home made outdoor waste oil boiler experiment

[gardrail]

Greetings,

I just registered the other night, and thought I'd post one of my projects. With the cost of heating going through the roof, and my cousin having a few hundred gallons of waste motor oil laying around, i thought I'd make an attempt of building a hot water heating system to beef up the heat in my garage and downdstairs when it gets cold.

The basic idea behind this is to get a large pipe, run some exhaust pipes up through it and cap the top and bottom with water tight welds. There will be two 2" bungs to allow for water circulation through the system...

During a salvage yard run, I managed to score some 16" diameter 1/2" wall pipe, and some 1/2" steel plate to serve as both a top & bottom cap of the boiler. The exhaust pipes that will take hot gas from the waste oil burner, up through the boiler is some 1" black iron pipe.

I'll have to upload some pictures later, but so far the top and bottom plates have been cut, and the 5 holes in each side cut out to accommodate the black iron pipe. The pipes have been tack welded in, and just tonight I managed to get an old stick welder out and weld up the pipes in the bottom plate. Keep in mind that this is my second welding project and I've only been welding for a couple months.


In the grand scheme of things, I want to have a cast iron radiator in the garage and setup radiant floor heating in the downstairs of my home. I figure the hard part will be building the boiler and making it water tight. After that I'll focus on an intermediate holding tank for the hot water (since the unit itself will only hold ~ 17 gallons), and running the PEX into the house about 50' away from the burner.

Managed to score pipe for the chimney (8"), and enough 16" diameter pipe to make a few boilers (and a nice piece of 1/2" plate)


Had to burn the paint/tar off of the casing (24" tall x 16" diameter)


The boiler core with the five 1" diameter exhaust pipes running through it tacked in place. will MMA it with 6011 to hopefully make a water tight seal

 

[magicheater]

Will this be a multi-fuel or strictly a waste oil boiler? Are you going with a water jacket or water tube type? How do you plan to introduce your fuel source and regulate it? Please post some of the dimensions you plan to use.

 

[gardrail]

Those are good questions - I'd like to focus initially on a waste oil, but I want to make it modular enough to where I could change out the burner (or firebox) under the thing.

I have no faith in my welds since i've only been doing it for about 6 months. I opted to fill the larger volume with water, and use the black iron to channel the hot gasses up and out to the exhaust above the unit.

The unit itself is 25" tall, 16" in diameter... When I get to the point of welding things up - i want to make sure i have a bung on the top to screw in a pressure relief valve, and do a leak test to see if my welds have gotten any better (they are getting better, but I don't think I should quit my day job)

There's a couple waste oil burners that interest me as a potential heat source... one is a gravity fed type where the oil is dripped down on a hot plate which vaporizes the fuel & continues the process... the other one that might actually work out a bit better (but will require some fiddling) is a burner that uses compressed air and a siphon nozzle to atomize the fuel (Waste oil Burner.wmv - YouTube)

 

[gardrail]

Managed to get a bit more work done on it. In order to ensure that I get a good weld, I took the time to take the oxy torch and attempt to bevel the edges of the various cuts that I made. Two holes are in the side of the tank, one at the top, one at the bottom that will accommodate two threaded 1" couplings.
(top hole - bottom hole not pictured)




At the top, I cut a hole to allow for a pressure relief valve in the off chance this thing actually produces pressure in an open-system configuration.





And Before I called it a night, I then beveled the edges of the top and bottom plate...



here's some close ups of the beveled edges - i'm planning on hitting them with an angle grinder to clean them up a bit... I'm still new at oxy-acetylene cutting so it's not very clean..

(bottom plate bevel)

(top plate bevel)



When it's all said and done, the piece i was cutting on should slide right into the outer casing something like this:

 

[vpd66]

What type of burner do you plan on using? I have an old Beckett oil gun I've been thinking of converting and retrofitting in to the door of my outdoor wood boiler. Then I can burn up my waste oil and it would still burn wood. It would be dual fuel.

 

[gardrail]

I'm planning on starting out with a waste oil burner primarily but am thinking of different ways of using either wood or coal in addition to waste oil.

 

[Stick895]

I'm no en-gineer but this seems like a project that shouldn't be done in a home built manner. Just my $.02

 

[gardrail]

yer probably right. but hey why not?

 

[hr3]

Ya why not,, keep it up I can't wait to see how you make out,,,

 

[gardrail]

Thanks for the encouragement. I'm hoping to make some progress this weekend to include sand blasting the inside bits. More than likely I'll find some cheap paint to coat every thing - even though it's going to be sealed up and have water in it.

With any luck I'll have it welded shut & test it for leaks.

 

[gardrail]

Managed to get some fittings welded into the holes that were cut in the top and sides.

Top bung - 3/4" with 1/4" bushing for pressure testing



Water outlets to circulate the water 1" bungs welded in-place. They are ground flush to allow the center bits to slide in for welding



Tractor supply primer painted on there to prevent rusting. I have a feeling this may cause some problems in the future - but hey, it's the first that may not work anyways

 

[chim]

I'm no en-gineer but this seems like a project that shouldn't be done in a home built manner. Just my $.02

I'm not an engineer either (nor did I catch a few Z's at the Holiday Inn Express) but am not all that concerned about safety. Gardrail did say it will be outside and will have a relief valve. My worry is the current design is short on surface area for heat transfer and cross-sectional area for exhaust flow. I would expect to see a bundle of tubes.

I do applaud the effort and it does look like an interesting undertaking. I have a bud who heats his shop with an old oil gun in a 14"Ø pipe. He uses regular heating oil in his though.

 

[Raspy]

As Chim said, the surface area seems really limited. Before you weld it closed, maybe put a baffle of some design to make the water pass back and forth over the tubes and be more turbulent.

At least you probably won't have any condensing problems in the exhaust system and it will be fun to see how it works. Then you can make the next generation and address any weakness.

BE SURE TO USE A PRESSURE RELIEF. A standard hydronic relief is set a 30 PSI, or are you planning on running the system at higher pressure?

I like projects like this.

 

[vwnotrunning]

Be sure to put more than enough relief valve(s)! Configure the exhaust tubes in a manner that will allow for easy cleanout / brushing. Waste oil gases and low temperatures will soot up quickly and will require frequent cleaning unless you get the burner tuned just right.

 

[gardrail]

Thanks for the suggestions!

I stopped by the local plumbing supply shop to pick up the couplers (lowes and home depot only had the cast iron ones) and priced out the residential pressure relief valve (30psi) - that's why I went with a 3/4" connector on the top so the valve can go there.

The idea of cleaning out the exhaust tubes that go through the boiler itself is in the back of my mind as I build this out. I'm envisioning some kinda flange that I can attach the chimney to that can be easily removed so that a wire brush can be run through the tubes every now and again. Until I get this thing dialed in, I expect to find soot everywhere.

On a side note - I bet a pretty sweet forge could be built using those siphon nozzles from Patriot Supply. With enough air/O2, and the 1 gallon per hour nozzle I bet most things could be rendered to ash or a molten puddle of ooze.

 

[stingray1]

I'm not an engineer either (nor did I catch a few Z's at the Holiday Inn Express) but am not all that concerned about safety. Gardrail did say it will be outside and will have a relief valve. My worry is the current design is short on surface area for heat transfer and cross-sectional area for exhaust flow. I would expect to see a bundle of tubes.

I do applaud the effort and it does look like an interesting undertaking. I have a bud who heats his shop with an old oil gun in a 14"Ø pipe. He uses regular heating oil in his though.

I agree,you need a lot more tubing to make this work.

 

[gardrail]

hot gasses go through the black iron pipe - not water

I don't trust my welds that much

 

[chim]

hot gasses go through the black iron pipe - not water

............................................

Yep, understood that. Our company installs - not designs -various heat exchangers. Some are steam to water, others are water to water. Two types we encounter regularly are plate type and tube type. All the tube type heat exchangers I've seen have bundles of tubes that are very close together. One big deal with any heat exchanger is having sufficient surface area for the heat to be "exchanged".

Google "tube type heat exchanger" and you'll see what I mean.

 

[gardrail]

Yep, understood that. Our company installs - not designs -various heat exchangers. Some are steam to water, others are water to water. Two types we encounter regularly are plate type and tube type. All the tube type heat exchangers I've seen have bundles of tubes that are very close together. One big deal with any heat exchanger is having sufficient surface area for the heat to be "exchanged".

Google "tube type heat exchanger" and you'll see what I mean.

Ah! I totally see what ya mean! Unfortunately I think I'm a bit too far in the design of the guts on this one. The next one I'll probably use 3/4" EMT instead of 1" black iron so that more surface area is available. I also got some ideas for baffles from a few of the images I saw - i think a 2.0 version will need to be built after I finish this one.

It's not a total loss as I'm picking up some welding skills, and if all of the welds are water tight - some confidence in my own abilities.

As far as surface area for this model, it looks like with the pipes i'll have ~ 497 square inches of surface area on the pipes, and an additional 30 square inches on the bottom plate

 

[Bigfoot62]

I'm impressed. At least you're trying. I've thought about a waste oil heater for years, but never did anything about it.

As far as your "engineering" goes, I wouldn't worry about it. I think it has to work. Maybe not the most efficient design, but we're talking waste oil. It's not like you're paying $4/gallon for it.
Think about a water heater in an RV. It is an air-to-water heat exchanger, and it has a single burner tube in a 6 gallon tank.