Started brewing this summer, fall is here, gettin' chilly outside. I put some of my bio in the refrig. Now the refrig runs 38F so I knew this stuff would jell and it did just that. I had never seen jelled bio and now I have. When I put the jar back on the shelf in the shed it does not want to go back to a crystal clear liquid; sat over one day at about 60F+ ambient temp. Jelled stuff is still on the bottom of the jar and the bio is cloudy. Another sample jar from the same batch is sitting beside this one, crystal clear.

What gives???
Mike...

Hi Mike

You've probably had moisture condense on the cold bio, which has upped its water content to the point where it goes cloudy.

Did you have the lid on it at all times? If warm moist air got to the cold bio, that's probably the reason for the cloudy bio on top.

The stuff at the bottom is probably higher melting point esters, which tend to be denser and sink, leaving the liquid esters on top.

Warm it up to around 120F and all should clear.

If it clouds when it cools again, the bio is still a little damp.

When I make my winter blend biodiesel, one of the steps is called cold processing.

I put my fuel in 5 gal cubies and I put them in the deep freeze for 24 hours. I learned a couple of very interesting facts by doing this:

1. The high melting point esters take some time to wax out into that yellowish sludge at the bottom of the cubie. Even though all the biodiesel hits 3F in two hours, it still takes about 24 hours for all the wax to precipitate out.

2. As an experiment, I took a cubie out of the freezer and allowed it to slowly warm up to room temperature. Some of the precipitated waxy sludge took DAYS to go back into solution, even though the whole cubie of biodiesel was back to about 55F in a couple of hours.

The moral of the story is that once you get the high melting point esters to precipitate into solid/wax, they don't want to liquify again without a lot of encouragement.

Finest regards,

troy

Hi Gram,
Thanks for not only answering my question once, but twice!!! I feel the love...

It was in a sealed mayonaise jar. (actually Miracle Whip (yum!), my wife prefers the mayonaise...yuck)

It looks like jelled bio. I fear that once jelled my bio is reluctant to go back into liquid at 60F. In the case I screw up and jell up a vehicle I may need more than garage temperatures to liquify the bio.

I am using hydrogenated soy shortening as my feedstock. This stuff is semisolid at room temperature.

quote:

Originally posted by troy:
When I make my winter blend biodiesel, one of the steps is called cold processing.


The moral of the story is that once you get the high melting point esters to precipitate into solid/wax, they don't want to liquify again without a lot of encouragement.

Finest regards,

troy

That makes a lot of sence. I just went back to the shed. The "control" jar is, of course, clear and beautiful. The cold test jar is dissolved on the bottom but I am seeing the whispy swirrling stuff still not quite dissolved. I guess this is even more reason not to jell up a vehicel. Could be a real problem

As far as the winter blend, I assume you jell up the bio and skim off the top and blend with...kerosene?...maybe.

Can you elaborate on you technique, I am going to have to come up with a reliable winter blend or shut down for the winter and go straight dino diesel (dread!!!)

Thanks,
Mike...

Hydrogenated oil that gels at or close to room temperature will produce biodiesel that will do the same, around 10C is the gelpoint in most cases I have seen. It makes great fuel, but is a summer fuel.
I used to use hydrogenated oil and even blending B20 didn't help in my freezer tests.

Mike
Time to swallow the pride and go to your wifes favorite chinese joint and ask for their oil,for the winter. Most places use non hydrogenated soy oil.
Some places use canola, if you can find that,you hit the mother load..........

Or if you could talk your establishment mgr(that shouldn't be too hard) into switchin to canola for the winter,YOU'D be settin in butter...
Jammer

Jammer,
Thanks for the encouragement. Unfortunately our KFC restaurant is under franchise agreement to use the hydrogenated shortening. We cannot change to any other type of cooking oil.

I am coming to terms with the fact that warm weather is coming to a close and I am going to be forced to discontinue my bio activities. I will have to switch to petro diesel for the winter for reliability. You have to understand the main vehicle that burns my bio is our F350 that pulls our catering trailer (seperate business from our KFC). I CANNOT have a breakdown on a $15K corporate catering this winter.

Since we work so hard in this business, I don't have a lot of time for many hobbies. This hobby, however, is one that fit into our business so well. Damn... I knew starting out this may be only a warm weather hobby but I got addicted along the way and now I don't want to give it up until March. But this is reality. A few hours ago I joined a beer homebrewers forum to take up an old hobby. I think this may tie me over until spring. At least I can drown my sorrows. heh heh heh...

Mike...

Mike you dont have to stop all together for the winter. Either stock up the WVO or convert to Bio and store it for the winter. We make more than we can use along with winter blending with petrol, we came out of winter with 700 gallons on hand! That was nice since two vacations were planned and the F250 takes 150 gallons to fill it up!
Rick H...

Here is a copy of a previous post concerning winter treatment of fuel. Please note that this process can be modified to use bigger amounts, as it is somewhat time consuming to do it with two cubies at a time. Since my VW gets over 40 mpg, I don't have to do a lot at once.



When you speak of winter treatment of biodiesel, you have entered the dark arts.

I say that because your starting oil might be a lot different than mine, your homebrew can be subtly or dramatically different than mine, your vehicle can be more or less tolerant of some wax precipitate, and your weather can certainly be different than mine.

Despite all that, here are some general guidelines:

A. Your starting oil matters. Unhydrogenated canola is generally considered to make the best winter biodiesel. Soy is pretty good. Animal fats, coconut oil and palm oil are terrible winter stocks. The resultant biodiesel gels in the temp range of 40-70F. Partially hydrogenated oils (shortening, often a semi-liquid) can give anything from good to terrible winter performance. Fully hydrogenated veggie oils (even canola) make lousy winter fuel. These oils are solid at room temperature.

B. Blending with winterized petro diesel works, kerosene works even better. The colder it gets, the more diesel or kero you need. I'll post some data from Duffscience later that shows how much petro diesel or kerosene it takes to attain a certain gel temp. There’s also a link with a nifty calculator to estimate how much K-1 you need.

C. Additives. None of the diesel additives for winter work as well in biodiesel as they do in petro diesel. Some additives work reasonably well if you double or triple the percentage added. This can get quite expensive. There is a lot of research going on right now to find the holy grail additive that will relieve us of the need to mix petro. So far as I know (September, 2006) it doesn’t exist yet.

Whatever scheme you decide on, be certain to do your own freezer testing to find out how your blend works. You should measure cloud temp (the temp at which the biodiesel starts to get wispy cloudy stuff (wax crystals coming out of solution)) and gel temp, the temp at which the biodiesel no longer behaves as a liquid when you tilt your container on its side. You can drive, for a time, with cloudy fuel. But eventually the wax crystals will plug your fuel filter and you will be walking. Once the fuel gels, you are totally beat. Cloud temp is usually just a couple of degrees above gel temp.

Here's what I do, which is a combination of blending with K-1, additives and cold processing to take the high temp waxes out.

1: Mix your washed/dried Biodiesel with some percentage of kerosene. I typically add enough kerosene to make true B-66.

2. Add 3x the recommended amount of Power Service DFS (Diesel Fuel Supplement) cetane improver. This comes in a white bottle and is available at most Wal-Marts and just about any truck stop. Mix well. Some sources say this step must be done at warm temperatures (like around 60F) to be maximally effective.

3. Cold processing. That's where you "refrigerate" your mix for a few days (which in my case usually means leaving it outside for a few days) and then siphoning out the liquid portion the next day and leaving the crystallized sludge portion for summer use. If I don’t get 3 days of good cold weather, I throw a couple of cubies in the freezer for 24 hours. A longer chill period is much more effective than a short one. It's amazing how much more junk precipitates after a full day in the freezer compared with just overnight. Then I let it warm up a bit to clarify the liquid fuel and really settle the waxes. This improves yields a little. Make sure you do this so you can go right to the siphoning step without disturbing the jug. Siphon the clear stuff out and you’re good to go. The finished product of course is no longer B-66, but something less than that, depending on 27 different things.

I use a siphon with a “J” shaped bend on the end that I made out of 2 copper 90’s. It makes it much easier to siphon from the top down and not disturb the waxy sludge on the bottom. The colder you chill the mix, the better the anti-gel performance in cold temps, and the lower your yield. Interestingly, the precipitated sludge has more BTU’s per liter, so you may notice slightly reduced performance on the winter blend. The “sludge” makes great summer fuel.

That's it for the fuel. Of course, there are other factors as well:

1. My car always sits in a garage overnight, along with my wife's car. This helps retain heat. Perhaps your car is exposed to the full fury of winter temps overnight…

2. I added a 120V coolant heater to my VW and use it religiously at or below freezing. So my engine does not start off stone cold in the morning. This increases under-hood temperatures and also makes my heater work right away, which is a nice bonus.

3. TDI engines like mine use a continuous fuel loop, so excess fuel (which is hot) gets returned to the tank. If it's cold out, it routes that hot fuel through the fuel filter canister. If your diesel doesn't do that, you could have a problem with wax crystals plugging the filter.

4. I have a Neoteric brand 12V fuel line heater activated by a rocker switch on the dash. This is in the fuel line just prior to the fuel filter.

5. Never fill the tank right full, so if you have a sudden -20F cold snap, you could dump a bunch of kerosene or winterized diesel in there, along with some more anti-gel additive. You’d at least stand a chance then.

6. I keep a quart jar of winter blend fuel outside on the way to the garage. That gives me a visual check of what's going on in the tank.

7. In some previous model years, they had a problematic fuel pickup in the tank that would plug with even trivial amounts of crystallization in the fuel. The newer design eliminates that problem. Who knows what your pickup looks like.

I am thinking about setting up a coolant loop to heat the fuel tank, like the SVO folks do.
(I have since discarded this notion, since my formula has been 100% successful the last two winters.)

Please note that you should mix your blend for worst case scenario temperatures plus a fudge factor of several degrees. You should not look at the forecast for tomorrow and mix your blend for that exact temperature. Or maybe you like living on the edge???

Here’s the charts and links I promised…

Here are two charts that summarize information from the nice folks at:
http://www.duffscience.com/biodiesel/biodiesel_blends.htm

They also have a nice calculator for various blends here:
http://www.duffscience.com/biodiesel/biodiesel_calculation.htm

These numbers are all based on mixes with biodiesel made from new soy oil. YMMV

% BioDiesel %Wint.D Gel temp in F
10 90 2F
20 80 4
30 70 6
40 60 8
50 50 10
60 40 13
70 30 17
80 20 21
90 10 25
100 0 32


% BioDiesel %Kerosene Gel temp in F
10 90 -28
20 80 -23
30 70 -17
40 60 -11
50 50 -5
60 40 2
70 30 9
80 20 16
90 10 24
100 0 32

Please note that there is a whole other vibrant informative discussion about winter issues over here: http://forums.biodieselnow.com

Finest regards,

troy

Muchas Gracias Troy. This is a great help as I am about to start my own tests and this is a good barometer of what I should expect. It looks promising.
The DuffScience site is dead BTW.