Design of S–CO2 coal-fired power system based on the multiscale analysis platform

This work presents a design of 1000 MW S–CO2 coal-fired power system, containing not only a new methodology of S–CO2 power system modeling, but also the specific directions for engineering design. The coupling between computational fluid dynamic simulations at boiler scale and the mathematical modeling of the thermal cycle facilitates a high reliability of the comprehensive design. Our analysis helps identify key questions and then delivers specific directions for engineering design, especially for the pressure drop penalty in tail flue and thermal-hydraulic performance of cooling wall. The proposed flue split method coupled with parallel utilization method can not only effectively reduce the pressure drop penalty but also simplify the system heater configuration. Moreover, the thermal performance of S–CO2 cooling wall is improved by using the flue gas recirculation and cooling wall arrangement optimization. The optimized position and proportion of flue gas extraction are further obtained. Comprehensively, the proposed design of S–CO2 coal-fired power system enhances the system net efficiency up to 51.00%, with an efficient utilization of residual heat and cooling wall temperature below 700 °C. •A multiscale modelling platform is proposed for S–CO2 coal-fired power system.•An improved system is obtained with system net efficiency up to 51.00% and cooling wall temperature all below 700 °C.•Flue split method and parallel utilization are developed for efficient recovery of tail flue heat.•Flue gas recirculation and cooling wall optimization are used to improve thermal safety of S–CO2 cooling wall.