Investment decision of monoethanolamine based post combustion CO2 capture plant via application of control strategies

Abstract

The abatement of anthropogenic CO2 gas and extensive demand for electricity has motivated cleaner power production from fossil fuels. Monoethanolamine (MEA) based post combustion CO2 capture plant (PCC) is a promising and mature technology to realize large scale cuts in carbon emissions at national and global levels. A carbon capture plant features non-linearity and multifaceted process interactions, therefore presents operational challenges requiring robust control strategies to ensure optimal but flexible operation of the plant as it responds to variable power plant output. This paper investigates two control strategies (viz, conventional feedback (PID) control and model predictive control (MPC)) with the control objective being formulated as economic functions around CO2 emissions (US$/t-CO2) and operational cost (US$/d). This presents a management capability to the power plant operator unlike the commonly used operational (technical only) objective of maximising CO2 capture (CO2%) at a given setpoint in conjunction with plant net energy performance (EPn). This economics-based formulation in the control strategy together with a demonstrated stability analysis fits well into plant-wide control implementation of MEA based PCC plants and supports cleaner production of electricity while helping such operation economically viable. It can be seen that embedment of MPC into PCC plant features attractive economic value (positive investment decision) based on the two above criteria. Whereas, CO2 emission cost and operational cost exhibit 30% and 60% of cost saving compared with the deployment of PID controller.