What do you guys think of this, or has anyone tried anything similar? Basically a rocket stove but instead of a feed tube for wood, there would be a hole in the floor with a sump below. The sump would have a wad of fiberglass insulation in it, sticking through into the air flow, and filled with waste motor oil. The sump could be wider than the tube, to allow for a fill port off to the side. Not sure how long the fiberglass would last but even if you had to buy it, it wouldn't take much.
I'm new to the rocket stove concept and am just running ideas through my head. If I ever get my pressing projects done, I have some scrap pieces of 5" diameter truck exhaust tubing from another project, also a 90 degree elbow.
I know a guy who put a waste veggie oil drip in his rocket stove.. He burns wood in it but also uses VWO as an extender.. I'm not to firm on the details.
I think the idea is worth exploring, though I'm not sure that fiberglass is up to the temperatures involved, might need to find an appropriate wick that won't just burn out right away. Also, you're likely to need to experiment with air intake sizes. Getting the fuel/air mixture right is going to be important. Try it (carefully) outside in a safe place, work out the bugs and post your progress here.
Post by swizzlenutz on Nov 5, 2009 13:30:31 GMT -5
I'd like to see how a veggie oil waste burner is set up. Could you mix the two? Say you are almost out of veggie oil and you have a couple quarts from an oil change in on top of it or would there need to be some kind of adjustment? I see veggie oil for free on craigslist once in a while and its usually 50 gallons. Swizzle
Post by swizzlenutz on Nov 5, 2009 16:38:17 GMT -5
I was thinking more of a drip into the burner. The drip area would need to be sealed so that it doesn't allow extra air through that entrance. You could maybe control air flow by adding a stove damper using a 6" or 8" stove pipe for the set up. Would you need a wick or just drip it into a shallow bowl or depression and light it up and start the drip. The bigger the pipe, the bigger the wick that would be needed. Otherwise the airflow might just blow out the fire. The airflow would also blow the oil sideways so maybe the burner plate could actually be more like a dust pan in the very end of the burn tunnel at the base of the riser? Swizzle
My friend with the drip said that it didn't work by itself. WVO needs high heat to get burning in the first place. Also, the drip is slow and the fuel isn't really set up from the beginning for efficient burn. In higher tech oil burning situations, there's either a wick (like kerosene heaters) or a vaporizing nozzle at pressure. There may be other ways, I'm just not aware of em.
It seems that a pure waste oil burner (rocket stove) would be much smaller, like 2 or 4 inch pipe. It would need a way to get the pipe up to temperature to begin to ignite the oil, like ... Like a small fire -- a tiny rocket stove for wood just to pre-heat the waste oil burner. It would need a way of vaporizing the oil into a fine spray, a venturi injector perhaps, or something like it.. Normally, all this is powered with an air blower. I wonder if a super-insulated heat riser could generate enough go to make it work.. ??
Post by swizzlenutz on Nov 5, 2009 21:12:46 GMT -5
I don't think I could get enough waste oil of any kind to make a specialized stove for it. So do you think a drip would work fine in a regular rocket as long as it has something to drip onto, in my case it'd be wood or maybe cardboard. Swizzle
Maybe, depends on what you expect to get from it. "Works fine", is a fairly subjective statement. What are the goals and how far do you need to bend to get there?
Got any restaurants nearby that deep fry? When they throw it out, maybe you can get some.. Instant waste oil. When you change the oil in your car, where does it go? Do you just take it to the shop and forget it? What does the shop do with it? Do they pay to have it removed? Could you offer to "disappear" some to save them some $$?
If fiberglass insulation won't work, I wonder if a woodstove door rope seal will provide enough wicking for a smaller rocket stove, as well as hold up to the heat. Figure they are seeing 700-1,000 F, I think they would. Plus, the max burn temp might not be seen at the wick's surface, but more in the burn chamber.
Post by swizzlenutz on Nov 6, 2009 12:57:36 GMT -5
I guess what I'm expecting is to just extend my free fuel options. If I can scrounge all spring, summer and early fall to get enough fuel for half the winter for free then I'm happy with that. If I could get enough for the whole winter then I'd be thrilled. I'm not sure if I'd want my house smelling like french fries all the time though. Swizzle
About the drip: I've heard someone filled the bottom of a stove with big nails. In such a way that the oil do spread over it in order to evaporate it. There's still the problem how to start the thing. Maybe with a blow torch?
Post by swizzlenutz on Nov 6, 2009 16:35:49 GMT -5
Now that you mention it I think I saw one on mother earth news where the guy used bolts. That's the type of stove that needs to burn really hot or you get a lot of nasties in the air. I think a rocket stove might be able to hit those higher temps but there's no telling how long it would take to warm it up that much. Each stove would be different. He did mention in his first attempts that the bolts would get so nasty with some type of build up that he would have to buy new bolts or really work at getting them clean to re-use. I'll see if I can find the article again. Swizzle
Hello, first time posting, just found these forums.
What you're discussing interests me quite a bit. I am going to be building a rocket mass heater in a treehouse soon, and the possibility of burning waste oil would be a huge benefit to me. As my neighbors and I are off-grid, there is quite a bit of used motor oil around from the various generators. Even if I needed to pre-heat the stove with fire, I would be stoked if I could burn this oil.
However, I'm not into covering the tree and my house with black soot, do you think the emissions from this activity would be considerably larger than burning wood?
I'll be watching this thread to see where it goes.