Post-combustion capture of CO_2 at an integrated steel mill - Part Technical concept analysis

摘要

In this study different possibilities for applying post-combustion capture at an integrated steel mill in order to reduce carbon dioxide emissions were studied. Implications of different amounts of CO_2 captured, different solvents for post-combustioncapture and different heat supply options for solvent regeneration to the energy balance and greenhouse gas emissions of the steel mill are compared to that of the base case for the steel mill. The case study is based on Ruukki Metals Ltd.’s Raahe steel mill that is situated on the coast of the Gulf of Bothnia. It is the largest integrated steel mill in the Nordic countries producing hot rolled steel plates and coils. It is also the largest CO_2 point source in Finland emitting approximately 4 Mt/year. Carbon capture processes were modelled using Aspen Plus process modelling software and results were used to estimate the potential for reducing CO_2 emissions at an integrated steel mill from a plant operator’s point of view. Different heat integration options and heat utilization scenarios were investigated. The heat available for solvent regeneration varied between these heat utilization scenarios and thus partial capture of CO_2 was investigated with the CO_2 amount captured depending on the heatavailable for solvent regeneration in the different case studies. The results of the study show a significant CO_2 reduction potential using CCS. Approximately 50-75% of the emissions from the site could be captured using post-combustion capture. Capturing a larger amount of emissions would be technically less feasible due to the large number of small stacks around the large, integrated steel mill site.