FUEL & OIL

Understanding Winter Diesel Blending

As temperatures drop, it is important to understand your fuel’s operability range and what you can do to extend that range into further negative temperatures. Typical #2 Diesel has a cloud point of about 14 degrees F. Cloud point is the temperature at which a haze of wax crystals starts to appear in the fuel. 

When blending fuel, it is important to understand that all fuels must be blended when the temperature of the fuel (not air temp) is 10 - 15 degrees F above the cloud point. In other words, the fuel temperature would have to be at least 25 degrees F to ensure proper blending. This is true when blending #1 and #2 fuels or when adding an additive such as a Cold Flow Improver (CFI). 

Cold Flow Improvers are designed to extend the operability of the fuel by changing the wax structure in diesel fuel by using wax dispersants, which keep wax crystals from congregating in the fuel. CFI will not reduce the cloud point of fuel. Using #1 diesel is the only way to reduce the cloud point. 

As you can see in the chart, using a 50/50 blend of #1 and #2 Diesel will only drop the cloud point from 14 degrees F to -2 degrees F, but using a 50/50 blend with a CFI additive will improve the operability by another 10 - 12 degrees F. 

When blending additives to your fuel it is important to remember to follow the recommended treatment rate. Doubling the treatment rate won’t typically have a negative impact, but it may also not improve operability. By tripling or more the recommended rate you risk the possibility of negatively impacting the operability and will be adding cost without any benefit. An extreme overdose of additive will not blend properly and can plug fuel filters. Never blend CFI into diesel that is at or below its cloud point, as it will have no effect on the fuel and will not blend until the fuel temperature reaches 10 - 15 degrees F above cloud point.