Thermodynamic analysis and optimization of Allam cycle with a reheating configuration

The Allam cycle is one of the most promising oxy-combustion systems and has attracted much attention from the energy industry. A novel layout of the Allam cycle, which combines a reheating configuration with the original Allam cycle, was proposed in the present study. The effects of key variables on the net cycle efficiency and net specific work of the new system were investigated. The Allam cycle with reheat was optimized to maximize the cycle efficiency and compared with other cycles. The results showed that the minimum cycle temperature and the outlet temperature of the second combustor have significant effects on the cycle performance, while the maximum cycle pressure has minimum effect on the cycle performance. The highest exergy destruction of the optimized cycle is contributed from the two combustors, which accounts for 25.42% of the total input exergy. The net efficiency of the optimized Allam cycle with reheat is up to 49.32%, a little higher than those of other oxy-combustion cycles and about 5 percentage points lower than that of the original Allam cycle. However, the net power output and net specific work are up to 904.6 MWe and 606.2 kJ/kg for this novel system, about 2.1 times and 2.2 times of those of the original Allam cycle, respectively.