Hi everyone;
Does anyone know what happens when KOH loses its efficacy?? I made a 1litre test batch last night with oil I've used before and NOTHING happened! I titrated twice (same number as before!), and redid the Dr. Pepper batch. What happens is; it appears to start to mix then 'smoothes' out i.e. takes on the viscosity of biodiesel but NO glycerine falls out!
Is this what happens when the KOH no longer works??
I am SURE I used the correct amount as this is the same oil I made 20 litres with a few weeks ago (which turned out fine.).

I also made another 40 litres today with brand new KOH and separation was almost immediate.
Just wonder if my old KOH got too much moisture in it?? (It's been very humid here lately and I've since moved my new stuff into the house in the same room with the dehumidifier and also in a sealed chlorine pail ).

Anyway, just wondering if that's what happened.
Thanks!

Hello VWScully

In my experience water in th reaction will do that

I would think if it were stored in a airtight container and was not clumped together it would be ok. The clumping would indicate moisture got to it.

hmmmmmmm wierd! I don't think there was any water in it!? I used a dry bottle and the KOH was not clumped up. It's also the same oil I used last week.
How odd
I didn't heat it up though (well, I left it in the sun before I put the methoxide in so it got a *bit* warm ), but maybe I'll try it again with heating it and see what happens.

It's just odd that I used the same oil last week (in the SAME way) and it's stored in a sealed drum, and then this week my test batch gives me no reaction!?
The plot thickens! .

btw, Tilly; I would have thought that water in the reaction would give me glop??

Hello VWScully

That was not my experience.
The very first litre of biodiesel I tried to make using KOH did exactly what you describe.
I was using tallow and the tallow was hard. I put it in a pan to heat it and some water went into the pan as well.
I am sure I was a bit careless taking the oil out of the pan and included some water in the reaction.
When I shook the reaction it looked great but NOTHING happened.

So is there a good way to remove the water? Sounds like it is in suspension and not likely to fall out over time. Is flash evaporation a candidate or might any unreacted methanol explode in a preheater on the way thru?

I have about two gallons of what VWScully is describing. From two batches where I acid-esterified and did not draw off enough water before moving to base stage (titration was very high; 36 with KOH).

Maybe it's just weed killer.

Horn

Well, if that's the case, then the mystery becomes; how the heck did any water get in there?!!?
The only other thing it *may* be is that I was getting close to the bottom of my oil-storage barrel and I don't usually use the bottom 6" or so cuz the water/crap/icky stuff tends to fall to the bottom.
I may have inadvertently scooped up some water from there??

However, the 40 litres I made today sure looks good . (of course that was heated to 130'F in the Appleseed too though prior to processing.).

well, the wierdness continues.................

Tilly,
What percentage would the water have to account for in order to kill the reaction? I'm wondering how much water you need to have in your oil before you run into this sort of problem.

I made a test batch that I knew had a small amount of water in it the other day (started popping a little around 120*) and while I needed an extra wash or two, I came away with a good end product (separated after a vigorous wash in five or ten minutes, leaving gin clear water).

Sounds to me like he must have had a good amount of water...but that's just a WAG.

Hello Progun

I have not actually done many tests with adding water. I know 95%methanol/5% water works ok.