Hi everyone, I have over the last few days firstly made up 5 trial batches using naoh from 4g -8g per litre of wvo, the 6,7 & 8 all took 72 hrs to clear and all seemed to make very clear bd with varying grades of soild glycerine on the bottom of the jars. Is this normal to take this long to clear and also they clear during the middle of the day then cloud slightly overnight. Also yesterday tried the titration method now using koh, used the titration method from Tilly , after adding one ml of titration fluid to the alcohol, phenol red and 1ml of wvo it turned pink and stayed that way but 2 mls did seem to make the pink stronger, so I tried another 500ml test with 4.5g of koh and 28hrs later still cloudy but good separation has occurred. What do you think? Sorry to ask such a long question . Cheers
Mark.

your doing fine. now just go make a 200l batch.

Ok so you have good seperation.

Next step is to try washing it. I would not be conserned about how clear it is or is not until after you have washed it as the cloudiness will wash out.

After washing and drying it should be sparkling clean.

Mark,
Are your test batches stored indoors where it is warm or outside and experiencing the range of temperatures day and night?

If the latter, this will affect settling time as the biodiesel viscosity will rise when it is cold. Biodiesel can take a long time to clear, but when methanol removal or washing are done, the biodiesel is cleared by these processes allowing the separation of the by-product or removal of it with the water.
Obviously, water washing then requires the biodiesel to be dried afterwards.

If you are using NaOH as your caustic, you will get solid By-product. If you use KOH you will generally get a liquid by-product

Is your oil liquid at room temperature? If not, overnight temperatures of 5-10°C and lower can cause it to cloud due to solidification of the higher melting point methyl esters in the biodiesel.

I hope this helps,
Tony

Hi Tony, the test batches are in a workshop , but the temp in there overnight would not be much warmer than outside , night temps on the Gold Coast at the present would be around 15 c , . I changed to koh because of the solids on the bottom and reading a post that naoh blocked up the pump, I didnt want that to happen and like I found out the koh mixes much easier and better than the naoh.