Method For Upgrading Metallurgical Coke Or Other Carbonaceous Materials
Tech ID: 18176 / UC Case 1991-045-0
Coke fed to the iron blast furnace serves three purposes, as a fuel, as a reducing agent, and as a structural material supporting the deep bed of coke/iron oxides/limestone that makes up much of the furnace volume. It is in this last role that coke properties are crucial. It is important that the coke not degrade (e.g., break up into small particles) during its descent through the oxidizing hot gases passing upward through the stack region of the furnace. Modification of coke so that it is less susceptible to oxidation in the stack is therefore likely to be advantageous, e.g., in terms of bed permeability, minimization of fines in the furnace and lower CO/CO2 ratio in the off gas (with consequent improvement in coke rate). Naturally such reduction in coke reactivity should not be so extreme as to reduce its ability to serve as a reducing agent lower in the furnace.
Laboratory studies at Berkeley have shown that a relatively simple gaseous treatment of metallurgical coke can reduce the rate at which it is oxidized. Oxidation has been carried out using CO2/Ar mixtures rather than theCO2/CO/nitrogen mixtures encountered in the furnace. However, the effect of the treatment is on the structure of the coke and therefore oxidation under actual furnace conditions should also be reduced.
Results of tests performed at Inland Steel show improvement of approximately 45% in coke reaction index and approximately 40% in coke strength after reaction.
improving the quality of existing metallurgical coke
converting other carbonaceous materials to a higher quality material comparable to metallurgical coke
|United States Of America||Issued Patent||5,486,216||01/23/1996||1991-045|