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 750-765 K) over a period of time (12-36 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:
@N04095@ is the premium product of the delayed @C01144@ process. It is generally produced from highly aromatic residues from, for instance, the steam @C01387@ of gas oil. Its appearance and preferred orientation of the @G02683@ is a consequence of the evolved gaseous products percolating through the @M03849@ which must not have too high a @V06627@. A close control of temperature, time and feedstock is essential. Lower grades, for instance @I03353@ cokes, are used for @C00829@ 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 (https://doi.org/10.1351/pac199567030473)