by Kent Gashaw (gashaka) on 05-07-2010 10:00 AM
Did you know that fuel is the single greatest factor affecting engine maintenance and operating costs? The reason is that the composition and quality of fuel affects the heat and other characteristics of combustion in the engine cylinders.
There are many sources of fuel that can be used in gas engines, including:
- pipeline natural gas
It is important to know your fuel. For example, varying levels of Low Heat Value (LHV) and methane can put air/fuel ratios out of balance. Fuel impurities can degrade engine components. There are several factors that can impact operating performance and maintenance needs, some of which I've outlined below:
Maintaining Proper LHV
Each commercial fuel gas is a mixture of gases. Some of the gases are combustible and some of the gases are inert. The compositions of these gas mixtures have extreme variations. Routine testing of the fuel will help you determine that the proper Low Heat Value (LHV) content is being maintained. The LHV of the fuel can impact the engines overall performance:
- LHV that is too low can result in starving the engine for the fuel energy necessary to produce power.
- LHV that is too high may cause the fuel system to be unable to mix air and fuel in the proper ratios, resulting in poor combustion and reduced power.
A fuel's potential for detonation is indicated by a methane number and should be monitored. Methane is the major constituent of natural gas and is released during the decomposition of plant or other organic compounds.
Depending on the manufacturer, gas engines can operate successfully on a range of gaseous fuels. However, adjustments must be made to the fuel system when the fuel is changed to maintain proper air/fuel ratio in order to comply with the emission requirements for your site.
Contaminants & Filters
Contaminants in the fuel can also affect engine life. Gaseous fuels contain a number of contaminants that can attack different engine components and lead to early failure. Monitoring your fuel will help you avoid costly down time and possibly major failures.
Fuel filters are no less important than air filters to protect gas engines from dirt and debris. A proper fuel filter removes impurities that can damage the internal components of the engine. Proper treatment can remove the following:
- Particulate Matter (PM)
- Siloxanes (partial removal only)
The gas must be supplied to the engine at a pressure that is acceptable. For optimum operation, use a fuel filter that is properly sized for the gas pressure. In fact, for many gas engines, fuel filters are a provision of the design for the application.
Do you regularly monitor you natural gas LHV and/or methane levels?
How do you reduce contaminants in fuel?
Are there any additional tips that you have on fuel not mentioned above?
Do you adjust your maintenance intervals based on oil/fuel sampling?
Please post your feedback below.
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