Development and key problems of ultra-supercritical double reheat plant in China

Significant development of coal fired power plant has been made in China in the past decades. Over 50 units of 1000MW ultra-supercritical (USC) plant have been constructed with designed net efficiency as high as 45%. Precious and critical knowledge for design, construction and operation has been accumulated from these units, which make China stepping into the advanced coal fired power industry field. To increase the plant net efficiency further, USC double reheat unit is proved to be a promising technology in the current industrial level while the 700∼800°C plans are the possible technology in the long term goal. In China, USC double reheat plan is now performing in Laiwu, Anyuan, and Taizhou plants. In this paper, fundamental problems including material over permit temperature, steam temperature adjustment, and exhaust gas heat recovery are discussed in detail. Based on the operational experiences worldwide, the USC double reheat unit is considered to gain satisfying performance in the future.