titless now.

[Dickjotec]

I hear what you say re meth etc but I often get away with single stage using the higher amount. Non of our vehicles need a perfect 10/90 so if it works on one stage I spend less time on it.
I will try a 3.5 and 16% next time.

[Jamesrl]

I hear what you say re meth etc but I often get away with single stage using the higher amount. Non of our vehicles need a perfect 10/90 so if it works on one stage I spend less time on it.
I will try a 3.5 and 16% next time.

If you don't have to have a full 10/90 why not just go for a single stage 80/90% and be done with it and save money on chemicals.

[Dickjotec]

I hear what you say re meth etc but I often get away with single stage using the higher amount. Non of our vehicles need a perfect 10/90 so if it works on one stage I spend less time on it.
I will try a 3.5 and 16% next time.

If you don't have to have a full 10/90 why not just go for a single stage 80/90% and be done with it and save money on chemicals.

I often do but sometimes do a second stage if it is cold or the first conversion is not good. With my usual oil in summer it is fine with 25l and 900 NaOH.
This oil was whites that I was donated plus some dregs from other drums. It was wet and my usual drying system got load of water out but probably not all of it. Only 20l of the meth was Virgin the rest reclaimed but I don't do a wash before demething.