New oil, Titrate??? I'm a newbee, Please don't judge.

[mrbearuk]

Hi, I've been thinking of making biodiesel for a while, I made a test run last year without success.
This time I am trying new clean sunflower oil instead of WVO. I've bought 15ltrs but only processing 5ltr at a time.
The first 5ltr batch I used 1ltr of methanol and 35 grams of KOH taking 7g as a base amount, Heated to 55c 130f added the methoxide and shook for 5 min and left to stand overnight. Following morning it looked alright so I drained off the biodiesel to get ready for the wash, I misted in about 500ml of hot water to the biodiesel and it turned into a white milky state.
  Following day I drained the water, rewashed but it just stayed this milky state.

  The 2nd 5ltr batch I did the same thing but without washing it, was too scared lol. I tested a sample of the biodiesel with half-strength methoxide to see what would happen and found about another 2.5% glycerol came out of solution.

Does New oil need titrating? Am I using the right mix?
Please help.

[dgs]

Hi there mrbearuk and welcome to the forum. Titration is really a thing of the past. Most on here do a 2 stage process and do a 10/90 dropout test after stage 1 to calculate the amount of oil to convert during stage 2.

New oil does actually titrate but only slightly, however even for new oil you need to use a base amount of KOH of 8gms/litre meaning you should have added another 5gms to your process.

Most don't water wash nowadays, it is an aquired technique and its maybe best to leave that until you havs a tighter grasp of the process. Just de-meth by bubbling and settle the bio, you can use hardwood chips to remove any residual soap.

I would assume as you under reacted your batch the unconverted intermediates (call them somewhere between oil and bio) caused your emulsion.

Have a look at the wiki here at the 2 stage process; http://www.biopowered.co.uk/wiki/Vegetable_oil_and_Biodiesel_wiki

[Tony]

Totally agree, you did everything right but ended up with an emulsion because the reaction didn't 100% complete, leaving you with the same components used to make actual mayonnaise (monoglycerides!)

With clean, dry oil there is little harm in using excess KOH, so don't worry about 10g per litre, or even 12.

Don't be disheartened, we all did this.  Except in my case it was 100l of gunge because I didn't experiment with 5l at a time first... so you're already ahead of me for being sensible.

[mrbearuk]

Thank you for those kind comments.
Over the last 2 days the white "emulsion" you called it has been sat on a 10Watt vivarium heat mat with a bubbler inside and it has gone back to an oily state. So should I do another methoxide cycle to completely transform the oil into biodiesel?
Thank you for your advice.

[Tony]

So should I do another methoxide cycle to completely transform the oil into biodiesel?

Yes, absolutely.  Then you'll have done the "two-stage" technique just with an unexpected wash in the middle.

It can be quite hard at the best of times to get the reaction to complete in a single stage.  If you make up the methoxide and use 80% of it to do a reaction, drain the glycerol, and then use the remaining 20% to react again (and drain the smaller amount of glycerol the second stage produces) it's more likely to complete the reaction successfully - which is essentially what you're planning on doing.

You'll notice the second stage glycerol is a lot lighter and runny, and a lot less of it.

But you're already getting into the advanced stuff with this.

[mrbearuk]

Thanks again for the advice.
I've been reading the page link that DGS posted, It's been very interesting, I've learned a lot.

Thank you.