Alrighty, lets hear the plans from BD users for cold weather operation.

The stuff I buy commercially clouds at 60F, and was pretty goopy at 40F.

I do not suspect water.

Best tests are by pouring your BD/Diesel mix in the tank, drive around for a few days, and then take a sample from the fuel filter and stick in freezer.

I am convinced that the 130F tank temps have a major effect on cloud/gel points, even after the liquid temps fall back.

Repeated heat/cool cycles (at least in the realm of what we are talking with fuel temps) shouldn't affect the actual crystallization point of the esters much. It is possible that continual warming/cooling could lead to condensation, leading to more dissolved water in the fuel, which could begin to change the gel point. If it is unwashed, off-spec fuel, you could have unreacted glycerides still in the fuel, which after being heated are still reacting. This would cause free glycerin to then be present in the fuel, which would show up as an elevated gel point. Spec fuel or even washed, non-spec fuel shouldn't have this problem, though.

As to what to do for cold weather operations, that is an issue. The only sure-fire way to burn B100 in really cold temps is to go with a 2 tank setup similar to a WVO conversion. Only you would use regular dino diesel in a small second tank (or main tank and have another tank for the bio). Start up on that, then switch over to the bio when the temp comes up. Use either a small electric fuel heater or coolant/fuel heat exchanger to heat the bio up above its gel point. Wouldn't take much.

Otherwise, blending the bio down will depress the gel point. Some anti-gel additives particularly for biodiesel are out or coming out in the near future, but I'm not sure the status of those at this time and how effective they even are.

I think that the repeated hot/cool cycles make the BD blend much better with the diesel.

I did two tests. ~B50 in the tank, driven for 50 miles. I took a sample from the fuel filter. Clear as could be. Looked great.

I took another sample of B50 made from adding B99 and ~50% diesel from the pump. I shook it real hard. Put it in the fridge for a few hours. It was cloudy, but not gelled like the B99 sample would have been. But, once I took it out, it refused to clear up. Cloudy for several days, until I poured it in the tank.

I think heat is a very necessary step in mixing D2 and biodiesel.

BTW, the biodiesel.org board has some real good info on cold wether BD operation. PDF style.

I can say with pretty good certainty heat has little to do with the blending characteristics. As long as it is warm enough to flow freely, the mixing process will happen at any temperature.

The phenomenom you describe, however, is indeed due to better mixing after being put in the fuel tank, I think. But, it isn't due to heat. Think about how much fuel is sucked through the fuel system vs what is actually burned. How many times do you think the same given volume of fuel travels through the fuel system before it is actually burned? The fuel pump performs the same function as a mixing pump on a biodiesel reactor. That constant circulation is what is aiding mixing, not the heat.

I waited a few days to post back here, I was doing an experiment.

Sample one: B50, mixed by shaking VERY hard for 20 seconds. Harder than it could ever be shaken in the truck unless I rolled her over. Put in fridge overnight, pretty cloudy in the morning. Not impressive.

Sample two: B50 in the truck, driven 100 miles or so to mix. I took this sample from the fuel filter by pumping. No water in this at all. Set in fridge overnight, and it is completly clear in the AM. Looks exactly like it did when it went in.

More is happening in the tank than meets the eye.

Have you looked in the biodiesel.org site? The cold weather biodiesel PDF is very informative.

More is happening in the tank than meets the eye.

Heating and filtering, yes?

Filtering does nothing for clearing up cloudy BD. Ive checked tank temps a few times with the predator, and it is around 130F. This is either evaporating water out of the BD (my BD seems to be quite dry) or allowing complete mixing to occur.

All I know is that there is a big difference between B50, and B50 that has been heated and mixed (at the same time) with diesel.

Manny, you're right about heat helping the blend.

Warm biodiesel does seem to blend better with petrodiesel than cold biodiesel. When temps get below 40F, I keep my BD inside the house to warm it up before adding it to the tank. In winter, I blend the warm BD in when the truck or car has been running for a while and the whole tank is warm. A couple of years ago, I learned the hard way that adding more cold dino diesel to an already cold tank of B80 or so doesn't blend. When the temperature here dropped from the 30s to the teens in December, the biodiesel segregated and gelled at the bottom of the tanks - in both the truck and the VW TDI. I had the truck's tank warmed, drained & refilled - and waited until warm weather (50F +) for the biodiesel in the VW to ungell. I spent a long winter filling up the VW before the tank got below half full; otherwise it'd stall when the fuel pickup hit "the lump".

I have been wondering the same , how much bd I can get away w/ this winter. The station where I buy my bd has a heated inground tank and they also add kero. The guy at the window didn`t seem to know.

I thought about a tank heater, I think I read somewhere that they can be bought. The problem is what to do during the day when the truck sits for long periods. I do home improvements, I suppose I could plug into their house. Anyway to run a heater off the trucks battery? Or would that drain the battery?

Even though bd has gone up to $3.92, I still get 1/2 back in Md.:)

Wayne

I called Tevis oil today and talked to the bio guy. He said it is ok to run it 50/50 in the winter. Even at 20 below I asked, Yes he said. With the additives in the bio and #2,he said it would be fine. Guess I can be the guinea pig.

Here is a link I foud http://www.grassolean.com/?textFile=wad

He runs B100 all winter, it doesn`t seem too hard to accomplish. Not sure how much it would cost.

Wayne

Ide take a sample from post fuel filter, and set it outside one night at 20 below. I bet you will have a jar of jelly on your hands.

Sample first. Running any IP dry is a bad idea.

Also make sure the fuel is clear.

I just started running winter fuel diesel cold flow checks and have several 80%#2, 20% B100 test results.

Untreated 80% #2, 20% B100
Cold Flow Filter plug Point +10 F, Cloud Point +22 F, Pour Point, 0 F. Untreated..

Treated 80% #2, 20%B100 treated 1:1200 with Primrose 4033 bio fuel treatment.

Cold Flow Filter Plug Point -9 F, Cloud Point 0 F, Pour Point -50 F. Treated, Primrose 4033 Winter Power fuel treatment.

George Morrison, STLE CLS
AV Lubricants Inc.
www.avlube.com

Interesting. I suppose that the results are not so good with B50 or more?

George,

I did not know Primrose had a bio fuel winter treatment.

Is the recommended usage for the product for no more than a 20% blend or is there guidance for higher blends...say 50%?