Optimization of coal cake stability for stamp charging coke making operation at Tata Steel

Revisit of the existing knowledge on coal cake stability was felt necessary when new batteries at Tata Steel were commissioned. As the proposed coals were different than the existing operation, stamping energy must be re-optimized for a low ash coal blend. In past studies, it was established that high mineral matter coals are easier to stamp as compared to low mineral matter contained coal. A fresh set of specific stamping energy values was forthcoming to stabilize the stamping process at coke plant. So, parameters viz. coal moisture %, crushing fineness %, bulk density (kg/m(3)), and specific stamping energy (kN/kg) and their interdependencies were studied and re-optimized to understand their impact on coal cake stability. To get the optimized value for shear strength, which is primarily responsible for cake failures, Mohr's circle from soil mechanics was used. This gave us theoretical lower limit for cake failures. Based on these values along with other parameters, operating conditions are defined to obtain specific stamping energy which can lead to stable coal cake. It was observed that surface moisture, specific stamping energy, and crushing fineness play the most important role in stable coal cake preparation.