Start-Up and dynamic processes simulation of supercritical once-through boiler

•Detailed component model of supercritical once-through boiler start-up system is established.•Six-equation solution of two-phase flow is employed in developing the model of evaporator.•Validated against design data of steady state showing a very good agreement.•Dynamic simulations of two different cold start-up processes are conducted and validated. The rapid expansion of the electricity demand causes the gap between the peak load and valley load increasing in China. Since the coal-fired supercritical power plant needs to be started up frequently, the operations of power plant become more flexible. During the start-up process, the operation parameters are off-designed, the multi-transient phenomenon is inevitable and the intensive emission always appears during varying working condition, it is difficult to ensure the operator of the real power plant to start up the boiler following the design curve. In this work, a new dynamic model for simulating start-up dynamic process of a 600MW supercritical boiler is introduced in this paper. The six-equation solution of two-phase flow was applied to modeling the evaporator, and the process from ignition to the load at 30% Boiler Maximum Continuous Rating (BMCR) was simulated. The results demonstrate that the model is reasonable and dynamic behavior can be observed clearly. Also, these prove that the control strategy is advisable. Moreover, the fuel consumption of the start-up process can offer a reference to operator of the real power plant. The validated model is of high relevance for further optimizing the boiler start-up process.