Water washing with acid - reverting soaps to FFAs - any issues?

[julianf]

My issue is that, no matter how long i demeth / settle etc. for, there's always some brown scum in the filter of the car, which i dont think is great (even though ive seen no ill effects from it)

So, Im considering water washing with acids - i know lots of people do this.

My question, however, is -

The acid is added so as an emulsion is not formed.  Im assuming what this is actually doing is converting the water soluable soaps into non-soluable FFAs, which, again i assume, are then soluable in the bio, and stay with the fuel.

I think this is the same sort of result that you would get from an ion exchange tower.

Given that most things have pros and cons, can anyone see any issue with this? 

I know that running a boiler on straight FFAs is not simple, which got me thinking...

[Tony]

Some of it is covered here:

http://www.biopowered.co.uk/wiki/Effect_of_biodiesel_on_fuel_injection_systems#Biodiesel_and_impurities

But IIRC countrypaul was running vehicles on high concentrations of FFA?

[julesandtash]

Salt seems to be all the rage at the moment for assisted water washing. Although I haven't tried it yet, I am tempted when I run out of Sulphuric acid.

[dgs]

My issue is that, no matter how long i demeth / settle etc. for, there's always some brown scum in the filter of the car, which i dont think is great (even though ive seen no ill effects from it)

So, Im considering water washing with acids - i know lots of people do this.

My question, however, is -

The acid is added so as an emulsion is not formed.  Im assuming what this is actually doing is converting the water soluable soaps into non-soluable FFAs, which, again i assume, are then soluable in the bio, and stay with the fuel.

I think this is the same sort of result that you would get from an ion exchange tower.

Given that most things have pros and cons, can anyone see any issue with this? 

I know that running a boiler on straight FFAs is not simple, which got me thinking...

High compression 2 made an interesting comment recently, which was if the acid is added before de-mething and at temperature, the FFA's formed will be converted to methyl esters because of the residual chemicals left in the mix.

I have heared others talk about the effect you describe, both in filters and at the bottom of tanks. I'm pretty sure this is glycerol, a very small amount left in suspension, then eventually settling or being filtered out. This can also happen if water washing in a meek and mild way (misting or a mild bubble wash) and this is the reason why I water wash very aggressively. I have cut my filters open/inspected them after 12 to 15000 miles and they are very clean.

As to the long term effects of FFA's in fuel, who knows, but the link that Tony put up doesn't look too good.

I would love to stop water washing but would not feel happy with de-meth, settle and filter.

[dgs]

My issue is that, no matter how long i demeth / settle etc. for, there's always some brown scum in the filter of the car, which i dont think is great (even though ive seen no ill effects from it)

So, Im considering water washing with acids - i know lots of people do this.

My question, however, is -

The acid is added so as an emulsion is not formed.  Im assuming what this is actually doing is converting the water soluable soaps into non-soluable FFAs, which, again i assume, are then soluable in the bio, and stay with the fuel.

I think this is the same sort of result that you would get from an ion exchange tower.

Given that most things have pros and cons, can anyone see any issue with this? 

I know that running a boiler on straight FFAs is not simple, which got me thinking...

High compression 2 made an interesting comment recently, which was if the acid is added before de-mething and at temperature, the FFA's formed will be converted to methyl esters because of the residual chemicals left in the mix.

I have heared others talk about the effect you describe, both in filters and at the bottom of tanks. I'm pretty sure this is glycerol, a very small amount left in suspension, then eventually settling or being filtered out. This can also happen if water washing in a meek and mild way (misting or a mild bubble wash) and this is the reason why I water wash very aggressively. I have cut my filters open/inspected them after 12 to 15000 miles and they are very clean.

As to the long term effects of FFA's in fuel, who knows, but the link that Tony put up doesn't look too good.

I would love to stop water washing but would not feel happy with de-meth, settle and filter.

If you want a really good way to de-soap then de-meth, settle overnight, mix at 30degs with 5% pure glycerine, settle, remove the glycerine (which will be a lighter colour than the bio) then you can water wash how you want and you will not cause an emulsion.

The glycerine is expensive but you can use it @ 10 times before it gets too much soap.

I've done it again, clicked the wrong thing, sorry.

[Julian]

I stopped acid washing a few months ago, due to severe problems with emulsions, even with the acid.

When I was washing, I still got the brown dropout ... quite noticeable in the dispensing tank and filters on the car.

I too thought it was stubborn glycerin which is slowly dropping out, but if I remember correctly it wasn't water soluble.  I have a small sample which I've been meaning to play with.  Can anyone suggest any simple tests?

[dgs]

That is interesting,
When I first started using 'spent glyc' to remove soap if I did not neutralise it first (it has a pH of @ 2.5) and just used it as is, I used to get the same material forming. A black, slimey sort of glycerol that wasn't water soluble. Could this be because of using acid (or in my case acidic glycerol)

[Julian]

Don't know, but I've been getting a similar dropout for years and long before acid washing.. Although I never looked at too closely, just assumed it was the remnants of the glycerin.

[Bio-boy]

What do you polish your fuel down too?
Do you cold filter or hot filter?
Do you use a centrifuge?

[Julian]

What do you polish your fuel down too?
Do you cold filter or hot filter?
Do you use a centrifuge?

Me?

1µ before pumping to the car.
Cold
No

[dgs]

And me,

    0.5 micron
    cold
    no

[Tony]

1u before pumping into the car
Cold
No

[therecklessengineer]

Whatever the rating is of the random filter I had floating around. 

Cold.

No.

[julesandtash]

Just to muddy the waters further. I acid wash followed by four water washes (at least for the road fuel, i only do two water washes for the heating fuel).
I filter cold to the car through 1um and no centrifuge. I dont get any brown dropout in the car or boiler filters.
I used to when i demethed and settled but not now.

[Twenty4Seven]

.....I too thought it was stubborn glycerin which is slowly dropping out, but if I remember correctly it wasn't water soluble...... 

I don't think it is glycerine. The clue is in your statement "wasn't water soluble" Pure glycerol is hydroscopic and completely miscible with water. My own view is that we are looking at oxidation products such as peroxides and polymers. I have seen this red/brown deposit in the bottom of cubies that have just a few ml of bio after standing for some time. The conditions in you vehicle are pretty harsh if you think about it. Fuel is constantly being circulated through the fuel system and back to the tank via the spill lines. So, it constantly being heated and cooled and exposed to the air.