Dynamic Characteristics and Thermodynamic Analysis of a Double Reheat Boiler During Loading Cycling Processes

With a double reheat tower boiler as the reference case, simulation models of the boiler and its temperature control systems are developed via the GSE platform and user defined codes. The dynamic characteristics of steam temperatures are obtained during load cycling processes with different amplitudes and rates. Moreover, changes of boiler's real time energy and exergy efficiencies during load cycling processes are obtained. Results show that the time that the steam temperature fluctuates after load command reaches its target prolongs with the load cycling amplitude. The real time efficiency increases with load cycling rate during load down processes. The real time efficiency increases with the decrease of load cycling rate during load up processes. Moreover, the time that the steam temperature fluctuates after load command reaches target prolongs with the load cycling rate, and the steam temperatures changing amplitude increase with the load cycling rate. When the load cycling rate increases by 0.5%, the steam temperatures changing amplitude increases ~2℃ during load down processes, and it increases ~1℃during load up processes.