Boiler operation consists of many tasks to keep a boiler operating safely and efficiently. These tasks include tracking many data points, such as boiler pressure and temperature, boiler exhaust temperature, feedwater pressure and temperature, and boiler and water column blowdown timing. Continual checks should also be a part of any maintenance program, including burner flame for proper combustion, proper operation of control valves for all systems, feedwater tank or deaerator operation and level, water treatment systems, and taking water samples for comparison to recommended chemistry guidelines.
There are other equally important tasks to ensure proper boiler operation that should be performed on a weekly, monthly, semi-annual, and annual basis in accordance with the manufacturer’s recommendations. Failure to comply with the equipment manufacturer’s recommended maintenance schedule may result in catastrophic failure due to problem indicators being missed from lack of regular maintenance. Keeping a boiler operator’s log helps to ensure all data points are recorded, all checks are performed, and poor performance indicators are addressed. In this article, I will discuss boiler maintenance and the danger of neglecting it.
Why boiler maintenance is neglected
There are many reasons why regular maintenance is skipped in a boiler room, but the most common are a lack of training and implementation of cost-cutting strategies. To combat a lack of training, some states and cities have adopted boiler operator licensing programs to ensure only experienced and knowledgeable personnel are operating each boiler in their jurisdiction. While training may seem like an unnecessary expenditure at times, properly trained operation and maintenance personnel will ultimately save the owner money by way of efficient operation, preventive maintenance, and continued service. The cost of employing properly trained and licensed personnel will extend the life of the valuable pieces of equipment while maintaining their safe and efficient operation.
When revenues are down, preventive maintenance is often seen as an area where expenditures can be minimized. The spare parts, cleaning and maintenance charges, and equipment downtime may seem like items that could be cut out to someone who doesn’t understand their importance. Due to the inherent danger of boiler systems (especially ASME Section I, Power Boilers) regular maintenance should never be neglected. Apart from the long-run savings already discussed, the safety of operational and nearby personnel is reason enough to keep the cost-cutting strategies away from the boiler room maintenance program.
The dangers of neglecting boiler maintenance
Now that we are aware of the importance of regular boiler maintenance, let’s look at some of the examples of boiler maintenance and the dangers of neglecting them.
Regular checks of safety equipment (LWCO, ALWCO, safety valves, gas/fuel train valves, etc.) is the first line of defense against major failure. While many of these items will be looked at during the annual inspection by the jurisdiction or the insurance company, once a year is not enough. All these items should be checked and tested regularly to avoid any problems. Neglecting to maintain these safety devices puts lives at risk due to the inherent danger of pressure vessels.
Tracking the boiler operating pressure and temperature as well as the exhaust temperature allows the operator to trace any system inefficiencies. If an operator notices the boiler pressure is consistently higher than the operational set point, that is reason to suspect an issue with the control switch operation. If an operator notices that the boiler exhaust temperature is consistently higher than 50°-100°F above the steam temperature, burner combustion should be retuned as well as checking the boiler internals for signs of scale, which will reduce the heat transfer rates and ultimately cause tube failures. When these daily maintenance checks are neglected, the small indicators of inefficient operation and internal scaling will be missed.
Tracking the feedwater pressure and temperature allows the operator to notice any trends in proper feedwater system operation. If the pressure or temperature are out of normal range, the feedwater may be unable to enter the boiler, or damage can result from thermal shocking. When the temperature differential between feedwater and boiler water is significant, thermal fatigue will begin to take effect on the boiler. This will be seen first at the feedwater coupling, which will develop cracks that will propagate into the boiler shell. Depending on operating pressure and temperature, a crack in the feedwater coupling and boiler shell may result in the release of dangerous fluids and vapors, putting operational personnel at risk for injury.
Checking the flame in the sight glass is an easy way to catch tuning or impingement issues before they become a major concern, and neglecting to check can result in poor combustion and potential boiler system failure. Although the boiler explosions that most would be familiar with are the result of water level issues, burner explosions are also a major concern to look out for. Regularly checking the sight glass and gas/fuel trains will alleviate combustion-related dangers.
Checking the water treatment equipment and taking water samples ensures treatment and supply issues do not go unnoticed, which result in boiler inefficiencies, improper operation, unsafe conditions, and even component failures. Infrequent or complete lack of blowdown during boiler operation will also result in a high concentration of impurities that contribute to scale, corrosion, carry over, and other operational concerns. When boiler water chemistry is not maintained in accordance with manufacturer recommendations, catastrophic failures are inevitable, including overheating of boiler tubes, corrosion of boiler metals, and steam line corrosion.
As more tasks are neglected, the problems and issues will compound and may ultimately lead to a catastrophic failure of the boiler system. Neglecting boiler maintenance will put operational personnel at risk, result in premature failure of components and equipment, and ultimately cost a company through inefficiency, downtime, repairs, and replacements. To mitigate these risks, follow the recommended guidelines for all regular maintenance tasks.