The Influence of Porosity on the Moisture Adsorption Capacity of Coke and Installation of Drying System to Minimize Coke Moisture Fluctuation

JSW Steel Limited, Salem Works is an integrated steel plant. It consists of three stamp charged non-recovery batteries having 120 coke ovens. It produces 0.5 million tons per annum of metallurgical coke and uses wet quenching technology to cool red hot coke. During quenching, coke adsorbs moisture due to the presence of porosity. Experiments revealed that, coke exhibiting poor coke reactivity index (CRI) and coke strength after reaction (CSR) properties possesses higher porosity than the coke exhibiting better CRI and CSR properties. Highly porous coke adsorbs more moisture in a shorter time span than less porous coke. Presence of more of highly porous coke leads to fluctuation in coke moisture, which in turn poses difficulties for smooth blast furnace operation. Coke porosity depends on porosity in coal, fluidity and other inherent characteristics of coals. Certain changes in coke making process parameters led to marginal improvement in coke porosity. But no major changes were effected in the coal blend due to limited use of prime quality coking coals, considering their availability and cost. Instead, a novel coke drying system has been installed to minimise fluctuations in coke moisture. The present paper discusses the result of experiments undertaken and the installation of successful coke drying system for minimizing undue fluctuations in coke moisture.