A Comparison of Mineralogical and Thermal Storage Characteristics for Two Types of Stone Coal.

Understanding the mineralogical and chemical characteristics of stone coal is imperative for exploring the thermal storage characteristics of stone coal. Two types stone coal (SC_wt and SC_hc) were sampled from the pond of a stone coal mine in Henan province (China), and the chemical composition, phase composition, and thermal behavior of the stone coal were investigated. Furthermore, the petrography of the stone coal was studied in detail. The mineral phases of the stone coal were quartz, kaolinite, roscoelite, and goethite, as distinguished by reflected light microscopy and further proven by scanning electron microscope-energy dispersive spectrometer (SEM-EDS). The thermal conductivity of SC_wt was 0.19 W m⁻¹ K⁻¹, while that of SC_hc was 0.24 W m⁻¹ K⁻¹. Stearic acid (SA) was blended with SC_wt and SC_hc to prepare SA/SC_wt and SA/SC_hc composites via an impregnation method, respectively. The thermogravimetric (TG) curves show that the loading capacity of SC_hc, at 17.40%, is higher than that of SC_wt (16.63%). The thermal energy storage capacities of SA/SC_wt and SA/SC_hc composites were 29.21 J g⁻¹ and 33.02 J g⁻¹ according to a differential scanning calorimetry (DSC) analysis. Therefore, SC_hc is a potential candidate for thermal storage applications due to more obvious thermal storage characteristics, including higher thermal conductivity and loading capacity. [ABSTRACT FROM AUTHOR]