Waste oil drip integrated to a rocket stove?

Hi,

My name is Christian, this is my first topic, I did some searching, and did not see any posts on the subject.

I do a lot of working on cars, and I live in Wisconsin, for about 6 months of the year, it is colder than I'd like, so I'd like to build an efficient heater for my shop. A batch style rocket mass heater sounds really great, efficient, clean burning, and low maintenance.

I am not too keen on mud being used, I know how to weld, so I am looking for minimal mud use (I would like to convince my wife to add one to our house as backup heat, and there is a hard "no" on bringing mud into the house, nothing made with mud will pass the test). If I can show her how clean and how well it works out in my shop, she may agree to having one in the house. I may encase some of the mud in metal so it isn't visible, I know it will kind of be needed to make the transition between the steel barrel, and combustion chamber. I have a bunch of old chimney brick from two chimney's from my house we took down. Not sure if they are good enough for the actuall combustion chamber, but some of them appear to be actual fire brick.

That said, being that I do quite a bit of work on people's cars as a side gig, I end up with quite a bit of waste oil, stuff you would not want to put in a diesel because it is pretty nasty, and old. It's not enough to run a full blown waste oil heater full time, but more than I like to just turn in to "recyclers" who probably just dump it out the back or sell it to someone else who is going to use it in THIER waste oil heater.

My thought was, have a steel line run into the combustion chamber of the rocket stove, where it isn't so hot it will melt the steel, but hot enough once it gets going to vaporize, and burn the oil. I've seen a few guys mod regular wood stoves for this, and thought it might work for a rocket, and actually burn it cleaner. It won't be the sole fuel for the rocket, my main source would still be wood, but it could cleanly and efficiently get rid of the waste oil, and benefit me by keeping me warm.

Has anyone done anything like this? I know it's not the most hippie thing out there to do, but honestly, it's gonna go somewhere, why not burn it in a rocket to make sure it is as clean as possible?

Thank you for any good ideas to help me!

Christian

Welcome to Permies, Christian!

I cannot help you with your main question, but the secondary problem that you have..

You could show this thread to your wife!

I hope one of our gurus will speak up to answer your question.

In the meantime, maybe this will help:

Neil said, "fine which I use for burning wood and old cooking oil but tried small piece charcoal in it the other day. Once it was well alight with wood and warmed up I filled the gravity feed tube with charcoal and boy did it heat up. It burnt really well and burnt everything in the tube till it was so hot the horizontal tubing was glowing red and there was no smoke at all.

https://permies.com/t/20896/coal-work-rocket-stove#620369

By the way, not all rocket mass heaters use mud. Some use bricks or pebbles:

https://permies.com/t/204583/rocket-mass-heater-tour-folks#1700713

https://permies.com/t/204583/rocket-mass-heater-tour-folks#1704081

What you propose should work. As you mentioned a rocket mass heater burns very efficiently.

I am in hydro now, but I was working at a trash to energy facility that basically was a rocket mass heater that made steam and turned a generator. As you can imagine it was highly regulated on emissions but we were less than one percent because it burned so clean. As for the oil, you should get the same sort of emissions.

An easy no cost way to test your thoughts on oil might be to just soak your wood in your free oil rather than set up a separate drip system.

Like you, I can get thousands of used oil to burn every year and thought of trying that first. If the oil seemed to burn well on soaked wood then maybe just set up a drip system if I thought it would improve life. My idea being, keep it simple at first.

I will say though that being a boiler guy, mine is not a rocket mass heater but a conventional wood boiler. Others might jump on here who have done RMH with oil drips though.