We propose using hydrates as a distinct chemical reaction field apart from the normal gas and liquid phases. The molecular dynamics of bulk structure II hydrates were explored to better understand the position and behavior of the guest molecules in the hydrate, which influences the hydrate's reaction processes. The location and rotational motion of the guest molecules in the cage were explored using the projection positions of the atoms on the cage faces to which the atoms were orientated. The hydrogen atoms radially connected to the six-membered ring and the center of the cage’s circumferential faces acted together to constrain the benzene and cyclohexane molecules. Cyclopentane and tetrahydrofuran molecules were less restricted because the number of hydrogen atoms radially bound to the five-membered ring did not correspond to the number of circumferential faces. Tetrahydrofuran rotated in the cage, with oxygen atoms aligned more strongly on the pentagonal faces than the hexagonal faces.

Gasification is one of the important technologies using coal and other solid feedstocks for high efficiencypower generation and chemical production. The gasification reaction consists of primary pyrolysis, gas phase, and char gasification reactions. The authors constructed models corresponding to the three reactions to describe several phenomena in actual gasifiers. Extended Chemical Percolation Devolatilization (Ex-CPD) model and Main Reaction path Extracted (MRE) model were constructed to predict soot yield in gasification. Partially Shared active sites Langmuir Hinshelwood (PS-LH) model was constructed to describe char gasification in the co-existence of CO₂ and H₂O. In this study, after evaluating the consistency between the char gasification model and experimental results, the effectiveness of the three models was evaluated by numerical simulation. Firstly, a correlation analysis revealed the correlations between the parameters of the char gasification reaction model including the PS-LH model and coal properties. Secondly, the PS-LH model was compared with conventional models and found to be the most accurate to describe the experimental results. Finally, 1D numerical simulations of the reductor part of the two-stage entrained-flow gasifier were performed to evaluate the effect of using the three models in combination. These investigations clarified the significance of using the models suited to the phenomenon.