delayed coking process

https://doi.org/10.1351/goldbook.D01578
A thermal process which increases the molecular aggregation or
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 750765 K) over a period of time (12 to 36 h). It is performed in a
coking
drum and is designed to ultimately produce
delayed coke
. The feed is rapidly pre-heated in a tubular furnace to about 760 K.
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.
Source:
PAC, 1995, 67, 473. (Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995)) on page 486 [Terms] [Paper]