System integration for coal-fired power plant with post combustion CO2 capture: Comparative study for different solid dry sorbents

Abstract

For post-combustion CO2 capture technology, integration of CO2 capture will lead to considerable efficiency penalty of the power plant. This paper quantitatively compares the thermal performance of the integrated system with CO2 capture by three different solid sorbents, namely the solid amine Pentaethylenehexamine (PEHA), Na2CO3 and K2CO3. Due to different regeneration temperature, the retrofit schemes of the integrated system differ for three different sorbents. The back-pressure turbines are used to retrieve the surplus energy of the extracted steam for PEHA and Na2CO3, whereas multi-stage compressors are used to increase the extracted parameters for K2CO3. The thermodynamic and exergy analysis results show that the thermal consumption of regeneration and the regeneration temperature are the two key parameters influencing the efficiency penalty. Efficiency penalty is increased by 1.4% per 1.0 GJ/tCO2 increment and 0.67% per 10 °C temperature increment of regeneration. Due to a low thermal consumption of regeneration and regeneration temperature, the solid amine sorbent (PEHA) performs the best out of the three solid sorbents with the lowest efficiency penalty of 9.59%. Besides, comparison with monoethanolamine (MEA) based solvent systems (efficiency penalty of 9.66%–13.73%) shows that, the solid amine sorbent (PEHA) exhibits promising competitiveness in terms of energy consumption.