Using Pure Vegetable Oil to Power Diesel Engines
Many people are familiar with the term biodiesel because this "new" fuel source is getting a lot of media attention. Basically, the biodiesel available at the local "gas station" is a blend of petroleum diesel and pure biodiesel processed from virgin or used vegetable oil. Depending on the location, 10%, 20%, 90%, or even pure 100% biodiesel is available to pump directly into your diesel vehicle.
Obviously, petroleum diesel is common, but the notion of combining it with renewable, plant based oils is a novelty to many. However, the only true novelty is the renewed familiarity with an old fuel source. I think it was back in the 1920's when Rudolf Diesel (sound familiar?) introduced a new engine powered by pure peanut oil. So, in essence, if you take things back to their roots, diesel fuel isn't a petroleum product at all.
The method by which vegetable oil is turned into biodiesel is a fairly simple process (but probably not for the average homeowner) involving the addition of methanol, lye, filtering, etc. and here's a link to learn more about manufacturing techniques if you're interested.
http://www.biodieselgear.com/documentation/index.htm
The focus of this page, however, is not biodiesel, but the use of pure (or not so pure actually) vegetable oil obtained as a waste product from local "fry pits". With a little time and labor, a diesel vehicle can be powered with pure, non-converted vegetable oil for approximately .05 a gallon. And since diesel vehicles get outstanding mileage in the first place, this can easily result in a nickel spent for every 50 miles of driving. Compare that to about $5.20 for the same distance traveled using gas at today's prices ($2.60/gallon). Of course, gas prices will drop dramatically in the near future...a,ha, just checking to see if you were still paying attention.
In theory, virtually any diesel appliance can be powered by pure vegetable oil. Cars, trucks, tractors, generators...even heating appliances burning No. 2 heating oil. But in practice, it's best to tread slowly into the world of vegetable oil fuel and resist the temptation to pour pure vegetable oil into every diesel appliance you own. Here are a couple of reasons why...
Viscosity
Unlike petroleum diesel fuel or biodiesel, pure vegetable oil thickens when the temperature cools. And nothing annoys an engine more than fuel lines clogged with congealed vegetable oil. To solve this problem, vehicles converted to run on pure vegetable oil are fitted with a second fuel tank. This second tank (veggie oil tank) contains a small heat exchanger plumbed in-line with the vehicle's radiator. After the vehicle warms up, hot antifreeze flows through the heat exchanger and warms the tank full of thickened vegetable oil, returning it to a nice, free flowing, viscous state even after the coldest winter night.
In warm climates like Mexico, the second tank is probably not necessary. Year round, straight vegetable oil can be added to the main fuel tank as if it were standard petroleum diesel. For colder latitudes, the driver, (knowing that after a frigid winter night the vegetable oil in his second tank is about the consistency of soap), starts the vehicle using standard, petroleum diesel from the main tank. The conversion kit includes a switch that allows the user to switch back and forth between normal diesel and pure oil. When the oil is too cold, i.e. solidified, to flow through the fuel lines, the driver powers the vehicle for the first 15 minutes on standard diesel. That's usually enough time to bring the engine up to temperature and "melt" the congealed vegetable oil.
In essence, the diesel fuel is used to get things going, then pure vegetable oil takes over.
One very important procedure bears mentioning here, namely, the last three miles of your journey. It's not so important in the summer, but in the winter, the driver MUST remember to switch back to regular diesel about three miles away from the final destination. If the destination is a quick dash into a convenience market, don't worry about it. But if the vehicle will be sitting in a cold parking lot for an eight hour workday, switch over to petroleum diesel three miles away from work. This gives the fuel pump plenty of time to replace the vegetable oil in the fuel lines with standard diesel. Remember, the heat exchanger can only warm the oil when it's in the veggie tank...and it can only do that when the engine is running. If the fuel lines are clogged with congealed vegetable oil, the engine won't even start.
Obviously, this is an important issue and an easy one to forget. For that reason, the veggie car conversion kit (www.greasecar.com) actually includes a special feature to address those times when, "OOPS, I forgot to switch to regular diesel and now I'm sitting in the parking lot looking like a guy with clogged fuel lines in my future." In this scenario, the options are idling the car for five minutes, driving around aimlessly for a couple of miles to charge the fuel lines with diesel, or using the convenient toggle switch to "purge" the lines of veggie oil by flushing them with diesel. Makes you wonder how many times the folks at Greasecar.com forgot to switch over before somebody added this feature.
Of course, it goes without saying that running the vehicle on pure vegetable oil should be confined to medium and long range trips. A quick trip to the store or post office probably won't warm the oil sufficiently in the winter to make it useful.
Purity
If a person with a diesel vehicle, on a warm summer day, ran out of fuel within walking distance of a supermarket, and the nearest gas station selling diesel fuel was ten miles away, he could simply purchase a gallon of canola or soy oil, pour it into the fuel tank, and drive away. Right out of the container, either of these oils is fuel worthy. But, that kind of defeats the purpose of using vegetable oil as a cheap alternative to petroleum diesel.
A much better approach involves "recycling" soy or canola oil that has already been used to deep fry food. Any restaurant selling fried foods uses oil suitable for fuel. For deep frying purposes, this oil has a limited life and, after repeated use, is poured into a waste container and recycled...at a cost to the restaurant.
Because of this expense, restaurants are happy to redirect this waste stream to someone willing to take it away for free. So, unless there is someone in your neighborhood also fueling a diesel vehicle with pure vegetable oil, you'll have no competition for an easy to obtain, free, "waste" oil suitable for fuel. And even if another greasecar roams the area, there's usually plenty of waste oil to go around.
So, once you've secured a supply of used fry grease, the next step is refining the oil into a fuel grade product and I'll illustrate the steps below.
Step #1 of the filtering process uses about .05 cents worth of filters per gallon
Since we're not making "biodiesel", the only treatment needed to turn used vegetable into fuel is filtering. A lot of fries have swirled around in this grease, so small, crusty debris is common in the raw waste oil. For the initial filtering process, basic restaurant cone-type strainers are used to pre-filter the grease.
Use two cones for this step. Pour in some grease and keep replenishing the filter until a noticeable slowdown occurs. When you feel that the top filter is too clogged to be useful, remove it and place a new filter under the bottom filter. In other words, the "cleaner" lower filter, becomes the top filter and the process repeats.
A note about grease: Experience has shown that not all waste grease is created equal. It's not so much the type of oil, i.e. canola as opposed to soy, but what was fried in it. By far, oil used exclusively to make French fries is best. Oil used to fry fish also flows well through the cone filter. On the other hand, waste oil used to fry chicken is almost useless. There is simply too much fat left in the grease. I've filtered (tried, that is) waste oil from a restaurant that cooks primarily fried chicken and it clogs the cone filters almost instantly. It's truly not worth the effort it takes to filter it.
Once you have a reasonably sized container of pre-filtered oil (five to twenty gallons), the step #2 filtering proceeds.
Step #2 of the filtering process utilizes an oil transfer pump and a standard whole house water filter with a 5 micron cartridge
The rig shown above was assembled in a couple of hours and costs about $150.00. If you're serious about producing fuel for .05 cents a gallon, this assembly will save money in the long run. It consists of an intake hose (see lower photo) an in-line strainer (optional), an oil transfer pump (Shurflo Model 4U125), and a standard whole house water filter fitted with a 5 micron filter. Two washing machine hoses tie the components together.
Pre-filtered grease is drawn from the collecting barrel, pumped through the 5 micron whole house filter, and then stored for later use in a 55 gallon drum.
The oil filter in the vehicle itself acts as the final guarantee that the oil entering the engine is as pure as petroleum diesel.
Radiant Heating with Used Vegetable Oil
If you can secure an abundant supply of used restaurant grease (500 to 700 gal. a year), have devised a good method of filtering it (see above), and want to use it to heat your home, a waste oil boiler can produce all the hot water you'll need to heat even a very large home. Rated at over 300,000 BTU's, a boiler from Clean Burn can pay for itself in less than two years. After all, the grease is virtually free and with #2 heating oil costing almost $3.00/gal. (and rising), the math speaks for itself.
Needless to say, if you also happen to have a supply of used motor oil, or just want to burn what you drain from your own vehicle every 3,000 miles, this boiler is ideal.
Once you're making all the hot water you need, heating a radiant floor is simple. Visit our main website at www.radiantcompany.com for all the details.