Ultra Low Sulfur Diesel (ULSD): What It Is & Common Questions
Preventative maintenance has always been crucial for any operating system, especially in mission-critical, life-saving emergency power systems. Relatively recently, EPA regulations have pushed diesel fuel systems into the spotlight of system maintenance. As of December 1, 2014, all diesel to be used in non-road diesel engines must be Ultra Low Sulfur Diesel (ULSD). While being effective and necessary for reducing the number of unhealthy emissions into the environment, ULSD poses a new set of problems for facility managers who are in charge of the preventative maintenance routines for diesel-engine based emergency power systems. Fuel plays an absolutely critical part, and yet is the least maintained. Studies show that almost 95% of generator starting failures are because of faulty fuel.
What is Ultra Low Sulfur Diesel (ULSD)?
Ultra Low Sulfur Diesel, or ULSD, is diesel fuel with singificantly reduced sulfure levels. ULSD has been the norm for nearly all petroleum-based diesel fuel distributed in North America and Europe since 2006.
Although it is cleaner burning and produces less harmful emissions, ULSD has significant drawbacks.
A much more stringent refining process is used, which includes catalytic cracking and hydrodesulfurization, significantly destabilizing the fuel and adding the need for closer monitoring of fuel and fuel tank conditions. Though all fuel must meet ASTMD975 test specifications before leaving the refinery, guaranteeing it arrives in the same condition is impossible. The inevitable passing through ships, tanker trucks, pipelines, and temporary storage tanks exposes the Ultra Low Sulfur Diesel fuel to ever-present contaminants. So, what can go wrong with ULSD?
fuel contamination over time
Almost immediately after leaving the refinery, diesel fuel begins many chemical changes. The potential for fuel to generate varnishes and gums increases over time; usually, 6 months before it begins producing solids and particulates that can attract other contaminants like rust and dirt. These can clog fuel filters and lead to complete engine shutdown.
mixing with water
Since the refining process removes some of the fuel’s natural lubricity, it mixes quite well with water, frequently acquired from condensation and leaky storage tanks. This can lead to many problems including corrosion of the storage tank and fuel lines as well as increased microbial growth.
Fungus and bacteria buildup
That’s right! ULSD is more prone to microbial growth which greatly accelerates the corrosion process, as well as significantly adding to the sediments that accumulate in filters and fuel lines. The buildup of these microbes; which includes yeast and mold, can cause a slimy coating called bio-film to form on the surface of the fuel, causing fouled plugs and damaging expensive monitoring equipment.
high Solvency
Due to its nature, ultra-low sulfur diesel has a high solvency rate; meaning it can actually soften and loosen hardened contaminants from the sides and bottom of the storage tank, effectively adding them to the fuel mixture. This can lead to a myriad of starting problems.
How To Avoid Problems with Ultra Low Sulfur Diesel
The time has passed to “fill it and forget”. Stored ULSD has the potential to cause serious damage to the life and reliability of your mission-critical emergency power equipment. Institute a “fuel quality assurance program”; buy only high-quality fuel, visually test a sample from the delivery truck before it goes into your equipment, inspect storage tanks and fuel filters regularly for signs of corrosion and sediment build up. Finally, partner with a reputable fuel management service provider who can help you implement all these changes and ensure that in the long run, your emergency backup power system will deliver every time.
For more information on fuel management and qualified fuel service providers in your area, give us call at 610-658-3242. We are happy to help.
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