Mathematical modelling of fluidized‐bed reactors for non‐catalytic gas–solid reactions

Abstract

Mathematical modelling of a continuous fluidized-bed reactor has been carried out for non-catalytic gas-solid reactions. The two-phase bubbling bed model has been used and the elutriation phenomenon for the fine particles has been investigated. The feed stream consisting particles with size distribution and reversible or irreversible first-order kinetics can be treated by the model. The reduction behaviour of solid reactants was described by the grain model. A program was developed in MATLAB software for solving the governing equations at conditions of different temperatures and pressures. The model was validated using experimental data and simulation results available in the literature for the iron ore reduction with a gas mixture containing hydrogen [Srinivasan and Staffansson, Chem. Eng. Sci. 45(5), 1253-1265 (1990)]. The mathematical modelling was also used for predicting the extent of reaction for reduction of cobalt oxide by methane.La modélisation mathématique d'un réacteurà lit fluidisé continu aété réaliséeà partir de réactions gaz-solide non catalytiques. Le modèle de lità bulles en deux phases aété utilisé et on aétudié le phénomène d'élutriation pour les particules fines. Le débit d'alimentation composé de particules avec une distribution de la taille et une cinétique de premier ordre réversible ou irréversible peutêtre traité par ce modèle. Le comportement de réduction des réactifs solides aété décrit par le modèle de grain. Un programme aété créé avec le logiciel MATLAB pour résoudre leséquations principalesà des conditions de différentes températures et pressions. Le modèle aété validé au moyen des données expérimentales et des résultats de simulation que l'on trouve dans la littérature pour la réduction du minerai de fer avec un mélange de gaz contenant de l'hydrogène [Srinivasan and Staffansson, Chem. Eng. Sci. 45(5), 1253-1265(1990]. La modélisation mathématique aégalementété utilisée pour prédire l'étendue de la réaction pour la réduction de l'oxyde de cobalt par le méthane.

Nickel carbonyl formation in a fluidized bed reactor: experimental investigation and modeling

“…The two-phase bubbling bed model The formulations developed by Maroufi et al and Srinivasan and Staffansson are used in this section to model the Mond process in a fluidized bed reactor. 20,21 In a fluidized bed, bubbles are formed within the bed as the gas velocity increases from minimum fluidization velocity to higher values. The bed will be fully fluidized when the bubble fraction inside the bed reaches a significant value.…”

“…The bed will be fully fluidized when the bubble fraction inside the bed reaches a significant value. 20 In a well-fluidized bed of solid, where the gas velocity within the bed is assumed to be much larger than the minimum fluidization velocity, the bed can be considered to consist of two phases: (i) emulsion phase, and (ii) bubble phase. 21 The formulation for such a bed was developed by Srinivasan and LI Staffansson 21 for the reduction of iron ores and followed herein by the reaction between nickel solid particles with carbon monoxide gas.…”

Reduction kinetics of cobalt oxide powder by methane in a fluidized bed reactor

“…Doherty et al [25] have studied the hematite reduction to wustite by considering different mixtures of CO-CO 2 , H 2 -H 2 O, and CO-CO 2 -H 2 -H 2 O in a small fluidized bed which has been operated under bubbling bed conditions. Maroufi et al [26] presented a mathematical modeling based on the grain model for noncatalytic gas-solid reactions in fluidized bed reactors. Gomez-Barea et al [27] presented a simplified model for non-catalytic gas-solid reactions in fluidized bed reactors.…”

Investigation of Direct Reduction Mechanism of Attepe Iron Ore by Hydrogen in a Fluidized Bed

“…[10] This is why DRI production worldwide has increased from almost zero in 1970 to 70 Mt in 2013. Fluidized beds are preferred as direct reduction reactors since they offer excellent heat and mass transfer properties, [11] and enable direct use of fine iron ores without any prior treatment like pelleting or sintering. [12] Reduction kinetics of iron oxides have been widely investigated by numerous researchers until today, and remarkable progress involving increasingly complex models has been achieved.…”