I followed the manager of the facility around and listened to the same old story. “It just keeps tripping out!” he said. I have heard that quote -- and related complaints such as “We just can’t keep all the burners lit!” and “The temperature! It just won’t stay consistent!” -- many times. Some people with heat processing equipment think they need to watch the calendar for full moons and plan their production schedules around them because they just cannot understand, or ever seem to fix, their reliability issues for long. However, you can achieve reliable, consistent operation of your fuel-fired equipment with a little understanding and action.
Most combustion systems have only one device that you can assume is providing “normal” operation: the fan or blower system. It is rare that fan and blower mechanical issues such as bearings become a problem that affects combustion system reliability. Instead, by far, reliability issues seem to relate to ambient conditions in which the safety interlock components are asked to operate. The two main culprits are dirt and heat. Dirt and heat can impact your reliability, but there are things you can do about it.
Fuel Delivery Systems. Reliable fuel-delivery systems are all about making sure you have no dirt or other contaminants and that you have proper pressures.
Oil. If you’re operating on oil, you need to ensure the fuel and everything it touches is always very clean. Dirt and contamination issues are the No. 1 problem with oil. To avoid these problems, take steps to avoid dirt and contamination. Possible steps may include adding biocides to oil that gets stored and used infrequently; scheduling regular cleaning of lines and strainers; installing duplex strainers to aid cleaning; and cleaning nozzle tips immediately before use.
Gas. Gas systems also can have their share of contamination. Therefore, when opening piping systems, be careful -- just the act of opening piping can move sediments around. Make sure that all fuel trains are protected with drip or dirt legs (which are the same thing), and strainers. Drip legs should be installed with sufficient room to allow removal of the pipe cap for cleaning. The drip leg should be emptied during routine maintenance scheduled based on past experience with contamination in the fuel train. Strainers must be oriented correctly so the screen can effectively capture particles. I typically recommend strainer screens that have 100 mesh (150 micron) or higher.