Study of Coal Cake Bulk Density and Its Shear Strength for Stamp Charging Coke Making Technique at Tata Steel

Parameters affecting coal cake breakage at coke plant were selected for carrying out this study. The analysis was focussed on analysing the influence of particle size distribution, blend moisture content, coal cake bulk density and stamping energy on coal cake stability considering the cake shear strength as the key factor responsible for major cake breakage at coke plant of Tata Steel (Jamshedpur). The lab scale study was performed using 5.2 kg of stamping hammer to examine the strength of prepared cake. Further, blend moisture content was varied from 7 to 14% and crushing fineness (-3.15 mm) from 86 to 92% to analyse the impact of aforementioned parameters on coal cake bulk density and shear strength at lab scale. It was found that cake shear strength greater than 1400 Pa is sufficient enough to avoid major cake breakage. Moreover, excess amount of moisture content (>11%) in the blend causes decrease in cake shear strength. Further, 30 days bulk density measurement has been carried out at coke oven battery of Tata Steel. In addition, previous plant data under two conditions viz. 'zero cake breakage' and 'major cake breakage' have been used to develop stamping time prediction model using multiple regression analysis.