Application of the DMXTM CO2 Capture Process in Steel Industry

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Abstract The VALORCO project coordinated by ArcelorMittal and funded by ADEME aims at reducing and valorizing CO 2 emissions from steel industry. This paper presents the main results of task 1.1A of the VALORCO project dedicated to CO 2 capture on blast furnace gases by means of amine scrubbing technologies. Blast furnace gases are characterized by high CO 2 and CO partial pressures and the absence of oxygen. Since few literature data are available on the effect of CO on solvent degradation and CO 2 absorption, experimental work was needed. In this context, three IFP Energies nouvelles (IFPEN) processes initially developed for CO 2 capture on coal power stations were evaluated for blast furnace applications: Hicapt TM process (MEA 30 wt.%), Hicapt+ TM process (MEA 40 wt.%) and DMX TM process (Demixing solvent). For the three processes, it was shown that CO absorption is slow and mainly physical even though kinetic studies highlighted a chemical absorption of CO in CO 2 -free amine solutions, especially for MEA solvents. This chemical absorption is however largely inhibited in presence of CO 2 which limits this phenomenon to occur in real process conditions. Degradation studies in batch reactors showed a low impact of CO on MEA solutions and no quantitative effect on DMX solvent. Compared to flue gases containing oxygen, amine degradation observed with blast furnace gases is globally negligible for all tested solvents. Above conclusions were confirmed with two long-run tests (∼1500 h) on a CO 2 capture mini-pilot at IFPEN. These tests also underlined a high CO 2 /CO selectivity with very few CO in CO 2 produced, the possibility of reaching high CO 2 capture rate (>99.5%) and the good operability for all studied processes. Moreover, DMX solvent allows using carbon steel as process metallurgy and producing CO 2 at 6 bara which turn into subsequent economical savings. Considering an available steam at 21 €/t, it would be possible to produce CO 2 from blast furnace gases at around 40 €/t by using the DMX TM process.