When are softened water and desalinated water used in circulating fluidized bed boilers?

　　After being softened, the water whose hardness drops to a certain level is called softened water. As the salt content of softened water remains unchanged, it is generally only used for make-up water for small and medium-sized boilers.

　　Demineralized water undergoes further demineralization treatment on the basis of softened water. Because of its high processing cost, high-pressure boilers and above use it as feedwater. Some medium pressure boilers also use it as the desuperheating water of the hybrid desuperheater.