抄録
Hyper-coal (HPC) process, a thermal extraction process of coal uses methylnapthalene-like solvent, presupposes the solvent recycling. It means that there is no need to replenish the fresh solvent from outside. To perform this, coal-derived fraction, which is distillable oil produced by the thermal decomposition reaction of coal, will be utilized as the solvent. Solvent loss will be replenished by the coal-derived fraction repeatedly, and composition of the coal derived fraction will become the equilibrium composition. Therefore, to satisfying the necessary and sufficient condition for solvent recycling, the process produces enough quantity and quality of coal-derived fraction. Recent study revealed that the yield of coal-derived fraction was several percent on coal and consisted with compounds having naphthalene ring structure mainly1)2). Improved estimation of the composition of coal-derived fraction was carried out subjecting the rapid-heating process. The rapid heating process improved coal extraction yield and produced several percent of distillate, same yield as conventional heating3)4). Compound compositions of coal-derived fractions were investigated by coal extraction experiments in diphenylether (DPE) as solvent. DPE was regarded thermally stable and not having interaction with coal5). As a result, coal-derived fraction was consisted with compounds having naphthalene ring structure (80%) and benzene ring structure (20%). In compounds having naphthalene ring structure, main compounds were 73% of 1-methylnaphthalene (1-MN) and 27% of dimethylnaphthalene (D-MN). On the other hand, composition of the naphthalene ring compounds was changed by using 1-MN as solvent. Composition of 1-MN and D-MN were decreased, instead of that, naphthalene (NP) and 2-methynaphthalene (2-MN) were increased. It was considered that those changing of component structure should be occurred by interaction between coal and solvent caused by active free radicals.
