The structural analysis of the rapid heating treated coal using high temperature in-situ NMR imaging

A new carbonization process with rapid preheating and coke discharging at m edium temperature has been developed in Japan. The result of this process s hows that even when non or slightly coking coal is by 50 wt% the coking pro perty is improved and a coking coke with cold strength usable at blast furn ace can be manufactured with the new carbonization process. The mechanism f or the improvement of the coking property was examined by coal properties w ith using mainly in-situ NMR imaging. To monitor the dynamical changes in c oals with temperature, an in-situ method must be used, therefore, we have a pplied Single-Point-imaging and have carried out the first systematic in-si tu variable-temperature NMR imaging study of coals between 25 and 500 degre es C with our newly developed high temperature imaging probe and systems. I t has been clarified that the macromolecular structure of coal is relaxed b y the rapid heat treatment and in addition there is a close relation in hyd rogen bond and relaxation of molecular structure of coal. The fact that rap id heating treatment of coal raised on D1150 is at almost 6 point in the tr eatment of temperature at 380 degrees C, compared to the raw sample and slo w heat sample is mainly caused by the decreasing of unsoftened area in coal . Rapid heat treatment is that the cohesion structure of coal molecule is r elaxed by rapid heat and the kinetic property of molecule increases. And fu rther, a bridge forming reaction generated by slow heating is suppressed an d high mobility component increases and as the above results, a softening a nd melting phenomenon is accelerated as a time of coking. Finally, we would like to propose the mechanism for the improvement of the coking property d uring this rapid heat treatment, which have the improvement of coal propert ies.