Post-combustion CO₂ Capture Using Amine-scrubbing at an Integrated Steel Mill

In order to achieve net-zero emissions by 2050, CO₂ emissions must be significantly reduced and, where feasible, entirely avoided. Carbon capture & utilisation is a potential option to transform CO₂ emissions from industrial plants into valuable products and thus avoid the use of new fossil based raw materials. This study shows the operation of an amine-scrubber pilot plant for post-combustion CO₂ capturing at the powerplant of an integrated steel mill. The contribution focuses on the optimisation of the process in terms of energy input and loss of chemical solvent. Even though amine-scrubbing has a high technology readiness level (TRL = 9) and high feasibility for industrial carbon capture, tests under real conditions are of utmost importance to gain operational experience at the respective flue-gas source. Major drawbacks are the high energy input required for regeneration of the chemical solvents and process-related solvent losses, which are the main challenges associated with this technology. The findings of this study reveal a minimum in specific regeneration energy of 3.2 GJ/t_CO2 at various process parameters. Additionally, the observed specific regeneration energy is most sensitive to changes in solvent flow rate, desorber heat duty, and solvent concentration. Finally, a long-term test (≈ 80 h) resulted in solvent losses of about 2.1 l_amine/24h operation.