It’s often associated with the Industrial Revolution and early modern transportation. But, steam still powers our lives today. In fact, steam turbines generated over 40% of US electricity in 2022. To maintain efficiency and safety in the boilers that drive those turbines, engineers have to carefully control the temperature and flow of the water supply. This is where boiler feedpump systems come in, regulating the flow of water fed into the boiler (feedwater) in a way that avoids overheating and excess pressure.
Florida Power & Light (FPL) provides clean electricity to more than 12 million people across America. To maintain a reliable service and affordable rates, they have to ensure efficiency throughout their energy production system. This includes their steam boilers. They approached Trimteck for a boiler feedpump recirculation valve, which ensures a minimum flow of water to the boiler to protect it from overheating.
Cross-sectional diagram of a boiler feedwater system, including control valves.
What did FPL need for this application?
Boiler feedpump recirculation valves need a highly versatile design due to their role in the boiler system. To ensure minimum flow, but also avoid excess pressure and overheating, they must be able to provide both tight shut-off and precise modulation of feedwater.
FPL needed ANSI Class VI shutoff and precise control of high-pressure (HP) feedwater. The control valve construction also had to withstand severe cavitation and flashing, issues caused by drops in pressure as steam is consumed by the boiler system. What FPL was facing was the rapid degradation of the existing valve’s ability to seal tightly. This ultimately causes massive steam loss and decreases the efficiency of the power plant. While cavitation is predictable and can be addressed in a straightforward manner, the occurrence and location of flashing are less intuitive. FPL’s feedpump recirculation valve needed to handle a 3250 psi pressure drop at 56,000 pounds per hour.
Without the right control valve for your application and regular checks, cavitation and flashing can erode and damage piping and other components.
What was Trimteck’s solution?
To keep critical processes flowing for FPL, Trimteck took a bottom-up approach and examined thousands of trend lines to determine exactly when and why the existing valves were failing. Using that information, we engineered and manufactured a custom specialty control valve. The 4” CL1500 OpGL-XT Angle Control Valve used our ST-2™ Multi-Stage Trim Anti-Cavitation Cartridge to eliminate mild to moderate cavitation and control the effects of heavy cavitation and flashing.
For the trim material, we used 440 C Stainless Steel for its excellent erosion resistance and enhanced this with our innovative CVD-5B™ hardening process. Originally used in the aerospace industry to harden rocket nozzles on space shuttles, this process can resist temperatures of up to 1200°F and doesn’t crack under duress.
Finally, we fabricated the body from F22 alloy steel for its excellent impact strength and combined FPL’s control valve with a custom-sized OpTK200 Piston Cylinder actuator. Our OpTK™ actuators allow tighter shutoff, thanks to their 150 psi (10.3 Bar) operating pressure that enables high thrust. But, this high thrust doesn’t sacrifice precision. This is thanks to the dynamic positioning of the piston which evenly distributes the pressure for stiff, precise operation.
Specialists in severe service applications
When homes across the country are relying on your service, you need to know you can rely on your process control components. To combat issues like cavitation and flashing, while also optimizing the lifespan and efficiency of your process control system, you need custom specialty control valves.
By working with Trimteck, you’ll always get the most effective solution for your severe service application. We use innovative designs, materials and processes to engineer rugged, reliable control valves. And, with the help of our Applications Engineers or AccuValve™ software, we can accurately specify the right control valve for your service. To find out how we could enhance your process control system, get in touch with one of our Sales Engineers.
