Thermolysis of Coal Tar Pitch α2-Fraction: Characteristics of the Coke Structure

Methods of scanning electron microscopy, NMR spectroscopy, XRD, thermal analysis and gas chromatography- mass spectrometry have been used to study the composition, structure and morphology of particles of alpha 2-fraction powders isolated by the method of selectively soluble groups from medium-temperature coal-tar pitch. It is shown that the alpha 2-fraction is mainly a mixture of condensed aromatic compounds containing N, O and S heteroatoms, while sulphur is mainly contained in the form of heat-resistant thiophene compounds. The study of coke particles formed during the thermolysis of the alpha 2-fraction showed that in the temperature range from 300 to 600 degrees C, a dense structure with carbon content 90-93 % is formed from the substances of the alpha 2-fraction. Further heating up to 1200 degrees C leads to an increase in the carbon content up to 97 %, while the coke particles form a layered structure with pronounced anisotropy, approaching the structural characteristics of La and Lc to premium class needle cokes.

Automated summary

Scanning electron microscopy, NMR spectroscopy, XRD, thermal analysis and gas chromatography-mass spectrometry were used to study the composition, structure and morphology of alpha 2-fraction powders isolated from medium-temperature coal-tar pitch. The study revealed that the alpha 2-fraction is primarily composed of condensed aromatic compounds containing N, O and S heteroatoms, with sulfur mainly in the form of heat-resistant thiophene compounds. The thermolysis of the alpha 2-fraction resulted in the formation of denser coke particles with a carbon content ranging from 90% to 93% at temperatures between 300 and 600 degrees C. Further heating up to 1200 degrees C increased the carbon content to 97% and led to the formation of coke particles with a layered structure resembling premium class needle cokes.