How to get a pellet stove to burn some veggie oil?

[Christ]

Originally Posted by rmay635703

Where would I get a flame arrester out of curiousity? I definately want a very small steel tube for the input and a shutoff. I want the flow rate as low as possible but am not sure how to accomplish it gravity fed given the viscousity of the oil.

That's some stuff I can't help with, but a flame arrester is nothing more than a screen somewhere in the line that forces flames which might make it up the line to spread out and cool.

Have you played with a Bunsen burner? When you put a piece of screen over it, the flame spreads out evenly around the screen. You'd just want to put it somewhere in the line of flow a few inches from the opening, at least. No need to buy anything, a small piece of chore-boy would work fine. (Steel wool, rather. Chore boy emits noxious gasses when it gets hot, because it's copper.)

We just happened onto a way to do it with crap (literally) that we already had laying around from fixing the house, the cars, or other people's stuff, and it worked pretty good.

If you have access to the inside of the firebox, add something for the oil to drip onto and expand/spread as it heats up, otherwise you might end up with a puddle of oil in the burner.

We used a piece of expanded steel turned at such an angle that the oil could spread (via gravity and heat expansion) over it, while the flames could climb up it, to ensure a fairly clean, complete burn of the used motor oil/cooking oil/brake fluid/whatever.

I'm almost certain you could just put a few lava rocks on a grate in the firebox and let the oil drip onto them, though. They'll absorb the oil somewhat, and the heat will wick the oil back out and burn it slowly.

[rmay635703]

Originally Posted by thatguitarguy

If you're talking about burning lard, I think you really need some kind of heat exchanger from your stove to preheat/liquify the lard before it goes into the stove to burn.

The "creamy" stuff liquifies at 75 degrees or so, needless to say it will sit gravity feed style above the flat surface of the stove which isn't hot but does get around 90 degrees or so. So it is liquid, no worries.

[Christ]

Originally Posted by rmay635703

The "creamy" stuff liquifies at 75 degrees or so, needless to say it will sit gravity feed style above the flat surface of the stove which isn't hot but does get around 90 degrees or so. So it is liquid, no worries.

Hey, I spoke with a friend of mine that has a corn/coal stove. He also burns waste oils (food oils, not petroleum).

He has a shoe-box sized (think kid's shoes) metal box that he got from a dumpster dive that sits inside the firebox, just a few inches above the bottom. Inside, there is a tube that feeds the box oils, and in the bottom, there is a grate with lava rocks on it.

Like I suggested earlier, the lava rocks soak up the oils, and the fire slowly heats the rocks until the oil expands out of the pores and burns.

He says he doens't get smoke from running with just the rocks lit when he doesn't have any biomass to burn (he doesn't burn coal, either. If he doesn't have any oils or biomass, the house gets very cold during the winter.)

Unfortunately, he doesn't own a camera, and uses the computer at his local library, as his home doesn't have electrical service. I envy him at times.

[rmay635703]

Originally Posted by Christ

Hey, I spoke with a friend of mine that has a corn/coal stove. He also burns waste oils (food oils, not petroleum).

He has a shoe-box sized (think kid's shoes) metal box that he got from a dumpster dive that sits inside the firebox, just a few inches above the bottom. Inside, there is a tube that feeds the box oils, and in the bottom, there is a grate with lava rocks on it.

Like I suggested earlier, the lava rocks soak up the oils, and the fire slowly heats the rocks until the oil expands out of the pores and burns.

My fire box is much smaller as my stove is a midget compared to his Shoe size box is about the size of my entire fire box! Except that it is quite deep for a shoe box.

I would probably have to suspend a lava rock or two above the point of flames and ash to dupliate his method.

[Christ]

That might work by just using a few pieces of heavy wire, making a "cradle" for the rock to sit in, and making a base that's wider than the cradle to sit in the ash at the bottom of the box.

Someone above mentioned pre-heating, and that's not a bad idea at all. You could use part of the heat from the exhaust vent to pre-heat the oil, which will make it quicker to combust and cleaner burning. To that end, you may even be able to drip the fuel slowly onto a plate or screen directly, and allow the flames to vaporize and burn it.

Most fatty oils (and several petro oils) will expand away from a heat source, thinning proportionately, so if you allow already hot oil to drip on a flame-licked plate, it should vaporize and burn quickly.

You'll need to adjust your mass intake accordingly, if it's automatically controlled.

[rmay635703]

Originally Posted by Christ

Someone above mentioned pre-heating, and that's not a bad idea at all. You could use part of the heat from the exhaust vent to pre-heat the oil, which will make it quicker to combust and cleaner burning. To that end, you may even be able to drip the fuel slowly onto a plate or screen directly, and allow the flames to vaporize and burn it.

You'll need to adjust your mass intake accordingly, if it's automatically controlled.

Oil will be rather preheated as it will sit next to the ducting that supplies the warm air to the house and sitting on the top of the insulated stove.

The design of my paticular stove has a floating burn pot in the center of an air filled space the heat exchangers & exhaust run around the burn pot in tandem. The stove has settings for draft fan hi, med, or off depending on corn, corn mix/soybeans or pure pellets. With oil I would assume draft fan would need to be set to med or hi depending on the rate of flow, the oil drip tube will go down between the heat exchanger tubing which will heat the oil to be dripped into the pot, contact with the "blast" furnace metal into the burn pot will also transfer a lot of heat.

[Christ]

Sounds like a plan!

I tried looking at our waste oil heater (not the one I mentioned before) in the garage to see how that was setup to move the oil from the pre-heater and burn it, but I can't easily get into the firebox to see anything significant, or of use to us here.

It seems, though, that it transfers the oil from the preheater into a spray bar which atomizes the fuel over a puddle flame (there'll always be a puddle in the bottom to maintain the flame for "idle" periods). I can't be sure about it, that's just how my brain put together the limited view I had of it.

[Christ]

I got a letter from my friend this past week, but there were no pictures included.

He says in the letter that he also uses the firebox to burn off glycerine from the biodiesel that he makes, which seems to burn forever in his fire box.

He's in the process of building a new "russian stove" as he calls it, which is just a masonry/clay stove built into a central wall with piping that runs back and forth through it to extract as much heat as possible from the fuel being burnt.

It's a biomass stove, but hand loaded, no hopper.