Enhancement of coking potential of coals with improvised crushing mechanism

Crushing mechanism plays a vital role in liberation of coal macerals (organic constituents), which aid in coke making. Due to the use of impact mills, vitrinite maceral grains shatter and participation in coke making is reduced. To address this issue, a new crushing machine based on a shear fracture mechanism has been developed and termed as coal shear crusher (CSC). It is shown that by using CSC one can take advantage of the viscoelastic property of vitrinite maceral. When compared to hammer mill, CSC processed coal showed improvement in plastic layer thickness (PLT), crucible swelling number (CSN), rank and coke strength after reaction (CSR) of the coal blends. Coals with vitrinite reflectance (Ro) greater than 1%, when processed using CSC showed greater improvement in coke properties as compared to coals with less than 1% Ro. Coal blend cost reduction can be effectively obtained if CSC technology is used, by increasing the portion of poor coking coal by replacing good coking coals. Present study scopes the utilization of up to 10% of CSC processed component in the coal blend, which is currently limited due to concerns related to coal cake stability which if overcome can increase the fraction of poor-coking coal in blends even further.