Simulation of the one-dimensional operational characteristics of a supercritical coal-fired boiler system under full operating conditions

The intermittency and variability of renewable energy generation often require coal-fired power plants to perform deep load-following and frequency regulation tasks. This operational mode frequently forces boiler systems to operate under off-design conditions, posing challenges to their efficient and stable performance. In this study, a 600 MW coal-fired boiler was modeled using the APROS simulation platform, incorporating a one-dimensional furnace and water-steam system. The variations in flue gas and water-steam parameters under different operating conditions were analyzed. The results show that as boiler load decreases from the rated level to 20%, the flue gas temperature gradually declines, and the flame center shifts downward. At 100% THA, the flame center is located at a relative height of approximately 0.4, whereas at 20% THA, it moves downward to about 0.2. The unburnt carbon rate increases with decreasing load, exceeding 5% at 20% THA, indicating that lower loads have a more significant impact on pulverized coal preparation. Furthermore, as the load decreases, the phase transition process of the working fluid inside the tubes intensifies, with the phase transition point shifting upstream.