https://doi.org/10.1351/goldbook.D01578
A thermal process which increases the molecular aggregation or ) over a period of time ( ). It is performed in a .
association
in petroleum-based residues or coal tar pitches
leading to extended mesophase
domains. This is achieved by holding them at an elevated temperature (usually coking
drum and is designed to ultimately produce delayed coke
. The feed is rapidly pre-heated in a tubular furnace to about Note:
Needle coke
is the premium product of the delayed coking
process. It is generally produced from highly aromatic residues from, for instance, the steam cracking
of gas oil. Its appearance and preferred orientation of the graphene layers
is a consequence of the evolved gaseous products percolating through the mesophase
which must not have too high a viscosity
. A close control of temperature, time and feedstock is essential. Lower grades, for instance isotropic
cokes, are used for carbon electrodes
applied, for example, in the production of aluminium.