The effects of kinetic parameters on combustion characteristics in a sintering bed Masoud Pahlevaninezhad a , Mohsen Davazdah Emami a, * , Masoud Panjepour b a Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran b Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran article info Article history: Received 23 November 2013 Received in revised form 23 May 2014 Accepted 1 June 2014 Available online 5 July 2014 Keywords: Kinetic parameter Coke combustion Energy Sinter quality Sintering time Iron ore sintering abstract Coke combustion is the main source of thermal energy for sintering of iron ores particles, and drastically affects the product sinter quality and productivity of the process. In this paper, simulation of coke combustion is performed for case studies comprising various operating parameters and coke sizes to assess the influence the coke combustion characteristics and operating conditions on sinter quality and productivity of the process. The sintering process was simulated with an unsteady-2D axisymmetric model. Effects of kinetic parameters including coke particles size, inlet air velocity, the amount of coke in the sintering charge and limestone particles size on product sinter quality and productivity of sintering process were studied. Simulation results of sintering process for coke sizes of 2 mm and 2.4 mm indicate that large particles size may reduce sinter quality and productivity. Combustion efficiency improves by optimization of the inlet air velocity. Moreover, simulation results for limestone particles size of 2 mm and 1 mm show that by decreasing the limestone particles size, the un-decomposed limestone in the bed may increase and sinter quality declines. Varying the amount of coke shows little change in the sintering time, but considerable change in the product sinter quality and energy consumption. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction The iron ore sintering process to produce improved blast- furnace charge is the main part of blast-furnace load preparation at modern iron making throughout the world. In the iron ore sin- tering process, a raw mix of iron ore, coke, limestone and moisture are charged on a moving grate and form a bed of 40e60 cm height. Hot gas jets from the ignition burners commence coke combustion at the top of the sintering bed, as shown in Fig. 1 [1].Beyond this point, the required air for the continuation of coke combustion in the bed is supplied via suction fans installed at the bottom of the bed. This causes the formation of a flame front at the top of the bed, which moves downward as the sintering bed travels. The flame front temperature is high enough to cause surface melting of the bed, which merges particles and forms the sinter product. The sinter grate speed is set such that the bed material is sintered by the time the grate reaches the discharge point. With respect to the fuel costs, which account for the major share in the total costs, considerable saving in running costs may be obtained from relatively small increase in the efficiency of the sintering process. In an attempt to achieve this, numerical simu- lation is a substantial step to optimize the process regarding fuel consumption, product sinter quality and productivity. In recent years many researchers have focused on the devel- opment of porous media combustion technology. This is mainly because combustion in porous media differs significantly from free flames due to two main factors: the high surface area of the porous media which provides an efficient heat transfer between the gas and the solids, and the well mixing of fuel and oxidant in porous media which augments effective diffusion and heat transfer in the gas phase. These phenomena may be referred to as internally self- organized process of heat recuperation [2]. Heat transfer mecha- nism in porous media results in several interesting characteristics such as higher burning speeds, extension of the lean flammability limits [3,4], and the low emission of pollutants [5,6]. Yoksenakul et al. [7] developed a SPMB (Self-Aspirating Porous Medium burner ) for replacing the conventional gaseous fuel, free flame burners. They showed that SPMB yields a more complete combustion with relatively low CO and NO x emission compared with conventional burning flames. From energy storage point of view, Nagel and Shao [8, 9] studied thermo-chemical heat storage through a porous media. They * Corresponding author. Tel.: þ98 3113915245; fax: þ98 3113912628. E-mail addresses: m.pahlevaninezhad@me.iut.ac.ir (M. Pahlevaninezhad), mohsen@cc.iut.ac.ir (M. Davazdah Emami), panjepour@cc.iut.ac.ir (M. Panjepour). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy http://dx.doi.org/10.1016/j.energy.2014.06.003 0360-5442/© 2014 Elsevier Ltd. All rights reserved. Energy 73 (2014) 160e176