The conventional co-fired power generation system using supercritical carbon dioxide(S-CO_2) cycle is lack of rapid and accurate boiler working fluid temperature control method

and the boiler's thermal efficiency and exergy efficiency is relatively low. To solve this problem

this paper proposes an improved recompression and reheat S-CO_2 cycle for coal-fired power plant. The steady-state models of the original system and the improved system are established using Aspen Plus. Systematic comparisons between the two cycle systems are performed based on the exergy analysis method. In addition

the temperature-regulating characteristics of the spray attemperator of the improved system are studied. The results show that

compared with the original system

the boiler exergy efficiency and system efficiency of the improved system are 53.41% and 48.24%

respectively

which increases by 2.76 and 2.32 percentage points

both grow significantly. The temperature adjustment ranges of the boiler working fluid of A1 and A2

B1 and B2 in the improved system are 0～16.96 ℃

0～19.44 ℃

0～19.43 ℃ and 0～21.03 ℃

respectively

which can meet the requirements of rapid and accurate adjustment of boiler working fluid temperature.