Heat and Mass Transfer in Reduction Zone of Sponge Iron Reactor

Abstract

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.

Detailed Modeling of the Direct Reduction of Iron Ore in a Shaft Furnace

“…With the aim of correctly describing the lateral gas feed, some studies have introduced two-dimensional models [ 12 , 13 , 14 ]; however, these models did not consider the presence of methane, which is responsible for important reactions in the process. More recently, several authors introduced other reactions [ 15 ] and accounted for the cooling zone [ 16 , 17 ]. Some even developed plant models [ 18 ]; however, these works were limited to one-dimensional models.…”

Reduction Behavior of Iron Ore Pellets with Simulated Coke Oven Gas and Natural Gas

“…The reduction has been carried out isothermally at temperatures in the range of 700–980°C. The temperature range was selected to simulate the reduction zone in Midrex shaft furnace and the maximum applied temperature in HyL process . The structure and morphological changes of reduced pellets were intensively studied and correlated with the reduction kinetics and mechanisms.…”

Iron ore reduction by methane partial oxidation in a porous media

“…A detailed derivation of these equations can be found in Refs. [7] and [11]. Mass transfer coefficients between fluid and particle ðk CO &k H 2 Þ and first-order rate constants for the surface reactions ðk '' CO &k '' H 2 Þ are calculated based on Parisi and Laborde [5] work as: …”

“…[6] proposed a shaft furnace model where reaction rate equations were derived from the three-interface model, including heat and mass balances. Alamsari et al [7] proposed a model for a countercurrent moving bed reactor, where the three-interface model was also considered. Methane reforming and water gas shift reactions were included as the reactions that occur in the gaseous phase.…”