Thermal Calculations for Co‐Firing of Hydrogen/Ammonia and Coal in 660‐MW Coal‐Fired Boilers

To achieve a clean energy transition under the dual carbon goals, blending hydrogen/ammonia into pulverized coal boilers represents a key technological pathway. Different hydrogen/ammonia co‐firing ratios (5%–50%) are investigated for their impact on the thermodynamic characteristics of 660‐MW supercritical boiler at 100% and 20% boiler maximum continuous rating (BMCR). The analysis is based on a coupled methodology, where computational fluid dynamics (CFD) simulations are validated against combustion experiments. The results indicate that hydrogen co‐firing significantly increases the theoretical combustion temperature, while ammonia co‐firing generally maintains it around a certain level. At 100% BMCR load, co‐firing optimizes combustion, leading to a notable reduction in furnace outlet gas temperature (a decrement of 46°C with hydrogen) and an improvement in boiler thermal efficiency (peak efficiency of 94.6% with hydrogen). However, under 20% BMCR load, heat transfer mismatch causes the exhaust gas temperature to rise (reaching 150°C with hydrogen) and thermal efficiency to drop below 91.6%. Furthermore, co‐firing elevates the flue gas acid dew point overall, increasing the corrosion risk for rear heating surfaces. This study elucidates the nonlinear effects on hydrogen/ammonia co‐firing with coal in key boiler parameters, providing an important theoretical basis for safe operation and energy efficiency optimization in engineering applications.