Diesel Properties And Problems

clean fuels

Common Issues with Diesel Fuel and Storage

There is a common misconception that diesel fuel, once stored, is “good for life.” However, that is not the case. Diesel fuel breaks down over time, which can compromise generator efficiency. When it comes to mission-critical facilities, keeping the lights on when the power goes out is a top priority. The integrity of the diesel fuel in the generator tanks makes or breaks this particular imperative. In this multi-part series, we’re going to take a look at a number of factors, including fuel quality and adverse factors, storage life, ways diesel can be compromised, storage life, problem causes, prolonging and improving storage life, and fuel polishing systems. Here are some interesting facts regarding diesel properties and problems associated with it.

First, let us consider exactly what diesel is. According to Wikipedia, diesel comes in many forms. For our purposes, we will be referencing petroleum diesel. Petroleum diesel, also called petrodiesel, or fossil diesel is the most common type of diesel fuel. It is produced from the fractional distillation of crude oil between 200 °C (392 °F) and 350 °C (662 °F) at atmospheric pressure, resulting in a mixture of carbon chains that typically contain between 8 and 21 carbon atoms per molecule.

When in its ideal state, diesel is a clear-to-brown liquid. However, there are many factors which can affect fuel quality. This, in turn, can affect engine performance. Modern diesel engines have a very complicated set of components that rely on specific fuel characteristics to perform efficiently. These properties include (but are not limited to) density, viscosity, burning characteristics, lubricity, flash point corrosivity, water content, ash formation, and rate of oxidation. When the fuel is out of specification, problems can include:

  • Low fuel density (lack of smoke)
  • High fuel density (black smoke)
  • High viscosity (black smoke)
  • Low viscosity (lack of power, poor starting)
  • Low cetane (poor combustion, rough running, emissions, noise)
  • Low volatility (poor starting, deposit formation)
  • High sulphur (increased emissions)
  • Low lubricity (injection equipment wear)
  • High wax content (freezing in cold weather)
  • High ash formation (engine deposits, poor running)
  • Poor stability (gum and deposit formation)
  • Water content (corrosion of injection equipment)
  • Low flash point (possible danger in handling)
  • High carbon residue (engine deposits, emissions increase)
  • High corrosivity (erosion of injection and fuel pump/tank surfaces)
  • High acidity (corrosion of fuel pump and tank)
  • High aromatics (increased emissions)
  • Low detergents (increased deposits, emissions)
  • Low anti-foam (poor filling properties, fuel spillage)

Many of these properties are interrelated, and diesel has a relatively narrow range of operation between conflicting requirements. Diesel fuel is generally of a very high quality, but can be contaminated by mixing or poor storage conditions.

In the next post, we’re going to look at these storage conditions, as well as the types of contaminants that can cause diesel fuel to be compromised.