Deliberately adding water to feedstock (pre-drying)

[julianf]

Ive been intending to try this for a while.

My drying method is -

Load feedstock
Heat to 65c
Settle out free water
Load glyc
etc.


If ive ever had tins that have been rained on, the free water seems to settle out without issues.

So, today, after loading up the reactor with some rancid kebab oil that ive had sitting about here for far too long, i added about 20ltrs to 150ltrs of feedstock.

Its still heating at present, but, what im hoping is that, all those little scraps of meat etc. that have found their way through the course filter, will migrate to the water layer on settling.


I know the glyc wash does the same - im really just trying another simple addition to try and get the scraps out prior.  Who knows if it will make any difference.  Possibly no benefit over just using the glyc.

[Tony]

Interesting idea and worth a shot.  I take it you are not mixing, as such, just hoping the crap will fall out of the oil into the water for draining?

[julianf]

Ive got an inline heater, so its being well mixed.

I plan to get it to (hot - pid is set to 85c, but im not going to be up that late tonight) and then ill just let it settle over night.

Sure, its an emulsion now, but ive never had a situation where ive poured a wet tin in, and its not settled out again, so will see.

There's a load of kebab oil / whites etc. and then 20ltrs of palm also.  So, if its going to go wrong, this will be the one!

[julianf]

Was at 75c when I shut it down.

Will check it in the morning if I'm feeling brave.  Smells pretty grim.

[Glycer-rides]

Yes, will be interesting.

I'd have tried it first cold and without without mixing.
Just add water...
The water sinking may take the solids down with it.

[oakwoodtv]

I was going to try something similar but from a different starting point have 400 litres of dregs / whites from the bottom
of 60 plus cubes had to melt the fat by in the bottom by standing them the Burco boiler plus some bottoms from 60 and 120 ltr
drums.

This was all decanted in to clean 25ltr drums and has settled out with between 5 to 20 % water in the bottom the plan is to
fill the reactor to the brim heat to 80 deg C stand over night drain of the free water top up with good oil and process as
normal what could possibly go wrong.

At least I will have 100 litres of something that will burn in the M67 at the BBB.           

[Julian]

I've been doing this inadvertently for many years.

I try to get the feed stock as clean as possible before putting it in the reactor.  My routine is to pump, or if I've had my Wheetabix, pour the good oil off the top of stabbed tins, leaving about 5ltrs in the bottom or to the point where I see water.  This is filtered into the first settling tank via a landscaping fabric sock filter.

The balance gets dumped into my "slops" tank (the one that's no an old gas cylinder) via a gauze filter to catch BCBs, and any free water drained via a valve in the bottom.  Mostly the water is a fairly clean brownish colour.  When the slops tank is full I turn the heater on ... think it's set to about 65ºC and let it stew for a while.  I then leave it to settle for a week or so when reasonable oil from the top can be pumped to the first settling tank.

What's left comprises more free water evolved by stewing and pretty manky oil.  I don't add any aditional water.  However, most times there's a phase between the two of water mixed with a sludge of fine food particles and very little oil.  I think it's this scenario for which you are looking.  It works but it takes a long time for the settling and separation to take place ... might work better with added water.  I'll be interesting to hear your results.

[oakwoodtv]

Am in the process of moving the plant in to the dedicated bio building started the move today hope to start brewing towards
the end of next week if everything goes to plan which may happen if things don't go base over apex.     

[dgs]

The only problem I can see with this is it is all very well for these nasty bits and pieces to sink to the bottom of oil, but if they arn't heavier than water they will stay at the interface of the two liquids.

I'm sure I arn't the first one to notice the bcb's etc that float on top of the glycerol after a pre-wash. When I didn't filter things as well as I do now I could always tell when I was getting to the end of the glycerol by the bits and pieces coming out.

Interesting though, I hope it works.

[julianf]

What would be them most interesting, not that im going to try it, is -


As mentioned, any free water always comes out brown.

I wonder what it would look like on the 2nd wash / settle.


Ie does it remove all that its going to remove in one pass, or does it continue removing 'stuff' thereafter?

And, yes, i too have seen the interface layer.  Im sure we all drain down below it to the clear above?

[julianf]

Initial results seem good.

I (intentionally) put in the 20ltrs, and drained about 40...

Points of interest -

Surprisingly, the water initially ran clear, then clouded up, but what was great was that the change to oil (the interface) was very defined.

I did not get that gloopy layer, which is mainly oil and bits.  Instead i got clear water, bitty water (but still nicely free flowing) and then an instant change to clear oil.

Again, none of that sludgey bitty emulsion layer - free flowing water direct to clear oil.


Im not going to be able to give any further results on this batch, as im adding a mix of other oils to it, so any results wont be in any way quantified.

I do think, however, that i will try this again, and possibly do it as standard if nothing negative arises.

[dgs]

You could always go one step further Julian and add a calculated amount of catalyst to the water to neutralise any FFA's. As long as you then got the resultant oil dry it should process as new oil ie. only having to add base quantitys of catalyst.

This method as per lojiuks' original then used glycerol to remove the cruddy water before drying.

[julianf]

I did  consider that, but was unsure which would happen in preference - sapponification, or neutralisation.

If saponification happened to much extent then the soaps produced would cause the water and oil to emulsify like crazy.

[dgs]

That is true.

Using the caustic stripping method as posted by IMB on infopop there is a time constraint that has to be adhered to, this avoids saponification to the greater extent.

I will see if I can post a link.

EDIT There are various refrences to the recipe in this long thread, one is on page 8 post No 13.

http://biodiesel.infopop.cc/eve/forums/a/tpc/f/5367078823/m/3897002473/p/8

[oakwoodtv]

The plant move has been done required a fair bit of re piping not with out some profanity's.

The first batch with the very wet sloppy whites went surprisingly well loading the reactor with to the brim
with the 25ltr drums of oil whites water the lot heated to 60C left over night and drained the water of the
next morning it was black and full of burnt food partials.

A glycerine wash followed by my normal first stage methoxide  gave a 3.2ml drop-out not to much more
than my normal 2.8 to 3ml drop out.

Second lot of this crap in the reactor now heated to 65C leaving over night will drain and process tomorrow

Heating poor feedstock with water seems to remove food partials and give you a good start on the first
stage.