Josh is right. I worked for years trying to get the best mix of waste oil and #5 fuel oil, or slurry as it's called (which we purchased from the refinery near Farmington - at Bloomfield I think). Both oils varied in quality from time to time and I would have to adjust the mixture. Waste oil can be either pretty good or awful, depending on the amount of synthetic oil or other products such as solvent, etc. The oil from the refinery could also be either great or awful. The main issue was what the refinery called the "coking factor" - something to do with the efficiency of the cracking tower to fully refine the oil (I'm not a petroleum engineer so someone else on this board may know more about this). Oil with a high coking factor carboned up the fireboxes something awful, so I'd try and mix in a little more waste oil to compensate. Sometimes you'd get a load of crappy waste oil and high coking factor load of slurry that would make everyone's life miserable for a couple of weeks until you could draw the tank down enough to get some fresh oil in. Ask some of the former Loop guys about climbing into a hot firebox to clean out a mountain range of carbon before you could run for the day.
I'd suggest getting at least a 10,000 gal tank - bigger if you can as it allows more flexibility in getting deliveries. Install an air line that goes in the top of the tank all the way to the bottom. Hook up an air compressor for an hour or so and it blends your fuel nicely.
I always made my fuel oil plans early in the year as the waste oil and slurry suppliers sometimes had all their production contracted out to asphalt plants even before the summer season begins. If you can't get a contract you'll have to pay a much higher price for the oil and face possible supply interruptions.
From time to time I had offers to take oil for nothing as if you want to get rid of oil you have pay handsomely for the privilege. This resulted in sometimes getting some spectacularly wonderful oil, but sometimes you'd get stuff that looked like oil but wouldn't burn or make any steam to save your life. We even tried waste vegetable oil but it made the engines smell like they were burning french fries and tended to clog up the works too much.
Getting the right fuel is a challenge. Sulfur = heat and I was always looking for high sulfur fuel. I'm constantly amazed at all the hype about "low sulfur fuel". The lower the sulfur, the lower the heat and the more you have to burn to generate the same amount of energy. Good luck to guys in Alamosa in getting the right fuel as it will make a big difference in how your engine performs.
Phil
