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.