Coal Fired Boilers

Supercritical Plant Startup Control Coal fired Supercritical Power Plants are an integral component of the strategy for many generation companies. With a higher pressure/temperature range near 4300 psi and 1100°F, supercritical plants operate more efficiently than their subcritical counterparts. Whether an older design base load plant is now called upon to cycle more often, or a newer Supercritical plant designed to do so, it is imperative that the startup system perform at optimal levels. Without the additional stored water and steam volume available in most subcritical boilers, large step changes don’t come easily in supercritical plants. But with thinner walled components and smaller storage capacity, shorter startup times are more common.  The various startup systems from each boiler manufacturer all serve a common purpose to provide an orderly sequence to synchronize and roll the turbine. This involves maintaining a constant flow through boiler tubes to prevent overheating, and to keep the pressure above the saturation point, to prevent flashing.  Literature Download the Supercritical Plant Startup Control Application Spotlight! Download

Superheat Attemperator Background Attemperators have been a key component of Combined Cycle Power Plants for many years. Back when these units were base-loaded, spray water control wasn’t an issue. In today’s world, however, plants are ramping up and down daily – consequently putting a strain on steam temperature control regulation. Controlling superheat temperature enables plants to maximize efficiency and improve heat rate.  Depending on their type and design, each plant uses multiple strategies across various systems to accurately control temperature. Almost all use superheat spray valves as the “final” control of steam temperature entering the turbine. Since plants need to cycle to lower loads more frequently, many now use feed-forward, cascade and adaptive-predictive control strategies which result in tighter control of superheat steam temperatures. With the wrong actuator operating the superheat spray valves, numerous issues can arise.  REXA Linear and Rotary actuators are key components in helping plants achieve their efficiency goals by maximizing performance through tighter resolution, stiff repeatable positioning and high duty cycle operation. Learn more in the full Application Spotlight below!  Literature Check out the full Application Spotlight to learn more!  Download