Flexible operation of CO2 capture processes integrated with power plant using advanced control techniques

In this work, a dynamic rate-base model is used to describe CO2 capture process in aqueous solution of MEA. The model has been implemented in the Matlab/Simulink software in order to do a part-load analysis and elaboration of control strategies of carbon capture process to be used within a power plant. The experimental results published in literature for Esbjerg CESAR pilot plant are used to validate the developed model. A good correlation between absorber's temperature profiles obtained by simulation and experiment was observed, R-squared value is of 0.936 in case of liquid's temperature and of 0.965 for gas's temperature. From environmental protection perspective, the primary control objective for the absorption column is the control of the carbon dioxide concentration in the sweet gas stream. Typical disturbances have been investigated, such as the step/ramp/sinusoidal increment in the flue gas flow rate with respect to its nominal operating point. Two different scenarios have been investigated using both the classical and the advanced control strategy approaches. The simulation results revealed that both PI and MPC controllers were capable to maintain the controlled gaseous mixture close to its imposed set point, rejecting the flue gas flow rate disturbance. Moreover, the MPC is capable to perform efficient control while conforming to constraints imposed on the maximum allowed value of the outlet CO2 gas concentration and improving the CO2 capture efficiency.