A combined post-combustion model (CPM) for smeltingreduction was developed in a multi-national research project supported by theEuropean Coal and Steel Community. The project partners were CSM, Rome,Hoogovens, ljmuiden, MPI, Düsseldorf, and TUB, Berlin This paper is a reportabout a flame model developed by TUB, Berlin. An oxygen jet is blown into acarbon monoxide containing slag foam. The jet entrains carbon monoxide andslag droplets. Carbon monoxide is combusted by oxygen to carbon dioxide andthe devel-oped heat is transferred by radiation from the gas to the surroundingslag and by radiation and convection to the entrained droplets. The droplets aremixed with the slag at the flame end so that also their heat content is finallytransferred to the bulk slag. The model consists. of a detailed treatment of theentrainment processes, the combustion reaction taking into account the carbondioxide dissociation equilibrium, the enthalpy changes, and the heat transferprocesses. One obtains two ordinary differential equations describing thetemperature and composition of the flame gas as functions of the flame pass-way.They are solved numencally by the Runge-Kutta method. As the results, themain flame properties, namely the flame velocity, the diameter and the upwardsangle of the flame, the amount of gas and slag entrained from the surroundings tothe flame, the oxygen utilisation, from which the post-combustion degree iscalculated, the flame temperature along the flame pass-way, and the total heattransfer from the flame gas to the slag, are described as functions of variousinternal and external parameters. The presented flame model is part of a generalpost-combustion and heat transfer model of a smelting reduction process withpost-combustion in the slag.
展开▼
