Development of tensile test method for high-density coal under carbonization

A new tensile test method under carbonization for high-density coal that would be used in coke making process in next century was developed to estimate the appearance mechanism of coke strength. This method can clarify the appearance mechanism of coke strength under carbonization. We obtained the result that the tensile strength and Young's modulus become large in proportion to the final temperature. In case of large heating rate, the tensile strength and Young's modulus were large. From the microscope observation, coal particles agglomerated to each other among the softening temperature and the strength increased with an increase of heating rate. We also estimated factors related with the appearance mechanism of the strength using a coal pyrolytic model, which was previously developed by authors. The results showed that the large strength is caused by the progress of coke graphitization and an increase of internal tar contributing to sticking on each particle.