Feasibility study of novel water-lean solvent technology for CO2 capture from iron ore pelletization flue gas

Abstract

Vale and RTI International performed the technical and economic evaluation of CO2 capture from Vale’s iron ore pelletization process using RTI’s eCO2SolTM (an advanced non-aqueous CO2 solvent). CO2 is to be captured from the flue gas containing up to 2 vol% CO2, 120 ppm SOx, 330 mg/nm3 NOx, and 40 mg/m3 of iron particles. The iron particles collected from a straight grate iron ore pelletizing plant located in Vale’s operation in the state of Espirito Santo, were added to fresh eCO2SolTM and showed that the presence of these particles have no impact on the solvent’s CO2 loading, viscosity, and degradation rate. Due to high SOx content, a direct contact cooler (DCC) upstream of a CO2 absorber is required to minimize solvent degradation caused by sulfate-derived salts in the system. The DCC was also found to be effective in removing iron particles from a gas stream containing 25-55 mg/m3 in our test. A 370 hr-testing campaign with 90%+ CO2 removal from a gas stream containing 1-2 vol%CO2 was conducted using RTI’s bench-scale gas absorption system. The test showed that CO2 regeneration energy ranges between 3.0–3.6 GJ/t-CO2 which is expected from capturing CO2 from a diluted gas stream. The test also highlighted the use of a rotating packed bed (RPB) as an alternative absorber configuration, which reduces process footprint and increases the gas throughput compared to a conventional absorber column. Technoeconomic analysis indicates that the cost of CO2 capture is dominated by CO2 absorber and fuel costs. Further optimization in absorber size could reduce the cost of capture further. Alternative fuels could be used to reduce the CO2 footprint of the capture process.