Waste vegetable oil burner

[Badfish740]

I've had my Englander wood furnace for two winters now and it has served me well with free wood that I've managed to scrounge. However, options are always nice, so I've been investigating ways that I can burn Waste Vegetable Oil (WVO) safely, cleanly and efficiently as I have a large supply of it since I use it to fuel my truck. I had read about folks rigging up contraptions with brake line to drip WVO into the firebox which does work, but it creates a smoky, dirty, and not particularly hot burn. I've also heard of people who have modified their home oil burners to run on a mix of heating oil and WVO, but since I rely on the oil burner as the SHTF backup, I thought it wouldn't be wise to mess with. I experimented with inspiration from this thread on a site which primarily deals with using WVO as a fuel for modified diesel engines, but they have a small sub-forum on space heating. I bought this nozzle along with the required adapter and this compressor as specified in the thread as well as some stainless steel braided hoses from McMaster-Carr and associated fittings.

As an experiment I removed the bottom draft wheel from the Englander and ran the hoses through the air holes which then when up through the firebrick grate. The nozzle was aimed into the center of the firebox and I built a small fire with cutoff scraps and paper. With the WVO feed and compressor turned on I got a nice orange flame with a small blue cone just out of the tip of the nozzle that burned long after the wood scraps had been reduced to glowing embers. Using a ball valve on the WVO feed I could regulate the size of the flame. I should have taken pictures. Stack temps never exceeded 500 degrees or so. The stack temp on my oil furnace measured about 650 the last time it was tuned up, but WVO has less BTUs per gallon than #2 fuel oil so that wasn't a surprise. Outside there was not a wisp of smoke nor the smell of french fries :lol:-just nice a nice clear wavyness coming out of the chimney. However, this success was short lived. As it turns out, IN the firebox is much too hot for the small viton o-ring in the nozzle, which melted and clogged the oil passages. Plain air from the compressor was still passing through the tip, but the oil passages were completely gummed up. This was a little disappointing since there is no easy way to mount the nozzle just outside the firebox without drilling into the body of the furnace which I wasn't keen on doing-then I had an idea:

One of the best features of the Englander add-on is the 9" x 9" window which is held in by four simple metal tabs bolted to the back of the door. I needed to remove the glass anyway because it's about time to replace the gasket, removing the glass revealed that it's about 3/8" thick and just shy of 9" x 9" (about 8 and 15/16") so I thought, why not replace the glass with a piece of steel plate with a hole in it for the nozzle? That way all draft controls would be in place and the nozzle would be mounted to a removable piece that doesn't modify the stove as it would "bolt on" just like the glass. I got out Google Sketchup and got to work:

I'm having a shop fabricate the plate since I don't have the equipment to cleanly cut or punch 1/4" steel plate. $60 and it should be ready next week. More pics to come then! Now the standard disclaimer, yes I know this is not what the stove was designed for, yes I know this voids the warranty (it's expired), yes I know the insurance company would declare my homeowner's policy null and void if my house burned down, etc... Basically this is more of an experiment than anything that I'm only going to be using when I can be around ie: the weekend. There is no way to turn the flame off and on automatically, so I just run it until the house gets nice and warm and shut it off or turn it down a bit. I do all of my own chimney cleaning so I'll be keeping a close eye on flue conditions, but since I'm getting such a clean burn I don't think that buildup will be an issue.

 

[Adios Pantalones]

I'm pretty impressed. I would like something like this as a pre-heater on my kiln. Did the feed etc work reliably?

Tell me about your oil supply- do you just pick it up locally and react it yourself?

 

[Badfish740]

I'm pretty impressed. I would like something like this as a pre-heater on my kiln. Did the feed etc work reliably?

The nozzle is a siphon type so as long as there is air flowing it will suction oil, but I have it setup as a gravity feed since it was easy enough to do. If you wanted to use it on the kiln you might have issues in cold weather since the oil needs to be at least room temperature-not an insurmountable problem as you could incorporate some sort of electric tank heater.

Tell me about your oil supply- do you just pick it up locally and react it yourself?

My oil suppliers are small restaurants who don't produce enough gallons of waste oil per week to interest the big rendering outfits (who turn WVO into animal feeds, lube oils, etc...) but can't really find another way to get rid of it. I had one guy who had been dumping it in the town's motor oil recycling tank. Also, I'm not reacting anything-this is not biodiesel, just filtered waste vegetable oil, also referred to as straight vegetable oil (SVO). Burning SVO in my truck required a conversion kit to heat the oil prior to injection. Burning SVO in a diesel engine at less than 160 degrees or so will result in injector/piston ring coking and ultimately $$$ damage. I have to filter the oil and make sure that it's free of water myself, which I do in my garage via a custom built filtration rig. The stuff I'm burning in the furnace is just strained through a t-shirt since the nozzles are built to pass particles as large as 250 micron. The oil that goes into the truck is filtered via a centrifuge to less than one micron. Any other questions, ask away!

 

[Badfish740]

Yahoo Groups has a WVO group I think. Temperature of the WVO & fluidity? A furnace tech may be able to analyze the fluegas so to tweak the burn.....keep posting!

The WVO is in a small tank sitting next to the furnace (36" away just to be safe)-since it's a furnace and not a regular stove it doesn't give off a huge amount of radiant heat (it's all going into the ductwork), but the stove pipe gives off some, so the basement usually stays just above room temperature (73-74 degrees)-I've never actually measured the temp of the WVO but its probably about the same. Warmer WVO might give a better burn since it would thin out a bit, but room temperature is certainly clean enough for my liking. Having to heat it more than that would get complicated. On the site I referenced the poster has the pot sitting on top of the stove but I'm not comfortable with doing that.

 

[Wood Duck]

I'm pretty impressed. I would like something like this as a pre-heater on my kiln. Did the feed etc work reliably?

The nozzle is a siphon type so as long as there is air flowing it will suction oil, but I have it setup as a gravity feed since it was easy enough to do. If you wanted to use it on the kiln you might have issues in cold weather since the oil needs to be at least room temperature-not an insurmountable problem as you could incorporate some sort of electric tank heater.

Tell me about your oil supply- do you just pick it up locally and react it yourself?

My oil suppliers are small restaurants who don't produce enough gallons of waste oil per week to interest the big rendering outfits (who turn WVO into animal feeds, lube oils, etc...) but can't really find another way to get rid of it. I had one guy who had been dumping it in the town's motor oil recycling tank. Also, I'm not reacting anything-this is not biodiesel, just filtered waste vegetable oil, also referred to as straight vegetable oil (SVO). Burning SVO in my truck required a conversion kit to heat the oil prior to injection. Burning SVO in a diesel engine at less than 160 degrees or so will result in injector/piston ring coking and ultimately $$$ damage. I have to filter the oil and make sure that it's free of water myself, which I do in my garage via a custom built filtration rig. The stuff I'm burning in the furnace is just strained through a t-shirt since the nozzles are built to pass particles as large as 250 micron. The oil that goes into the truck is filtered via a centrifuge to less than one micron. Any other questions, ask away!

I think I passed you on the street yesterday. I recognized you by your shirt.

 

[Badfish740]

I think I passed you on the street yesterday. I recognized you by your shirt.

LOL...Nahhh...wasn't me-I'm about 200 miles east of where you are :lol: I was using my old t-shirts til I ran out-now I buy them at the thrift shop.

 

[Jags]

Cool project. Makes me wonder just what will be the results on the chimney. It will be interesting to find out.

 

[Badfish740]

Cool project. Makes me wonder just what will be the results on the chimney. It will be interesting to find out.

I've actually been burning WVO in a different form in this furnace for a while, albeit in small quantities. I rough filter my oil with natural cotton cartridges that have stainless steel cores. Once they're completely plugged with fats, hydrogenated oil, french fry bits, etc...I burn them. They're great for a quick hot warm up fire on a cold morning. They too burn with little smoke. I was leery at first because I used to work at an ice rink with a snack bar that of course had an exhaust hood that would capture all of the cooking fumes/smoke and vent it to the outside. Cleaning those things was a nasty job as they became thick with oily soot. Then I thought about it a little and realized that the fumes going through the hood were far from completely combusted whereas anything I put in the furnace (with the proper amount of air) would be. I've never noticed any ill effects from the filter cartridges and don't expect any from the burner nozzle (which should be more efficient in theory), but I'll be monitoring closely.

 

[Badfish740]

How do you separate the water from the WVO?

There are many ways to do it-some people just heat their oil, let the water settle out, and drain it off the bottom. I use a centrifuge along with heat which cleans the oil and dewaters it at the same time. I pump 160 degree oil into the centrifuge at 90 psi. The oil floods the rotor and is forced out through two tiny opposing jets which propel the rotor at about 8000 rpm. At this speed all of the particles in the oil down to less than 1 micron are forced against the side of the rotor and clean oil drains out of the bottom. When the 160 degree oil escapes through the jets and goes from 90 psi to atmospheric pressure the water flashes off as vapor. I only do this for the oil that goes into my truck though-water free WVO is critical because any water in the fuel will damage injectors. For heating fuel it's not nearly as critical. I just "rough filter" it through the cotton filters that I end up burning. That gets enough crud out so that the oil will pass through the burner nozzle no problem.

 

[maverick06]

I've burnt small quantities of veg oil before with no issues. Its a good way to get rid of the oil. I just pour it into a old soup can and wait until shortly after the fire has burned down to coals. This way its really hot in the firebox. From there, just pour the oil into the can and put the can into the stove. A few min later it has caught on fire and it burning. It is limited by the size of the can. It works well but I wont be switching over to only be burning oil

 

[WES999]

Interesting project. A few years age I made one of these:

http://journeytoforever.org/biofuel_library/ethanol_motherearth/me4.html#mwoh

A waste oil burner featured in MEN. I installed the burner in my stove rather than a water heater as in the article. If did work for the most part but not as good as wood so I removed it and converted the stove back to wood.

On feature that may be of interest is the oil is preheated by the copper tubing being wrapped around the stove pipe. Maybe it would work for your setup. BTW viton O i rings are only good to 400 °F .

 

[Badfish740]

It works well but I wont be switching over to only be burning oil

I'm just going to use it for the remainder of the cold weather this year-next year who knows. This winter took me by surprise by getting very cold very early, plus the scrounging didn't get really good until October or so. I have 4 cords of red and pin oak, black walnut, and assorted junk wood (poplar, silver maple, etc...) in the shed but none ready to burn. I ran out of seasoned wood about a month ago. The shop making up the plate should have it ready by next week, so I'll use that to finish out the season-next year I'll be enjoying the warmth of all that oak! I figure maybe one day I'll retire the Englander to a life as a shop heater and convert it to WVO full time.