de-meth and water wash

[bertle]

Thought I would post this on here, (put it on vod last night) for you lot to see if you don't visit the other side.....

I have, after 6 years, stepped into the dark side and done my first ever water wash, but with a bit of a difference.
I have not been happy lately with the soap content of my bio taking ages to settle and the bottom bit never clearing as it should. Most of the reason for this I suspect is my sodium is quite old and has become less effective thus I am using more per batch resulting in over soapy bio.
I have no mains water near my processor so mist washing is not easy to set up. I have been looking at acid washing but don't have the titration kit needed. So I made my batch as normal then de-methed blowing air through a sparge tube venting to atmosphere, (about an hour), same as normal, then I chucked 20L of water in and turned the pump on for an hour or so. I left to settle over night drained and did another 20L, left to settle for 5 or six hours, drained and another 20L, and left to settle overnight. Today I draind some quite clear looking water and warmed the batch back up to dry with the sparge tube.
Tonight I seam to have 170L (from a 180L batch) of good clean and dry bio. I will let it settle for a couple of days for good measure and that should be that.
I guess that was a success then?

[Julian]

Welcome to "Water World".

Do try acid washing, I think you'll be impressed.  If you have a soap test kit, you can use the indicator solution from that.  If not try simply adding a guesstimate.  I use about 20 ml of conc. sulfuric for an 80 ltr batch.

From experience (pH testing subsequent washes) and from discussions with a mate who's a PhD in chemistry, you can't end up with aqueously acidic bio provided you dry it thoroughly.

I only pump wash for around 10 minuets, an hour seems an awful long time to me.

Take care demething with a sparge pipe.  I tried that method with a low capacity compressor for a while but had problems with contaminated methanol and wet oil when ambient humidity was high.

[bertle]

I don't have a soap test kit so no means of titrating. I did consider getting some vinegar but was unsure how much to try. The sparge tube is supplied with dried air from our works ring main. Also I just vent the meth to atmosphere so not worried about that, also I don't use it to dry the oil, maybe I should, although I did use it to dry the washed bio. At the moment I heat and settle then glyc wash to dry the feedstock.

[Tony]

I know it seems counter intuitive but have you tried agitating a settling batch?

I find that mixing the thing up again often helps accelerate the settling - suspect all the larger soap clumps falling through the mix take the smaller ones with them on the way down.