LAUSR

Abstract Boiler is key to influence supercritical carbon dioxide (S-CO2) cycle performance. Here, S-CO2 cycle driven by pressurized fluidized bed combustion (PFBC) boiler is investigated. The proposed systems A and B include recompression cycle with reheating (RC + RH), air compression-gas turbine (AC-GT), simple Brayton cycle (SRC), and RC + RH, AC-GT, respectively. A simulating code is developed for system analysis. We show that system A has higher efficiencies than system B. Larger flue gas pressure drop in PFBC boiler apparently worsens system performance. Effect of combustion pressures of PFBC boiler (Pfur) is thoroughly analyzed. Energy distributions in the system is affected by Pfur. With Pfur increase from 1.0 MPa to 3.5 MPa, boiler efficiencies are increased due to the decreased flue gas heat discharged to environment. Power generation efficiencies are increased but approach constant value. To overcome the challenge of heating surface arrangement in boiler, bubbling PFBC boiler is recommended. Compact heat exchangers are suggested in the top “pure” flue gas region. To further make it easier for heating surface arrangement, excess air coefficient is suggested to be increased to decrease thermal load fraction in furnace αfurnace. Flue gas recirculation is a better way to decrease αfurnace, which is applicable for system B.