Development of novel absorbents for CO2 capture from blast furnace gas

In order to establish energy-saving technology for CO₂ capture from blast furnace gas, novel absorbents were developed in the laboratory and evaluated at a 1 t_CO2/d test plant. At first, CO₂ absorption and desorption behaviors of single-component amine solvents for simulated blast furnace gas (CO₂/N₂ = 20%/80%) were investigated through a screening test using a small scrubbing bottle. These amine solvents were additionally analyzed using nuclear magnetic resonance (¹³C NMR) spectroscopy and reaction calorimetry. The results of the laboratory experiments showed that there was a trade-off between absorption rate and enthalpy of absorption but some absorbents had unique features. For example, 2-isopropylaminoethanol (IPAE) had high absorption rate and small enthalpy of absorption. Then, new IPAE-based amine solvents (RITE solvents: RITE-A and RITE-B) were formulated and evaluated at the 1 t_CO2/d test plant. CO₂ regeneration energies of the RITE solvents were 3.3 and 3.1 GJ/t_CO2, respectively. With certain process conditions and plant specifications optimized, RITE-B was estimated to have the potential to achieve 2.5 GJ/t_CO2.