COAL‐DERIVED PITCH COKE is the primary industrial solid CARBONIZATION product obtained from COAL‐TAR PITCH and is mainly produced in chamber or DELAYED COKING PROCESSES.
See: CARBONIZATION, COAL‐TAR PITCH, DELAYED COKING PROCESS.
Notes
COAL‐DERIVED PITCH COKE, although it exhibits a pregraphitic microstructure, has often a lower graphitizability than PETROLEUM COKE. Fractions of COAL‐TAR PITCHES (obtained by extraction or filtration) may form COKES with needlelike structures and have an improved graphitizability. The usually lower graphitizability compared to PETROLEUM COKE is due to an inhibition of mesophase growth because of chemical and physical differences of the cokes.
See: COAL‐TAR PITCHES, COKE, PETROLEUM COKE.
Coal‐Tar Pitch
Description
COAL‐TAR PITCH is a residue produced by distillation or heat treatment of coal tar. It is a solid at room temperature, consists of a complex mixture of numerous predominantly aromatic hydrocarbons and heterocyclics, and exhibits a broad softening range instead of a defined melting temperature.
Notes
The hydrogen aromaticity in COAL‐TAR PITCH (ratio of aromatic to total content of hydrogen atoms) varies from 0.7 to 0.9.
Coalification
Description
COALIFICATION is a geological process of formation of materials with increasing content of the element carbon from organic materials, which occurs in a first biological stage into peats, followed by a gradual transformation into coal by action of moderate temperature (about 500 K) and high pressure in a geological stage.
Notes
COALIFICATION is a dehydrogenation process with a reaction rate slower by many orders of magnitude than that of CARBONIZATION. Some specific reactions approach completion before others have started. The dehydrogenation remains incomplete. The degree of COALIFICATION reached by an organic material in the process of COALIFICATION increases progressively and can be defined by means of the measured C/H ratio and of the residual contents of oxygen, sulfur, and nitrogen.
See: CARBONIZATION.
Coke
Description
COKE is a solid high in content of the element carbon and structurally in the NON‐GRAPHITIC state. It is produced by pyrolysis of organic material, which has passed, at least in part, through a liquid, liquid‐crystalline, or solid state during the CARBONIZATION process. COKE can contain mineral matter.
See: CARBONIZATION, NON‐GRAPHITIC CARBON.
Notes
As some parts, at least, of the CARBONIZATION product have passed through a liquid, liquid‐crystalline, or solid state, the resulting NON‐GRAPHITIC CARBON is of the graphitizable variety. From a structural viewpoint, the term COKE characterizes the state of GRAPHITIZABLE CARBON before the beginning of GRAPHITIZATION.
See: CARBONIZATION, GRAPHITIZABLE CARBON, GRAPHITIZATION, NON‐GRAPHITIC CARBON.
Coke Breeze
Description
COKE BREEZE is a by‐product of COKE manufacture; it is the residue from the screening of heat‐treated COKE; the particle size is less than 10 mm. Generally, COKE BREEZE has a volatile matter of <3 wt%.
See: COKE.
Colloidal Carbon
Description
COLLOIDAL CARBON is a PARTICULATE CARBON with particle sizes below approximately 1000 nm in at least one dimension.
See: PARTICULATE CARBON.
Notes
COLLOIDAL CARBON exists in several morphologically distinct forms.
See: CARBON BLACK, PARTICULATE CARBON.
Delayed Coke
Description
DELAYED COKE is a commonly used term for a primary CARBONIZATION product (GREEN or RAW COKE) from high‐boiling hydrocarbon fractions (heavy residues of petroleum or coal processing) produced by the DELAYED COKING PROCESS.
See: CARBONIZATION, DELAYED COKING PROCFSS, GREEN or RAW COKE.
Notes
DELAYED COKE has, with only a few exceptions, a better graphitizability than COKES produced by other coking processes even if the same feedstock is used. DELAYED COKE contains a mass fraction of matter between 4 and 15 wt%, which can be released during heat treatment.
See: COKE, DELAYED COKING PROCESS.
Delayed Coking Process
Description
DELAYED COKING PROCESS is 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 hours). It is performed in a coking drum and is designed to ultimately produce DELAYED COKE. The feed is rapidly preheated in a tubular furnace to about 760 K.
See: COAL‐TAR PITCH, DELAYED COKE.
Notes
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 the
