An Investigation of the Elemental Composition, Surface Properties, and Soluble Fraction of Kaiyang Bituminous Coal Chars

Abstract

The effects of heating manner and charring temperature (CT) on elemental composition, surface properties, and soluble fraction of chars from the pyrolysis of Kaiyang bituminous coal (KBC) were investigated. The results show that the chars formed by slowly heating KBC to higher CTs have higher ash and carbon contents but lower volatile matter yield, hydrogen, nitrogen, and sulfur contents, smaller specific surface area and pore volume, and lower extract yields in isometric carbon disulfide/acetone mixed solvent. The compounds detected in the extracts can be classified into aromatics, normal alkanes (NAs), and hexadecane derivates (NADs). The total contents (TCs) of the group components (GCs) in the extracts of the chars formed from rapidly heating KBC increased in the order: aromatics > NADs > NAs, but the TC of aromatics decreased, whereas the TCs of other GCs increased with raising CTs. In contrast, the TCs of the GCs in the extracts of the chars formed from slowly heating KBC to 950°C increased in the order: NADs > NAs > aromatics, while the total content of aromatics increased, whereas the the increase in the TC of aromatics, decrease in the TC of NADs, and almost no change in the TC of NAs were observed.

Keywords::

• carbon disulfide/acetone-soluble fraction
• coal char
• pore size distribution
• specific surface area