Running diesel generator on used cooking oil?

I was just wondering if anyone has ever actually tried using filtered, used cooking oil (straight cooking oil, not biodiesel) in their diesel generator? I hear it can be done, but I'm curious about hearing the experience of anyone who has actually done it. I suspect everything is pretty much the same except that the air smells like whatever was cooking in the oil.

Almost any diesel will run on filtered cooking oil but you have to get the engine temp. up with regular gas or biodiesel first.

You can buy kits which have two fuel tanks and electrically powered valves that switch to the oil once the engine temp is up.

Note I've never done it but know people who have experimented with it.

I imagine this as an experiment with a VW Rabbit diesel after the doors fall off. I suspect the particulate output and general fouling with soot would be rather nasty.

The engine would certainly have to be hot. And ideally, the oil should be preheated to thin it out. Don't try it in a cold climate; even after conversion, biodiesel gels rather easily.

And would the injectors clog running fast food fat (like arteries, perhaps)?

Horsepower falloff? Perhaps. Might be more suitable for a stationary generator than a car on the highway.

In a survival situation, at least in the longer term, calories will trump fuel. Feed it to the creatures that feed you.

Last thought: used cooking oil from fast food joints is now worth a substantial amount of cash. It's not waste any more. So it's best to have a legit source (i.e., ask permission).

If anyone tries this, make sure to post the results!

For these converted diesel vehicles with the dual tanks--do they have to switch back to diesel before shutting off their engines? I'm just wondering, if you turned off your engine while it was running cooking oil, and it was cold, it would seem that the oil would really gum up the engine when it eventually gels.

But back to the generator, I don't see any convenient way to switch between diesel and cooking oil except for warming it up on diesel and then adding the cooking oil to the tank. And then what? Adding diesel back again when you're getting near to shutting it down? That sounds like a pain, and when you shut off your generator is not always something you can plan ahead for.

Does all cooking oil, solidify, doesn't vegetable oil remain liquid even at room temperature?

The only reason I ask was that one of our technicians scrounged a few litres of the stuff from our canteen, the used stuff of course, filtered it and poured it straight into his tank. I think the ratio was 1:15 or 1:20 I can't remember exactly and the guy's moved on now so I can't ask.

What was noted was a huge cloud of black smoke, I mean most diesels give off smoke, but you could always tell this one because he very nearly had to keep his lights on all the time the cloud was so thick. Strangely enough the smell wasn't as strong, as it would be if it were just of diesel.

My irrepressible curiousity drove me to read some about this topic. This was one of the best sites on trying to do it: http://www.me.columbia.edu/me3410/spring06/group01/

I haven't run a generator on used oil but I have a car that runs on it and will shortly have another one once it gets some other work done to it.

There is a lot of misinformation as well as truthful information available about doing this sort of thing.

From people who are actually doing it to those who haven't even tried it claiming it won't work.

All I can tell you is this: my Mercedes diesel has been running on straight, filtered, used cooking oil for the better part of a year now, with an occasional gallon of diesel fuel when traveling or when my oil supply ran short. I don't have 2 tanks, I don't pretreat or preheat the oil other than running it thru my 2 barrel filtering system. While we've had a couple of issues with the car, none of them were traceable back to using the oil for fuel. The car puts out less noxious emissions using oil than it did using diesel fuel, that smoke you referred to was carbon being burnt off, a byproduct of using diesel fuel. There is evidence to suggest that using veggie oil is much cleaner than using diesel fuel. Most of the negative things you'll find are either produced by people who have never tried the process or who have another agenda.

There is a ton of information about these sorts of things on the internet, I'd suggest that you look up the biodiesel/svo webforums for a start, do a google search for them and then take what you learn, decide if you want to do the necessary work and make an informed decision.

I'll end with this, the inventor of the diesel engine, Rudolf Diesel,designed it to be run on vegetable based oil.

John E

Great post, JohnE. Where do you get your oil?

BTW, it's interesting to know you don't need any preheating or fuel switching in California. In colder climates, I'm not so sure. In a Canadian winter, for example, we have to switch to a winter formulation even for standard diesel; the summer stuff will gel up.

Doing a little reading last night, I get a little confused about the heating issue. At the moment, I get the impression straight vegetable oil (like, a brand new 5-gallon container you buy at the big box store) requires heating, while using used cooking oil (my original question) seems like it doesn't...but maybe I'm wrong on that.

Not sure if this has anything to do with it, but used cooking oil contains far less water than "new" vegetable oil due to it being burned off in the cooking process.

Have done quite a bit of reading on the subject, i have not run SVO in a diesel so for what it's worth. Heating SVO is to thin the viscosity of the oil so that it is about as thin as diesel fuel. And from what i have read and the people that i have talked to that have done it older engine designs are much more tolerant of thicker fuel. So if you are in a warm climate and have an old diesel you might be ok with out heating the fuel. If your engine is not tolerant of thick fuel you will damage the injectors $$ or the injector pump $$$$.

There is more information out there but here is a place to start,

http://journeytoforever.org/biofuel_library.html

In several of the posts have touched upon the salient points.

The original Diesel engine war designed and developed to run on peanut oil.

Yes the newer electronically controlled engines have tighter tolerances and are less forgiving of using straight vegetable oil.

There are 3 primary reasons for processing vegetable oils into bio-diesel.

First the process removes glycerin and other impurities above and beyond simple filtering. This makes it cleaner burning and more efficient. Since it is a relatively simple process. It is worth while to do. The only real problem is the initial expense of the equipment. But a good scrounge could easily over come much of these problems.

The second is viscosity. The process does thin out vegetable oil to more the consistency of commercial diesel.

The third is temperature tolerance. Diesel as well as vegetable oils have a nasty habit of getting thicker as the temperature drops. If it gets cold enough even commercial diesel gels to the point you can't pump it from the tank. That is why there are winter formulations for diesel fuel. It is also one reason many truckers leave their engines idling when stopped for sort periods of time. Such as rest stops and meals. The Bio-diesel process lowers this critical temperature somewhat for vegetable oils.

The reasons for preheating and the duel tank systems is to help over come this viscosity problem.

It is somewhat easier to start a more modern engine on diesel than vegetable oil. It simply takes more cranking to get the engine running on straight veggie oil. But it is do able.

It's true I live in SoCal where the normally warm weather is particularly conducive to veggie oil driving. As for where to get oil, we have a small network of local restaurants that give it to us. While it is becoming more valuable, more often than not restaurants are still having to pay to have it taken away by registered "grease" haulers.

There are very strict rules regarding the disposal of used cooking oil in Los Angeles county and I would imagine in most other parts of the country. It's not toxic nor is it dangerous but it is messy and the authorities don't want it poured down the drain and allowed to mix with the normal sewage here.

As for solidifying, true vegetable oil will solidify at whatever it's freezing point is, hydrogenated vegetable oil will solidify at a much higher temperature. There is no practical difference between new and used oil so far as solidifying in my experience.

The idea of pre-heating is the one which prompts most of the battles between the "2 tankers" and the "single tankers" in the veggie oil conversion world. There are solid reasons, no pun intended, to use either system. It all depends on the type of engine you're going to use, the normal ambient temperature where the engine will be used, how much money one wishes to spend, etc. One system that I'm planning on adopting is adding fuel line heaters to my single tank converted car. These are electrical heaters that are wrapped around the injection lines, they preheat the oil prior to it being injected into the engine. I've gotten very positive comments about using them from fellow single tankers even here in SoCal.

I will add that I am doing this using a 1985 Mercedes with the almost bombproof 5 cylinder engine. There are examples of these engines lasting for well over 500,000 miles. My current car has close to 400,00 kilometers on the original engine, it was originally a Canadian import and has a metric odometer and as I wrote earlier, we have had no engine problems that could be traceable to using veggie oil for fuel.

I would urge anyone interested in either trying this or learning more about it to research the net, there is a lot of info out there and more than just a little snake oil too.

John E