Relationship between the tensile strength of irregularly shaped coal particles and various fuel properties

To gain a better understanding of inner-stress-induced coal particle fragmentation during coal utilization processes, the tensile strength of small and irregularly shaped coal particles was investigated, using eleven kinds of coals in the size range of 0.8-6.3 mm. It was found that the tensile strength significantly depends on particle size. As the particle size increases, the tensile strength asymptotically decreases, and the correlation between them could be described by a power function, requiring only different parameters for different coals. In addition, the effects of various fuel properties on the tensile strength are discussed. Coals with medium volatile matter content show the highest tensile strength, and the tensile strength generally increases with rising ash content and decreasing porosity. Based on the obtained results, a simplified model for the approximation of the tensile strength is developed involving the particle size and different fuel properties. A correlation analysis has exhibited that the number of required fuel parameters can be reduced to only two independent ones. This makes the tensile strength of coal particles directly predictable from the proximate and ultimate analysis of coals. With the aid of this prediction model, a better description of conversion processes may be achieved.