oil and water

[dmj]

Hi, first post an fron UK and have a 55kw Giersch preheat pressure system
Problem is have the first batch of oil that has been delivered from a waste oil pick up tanker.
After a few days of this oil am having cut out problems

No water  drains off from bottom of the tank but foamy bobbles with 'milky' appearance if I heat to 110c to try and get it to ignite. Lower temps not lighting and foam overflows and shuts off system

Ha, have it running on half diesel and half oil at 90C  Next is to reduce tractor diesel %

[RichScorze]

Hi,
I'm a newbie myself but I am an engineer which means I must know everything!

I've got several thoughts about your post...

1) It sounds like your "milky" oil may be oil with water churned in it.  When you preheat the oil, the water should fall out.
2) Since you purchased this from a waste oil delivery truck, the source may be questionable.  Us biodiesel guys occasionally have an "oops" where we create an emulsion that is more like soap ...not biodiesel.  What to do with it...throw it in the nearest waste oil container...or should I say, "sneak it in..."  You may not have good waste oil.
3) you said this is a pressure system.  Is it possible that you have an air leak somehow and you are churning air bubbles into your oil with your own pump?  This would cause a very erratic flow and irregular spray pattern which would result in a poor flame.

Good luck ...let us know if you determine your problem!

Rich

[Russ]

Wow, yea that is a strange one.  Something is definitely mixed in there.  I would think after it settles you could drain off whatever it is.  But it doesn't seem to be separating?

Hope you can find a way to burn it!

[dmj]

Hi rich, I have 3000litres of this oil. Its been standing for 2 weeks or so and there is zero water in the bottom. Shiny black used oil.
There is no air to bubble thro the preheat tank it is black and only foames if heated above 100 C  ie boiling point of water.
Does the term 'hydroscopic' come in to this.

At the moment it is running fine at 90 C on half gas oil and half this suspect oil but this does spoil the economics of the job