DYNAMIC SIMULATION OF MEA-BASED POST-COMBUSTION CARBON CAPTURE SYSTEM

摘要

Coal-fired power plants are the primary targets to reduce CO_2 emission due to their largest CO_2 emission of single source,relatively centralized regional distribution and thus good potential of CO_2 reduction. Post-combustion carbon captureusing aqueous MEA solution is the most likely technology to be deployed in coal-fired power plants. Some studies havefocused on the dynamic modeling of MEA-based post-combustion carbon capture system recently to facilitate the CCSpractice in coal-fired power plants, however a clear strategy is still lacking in how to handle the CO_2 capture units intransient mode. In this paper, a dynamic model of MEA-based carbon capture system for coal-fired power plants wasbuilt up and validated to study its transient responses. The model was implemented in Invensys Simsci DYNSIMplatform, and the stage efficiency was used to correct the assumption of vapor-liquid equilibrium in tower model. Thepilot carbon capture facility set up at the University of Texas at Austin was simulated in this research, and the experimentdata of case 28 was used for model validation. The local control systems of gas pressure, liquid level and flowrate weredesigned to keep the system working. The comparison among the pilot test data, simulation of Aspen Plus using ratebasedmodel and simulation of this paper was carried out on the temperature profile inside the absorber and stripper. Theresults show that the steady state of developed dynamic model fits the measured data fairly well. This dynamic modelwas then used to study the dynamic character of CO_2 capture system under the flowrate disturbances of flue gas and leansolution. The transient responses of CO_2 loading and CO_2 capture rate were observed and analyzed, providing basis forfurther study of disturbance rejection control.