Pyrolysis Characteristics of Vitrinites in Coking Coals with Different Coal Ranks

ABSTRACT

The vitrinite-rich concentrates were produced from five coking coals with different ranks (Donghuantuo gas coal, Tangshan 1/3 coking coal, Zhongliu fat coal, Hongsheng coking coal, and Lvjiatuo coking coal) by float-sink separation under centrifugal force. The relationships of the pyrolysis characteristics of raw coals (RC) and vitrinite-rich concentrates (VC) with the coal rank and elemental composition were studied by thermogravimetric analysis and ultimate analysis. The results show that vitrinite-rich concentrate have greater weight loss and a higher weight-loss rate than the corresponding raw coals. Also, VCs have higher H, C, and N content and lower O and S content. With an increase of coal rank, the weight-loss rate (ΔTG) and maximum weight-loss rate (DTG_max) of VC decreases, and the temperature with DTG_max (T_max) of VC increases, and the C/H ratio of VC also increases. The analysis of thermogravimetric parameters and elemental composition of VC shows that the ΔTG and DTG_max decrease linearly with the C/H ratio, and T_max increases linearly with the C/H ratio.

KEYWORDS:

• Coking coal
• vitrinite
• coal rank
• pyrolysis
• C/H ratio

Funding

We are grateful for joint funding by the National Natural Science Foundation of China and the Shenhua Group Corporation Limited (No. U1361212).

Additional information

Funding

We are grateful for joint funding by the National Natural Science Foundation of China and the Shenhua Group Corporation Limited (No. U1361212).