Modeling of the Coke Quality Parameters CRI, CSR, Stability and Hardness Values from Chemical and Ash Component Analysis Results of Metallurgical Coke
Can Erarslan Tayfun PAMUKÇU Erdem YILDIZ
AbstractBlast furnaces are vertical melting furnaces and their capacities change according to their height. They are used in the production of liquid raw iron by melting coke, limestone and iron ore. High quality raw materials are demanded for the blast furnace operations and from one of the raw materials, metallurgical coke, is produced in the batteries of coke plants. Coke production take place by mixing low, medium and high volatile coking coal in calculated proportions, than feeding this blend into closed system, airtight ovens and heating the blend to 1250 ° C - 1350 ° C for 18-19 hours. In the coking process, first the moisture in the coal is separated by vaporization, then the volatiles separates by gasification after a series of cracking reactions. The final product is metallurgical coke which is rich in carbon, porous and has a hard structure. The quality of the produced metallurgical coke is directly affected by the coals used in the blend and the coking conditions. Because of the increasing production targets and needs, integrated iron and steel plants can supply metallurgical coke from outside producers. One of the most important input that increases the cost of liquid raw iron is the amount of coke used in blast furnaces. The most important parameters that determine the quality of the coke are CRI, CSR, Stability and Hardness. Considering that the facilities provide coke from suppliers in order to meet their production targets, the quality of the purchased coke affects the consumption in the blast furnaces and has a direct negative or positive impact on the costs. From time to time, it is observed that the analyses result of the four quality parameter values mentioned above in the loading port and discharge port are not matched, the discharge port sample’s analysis result are low than loading port. In such cases, the articles in the contract are valid and buyer can accept the shipment with penalty or reject the raw materials. In this study, the results of CRI, CSR, Stability and Hardness analysis are modeled from the ash, volatile matter and ash components of coke and 77,14% - 77,30% - 91,51% - 80,8% R-square values were obtained respectively. With the model a tool has been developed, which can be used by the purchasing departments at the proposal evaluation stage.