Seems to me this might be more complex than simple incomplete reactions or soap formation. Since you are using blends of B5-B20, I would investigate the possiblilty that you are getting waxing from the dino diesel, with precipitation being enhanced by the blend with bio. If the precipitate readily warms and turns liquid above 30, I would bet that it's a wax more than a soap. The best bet would be to have the precipitate analyzed and find out what it's structure is. A run through a gas chromatograph or scanning infrared spec would give that quickly and should be relatively cheap.

 

I would not be suprised if there is something like that going on. There is still a lot to be learned with Biodiesel blends and ASTM specs need to be generated or revised to cover these blends and how they should behave as they reach the freezing point and what happens after they thaw.

Seb...

 

It was -10 here this AM with windchill of -25. We had a high of +7. Went to work in the 5AM rush with no problems. But I had the power on for the block heater for 3 hrs before I started the truck. I was running a premium fuel with B5.

It is going to be the same temps tomorrow.

 

It was 45 degrees and partly sunny here today, and should be in the high 40's all week......... Back to using B-100 today!

 

I disagree that a spec for each blend of BD/Dino should be developed, It would be a nightmare to enforce. You would have to address each 1% increment from B1 to B99.

A better solution would be to establish a very stringent standard for the B100 stock used to make blends. D-6751 doesn't make it. It must address removal of ALL contaminants. Note realistically that is not possible but you can get 99.999% purity

 

Agree on both points. I would like to make another Point; I have been doing some research about many of these same problems from around the world. I've come to the growing conclusion that oxidation of biodiesel from various post- processes will be found to be causing many of the problems people are experiencing.

Oxidation of biodiesel promotes the development of Polymers [think plastics] and can be disastrous to a diesel engine, and Lipids, which will come out of suspension when chilled and will not recombine with the bio. Sound familiar???

Could you please explain Polymerization better, and the possible problems with burning it in our engines? My Chemistry is really rusty!

 

Same here Big Red . I didn't plug mine in yet . I really wanted to see if there is a temp were it won't start.
I'm running about B-20 now and still no problems . No additives

I think the premium fuel has alot to do with it.

 

It sure does sound familiar.

OK here goes the explanation of polymerization

Quite simply polymerization is the joining together of two or more molecules to form a single macro molecule. This can be pretty dramatic joining molecules with molecular weights in the low hundreds to form macromolecules with weights in the millions. For example BD has an average of 12 Carbons, 2 oxygens, and 24 Hydrogens carbons atomic wt = 12, oxygen aw = 16, and hydrogen aw=1 so tne molecular weight of an average BD molecule = (12X12)+(2X16)+24 = 200. Add 10 of them together and you will start to see a significant increase in viscosity atick a couple of those together and you are talking grease.

How does it happen

a couple of ways

First and most common is because of oxidatiom occurring in the hydrocarbon chain.
BD has a fairly low surface tension which means atmospheric oxygen can disolve in it fairly easily. This oxygen attacks unsaturated (double bonded carbon) locations on the hydrocarbon chain breaking the doublebond inserting the oxygen.
A note here remember free oxygen exists as O2 (2 oxygen atoms bonded together) this is a double bond and its written as O=O. Unsaturated (double) carbon bonds are written as C=C. single bonds are written as C-C or O-O ( O-O is a very unstable compound)
Also remember that shorthand notation for a generic (any length) hydrocarbon chain is R. Areas of interest in a carbon chain can be detailed by simply showing the special feature with an R before and/or after it. Confused ? I will demonstrate.
a hydrocarbon chain that has a double bond in the middle can be represented as a simple R. If the double bond is of interest, lets say it the site of a reaction that is being illustrated, it can also be represented as RC=CR.
Allright enough about notation.

Like I said earlier atmospheric oxygen, O=O, easily dissolves in BD. It then attacks BD molecules that contain doublebonds, RC=CR, producing RC-O-O-CR. Thats what is meant by oxidation. Certain conditions can increase the likelihood of oxidation reactions among them are the presence of metal ions, Ultra violet light, heat, time (you might ask where the metal ions come from well FFAs are acidic so if your BD has residual FFAs and it is stored in a metal tank the FFAs attack the metal producing metal ions.

Now the fun starts. The O-O bond is fairly weak and easily broken so RC-O-O-CR becomes
2 RC-O. RC-O is an organic peroxide and it is an initiator for polymerization reactions. The peroxide opens one half of a double bond in another BD molecule when two such molecules (each with an open bond site) get together they combine to form a single larger molecule and so on. Sometimes these new molecules are linear but most often as they grow larger and larger they resemble a spider web.

Polymerization can also occur when BD is subjected to heat because heat can break ester bonds leaving two reactive molecules which can bond to other molecules forming longer chains. And then a certain amount of polymerization will just occur over time remember all chemical formulas are equations and work in both directions so what has been put together can and does seperate, some ester bonds will break and some longer chain molecules will form

Best advice;
Clean your fuel as well as possible to remove FFAs.
Dont heat it anymore than necessary (every 10 degree rise will double even triple oxidation)
If you heat dont keep it there any longer than necessary
Use lined storage tanks to avoind exposure to metal
Dont store fuel for extended periods
Keep the exposed surface area small to reduce adsorption of O2, Tall thin tanks are better than short wide ones

 

Since I buy my Biodiesel I don't have control over items 1 thru 3 above.

Item 4 would be very expensive for me to convert both my fuel tanks with liners.

Item 5, Agreed I never hold on to the fuel for more than a month in my tanks.

Item 6, Large storage tanks are usually built short and wide because of the cost of foundations to meet earthquake requirements. Oxygen can be kept away with the use of floating roofs like they use on gasoline tanks. Floating roofs are typically not used on distillate tanks due to the cost which can easily by more that $ million per large tank as they are not required for low vapour pressure fuels like diesel.

Note, I did make one more very disturbing observation recently, when I changed the Racor fuel filter on my 93' there was "heavy corrosion attack" on the inlet side of the filter which is made of carbon steel. The rest of the filter housing which is stainless steel was in good shape. Luckyly any corrosion products would have been caught by the filter element before it would have gone to the IP. Note, I had not changed the filter in the 93' for atleast two years as it is the oversized R60S filter. I just ran regular diesel in the 93' this winter as I did not like all the trouble with filter plugging I saw on the 91'.

The fact that BD readily oxydizes is concerning as most of the intricate fuel system components are made of ordinary carbon steel components. (i.e. IP and injector nozzles) Any water in the BD mixture that comes in with the regular diesel used for blending could spell major trouble.


Seb....


Seb...

 

Items 1-3 I know and its a bummer. Thats the source of many of the BD problems seen today poor quality fuel from suppliers.

Item 4 applies more to storage tanks than your vehicles fuel tank.

Item 6 Anything you can do to reduce the surface area that is in contact with air will help.

The problem of corrosion and water is really only applicable if there is a fair amount of unreacted FFAs in the BD since they are the acids that cause corrosion. If you are having corrosion problems you are not getting clean BD.
Ask Fab but I believe that most commercial BD makers water wash their BD if they wash. If they dont wash their product has high contaminants. I firmly believe the Magnesol and PAM, or some sort of molecular sieve, is essential to the production of GOOD QUALITY BD

 

[I firmly believe the Magnesol and PAM, or some sort of molecular sieve, is essential to the production of GOOD QUALITY BD[/QUOTE]

Thanks,

Since the future of BD seems to be as a blend stock, (atleast that is the way it is going in Europe) it will be just as critical to make sure you have quality diesel fuel for blending.

All my trouble started just when we switched to blends using winter diesel. I would not be suprised if part of my filter corrosion problem came about because there was some water in the blend diesel stock which then became acidic when it reacted with the Biodiesel. The B40 I purchase is inline blended right on site and while they

This still does not explain the margerine like solids that were left behind after the solidified B40 re-liquified, or does it?.

 

In order for water to be the source of corrosion you would have to have some FFAs or slufur compounds present. The two mixed together are a real problem for metals. The FFAs would come from the BD and sulfur compounds from the dino. If it was that new ULSD diesel its doubtful there was much sulfur present.
Good BD wil reliquify 100% after gellation. There are only two possibilities for the "margerine" soap or polymerization product.
Ask your fuel source how long they keep BD around before it is sold.

 

earlier in this thread you were talking about re-using the gelled up filters. How bout a jar that fits the filter real nice and soaking it completely by filling up the jar entirely with a bottle of dieselKleen? If a bottle doesn't soak it completely top it off w/ some dinoDies. I dont know waht the filter looks like on your truck but if it's the type that screws on like the 6.9L I have..screws on just like an engine oil filter, just fill the thing up w/ the dieselKleen, let it soak for a little while, reinstall or pour it into another filter. For a $10US bottle of DieselKleen you could probably clean a bunch of filters that are gelled up w/ that margarine stuff.
I know you weren't expecting to have problems that day w/ the weather change and all so you weren't prepared, but in your situation I probably would have dumped a whole bottle in 1/2 tank(10 gallons) or 2 bottles in a relatively full tank, and then I would have taken the fuel filter off, dumped what was in there right out, and filled the whole thing with dieselKleen. Drive away and fill up w/ B5 or if you got problems w/ your supplier's fuel switch over to dino. A bottle of that cleaner is rated to de-gel up to 100 gallons but isn't going to harm anything at full concentration, in fact a lot of guys w/ the older 6.9's/7.3's recommend that you fill your new filters with dieselKleen(or any antigel/cleaner) as part of regular maintenance to clean your injectors etc.

 

The "stuff" that's clogging up fuel filters seems to be only with the commercial biodiesel blends, and I would NEVER try and save a plugged filter.

Most "homebrewers" seem to produce better quality biodiesel. I've tried to reproduce the problems others are talking about, but with my fuel no matter how many times I freeze it nothing seems to come out of suspension!

Over the next few months I'm going to do a lot more testing and see if I can figure out what the problem is. Just have to finish building my lab, and get my GC machine running......................

 

Everyone,

I just yesterday made an inadvertant observation that may help explain some of the problems you all and myself are having.
Near the end of Dec. after experiencing so problems with BD Blends (I make my own BD) I discontinued using BD, cleaned my tank and have been using straight petro diesel for several tank fulls. I usually run my tanks close to empty before refilling so there should be very little if any BD in the system (in fact I ran out once, embarrassing)
I also have a farm tractor with which I feed cattle. In Nov. I drained the tank almost completely and refilled with farm diesel. It has been working fine.
Last week when the first cold snap arrived I had a fuel starvation problem which I put down to moisture in the lines since adding 8oz methanol seemed to solve the problem. Plus the temperature also returned to more moderate temperatures.
A few days ago just before the latest cold snap I put some ULSD (and good dose of Polar Power treatment) into my truck and filled a 5 gal can for the farm tractor. When the cold snap (0 deg F) came this past Monday the truck fuel starvation reoccurred. This time methanol didn't help (because the temps stayed low).
However my tractor has a fuel/water seperator which has a clear glass reservoir. It is about 4 inch in diameter and 2 inch tall. I noticed that it was about half full of gelled fuel. It is pretty clear to me that the real culpit might just be the ULSD. In the case of my truck it makes sense because I have a 75 um filter between the tank and the electric lift pump on the frame. It wouldn't take much to plug it.
This morning I took the car to town and purchased 2-5 gal cans of K-1, one for the truck and tractor. With temps going to -5 F tonight we'll see.
For what it's worth.