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Flame formation and post‐combustion at blowing of oxygen into a carbon monoxide containing slag foam
Author(s) -
Zhang Liuyi,
Oeters Franz
Publication year - 1999
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199905606
Subject(s) - combustion , carbon monoxide , slag (welding) , adiabatic flame temperature , heat transfer , premixed flame , laminar flame speed , chemistry , smelting , combustor , oxygen , thermodynamics , materials science , waste management , metallurgy , organic chemistry , engineering , catalysis , physics
A combined post‐combustion model (CPM) for smelting reduction was developed in a multi‐national research project supported by the European Coal and Steel Community. The project partners were CSM, Rome, Hoogovens, Ijmuiden, MPI, Düsseldorf, and TUB, Berlin. This paper is a report about a flame model developed by TUB, Berlin. An oxygen jet is blown into a carbon monoxide containing slag foam. The jet entrains carbon monoxide and slag droplets. Carbon 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 radiation and convection to the entrained droplets. The droplets are mixed with the slag at the flame end so that also their heat content is finally transferred to the bulk slag. The model consists of a detailed treatment of the entrainment processes, the combustion reaction taking into account the carbon dioxide dissociation equilibrium, the enthalpy changes, and the heat transfer processes. One obtains two ordinary differential equations describing the temperature and composition of the flame gas as functions of the flame 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 from the surroundings to the flame, the oxygen utilisation, from which the post‐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 described as functions of various internal and external parameters. The presented flame model is part of a general post‐combustion and heat transfer model of a smelting reduction process with post‐combustion in the slag.