Octane And Bio Diesel In Diesel Fuel

[gorm50]

Returning from Madison I am concerned about comments made by a fueling trucker at Pilot.

1) It seems CETA octane ratings were reduced years ago and never restored. That means we are paying more for less. How can we and FMCA petition Congress to restore diesel octane ratings? While lower ratings benefit refineries and oil companies, they do NOTHING for consumers except cost us reduced performance and MPG!

2) Apparently, Pilot is lacing diesel fuel with a percentage of biodiesel at SOME stations and per the trucker he has experienced algae, clogging filters and necessitating tank and line cleaning TOTALLY NEGATING any intended economies.

With motorhomes used sparingly or stored, biodiesel constitutes a COSTLY RISK! Calling Pilot I learned ONLY SOME STATIONS pump a biodiesel mix. Luckily, mine was not. Pilot could not answer whether that BLEND is posted at applicable stations. He could only consult a list of those pumping biodiesel. Pilot has received NO complaints of algae from pumped fuel. The Pilot rep was to have someone more familiar get back to me to answer concerns. Hasn't happened yet. My understanding is that some engines, particularly Onan diesel generators are sensitive to anything above 5% biodiesel.

I know the EPA has approved 15% ethanol into gas, a 50% increase, a risk to some engines and a wasteful filler that has been proven to be COST INEFFECTIVE.

Does anyone have a factual source addressing my concerns? I certainly don't want to see biodiesel adversely affect my coach, travel disruptions and operating costs.

Gorm

[wolfe10]

Diesel "octane" is referred to as Cetane: http://en.wikipedia.org/wiki/Cetane_number

I am not a chemical engineer, nor have I discussed needed Cetane with any of the diesel engine manufacturers to get their view on minimum acceptable Cetane for their engines. And, the recommendations may vary by engine and year model. That would be a first step if this is a subject you want to pursue.

I will comment on the storage of diesel with bio-diesel content-- It is widely agreed that bio-diesel has a shorter shelf life than 100% diesel. So if you are storing your coach, yes, seek 100% diesel. This excerpt from an EPA document: http://www.nrel.gov/vehiclesandfuels/npbf/pdfs/43672.pdf:

Storage Stability

Although biodiesel blends have adequate storage stability for normal use, special precautions must be taken if

they are to be stored for extended periods. This might occur in a snow plow or farm implement used seasonally,

or in the fuel tank of a backup generator. If the fuel will be stored for more than a few months, a stability additive

is recommended, and acidity should be measured monthly.

Finally, biodiesel is generally more susceptible than petroleum diesel to microbial degradation. In the case of

spills in the environment, this is a positive attribute because it biodegrades more rapidly. However, microbial contamination of fuel storage tanks can plug dispensers and vehicle fuel filters and cause vehicles to stall. This is not

unheard of for petroleum diesel, but anecdotal evidence suggests it is a greater problem for biodiesel blends. The

best way to deal with this issue (for both petroleum diesel and biodiesel) is adequate fuel storage tank housekeeping and monitoring, especially minimizing water in contact with the fuel. Water bottoms must be removed from

tanks, and standing tanks should be sampled and tested for microbial contamination.

Each engine manufacturer will have specs on acceptable quantities of bio-diesel. I know the Caterpillar Maintenance Seminar in Madison discussed this. The acceptable quantities of bio-diesel varied by engine and year model.

Lots of opinions on this subject-- I agree with you, would like to see some factual information. Oh, and let's keep politics out of this.

[gorm50]

Thank you for your post Mr Wolfe;

Just finished a call with Mr Brian Stickley at Pilot.

He tells me:

1) CETA rating minimum of 40 remains unchanged.

2) Biodiesel acts like a solvent, cleans tanks and lines and on first/second use can clog fuel filters.

3) All Pilot sites pumping a biodiesel blend are posted.

4) Blended percentages vary from low of 5% to high of 15%, with the latter percentage quite rare, and 5% the norm.

5) Algicide is added to all tanks to reduce incidence of algae and I should incur no problem storing in MI and supplementing as I have prestorage with Stabil.

Gorm

[tbutler]

In the EPA document Brett cited, the mention of water as a factor in storing biodiesel should reinforce the recommended storage procedure of storing your motor home with a full tank of fuel. A partial tank of fuel breathes as air temperatures and pressures change. Each intake of new air into the tank brings in water vapor. The fuller the tank, the less breathing room for bringing in new air thus less moisture gets into the fuel tank.

The last stop I make each fall is to add Sea Foam fuel stabilizer and top off the tank. Since we winter in south Texas, all the fuel in the tank is fresh before I add the stabilizer and top off the tank. On the way from the fuel station to our winter home I run the generator so its fuel system gets an initial dose of treated fuel. I have never worried about the biodiesel issue and haven't had any problems.