It’s been a few years since I cold-flow tested my biodiesel. According to my last tests, I start blending 50/50 when the frost comes, and turn to pure petrodiesel when temps stay below freezing. Looking at the new tests, I think I could keep a little biodiesel in the tank for lubricity – but otherwise they confirm what I’ve been doing. Of course, the heated SVO runs all winter.
This last batch of biodiesel from used fryer oil was a mix of pure soybean oil from Jalapeños Mexican Restaurant in Eagle River and pure Canola oil from McLaughlin Youth Center in Anchorage. Jalapeños fries mostly tortilla chips, with a little chicken and other meat in their flautas and chimichangas. Their jug sludge is mostly fried foods, not fats. MYC fries more meaty fatty stuff, and although their oil is clear non-hydrogenated Canola, they do have an inch or so of creamy tallow/lard/fat on the bottom of about half of their jugs.
The diesel I used was from the local Chevron, from the ultra-low-sulfur-diesel pump labeled “not a Chevron product.” I’m assuming it’s a winterized #1/#2 blend since it’s November and nighttime temps have already dipped below 0F.
I filled a series of bottles: B100, B50, B33, B20, B10, B5, and pure petrodiesel. It went to 7F last night, and this morning at 11F the B100 was solid, while the B50, B33 and B20 were liquid, but had varying amounts of wax crystals settled out. The B10 and petrodiesel were both crystal clear (the B5 has some contamination and is a little cloudy at room temperature – I’m assuming a few drops of water).
Looks like B10 at 10 degrees is my new mantra.
P.S. www.make-biodiesel.org has some good biodiesel winterization tips.
UPDATE: the B10 and B5 dropped waxes out at 5F. Looks like it’s petrodiesel below 10F, at least with my used soy/Canola/animal-fat biodiesel.