Study on Depressurized Steam Blowing of Demonstrative 1 000-MW Unit with Double Reheat Cycles

Double reheating is the key technology developed for the ultra-supercritical coal-fired units. According to the characteristics of the demonstrative 1 000-MW unit with double reheat cycles, in this article, the two-stage depressurized steam blowing approach is proposed, which is to blow the primary and the secondary reheaters as well as the superheaters separately. The process design and the parameter selection are performed for this approach. With the boiler operating situation during blowing being taken into account, the characteristics of the parameters are analyzed with reasonable control methods and attentions over the parameters being presented in detail. The study may provide instructions for depressurized steam blowing in the boilers of the same type.