Nonlinear dynamic analysis and control design of a solvent-based post-combustion CO2 capture process

A flexible operation of the solvent-based post-combustion CO2 capture (PCC) process is of great importance to make the technology widely used in the power industry. However, in case of a wide range of operation, the presence of process nonlinearity may degrade the performance of the pre-designed linear controller. This paper gives a comprehensive analysis of the dynamic behavior and nonlinearity distribution of the PCC process. Three cases are taken into account during the investigation: 1) capture rate change; 2) flue gas flowrate change; and 3) re-boiler temperature change. The investigations show that the CO2 capture process does have strong nonlinearity; however, by selecting a suitable control target and operating range, a single linear controller is possible to control the capture system within this range. Based on the analysis results, a linear model predictive controller is designed for the CO2 capture process. Simulations of the designed controller on an MEA based PCC plant demonstrate the effectiveness of the proposed control approach. (C) 2018 Elsevier Ltd. All rights reserved.