filtration by "settling out"

[mikenash]

Here at work we generate several tonnes of waste oil each year.  This year I would like to harvest some of it

One of these days I'd like to have an oil-burning drip-feed heater (and yes, I think I'm cogniscent of the pitfalls/problems around how temp changes viscosity, how they can't be left to run unattended etc etc) because I think my circumstances will suit one AND I have, potentially, a LOT of oil

I made a prototype a while back and have just about finished building Mk11 at work with some options to control primary, secondary & tertiary air intakes - hope to do some trial burns when this Covid shit is over and life can resume

So today at work I welded in a 40mm BSP socket to the side of an empty 44-gallon (200 litre) drum about 150mm (six inches) above the bottom.  I'll use the air-pump oil-transfer thingie to fill it up next week at work

What I reckon/hope/wonder is this:

My observation is that the oil is pretty non-hygroscopic.  When I drain gearboxes first you get a stream of clear water, then a stream of clean oil.  You don't get any white stuff

So I'm hoping that if it sits in a drum for a few years, that any water and whatever "dirt" is in there (no combustion by-products are present) will simply "settle out" and if I write off the bottom six inches by just draining it down to the new bung on the side - I might end up with quite a "clean" product

It has been bothering me for years that we just throw this stuff away by giving it to the recyclers.  It seems to me it's potentially a resource I should be harvesting.  There's probably nothing to stop me welding a socket in a heap of drums and harvesting a tonne or two

I'd be interested in any thoughts from folks who are experienced in dealing with "waste" oils

Cheers

[veggie]

WMO is a moving target. It's made up of all kinds of oils, additives, solvents and even anti-freeze.
The varying concentrations of these components means that every user will have a different base fuel to compare to others.
What works for one person may fail miserably for another even though the engines are prepared identically. Why, because the fuels are almost guaranteed to be different (even though they are both WMO).
If your oil is free from other contaminants and is non-synthetic, you may have good luck using it as a fuel if you clean it adequately.
Some people add 10% gasoline to reduce the viscosity.
Just for contrast, here are nominal flash points for various fuels and oils..

Flash Point Under Compression Ignition:
===============================
Diesel #1 ---100f
Diesel #2 ---125f
Kerosene ---150f
Biodiesel ---260f
Motor oil --- 450 f
Petroleum synthetics--- 485f
PAO Synthetics ---525f
Olafin Ester Synthetics ---725f

As you can see, the high end synthetics have a strong resistance to auto-ignition. (Diesel=100f vs. Olafin Synthetics=725f)
That's why synthetic oil works well in severe heat applications.
One can clearly see the massive difference in "burnability" (if that's a word ?) and how varying concentrations of these oils could drastically effect the combustion process.

[mikenash]

Yes.  Good comment and just the sort of thing I need to know

Once the #2 burner is up and running maybe I'll burn a few litres of new oil and see what the "burnability" is before I get too excited

Thanks

[veggie]

This fellow seems to have had good luck with WMO
https://www.youtube.com/watch?v=dYZqAzEuPE8

[EdDee]

Hey MN...

"When I drain gearboxes first you get a stream of clear water, then a stream of clean oil." - This to me, is the Holy Grail.... Stick it through a fuge, re-use!!

In fact, 1/2 drum at a time, brought to the 100C mark slowly, no water left - re-use!!

Cheers
Ed

[mikenash]

Hi Ed

Yes, good thoughts

I need "simple" so am just gonna have some plays.  Starting off with a simplified pot-and-heater style device in my exisiting woodstove.  Over the past week I have built all the bits apart from drilling a fe holes through the double-skin 12mm & 10mm sidewalls.  Why did I make it so heavy?

Hope to be up there to have a play next weekend or the one after.  If it works with "ordinary" oil well enough to be the beginnings of a "proof of concept" - then I'll have a play with the heavier oil

Cheers