Starting waste oil furnace

[elt]

I've been wanting to build a waste oil furnace for my shop. I googled and surfed yahoo groups. It looks to like the basic procedure is to make a shell and then keep building burners until you get one to work.

I intend to start out with the Roger Sander's version of the MEN drip furnace with its conical burner but, reading here, I really like Old F's upside down bowl burner and will try that out too before I move on.

I don't expect to add to the science of burning waste oil, I just like to post what I've do in my diary...

I got an old electric water heater on Friday. "Old" was nice because the tank was wrapped in fiberglass and a lot easier to get out of the liner than if it would have been if ti were encased in blown-in foam like the newer ones.

Using dimensions from the plans, I used a 4" hole saw to cut the center hole for the air pipe and a sawzall to cut the 6" hole for the flue and rectangular opening for lighting.

I was eager to light something in it :-) so put a little hibachi of coal in it and a makeshift conical burner. I don't have anything attached to the furnace yet so I just covered the top air hole and stuck the flue pipe in. I poured some motor oil on the coals and tried to light the oil. No. Threw some paper on them and lit that. Still didn't light the oil. I thought oil would be easier to light! Splashed a little napha on the coals; that did the trick.

I hope to get some rudiments of the drip system working tomorrow. Today, I started out by pouring about a half of cup of oil down the middle. That burned but wasn't interesting. Next I put the cone I made on the coals and ladled some oil on to that. The oil boiled and soon the vapors lit, wow it roared!

I experimented ladling in less. (Turns out that my thin cone had burned through and some was leaking onto the coals.) About 1/8 cup looked like a good amount:





Once the vapors ignited, spiraling columns of flames were produced. As the oil burned, the pool got smaller but still burned fiercely. I really can envision a steady drip stream holding the pole at a desired size (which will allow me to adjust the output of the furnace.)

BTW, I don't have a chunk of aluminum to make the conical burner the way Sanders did so I just bent a piece of flashing into a cone a brazed it shut. In addition to reflowing my brazing, the flame burned though the thin alu.

Well, that was fun! Next I'll post more when I do more.

- Ed.

[chubbytrucker01]

Be very careful with your oil. Make sure it is dry. I had a friend burn down a transmission shop with about a million bucks in inventory over about a half a cup of water. He said it caused a flashback into the oil tank. He had been using this heater for about ten years and He thought he was being careful with it. Insurance didn't cover it either.

[jonas302]

A large tank with a drain on the low side really helps the water situation I burn 600-1000 gallons of oil  a winter and might get up to 5 gal of water drained

[elt]

Thanks for the heads up... I've read to drain the water off the bottom but I'm of the school that anything that can happen, (especially problems,) will. I'm using new oil right now so I don't have those headaches but maybe further on (while the furnace is still outside) I'll play with some water to see if the danger of flashback is something than can be minimized...

 - Ed.

[lglagasse]

Let me share my 2 cents with you on burning old motor oil. Keep the supply tank in an area where the temperature will not change much. Cold oil flows very slow, warm oil flows faster. In other words you might light the stove and turn on the valve for the oil to flow and 1/2 hr later the flow is greater as the oil warms which could cause flooding.

The best way I have found to burn oil is dripping it on a wood fire.

The systen that you have might work OK if you add some air flow around the burner area, ma by a small fan feeding a tube that would blow air. You will know when you have it right when the chimney stack has a gray ash film. I suspect the current set up leaves black soot in your chimney.

Be also cauthious of oil contaminated with antifreeze, this can cause a big flash.

Never leave a fire like this un attended.

Good Luck

lglagasse

[tecker]

Seems to me you could adapt a fuel oil burner to that oil with a little heat as was mentioned. Maybe use the blower also .Less smoke and soot more heat .  I think the blowers are brush motors so you can run them on 50 or 70 volts dc or an inverter.

[elt]

Second installment -

I finished the shell (sealed holes, attached air pipe and flue, made removable door) yesterday and worked on the fuel feed system today. I used one of the top pipe hole on the shell as a support to mount my prototype oil drip system. I had two valves to test and used a one inch pipe as an mini oil reservoir. FYI, The support pipe is plugged with flue cement and ceramic wool on one end and Bondo on the other to keep flames away from the reservoir. Oil comes out the other side of the pipe tee and goes to the 1/4" copper feed line.

I estimate that I need 30k to 40k BTU/hr and swag that to be a feed of about 1/2 ounce per minute. I calculate 1.8" of oil per ounce in 1" pipe so I figure that about 1" drop in level per minute would be about 35k BTU/hr input to the furnace.

The first valve I tested was from a freon tank. I couldn't seem to get any oil through it with the flare attached though it dripped oil on its own. The second valve I got was a spare propane cutoff value from my mini-forge. It was twitchy, a pain to adjust but it worked.

Sanders considers a quart and hour to be a "medium" feed rate and suggest that it should burn cleanly at that rate. I haven't seen that yet. It's hard to get a picture of the flame since opening the door instantly disrupts it:





It's not burning hot or clean enough but I think I'm on track. Sanders wrote:

The oil drip pipe that ends above the burner should be smaller than the 1/4-inch copper tubing (6.5 mm) that is usually used. When such large tubing is used, the oil comes out in big drops that cause relatively large waves as they drop onto the oil pool's surface. This disrupts vaporization to a significant degree when the heater is first started and not very hot.

I'm still using the 1/4 tubing and it's certainly making waves, Here's a picture down the air tube:





You can clearly see the oil pool and the waves caused by the large drops.

I'll pinch the tubing and drill a 3/32" hole (as Sanders recommends) tomorrow. Hopefully I can get the burn temperature up... There's more diddling to do with the fuel piping but I want to make sure the furnace is burning the oil cleanly first.

- Ed.

[libra]

I have played with a drip burner that was outside the house and 50 feet away. I found that the oil dripping on the wood worked well and if you get the right air combination the oil itself works well. My burner was a small cast iron frying pan. The oil viscosity is a big deal. As others have said it changes fast and can cause a roaring inferno. Never leave it unattended and keep a fire extinguisher handy.

 I thought of trying to use a carburetor from a old oil space heater but never got around to it. It may save you lots of problems

Libra

[pepa]

 hi Ed, everything looks good so far, this is the picture of a used veggy oil heater that i set up and used last winter, in my shop with good results. the valves that i use are from old lawnmore tanks and they work well with the oil and can be adjusted easy enough.

   i cut the end off a air tank and welded legs to it for my burner inside the stove, i also welded a small round metal bowl upside down inside the burner pan to spread the oil as it hits and to stop any splatter that may occure. make shure the oil is drained of water and it will burn without smoke after rhe burner heats up. i store my strained oil in several large drums and draw oil from the lower middle and water from the bottom. i have enough oil that i can let it set for a while and the o

il that comes out is free of water and other sedimenr. stay worm, pepa.

[lglagasse]

Hi elt:

 Your getting there. I think if you make a hole in the side of the tank above floor level to inject some air you will have better combustion. A small fan might do wonders, give it a try.Another point is your drip tube is going to build up soot and plug up, arrange it so it can be cleaned freqently. Note the pot burner had a fan on the back side.

Good luck

lglagasse

[ghurd]

Pepa!

I was ready to post something like "read pepa's stuff"!

How's it going?

G-

[pepa]

thanks Ghurd, everything is still slow and go. pepa

[spinningmagnets]

Thanks for posting this elt, your pics and description really got me interested now in this as a future option.

"BuildItSolar.com" has a great solar water-heat panel project that covers the south side of a garage, and the warmed water drains to an underground insulated pit. The warm water is used as a domestic hot water pre-heater, baseboard room heater, and circulated through tubes in the floor of the house.

This would be a great back-up for occasional "no-sun" winter days, and for me, your burner really makes that solar project more viable.

I wasn't quite sure how every part of it worked, so I did some reading up.

Here's two clear diagrams and a write-up from Mother Earth News...

http://journeytoforever.org/biofuel_library/ethanol_motherearth/z/woh1.jpg

http://journeytoforever.org/biofuel_library/ethanol_motherearth/z/woh2.jpg

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

"I once gave a despicable scoundrel a sound beating and was arrested, but after I explained that he had accused me of being a politician, I was released" -Mark Twain

[elt]

Hi Pepa,

I've done something similar - I cut the top off of a freon bottle to use the tank as the base of my knife forge; that left the top laying on the scrap pile and I used that as the burner base. With the ?valve guard? still in place, I didn't have to weld on legs. I had cut the valve off and thread the base for 1/8" NPT, hoping that was an all-in-one solution, but that was the valve that I couldn't get oil through.

So far the drip rate on the valve I'm using holds pretty constant one I get it set but it's still a real PITA for about 10 minutes. I can see that I am likely to build a metering pump before this project is finished.

I haven't tried a bowl on top yet but that will be one of today's experiment. Now that I have a good idea of that the feed rate should be, I will also hook up a bigger tank so I can get a longer burn.

I'm not adverse to blowing air in if I have to but would prefer if I didn't have to. So far I'm doing this all outside because I don't have a chimney yet. Yesterday I extended my flue from 4' feet to 8' and I got a much hotter burn... could see a tiny bit of blue in the yellow from time to time but still not hot enough. I'm going to have to work on some way to support the flue before I fell good about going any higher.

I've been scanning Craig's list hoping to find a free or cheep chimney. So far just about everything I've built with has come free from there. (And that's pretty much my budget!)

Thanks everybody,

- Ed.

[Bruce S]

WOW Pepa;

I was looking to post some of the pics I took while there. You beat me to it!!

Ed-

Let me be one who can atest to how well his works, once oil is going it'll run you away from the burner. The little adjustables Pepa uses works like a charm too, he's able to twist it down to off .

The pic of the oil doesn't do it justice, the stuff he gets has been nasty and the stuff he show pouring out is as clean as new, no water at all.

His secret BTW is time :-)

Bruce S

[elt]

Hi all,

I put a spigot on a one gallon jug and hung it, that gave me time to play with different things. A fan didn't seem to help the burner burn cleaner; I didn't try a "blower" though...

Without going through all the trials, I did get the burner to burn cleanly. Basically, I put a "lid" on it.





I cut a hole in the aluminum disk that I used in my first test, turned it upside down and let the oil drip trough that. Under the cover, the oil got hot enough to boil, that made vapors and the vapors burned cleanly. With this setup I get a "soft roar" at the top of the air tube indicating a much stronger draft that I was getting before.

When the feed was turned up, I noticed that some of the oil would bubble through the middle hole and fall on the lid and vaporize there.

One thing, though, is that the burner will not burn out. When the drip is stopped there's a point where it just goes out and leaves a little unburned oil in the bottom... a little less than in the picture; I had disconnected the feed line and what was in it ran down into the burner as well. I'm guessing that a much smaller fire needs a smaller lid.

I ran the burner for about two hours and burnt a half gallon of used motor oil. I know that's not an exhaustive test but I think now that it will do what I want it to do.

I need a crash course in waste oil management. I have 55 gallons coming Sunday and I have to get straining, draining and dispensing worked out.

I do have an idea for a metering pump: I'll chuck up a big lag screw in my lathe and touch up the threads to make sure the are all exactly the same diameter and then polish them smooth. I'll drill a hole the same diameter in block of something and drill tap two holes, one near the top and the other at the bottom... use the top as the inlet and push the oil "down" to the outlet as the screw turns. If it works, a small gear motor or stepping motor should be able to turn the screw at a constant rate. I'll see if I can do something like that this weekend.

 - Ed.

[elt]

Hi all,

Yoo-hoo! I did come home with 55 gallons of waste motor oil today.

Burning vegetable oil:

I was curious if I could burn vegetable oil so I sacrificed a half gallon to curiosity yesterday. (It was clean oil, I didn't have any waste.) I'll say that the oil was not impressed with my "lid" or at least not the way I was trying to light it; not sure which.

The way I've been lighting the motor oil is to put a 1/4 cup of kerosene in the burner, light it, then start the drip. But the veggie oil went out on twice before I gave up. I had a bunch of oil in the burner that I wanted to get rid of so I wadded up a half a paper towel and put in the burner and lit that. Burning from the "wick" I got a little bit of flame and after a while I noticed that the flame was trying to spread a little so I started the drip again right on top of the ball of paper towel. After twenty minutes the VO did catch fire and I had the same rosette of flames from the down draft that I get from motor oil. While the draft wasn't strong enough for the intake to roar, the exhaust coming out the flue was somewhere between white and invisible. I don't know if WVO is dirtier but I can say that new stuff burned cleanly.

Easy way to clean the furnace:

Burning motor oil with the "lid" leaves a little unburned oil when the flames go out. Am I being stupid? I notice that kerosene floats on oil and adding a little to the bottle means that I get a minute or so of rip-roaring flame when the oil runs out and that dries out everything in the burner nicely.

Thanks again,

 - Ed.

[pepa]

use the paper towel along with a shot of charcoal lighter and you will get a fast start for your burner. pepa

[elt]

Thanks pepa, I'll give that a try.

 - Ed.

[dngspot]

1/08/09

I gave the MEN information to a couple of guys at work. We have an endless supply of used oil so why not make it happen. One of the guys has finished his unit. He did a 5 hour test run with a chimney sticking out the side door of his garage. It was 20 deg out and about 75 deg in the garage. His unit did not use the conical burner; he used a stamped metal pan. He also used a 4 inch computer fan to blow in the air tube. Over the five hours it used 2 gallons of oil. His tank is located above his heater off to the side. It is also attached to the heater. It also uses a simple needle valve for oil control. During the visit he never adjusted the oil flow.

I have started mine. I will be using a conical burner. I have pressed it from 1/4 steel. If it does not heat up enough during start up then I will go through the hassle and make one from aluminum. Tonight I stripped the hot water heater and cut a door in it. Then I noticed that I only have a 3 inch draft tube. Since Roger Sanders reduces his to 2 inch to slow velocity I will leave it alone. I will test it this way and if needed will still reduce it or weld in a 4 inch tube. I will also mount my tank similar to the unit my buddy made. I am hopping to have it finished by next week.

I intend to show pics as I progress.

The burner.



1/12/09

Just about 30 minutes of work today. I cut the hole in the top of the heater, cut the stack and welded it into place. Dad always told me to clean metal before I weld. Yea he is right the weld is not pretty but, it will not leak.

As for the tank I have a pic of it finally. This thing is upside down, the fitting on top is the drain into the heater.

Side note. My wife had that garage looking pretty nice. A half of an hour, now I am feeling at home.

The heater.



The oil tank.



1/13/09

No real progress today. I was held up at work.
I did start on the hinges. They are made from a tube that was used as a push tube for valve rockers in a 3406 Cat engine. The pin is a 3/8 inch bolt that I lathed the head to be round and its o.d. the same size as the o.d. of the tube.
I also built inner frame for the door opening. I cut the material and welded the ends to make a square. I bent the frame as best I could on the outside of the heater then clamped it into the inside of the heater. I used a torch to shape it the rest of the way. It is cooling now.
That is all. Tomorrow may be a better day to finish more.

[elt]

You do some very neat work!

I switched to a needle valve too ($6 USD from Lowes) and now my drip is steady enough for the furnace to run un-fiddled-with as well.

I'm back to using a conical burner but I didn't machine it, I folded and braised a piece of sheet metal to make it. A six inch circle with a .6" pie slice folded over (or removed) gives the correct cone. I think aluminum works better but I've yet to braise/solder one without burning through. My sheet metal ones light quickly but I only get about a 30 degree temperature rise for about the first 45 minutes then all of a sudden it jumps to about a 70 degree temperature rise. (Mine is set up to circulate air versus being a radiant heater.)

I think (really just a guess) that your reasoning about the 3" draft tube is on the money; I generally can't open my 4" tube more than a quarter way without blowing out the flame. I can't imagine blowing air down the tube with a fan. I am getting some soot so I am going to look at blowing air in at the bottom as some folks here recommend.

I did make a change to my furnace. I put a baffle in it to lengthen the path of the exhaust gasses to he flue. I got the idea from a drawing of a wood burning insert at www.epa.gov. The bottom of the furnace is definitely warmer than it was but I can't say that I see the difference in the temperature of the room.

I am eager to read how yours works for you and please take more pictures!

- Ed.