Flame formation and post-combustion at blowing of oxygen into a carbon monoxide containing slag foam

A combined post-combustion model (CPM) for smelting reduction was developed in a multi-national research project supported by the European Coal and St eel Community. The project partners were CSM, Pome, Hoogovens, Ijmuiden, MP I, Dusseldorf, and TUB, Berlin. This paper is a report about a frame model developed by TUB, Berlin. An oxygen jet is blown into a carbon monoxide con taining slag foam. The jet entrains carbon monoxide and slag droplets. Carb on monoxide is combusted by oxygen to carbon dioxide and the developed heat is transferred by radiation from the gas to the surrounding slag and by ra diation and convection to the entrained droplets. The droplets are mixed wi th the slag at the flame end so that also their heat content is finally tra nsferred to the bulk slag. The model consists of a detailed treatment of th e entrainment processes, the combustion reaction taking into account the ca rbon dioxide dissociation equilibrium, the enthalpy changes, and the heat t ransfer processes. One obtains two ordinary differential equations describi ng the temperature and composition of the flame gas as functions of the fla me pass-way. They are solved numerically by the Runge-Kutta method. As the results, the main flame properties, namely the flame velocity, the diameter and the upwards angle of the flame, the amount of gas and slag entrained f rom the surroundings to the flame, the oxygen utilisation, from which the p ost-combustion degree is calculated, the flame temperature along the flame pass-way, and the total heat transfer from the flame gas to the slag, are d escribed as functions of Various internal and external parameters. The pres ented flame model is part of a general post-combustion and heat transfer mo del of a smelting reduction process with post-combustion in the slag.