Abstract
This study aim to investigate the effects of HPC, High Performance Coking additive, addition on the thermoplasticity of non-coking or slightly-coking coals. The thermoplasticity of the coals with HPC were monitored with in-situ high temperature 1H-NMR relaxation measurement. The echo signals obtained during heat treatment under a flow of nitrogen at a heating rate of 3K/min were deconvoluted into a set of one Gaussian and two Exponential decay components which represent the immobile, intermediate and mobile component, respectively. The changes in the fractional intensity of mobile component, f_<Hm>, calculated from the signals were well corresponded to the softening and resolidification phenomena of coals. The f_<Hm> and molecular mobility of mobile component represented by Spin-Spin relaxation time, T_<2Hm>, increased with HPC addition. The results obtained from H-NMR relaxation measurement demonstrated that the improvement of the thermoplastic phenomenon of non-coking or slightly-coking coal with HPC is evaluated both qualitatively and quantitatively by the variation of f_<Hm> and T_<2Hm>. It is confirmed that the H-NMR relaxation measurement is the appropriate dynamic measurement technique to characterize the thermoplastic properties of coal.
