Modified wood stove to burn used oil:

crazyal · Feb 12, 2014

My neighbor would cut oil filters apart and burn the filtering media and throw the metal in the scrap metal section of the dump. He would have plastic trash cans full of them from oil changes over the summer. He would also use the filters from furnaces. He would just throw them on the fire like a log. It was at least 3 decades ago so my memory is a little fuzzy but I think he had a can opener like device. He would pull a filter out of the garbage can, cut off the top, and throw it in the fire.

tnmike · Feb 12, 2014

Call me a nervous nellie if you want but I would want the oil bucket located farther away from the heat source. You could use a plastic bucket with a screw on lid if it was. I would also change the tubing that entered the stove to stainless. It would last a lot longer. Looks like a good low tech system that works. Atomizing the oil mixture would improve the heat gain but would also require electricity and possible a thermostat for unattended operation. This is simplicity at its finest.

MotorSeven · Feb 12, 2014

The melting point of copper is 1981 degrees. I agree that a flue fire can reach 2,000 degrees if it is fueled by creosote. Stainless melts at 2550, carbon steel between 2500 and 2700 depending on the amount of carbon. So yes there is some extra margin of safety. However, the shop is all steel, the floor is concrete, and I will not run it unless I am there supervising the burn temps. When I build a burner I will use SS for the air tube feed and the oil feed since the burner might reach 2,000 degrees.

http://www.garelicksteel.com/pdfs/Melting_Points_of_Common_Metals.pdf

I don't know what my low tech drip is capable of in degrees. Today I was running the drip at 3/4 of a turn off of the closed position. Stove fell off of the wood burn to 400, so to see what it would do I added complete additional turn to the valve. Immediately the stove temps responded and within 20 min I was at 600 flue and a surface temp of 780. It ran that way for about 45 min, so I opened the doors to see how much log was left....it was 3/4 burned away, but the entire top surface that was catching the oil was burning very well. After it climbed to 650 I throttled back a half a turn on the valve & it settled in at 550:

So what I discovered that if I feed it more oil, I get more heat and that I have been rather conservative in the DMP up to this point. I do think that 600 is too hot, so now I need to find the sweet spot which I think is about 500 flue temp.

Raspy · Feb 12, 2014

I had a Dickinson Diesel heater on my boat for years. It used a system for the oil that metered it into the bottom of a bowl shaped pan. The oil comes up into the center of the bowl and vaporizes then burns. It may be a better way to deliver the oil than dripping it into the fire from above. It prevents flashing each drop and it prevents coking up the end of the tube. The flow rate also varies significantly by temperature. Dickinson makes a nice metering valve, or you can use a small needle valve.

mx842 · Feb 13, 2014

Raspy said:
I had a Dickinson Diesel heater on my boat for years. It used a system for the oil that metered it into the bottom of a bowl shaped pan. The oil comes up into the center of the bowl and vaporizes then burns. It may be a better way to deliver the oil than dripping it into the fire from above. It prevents flashing each drop and it prevents coking up the end of the tube. The flow rate also varies significantly by temperature. Dickinson makes a nice metering valve, or you can use a small needle valve.

Just wondering, what causes the oil to vaporize? Is it pumped in under pressure by a pump of some type or is it forced in under air pressure? I'm working on doing some sort of waste oil conversion for my old wood burning boiler stove. I just can't get enough heat into the water with the wood I am burning. Even with good dry wood scraps like 2x4's, plywood and the like I can still not get much more than 95 degree water out of the exit pipe. I know it's a poor design and I have done a few things to make it work better. Now as long as the air fan is supplying a good air supply around the inside of the firebox it burns fairly well and the stack temps get to just above the creosote making stage but as soon as I shut the fan off the black goo starts leaking out and running down the stove pipe from where it goes out the building.

I've had to pull the pipe out and clean it twice in less than 2 weeks and it needs it again now. I have been trying to figure out how to get the gases that the wood put out to burn so I can get the full potential of what the wood is capable of putting out but it's hard to do that with a updraft type setup like this stove is. The firebox is not really large enough to install any kind of a baffle in the back of the firebox but I did fab in a chamber in the top that forces the gases to exit through some holes I put in the back part of this plate and not right straight up through the fire tubes. I put in a sliding plate damper that I can slide open and close to let the gas and smoke bypass until the fire gets hot enough then the idea was to close the damper closed and inject air into the back of the chamber hopefully igniting the flu gas but it has not worked out at all. Although the the water temp does rise a couple degrees once I close the draft control but the flu temps are still only around 215 degrees right where it exits the fire tube and once it gets to the 90 degree turn to exit the building it has cooled down to 125 degrees, that's just to cool.

Smokepole62 · Feb 13, 2014

Along this line of thinking, you should google:

Babington burner.

there is a lot of useful info at this sight for us DIYers.

Raspy · Feb 13, 2014

mx,

The oil arrives at the bowl by gravity or by a small transfer pump. It is not sprayed under pressure. It vaporizes because of the heat of the fire.

Dickinson burners are either about 6" or 4" in diameter and about 6" deep. This bowl is where the fire is. Air enters this bowl through perforations all around the perimeter. It's a very simple and well proven design.

I ran thousands of gallons through mine over the years and was able to keep my exhaust pipe a light brown inside. No visible smoke. Of course, I was running diesel, but used oil should work fine in this type of setup, if a bit dirtier in the exhaust.

MotorSeven · Feb 13, 2014

I found these interesting numbers on the net:

* diesel (~140,000 BTU/gallon)
* biodiesel (~130,000 BTU/gallon)
* kerosene (~140,000 BTU/gallon)
* trans / motor oil (~150,000 BTU/gallon)
* vegetable oil (WVO) (~130,000 BTU/gallon)

PRF · Feb 13, 2014

My grandfather had a set up similar to that back in the 1950's when we heated the entire shop with wood.. The steel pail sat on a metal shelf lagged into the cinder block walls.. Had a little petcock valve that worked great... One thing that I remember happening as a kid was if the drip dripped just a little too fast it would get that old converted 275 gal oil tank stove RED hot !! But I remember we could burn just about any kind of wood, even fresh cut green wood, and the oil would burn everything up..