Structural Changes during the Calcination of Petroleum Coke (Part 1)

Changes in Structure, Texture, Density of Coke

Abstract

The effect of temperature and holding time on structural changes during the calcination of raw petroleum cokes was studied by means of X-ray diffraction, microscopic.observations, density measurements and elementary analysis.
From the microscopic observation, it was found that the formation of pores and cracks during calcination depends strongly on the texture of the coke.The average d-spacing of (002) planes showed the highest value in the range from 1200 to 1300°C.This result suggests that thecondensation polymerization and dehydrogenation reactions lead to the formation of crystallites and parallel stacking of carbon layers in this calcination process.By means of the superposition method, apparent activation energy estimated from the changes of real density with holding time during the calcination process was about 70 kcal/mol.The value seems to be reasonable in comparison with those for carbonization and graphitization.