Friday, August 18, 2006

WVO filtering station complete

This system has been updated to v2.0

I've just completed the filtering / dewatering station. It is based on erikk's set up he posted on the SVO forum. Many thanks to erikk and everyone who posted.

Basically the system is a 2 tank system with the oil initially settling in 35lb cubees for at least 2 weeks. The soy oil I receive is used once. After the settling period it is then poured through a 25 micron sock filter (soon to be changed to a 15). Once the first drum is full it is heated for a few days to dewater the oil and reduce it's viscocity for filtering to the next drum. While still warm (about 95- 100º)it is then pumped through a 10 micron Goldenrod and then through a 5 micron sock into the 2nd drum. Once the 2nd drum is full it is again heated for a few days to dewater again. Finally while being pumped into the car it goes through 2 micron Permacool filter.

I have a 3rd drum for settling that I keep for extra oil as someone delivered about 30 gallons to my house and it had a lot of emulsivied water in it.

Each drum has wrapped around it a 30' long, 60 watt pipe heater cable

After aquiring 2- 55 gallon drums I purchased 2 - 30' wrap on pipe heaters (pictured right). I live in Southern California where it is extremely rare for it to get below freezing so I had to purcahse them on the net from They come in different lengths and in hind site I think I would order the 45' cable because it would heat faster and probably be a little hotter.

What made me decide on this set up is the fact that since the heater is wrapped around the side of the barrel it is not centralized. With a centralized heating source there is a greater chance of convection currents (ie: water heater element). These currents stir the oil up while heating thereby not letting the microdropplets of water settle out.

The other thing (and perhaps a water heater element is the same) is that it doesn't use that much engery. It is the equivilant to using a 60watt light bulb. Now granted it takes a day or so to heat it dependig on the ambient tempature but still that doesn't seem like much. The whole idea for me is to use the minumum amount of energy that is required. Plus the pipe heater is so much cheaper then the 55 gallon drum heaters. Beaware though that you are not using this heater for what it was intended for. Use at your own risk.

Before installing heater band I installed a bulkhead pipe fitting into each steel drum. I figured that this might be an easy way to drain it when the time comes. The consensus is that the muck that forms on the bottom of the drum somehow acts like a magnet for microdroplets of water and attracts them to it once it builds up. So draining the drum is something I would only do rarely as to maintain a layer of muck(emulsivide water) at the bottom.

You will have to override the thermastat on the pipe heater cables as they were only designed to come on at freezing. In the photos you can see a clothes pin. It was used to activate the test button thereby overriding the thermastat. The brand of heater I have has a light that come on when the heater is activated.

The pipe heaters - one on each drum - were wrapped around the drums starting at about 6-7 inches off the bottom. Be careful as not to overlap the cable ontop of itself as this will cause it to get too hot and possibly overheat.

In the end I ended up doing it a little differently then what is pictured at right. I had to go back & move the heater cable so that I could reach an electrical outlet. After rereading the forum thread some people suggested spreading the cable out, so that is what I did. It still goes from about 7" from the bottom but goes up to about the 2nd ridge. That is what made me think a 45' cable might be better, but actually the 30' seems to be good so far as the oil was over 100ºf

After the pipe heater was installed the drums were wrapped in R-13 insulation. This prevents convection currents and is obviously the only way to retain the heat when cold outside. Before the drums were insulated I tried the heater and wasn't even sure it was working but when I tried it wih the insulation is was extremely hot. Someone on the forum said they built a box around there drums and filled it with styrofoam peanuts as an insulator. I would have preferred to do mine that way but I was aready down this road.

So both drums have the electric pipe heater, are wrapped in insulation and also wrapped in clear pallet wrap (kinda like syrane wrap) . The first drum's lid has 2 - 5" x 17" 25 micron socks hanging from it. I went with the 17" length because the 22" are very close to the 6" barrier above the bottom of the tank and I thought why disturb it if I don't have to. As for the 5" diameter I thought who needs a 7". In hindsight the 7" is better because the cubees are easier to pour into a 7" opening and less messy as I spill / splash some because of the 5" opening. I plan on changing the 25 micron to a 15 micron because my oil is only used once so I think a 15 would be OK and extend the life of the Goldenrod.

The plan is to wait until the 1st drum is full and move it's contents to the 2nd drum. This way I'm only heating the oil in the first tank once. So a day or 3 before I wish to transfer the contents from the 1 st tank I turn on the heater. This promotes dewatering and reduces the viscocity. The Harbor Freight pump is used to push the warm oil through a 10 micron GoldenRod filter which goes down through a clear piece of tubing (easier to work with and I can see the clarity of the oil) into a 5 micron sock. From there I just need to heat it for a few days to dewater it

The final stage is a 2 micron PermaCool filter that the oil passes through on it's way to my car via way of a Northern Tool 12v diesel pump. I try and fill up the tank while the oil is still warm in the 2nd tank as not to tax the pump more then I have too. I plan on heating the oil for a day or so before each fill up to warm it during the winter months.


  • 2 - 30' pipe heater $75
  • 2 - 55 gallon drums $20 each
  • Harbor freight hand pump - $40
  • Northern tool pump - $150
  • Golden rod $3o
  • Permacool filter - $50
  • Insulation - $15
  • Earthquake Straps - $20
  • Misc pipes / tubing / PVC - $30
rough total = $430