Functional Mechanism of Inorganic Sodium on the Structure and Reactivity of Zhundong Chars during Pyrolysis

The reactivity of Zhundong chars is remarkably affected by the high sodium content of their parent Zhundong coal. The functional mechanism of inorganic sodium (NaCl) on the structure and reactivity of Zhundong chars was investigated in this study. Chars were prepared in a single-bed reactor under different pyrolysis temperatures and durations. Preliminary experimental results showed that inorganic sodium has a dual effect on the char yield of pyrolyzed Zhundong coal: inorganic sodium can decrease char yield at high pyrolysis temperatures of ≥600 °C but increase char yield at the low pyrolysis temperature of 400 °C. Nitrogen adsorption technique and scanning electron microscopy were utilized to identify the effects of inorganic sodium on the physical structure of Zhundong chars. The results showed that inorganic sodium affects pore structure detrimentally, inhibits the growth of char vesicles, and enables the formation of smooth char surfaces. Fourier transform infrared spectroscopy and Raman spectroscopy ...