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Aaron IIA
23rd June 2008, 12:34 PM
I am considering running my 2.25D on vegetable oil. I can work out the whole system, filtering, twin tanks, and heating the lines, but how should I first de-water the oil? Is the water trap in the bottom of the filter housing enough? How do other people de-water their oil?
Aaron.

Bigbjorn
23rd June 2008, 02:36 PM
Get a Racor separator and fit it in the fuel line. any truck or diesel shop will have them or point you to someone who has. Racors have a cyclonic separator section like a Donaldson air cleaner. They spin water and heavy particles out of the fuel and deposit the unwanted stuff in a bowl for emptying. They are absolutely brilliant and the answer for most kinds of fuel contamination.

abaddonxi
23rd June 2008, 03:07 PM
I think you need to get the water out of the oil before it goes into your tank. Even with a later stage separator as Brian suggests, you don't want water sitting in your tank.

I think most people dewater before putting it into the tank. I think the easiest way is letting it settle out, followed by a filter.

I'm sure you've probably seen them, but these are helpful-

Biofuels: Journey to Forever - how to make your own clean-burning biofuel, biodiesel from cooking oil, fuel alcohol (http://journeytoforever.org/biofuel.html)

Australian Biofuel Users - Home (http://www.biofuel.org.au/)

Sydney Biodiesel Users Group - Home (http://www.sydneybiodiesel.com/)

Cheers
Simon

isuzurover
23rd June 2008, 03:28 PM
Aaron - apparently the CAV DPA injector pump (that the 2.25D has) isn't suited to veg oil. There is a small scroll inside the pump that can't handle the increased viscosity (you would need to preheat (most oils) to about 120oC to eqalise viscosity).

However if you have a spare pump and are willing to risk it...

barney
23rd June 2008, 04:51 PM
careful what you use Aaron, some oils solidify at room temp.
i work on catering equipment and deal with cooking oil all the time.
the best way to get the water out of it is to heat the oil up over 100 degrees celcius. the oil can handle it, it's normal operating temp is between 160 and 200 degrees.
not too much above 100 though, if the water boils out too quickly, it will froth and overflow. water expands to either 500 or 5000 times it's volume when it turns to steam ( can't quite remember but it's pretty big).
and if it overflows, it can catch alight from the flame you are using to heat it.
you will also have to do some serious filtering of the stuff before you use it. the waste oil that the users disguard is usually full of contaminants and carbon. you can buy filtering paper from hospitality suppliers, but it will be a slow process if you are doing it by gravity, and it's best done while the oil is hot as it will filter better.
you can buy oil filtering machines, but they are expensive, like a couple of grand expensive.
if you process it right through to biofuel, you will have a better result, but for the savings alone, it sounds like a lot of work to me. the only real advantage, if you count your time spent making the stuff, is the warm fuzzy feeling you get when you save the planet a little when you use the stuff.
good luck

ladas
23rd June 2008, 05:15 PM
What Barney said

You need to raise the temp above 100 Deg C to boil off the water.

barney
23rd June 2008, 05:47 PM
to back up my argument with some facts thanks to google,
Water turning to steam expands 1600 times in volume -- so 2000 gallons of water instantly vaporises to 3 million gallons of steam!
and this little gem;-
The Smoke Point
Knowing the smoke point can also save you money, because each time you deep-fry, you lower its smoke point irreversibly. If your oil's smoke point is just above 190 degrees C (375 degrees F), which is the normal deep-frying temperature, chances are its smoke point will drop below 190 degrees C (375 degrees F) after its first use, rendering it useless. If you want to save money by reusing an oil as many times as possible, select one with a high smoke point.
Smoke Points
Safflower 265 degrees C Sunflower 246 degrees C Soybean 241 degrees C Canola 238 degrees C Corn 236 degrees C Peanut 231 degrees C Sesame 215 degrees C Olive 190 degrees C Lards 183 to 205 degrees C

An oil reaches its flash point (about 320 degrees C (600 degrees F) for most oils) when tiny wisps of fire begin to leap from its surface. If the oil is heated to its fire point (slightly under 400 degrees C (700 degrees F) for most oils), its surface will be ablaze.

choose the oil that's best for you

isuzurover
24th June 2008, 03:10 PM
As long as you have liquid oil and liquid water, they are quite easy to separate. Heating oil up to 100oC and boiling off the water is the least (energy) efficient way to do it. It isn't what is done in industry - modern oil/water separators using hydrophobic media work VERY well.

Aaron - you will need to filter the oil before use. You can include water separation into the filtration system.