Modeling of counter current moving bed gas-solid reactor used in direct reduction of iron ore

Parisi, Daniel R.; Laborde, Miguel

doi:10.1016/j.cej.2004.08.001

Cited by 142 publications

(136 citation statements)

References 12 publications

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“…For example, taking the gas volume flow rate in three-dimensional model instead of the gas velocity in two-dimensional model as the gas inlet boundary condition actually represents the practical operation condition. 17) On the other hand, although similar works related to the shaft type furnace of SC 18) or MIDREX 19) process had been reported, the COREX pre-reduction shaft furnace differs from others not only in the furnace structure, but also in operation conditions. As a result, the present work develops a three-dimensional full scale mathematical model combined with mass, momentum, energy transfers and chemical reactions under steady state to study the inner characteristics of the COREX pre-reduction shaft furnace.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of the Characteristics Inside Pre-reduction Shaft Furnace and Its Operation Parameters Optimization by Using a Three-Dimensional Full Scale Mathematical Model

Kou

et al. 2013

ISIJ Int.

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Numerical simulation is considered to be an important method to study the inner characteristics of metallurgical processes, thus providing effective strategies for practical smooth operations. A three-dimensional full scale mathematical model considering mass, momentum, energy transfers and chemical reactions under steady state is developed in the present work to describe the characteristics inside the pre-reduction shaft furnace of COREX smelting reduction ironmaking process. The uneven gas and solid flow distributions in both radial and axial directions not only restrain the gas utilization but also cause the difference in the solid metallization between the center and near wall to reach as high as 0.4. Predicted by the established model, the CO-CO2-H2-H2O reducing gas with the temperature 1 050-1 100 K, the volume fraction of CO+CO2 around 70%, the ratio of CO to CO2 5-7, as low as possible H2O content, and the reasonably matched burden solid charging rate to control the top gas consumption per ton burden solid (TGC) in the range of 800-1 000 Nm 3 /t, are the optimal operation conditions to further improve furnace efficiency.

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Section: Introductionmentioning

confidence: 99%

Numerical Analysis of the Characteristics Inside Pre-reduction Shaft Furnace and Its Operation Parameters Optimization by Using a Three-Dimensional Full Scale Mathematical Model

Kou

et al. 2013

ISIJ Int.

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“…However, with the development of computational fluid dynamic, numerical methodology has been widely used in simulating metallurgical iron-making processes, such as traditional blast furnace process [7][8][9][10][11][12][13] and latest Midrex ® process. [14][15][16] Although the role of COREX ® shaft furnace plays is similar with that of lump zone in blast furnace, there are some differences existed between them in term of initial reducing gas composition, distribution and temperature, as well as burden distribution pattern. And COREX ® shaft furnace also differs from Midrex ® counterpart in many aspects, such as reducing gas type and furnace structure.…”

Section: Corexmentioning

confidence: 99%

Basic Characteristics of the Shaft Furnace of COREX® Smelting Reduction Process Based on Iron Oxides Reduction Simulation

Yang

et al. 2010

ISIJ Int.

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A two-dimensional mathematical model is developed to describe iron oxides reduction in the shaft furnace of COREX ® smelting reduction process. Combined with mass, momentum and heat transfers between gas and solid phases in steady state, the model calculates and demonstrates the basic characteristics of the shaft furnace, such as velocity, pressure, temperature fields of relevant phases and species' mass fraction distributions. The reduction from magnetite to wustite occupies most part of the furnace, and the reduction degree of burden located near wall is comparatively higher than that close to centre. The model also considers the influence of down pipe gas, driven by the pressure drop between the shaft furnace and melter gasifier, on the reduction behaviors inside furnace. Compared with the base case, the down pipe gas featuring higher temperature prefers to flow toward the symmetry axis, where both gas temperature and solid metallization are promoted remarkably.KEY WORDS: shaft furnace; mathematical model; iron oxides reduction; down pipe gas.The assumptions in the two-dimensional, axisymmetric mathematical model are given as below:(1) The volume fraction of gas in the packed column is set as constant 18) ; (2) Ignoring the wall effect as the gas flows near the wall; (3) The solid flow velocity is uniformly distributed in both radial and axial directions; (4) The solid particle diameter and shape factor always keep constant; (5) The flux decomposition reactions, non-iron oxides reduction reactions and other reactions are not considered in the basic model. Conservation EquationsThe fundamental conservation equations of continuity, momentum, energy and species transport for steady state could be described by Eq. (3). 19) .......... (3) The variable f, dependant diffusive term G f and source term S f all varies with different kinds of conservation equations as summarized in Table 1. Phase PropertiesAccording to the ideal gas equation, the density of gas phase is a function of local temperature and pressure. The viscosities and thermal conductivities of species in gas phase are obtained by Sutherland's law 20,21) and the modified Eucken equation 22,23) respectively with the relevant data from Eckert and Drake's work.24) Based on each specie's viscosity or thermal conductivity and mole fraction, both the gas mixture viscosity or thermal conductivity could be derived from Eq. (4), which is in accordance with Wilke's work. where, V represents viscosity or thermal conductivity;As for solid phase including lump ore and pellet, the average apparent density and particle diameter are measured by experiment with the results as 4 190 kg/m 3 and 0.154 m respectively. The solid viscosity is 6 kg/m · s and its thermal conductivity is 0.8 W/m · K. 10)All species' thermodynamics data, such as heat capacity, enthalpy and entropy, are all from Perry's book, 26) and the gas or solid phase thermodynamic data are computed based on a simple mass fraction average of the species' if needed. Mass TransferDue to iron oxides multi-stage s...

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“…Overall kinetic constant on gas film k GAS is calculated based on formulation proposed by Parisi and Laborde [6] as stated as…”

Section: (3) Chemical Reaction Controlsmentioning

confidence: 99%

“…The model is derived based on unsteady state condition. Parisi and Laborde [6] proposed a model for moving bed counter current reactor. The model is limited on reduction zone of iron ore reactor, and only reduction reactions are considered in the model, in which plug flow is used as an approach for the model.…”

Section: Introductionmentioning

confidence: 99%

Heat and Mass Transfer in Reduction Zone of Sponge Iron Reactor

Alamsari

Torii

Trianto

et al. 2011

ISRN Mechanical Engineering

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Numerical prediction is performed on reduction zone of iron ore reactor which is a part of counter current gas-solid reactor for producing sponge iron. The aim of the present study is to investigate the effect of reduction gas composition and temperature on quality and capacity of sponge iron products through mathematical modeling arrangement and simulation. Simultaneous mass and energy balances along the reactor lead to a set of ordinary differential equation which includes kinetic equations. Kinetic equations of reduction of hematite to iron metal, methane reforming, and water gas shift reaction are taken into account in the model. Hydrogen and carbon monoxide are used as reduction gas. The equations were solved by finite element method. Prediction shows an increase in H 2 composition while an attenuation of CO produces higher metallization degree. Metallization degree is also increased with an increase in gas inlet temperature. It is found that reduction gas temperature over 973• C (1246 K) is not recommended because the formation of sticky iron will be initiated.

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Modeling of counter current moving bed gas-solid reactor used in direct reduction of iron ore

Cited by 142 publications

References 12 publications

Numerical Analysis of the Characteristics Inside Pre-reduction Shaft Furnace and Its Operation Parameters Optimization by Using a Three-Dimensional Full Scale Mathematical Model

Numerical Analysis of the Characteristics Inside Pre-reduction Shaft Furnace and Its Operation Parameters Optimization by Using a Three-Dimensional Full Scale Mathematical Model

Basic Characteristics of the Shaft Furnace of COREX® Smelting Reduction Process Based on Iron Oxides Reduction Simulation

Heat and Mass Transfer in Reduction Zone of Sponge Iron Reactor

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