[Objective] In the context of achieving the “dual-carbon” goals in the new era

coal-fired cogeneration systems are required to be highly efficient

flexible

and low in pollution and carbon emissions. [Methods] To tackle these challenges

this study proposes a novel system that integrates a supercritical CO2 cycle with split-flow heating and low-temperature regeneration(SR-SCO2-CHP)

an ultra-low emission(ULE) flue gas control module

and a vacuum temperature swing adsorption(VTSA) carbon capture module(denoted as the SR-SCO2-CHP-ULE-VTSA system). A system using monoethanolamine(MEA) for carbon capture(SR-SCO2-CHP-ULE-MEA) serves as the benchmark for comparison. A comparative exergy analysis is conducted. [Results] The results demonstrate that the proposed system achieves superior exergy efficiency across all electrical loads

because the exergy loss of the VTSA carbon capture submodule is less than one-third of that of the MEA. The exergy losses of MEA mainly occur in the absorption tower and desorption tower

which account for 80% of the total exergy losses of the carbon capture submodule. However

the exergy losses of VTSA adsorption & desorption tower and the pressure machine are relatively large

accounting for more than 60% of the total exergy losses of the carbon capture submodule. At full load

its exergy efficiency reaches 39.84%

significantly outperforming the benchmark system's 35.16%. Furthermore

the proposed system enables effective thermo-electric decoupling through adjustments in the heat split ratio(x1) and the split ratio of CO2 turbine driving vacuum pump(x2). The exergy efficiency of the system decreases as the split ratio x1 and x2 increase under any electrical load

and the optimal split ratios of x1 and x2 increase as the electrical load decreases. At 100% electrical load

the optimal values for x1 and x2 are 0.52 and 0.14

respectively. The carbon reduction capability of the proposed system is also remarkable. Across the electrical load range from 100% to 30%

the carbon reduction increases from 11.9 g/(kW·h) to as high as 85.3 g/(kW·h)

demonstrating a significant advantage over the benchmark system. [Conclusion] This work confirms the SR-SCO2-CHP-ULEVTSA system as a promising solution for highly efficient and low-carbon coal-fired cogeneration. It should be noted that in terms of economic performance

the initial investment of the carbon capture module of the SR-SCO2-CHPULE-VTSA system is closely related to the performance of the adsorbent material

and further optimization of the adsorbent is required to reduce equipment size and cost. Additionally

in terms of operation

its carbon capture module has a complex structure and high requirements for multi-tower operation switching

so its technical maturity needs to be further improved to promote its industrial application.