Abstract
A clean energy revolution is occurring across the world. As iron and steelmaking have a tremendous impact on the amount of CO2 emissions, there is an increasing attraction towards improving the green footprint of iron and steel production. Among reducing agents, hydrogen has shown a great potential to be replaced with fossil fuels and to decarbonize the steelmaking processes. Although hydrogen is in great supply on earth, extracting pure H2 from its compound is costly. Therefore, it is crucial to calculate the partial pressure of H2 with the aid of reduction reaction kinetics to limit the costs. This review summarizes the studies of critical parameters to determine the kinetics of reduction. The variables considered were temperature, iron ore type (magnetite, hematite, goethite), H2/CO ratio, porosity, flow rate, the concentration of diluent (He, Ar, N2), gas utility, annealing before reduction, and pressure. In fact, increasing temperature, H2/CO ratio, hydrogen flow rate and hematite percentage in feed leads to a higher reduction rate. In addition, the controlling kinetics models and the impact of the mentioned parameters on them investigated and compared, concluding chemical reaction at the interfaces and diffusion of hydrogen through the iron oxide particle are the most common kinetics controlling models.
Highlights
Nowadays, carbon dioxide emissions have become one of the most important environmental concerns, the consequences of which include global warming
Among the technologies being developed in this regard, hydrogen as a reducing agent [3,4,5,6], carbon capture and storage (CCS) [7,8], carbon capture and utilization (CCU) [9,10], biomass as a reducing agent [11,12], and electrolysis can be mentioned [13,14,15]
0.045 mm the dependence of reduction rate on particle size is not considerable, the internal diffusion resistance is neglectable for particle size below 0.045 mm [19]. because the internal diffusion resistance is neglectable for particle size below 0.045 mm [19]
Summary
Carbon dioxide emissions have become one of the most important environmental concerns, the consequences of which include global warming. Diffusion of hydrogen through the film surrounding the iron ore particle. “ρ” is theτdensity of solid reactant, bk Cg“R” is the radius of the particle, “b” is the stoichiometric coefficient of the solid reactant when the stoichiometric cowhere “t” is time, “X” is fraction of reacted material (reaction fraction), and “τ” is the efficient of the gaseous reactant is equal to 1, “kg” is the mass transfer coefficient. The studies that have determined the effect of different parameters the kinetics of reduction by experiment, modeling and simulation are reviewed. On the kinetics of reduction by experiment, modeling and simulation are reviewed
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