Integration and evaluation of a natural gas-ammonia complementary power generation system based on ammonia-driven calcium looping for CO2 capture
Natural gas power plants will play an important role in scenarios with high renewable energy input due to their clean,efficient and excellent peak-shaving capacity.Although natural gas power plants have lower carbon emission intensity compared to coal-fired power plants,they remain a major source of global CO2 emissions.CO2 capture,utilization,and storage(CCUS)technologies are essential for achieving carbon neutrality,with post-combustion calcium looping technology drawing significant attention due to the widespread availability and low cost of its absorbents.Traditional oxy-fuel calcium looping capture technology uses pure oxygen and fossil fuels to supply heat for the calcination process and recovers the constant-temperature heat from the carbonation reaction by directly heating steam,resulting in high energy penalties.A novel ammonia-driven calcium looping CO2 capture system for natural gas-ammonia complementary power generation has been proposed,in which ammonia replaces fossil fuels as a zero-carbon fuel.This new system avoids the additional carbon capture demand caused by fossil energy heating and utilizes ammonia pyrolysis to recover medium-temperature heat released from the carbonation reaction,avoiding large temperature difference heat exchange losses when directly heating steam.The results show that,compared to traditional oxy-fuel calcium looping systems,the efficiency penalty of the new system drops from 9.4％to 0.6％,and the CO2 avoided energy consumption decreases from 4.7 to-8.1 MJ/kg,significantly improving its thermodynamic performance.At the same time,the carbon emission intensity of the new system is significantly reduced compared to the oxy-fuel calcium looping system,reaching 18.6 kg/MWh.An analysis of the effect of gas turbine inlet temperature and pressure at ammonia side on the new system's performance shows that the new system performs well across a wide range of operating parameters.
ammoniacalcium loopingpost-combustion capturenatural gas combined cycle power plantsystem integration
NETL
NSTL
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