Sustainable Aspects of Ultimate Reduction of CO2 in the Steelmaking Process (COURSE50 Project), Part 2: CO2 Capture

Abstract

COURSE50 (ultimate reduction of CO2 in the steelmaking process through innovative technology for Cool Earth 50) aims to capture, separate, and recover CO2 from blast furnace gas. From a practical realization viewpoint, three points are important. The first is energy consumption to regenerate the absorbent, second is the energy cost of the heat for regeneration, and third is the facility cost. The advantage afforded by the COURSE50 approach in relation to the CO2 capture process is the utilization of unused waste heat from the steel mills. Energy consumption to regenerate the absorbent is determined mainly by three factors: the regeneration reaction determined primarily by the structure of the chemical absorbent, the energy required to heat that volume of absorption liquid, which is affected by the absorption rate of the agent, and the heat loss from the processes. The most influential factor is the energy required for the regeneration reaction. We discovered high-performance absorbents with the advantages of high absorption rates, high cyclic capacities, and low heats of reaction, and we then compared these with monoethanolamine (MEA) and N-methyldiethanolamine (MDEA). The newly discovered absorbents performed well in terms of absorption rates and cyclic capacities. Among these absorbents, some showed lower heats of reaction than MDEA. These results provide a basic guideline for the discovery of potential amine-based absorbents that may lead to the development of new absorbent systems for CO2 capture.