Optimisation of chemical absorption for the decarbonisation of the iron and steel industry: an integrated simulation and pilot-scale investigation to benchmark capture performance from high-CO2 process emissions

Decarbonisation of critical hard-to-abate industrial sectors such as the iron and steel industry is crucial for meeting climate targets, with chemical absorption carbon capture identified as a key transitional technology. However, its application to these industrial sectors is hindered by a significant knowledge gap: the absence of publicly available and transparent performance benchmarks using a conventional capture plant under elevated CO2 conditions that are typical of industrial process emissions.

This thesis addresses this gap through a synergistic methodology combining process simulation with pilot-scale experimentation. An initial process simulation model was developed in Aspen Plus to identify parametric trends and plant performance across a wide range of operating conditions. The results from this investigation were used to inform initial starting conditions for a targeted experimental campaign on a conventional packed bed system.

The experimental campaign established a novel performance baseline for the treatment of flue gas with CO2 concentrations ranging from 10 to 25 mol.% CO2, using a solvent of 35 wt.% monoethanolamine. The dataset was then used to calibrate and enhance the simulation model to create a high-fidelity predictive tool that forms the foundation of a digital twin for the capture plant. This was achieved using a novel Python automation framework developed to control Aspen Plus. The enhanced model was successfully used to interpolate and extrapolate performance of the capture plant, identifying optimal operating conditions beyond the experimental scope.

The novel baseline performance dataset can be used to compare the capture effectiveness of alternative and advanced process configurations in the treatment of heavy industry process emissions. In addition, the methodologies outlined in this thesis can serve as a guide for the development, validation, and enhancement of representative process simulations of other chemical absorption systems. This work ultimately seeks to accelerate the deployment of carbon capture for industrial decarbonisation.