Black Fuel Filters - Asphaltenes - Re-polymerization

Black Fuel Filters – Asphaltene Production and

Re-polymerization in ULSD Fuels

Have you seen filters that look like this.

There is a difficult new problem with ULSD fuels. Today most ULSD is derived using the process of catalytic cracking. This form of refining uses very high temperatures, high pressures, and chemicals known as catalysts to refine crude oils into various fractions including Ultra Low Sulfur Diesel. The fuels derived using these processes suffer from a wide range of problems including a lack of oxidative and thermal stability.

This lack of stability manifests itself in many ways including an increased ability to hold dissolved water, an increased negative reaction with oxygen, and a far greater inability to handle high temperatures over time. Different refining processes and catalysts can make these problems better or worse. It appears that certain refineries produce fuels which are far less stable than that of others.

Diesel engines recirculate fuel to lubricate and cool the fuel system and engine components, In the past fairly large volumes of fuel were recirculated and this tended to keep temperatures lower, generally in the 140°F to 160°F. Today some of the newer engines can heat that fuel to temperatures that can exceed 200°F or even 220°F.

When some catalytically derived fuel is exposed to temperatures above 100°F for extended periods of time such as when fuel is recirculated in a diesel engine, the catalytic process starts up again re-polymerizing parts of the fuel. This results in rapid deterioration and darkening of the fuel. In this process small droplets of asphaltenes (heavy oils) are formed.

When the fuel is again pumped from the tank, the fuel filters will pick up the tiny asphaltene droplets, agglomerating them until the filter or filters are plugged. This can happen in 3000 to 5000 miles with some instances of plugging in less than 1000 miles.

While there are additives that can add thermal and oxidative stability to fuels, they are not commonly used by refiners or fuel distributors. These additives are not found in most aftermarket additives.

Use of Diesel Fuel Additives - Year Round

Use of Diesel Fuel Additives
or
Additives's it’s not just for winter anymore

Once upon a time diesel engines were relatively simple pieces of big heavy, hard to break iron. You could put almost anything from kerosene to heating oil in them and they would run, maybe not well, but they would run.

Diesel fuel was considered a residual fuel, something left over from making the good stuff (gasoline). It was not supposed to be a good fuel; it was supposed to be a cheap fuel.

Even if this fairy tale was ever true (it actually was not), those days are long, long gone. Diesel engines today are as sophisticated as those of the worlds fastest Formula One race cars. These engines can have fuel system pressures of up to 35,000 psi and injector machining tolerances of 2 microns or less. Fuel filters that used filter down to 30 or 10 microns, now regularly filter down to 7, 5, and even 2 microns.

The new Ultra Low Sulfur Diesel (ULSD) that is now on the market is derived using various Catalytic Cracking refining processes that affect the quality of the fuel on many levels. The “new” ULSD has less oxidative stability, holds more suspended water, forms gums, varnishes, and carbon deposits more quickly, has less lubricity, gels at higher temperatures, is less thermally stable, is more corrosive, and in general is much more problematic.

In short the quality of the fuel has not kept up with the sophistication of the engines.

As a result you can no longer expect untreated fuel to meet the needs of your engines.

It is no longer good enough to treat your fuel just when it is cold outside. The needs for additional lubricity, higher Cetane, water dispersion, higher levels of oxidative and thermal stability, fuel injector cleaning, corrosion inhibition, fuel atomization require continuous year-round treating to protect your equipment and to maximize performance.