Performance evaluation of a novel double-reheat boiler with triple-rear passes

Double-reheat technology effectively increases the efficiency of coal-fired power plants. The bases for a double-reheat boiler design are reliability, efficiency, and controllability. A novel double-reheat boiler with triple-rear passes was proposed in this study to address several issues, such as low reliability and control precision of double-reheat steam temperatures of conventional double-reheat boilers. Dynamic models with a control system were developed with GSE software to examine the performance of the proposed boiler. Simulation results under steady-state working conditions showed that double-reheat steam temperatures can achieve design values in a wide load range. Then, the dynamic characteristics of the boiler were studied. Results further showed that a coordinated regulation of dampers in the triple-rear passes can effectively control double-reheat steam temperatures. Moreover, double-reheat steam temperatures can be controlled within an acceptable range during load cycling processes.