Techno-economic assessment and comparison of absorption and membrane CO2 capture processes for iron and steel industry

Highlights: • Absorption- and membrane-based CO₂ capture for the iron and steel industry. • Process optimization of absorption- and membrane-based CO₂ capture process. • Techno-Economic Assessment of post-combustion CO₂ capture process. • Techno-economic impact of CO₂ concentration in the feed gas on capture. An economic assessment of the post-combustion CO₂ capture process for the iron and steel industry is presented herein. Absorption- and membrane-based CO₂ capture processes were modeled and simulated using Unisim_® and MATLAB_®, and an economic assessment based on the multiparameter scaling methodology was used to evaluate the economics of the CO₂ capture processes. Flue gases with CO₂ concentrations in the range of 4.8–27.3 mol% were selected from a typical steel plant, and their techno-economic impact on process design and CO₂ capture cost was systematically analyzed. As the flue gas CO₂ concentration increased from 4.8 to 27.3 mol%, the CO₂ capture cost of the absorption-based process without CO₂ compression decreased from 73.5 USD₂₀₁₉/tCO₂ to 55.3 USD₂₀₁₉/tCO₂, and that of the membrane-based process decreased from 271.7 USD₂₀₁₉/tCO₂ to 41.7 USD₂₀₁₉/tCO₂. The economics of the CO₂ compression process integrated case were also evaluated. This dramatic change in the capture cost for membrane systems is related to the high partial pressure of CO₂ being favored for membranes, compared to absorption-based processes. The case study confirms that the membrane-based CO₂ capture process becomes more cost-effective and energy-efficient than the absorption-based process as the CO₂ concentration of flue gas increases.