The carbonization process of FCC-decant oil in a tube bomb has been studied by sequential observation of carbons produced at different carbonization times and pressures to establish the carbonization scheme, leading to a needle coke. The amount of gas evolution was also followed during carbonization. The formation of anisotropic spheres was followed by their growth, coalescence, and precipitation to form bulk mesophase first at the bottom of bomb and gradually to the whole region. The bulk mesophase was rearranged into the flow texture parallel to the bomb axis by the gas evolution just at the solidification of the mesophase into a solid lump of needle coke. This timing was strongly influenced by the carbonization pressure to control the extent of orientation in the resultant coke. Only a range of pressure (around 16 kg/cm2) could provide an excellent flow texture in the coke of the lowest coefficient of thermal expansion at 500°C. Such a scheme provides the three-dimensional structure of a lump of coke that may define its structural change at the calcination stage and its properties.
All Science Journal Classification (ASJC) codes
- Materials Science(all)