Winter Blended Diesel Fuels

Revised 06/20/2007

#2 Diesel Fuel contains a significant amount of paraffin wax. On the positive side this wax contains a lot of energy (Btu?s) and adds viscosity and lubricity to diesel fuels. The downside of paraffin wax is that it causes cold weather problems for users. As the fuel gets colder the wax crystals grow in size until they become visible (cloud point (CP)), next they begin to interfere with each other and inhibit the movement of the fuel (cold filter plug point (CFPP)), and finally they grow together turning into a semi-solid (pour point (PP)).

#1 Diesel, Kerosene, and Jet Fuel are lighter versions of regular diesel, having a different boiling point and much less paraffin wax.

There is a lot of misunderstanding about Winter Blended Diesel Fuel, what it is, and what it can do.

You can improve the cold weather characteristics of diesel fuel in several ways. You can remove some or even most of the wax. This lowers lubricity, reduces Btu?s (causing lower mpg and engine power output), lowers the fuels viscosity, and raises the refining cost.

Prior to the rules regarding Ultra Low Sulfur Diesel, you could add #1 Diesel, Kerosene, or Jet A to the #2 fuel. This would lower the CFPP and PP by approximately 5?F for each 10% of the lighter fuel added to the #2 Fuel. You could also treat with additives commonly referred to as an anti-gel (cold flow improver, wax modifier, or solvent) to the #2 fuel to lower CP, CFPP, and PP. You can also use a combination of two or more of the above to achieve the necessary reduction in gel point.

Under the new EPA mandated ULSD rules you can no longer use High-Sulfur Kerosene, High-Sulfur #1 Diesel, or Jet-A for winter blending of diesel. You can only use ULSD #1 or an additive containing 15 ppm or less of sulfur.

This new ULSD #1 has significantly different characteristics than the fuels previously used for blending. It has lower aromatic content and much lower solvency. These new characteristics mean that blending 10% of this fuel will improve CP, CFPP, and PP by only 2?F or sometimes 3?F. In the past you would have expected a 50-50 blend to reduce CFPP by 25?F. With today?s new fuels a 50-50 blend will reduce CFPP by only 10?F to 15?F and in many cases there can be even less improvement.

Also, many of the so called ?anti-gel? fuel additives no longer work as well as before. In many cases testing has found that some of these additives provide little or no improvement in CP, CFPP, and PP of ULSD fuels.

These various ways of treating have advantages and disadvantages depending on a wide range of variables.

In the Northern States fuel suppliers offer ?Winter Blended Diesel Fuels? for use during cold weather. This is a poorly defined term that can mean almost anything. Unfortunately there are a few fuel suppliers that take advantage of these poorly defined terms to the detriment of their customers.

Unless your fuel comes directly from a refinery (most does not), it is made to a ?pipeline spec?. The pipeline operators require fuel in their lines to meet certain minimum specs to protect their equipment from cold weather damage. The pipeline CFPP is generally 15?F lower in the winter than it is during the warm weather months.

In the past distributors had stocks of kerosene and or Jet A in stock and they could easily blend a percentage of this fuel with the #2 as they loaded their trucks. This meant they did not have to stock any special fuels or additives for cold weather use, fuels or additives that might sit in a mild winter or be left over at the end of winter. Kerosene and Jet A was something they could always sell, ULSD #1 is not as easily moved in warm weather.

The Kerosene or Jet A used to have a cost very close to that of #2 diesel, so there was not much disadvantage to distributor. However there is a large differential in the selling price of ULSD #1, anywhere from $.30 to as much as $1.00 per gallon.

As winter spec #2 ULSD fuel is generally safe to 0?F as it comes from the pipeline in the winter some distributors will claim to be adding kerosene or additives, when in fact they add nothing. If you have ever had a distributor who brings you ?free? kerosene when the weather is predicted to be unusually cold you should probably be checking to see what is actually being delivered to you in the first place. There is no free fuel.

It is very important that you learn which form of blending your supplier is using. If it ULSD #1, you should ask for documentation that this fuel was actually loaded at the rack. Many customers require that this fuel be delivered in a separate compartment in the delivery vehicle to ensure that they actually are getting what they order.

If the supplier is using an additive, you should ask which additive, how much is being used, and obtain the specifications on that product.

In most cases the best way to be sure you are getting what you need and what you pay for is to additize the fuel yourself.

As with all businesses most fuel distributors are honest and strive to provide the best products and services possible. The honest ones will have no problem with you asking questions that protect your interests.

Enertech Labs will work with you to ensure that you have fuel that meets your needs and requirements.

William Richards 06/20/2007

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Last modified: 01/12/09