Relation between char structures and formation of volatiles during the pyrolysis of Shenfu coal: Further understanding on the effects of mobile phase and fixed phase

Proposed reaction pathways of volatiles responsible for the evolution of chemical structures of coal: Firstly, the primary devolatilization process would produce large amounts of free radicals. Then, the alkane radicals would participate in methylation and dehydrogenation reaction (secondary reaction), leading to the attendant phenomenon of alkanes and alkenes in light tar (or gas product). The decomposition of asphaltene in mobile phase and thermal cracking of polar radicals and decomposition of solvent extracted metaplast materials made predominant contribution to tar formation. The cracking of peripheral aromatic structures of coal skeleton structure, through which secondary reaction took place, resulted in tar formation.133