Much of what power plant operators think of when they plan regular power plant maintenance involves the power generating units themselves – namely, boilers and generators.
However, plants don’t place nearly as much attention on maintaining and inspecting the support systems that enable energy generation, known as the balance of plant (BoP) systems.
Over the decades that we’ve had power plant maintenance as a service, we’ve learned that paying attention to BoP systems can have a significant impact on efficiency. An increase in efficiency leads to better bottom-line results. Hence, paying closer attention to BoP systems through power plant maintenance can affect a plant’s bottom-line performance.
There are three areas in particular that are part of a plant’s BoP that need regular attention: recirculating pump inlet screens, cooling tower fill, and vacuum pumps.
Recirculating Pump Inlet Screens
Recirculating pumps are an important part of a cooling tower’s performance and efficiency. But sometimes, the inlet screens become clogged with material and debris, collectively known as total suspended solids (TSS). One common example of TSS is algae build up that slows down – or completely obstructs – flow through the inlet screen.
Obstruction of the pump inlet screens can cause water flow to be reduced, which will steadily increase the amount of heat contained in the water. Higher water temperature will influence back pressure and cause back pressure penalty if left unchecked.
The solution is to regularly check and clear recirculating pump inlet screens. Flow rates will dictate how often this happens, but it’s important that maintenance is conducted regularly. Over time, particulate flow from TSS will steadily degrade the integrity of the screens – and of the recirculating pumps themselves – requiring refitting at some point in the future. Regular maintenance allows you to predict that date with more accuracy.
Cooling Tower Fill
Another function of cooling tower performance in BoP systems is the flow distribution through the tower fill.
Tower fill is a medium by which the maximum amount of water surface in the tower is exposed to air, which increases heat transfer rates. The goal is to increase the amount of time water comes in contact with air in the tower by obstructing the flow of water so that heat transfer rates stay high and steady.
There is a correlation between increased cooling water inlet temp and increased back pressure. Keeping inlet water temps steadily low through proper cooling tower fill construction and maintenance can help maintain back pressure – and thereby improve BoP performance.
Proper maintenance and engineering are both necessary. The fill system must be properly designed to get the transfer rates desired. Maintenance is necessary to ensure that fill continues to function as designed and maintains its integrity through repeated use.
Finally, vacuum pumps are integral parts of a plant’s BoP systems, but are among the plant’s most vulnerable components.
Unfortunately, vacuum pumps are often not inspected or maintained with any regularity. This is unfortunate because even subtle changes in the efficiency and performance of your system’s vacuum pumps can lead to reduced condenser efficiency. Most of the time, though, operators look at other systems instead of vacuum pumps when something goes wrong, or during the regular course of plant optimization.
One problem with vacuum pump maintenance is that even if data is collected (which it often isn’t), it’s usually labeled as “no-action”, which means it doesn’t trigger alarms or isn’t actively monitored as other data sets from other systems are.
The solution is to incorporate vacuum pumps into a plant’s BoP system maintenance plan. A plant’s efficiency depends on even the most overlooked parts, like vacuum pumps, receiving regular attention. Often, even that small step is enough to improve performance.
Adapting Your Power Plant Maintenance Plan
Power plant maintenance is an essential but overlooked part of a comprehensive plant operation strategy. Most operators understand the importance of maintenance, but sometimes, even the most diligent managers overlook small yet crucial components like the three outlined above.
Contact Southern Field for more information on creating a comprehensive maintenance plan that covers all necessary areas, not just the major systems that are easier to notice.