Extraction of coal tar pitch using a mixture of compressed CO[sub 2] and toluene
- Univ. of Kentucky, Lexington, KY (United States)
The removal of low-molecular-weight components from commercial pitches is a critical step in the production of suitable precursors for isotropic carbon fiber formation. A unique extraction process employing a one-phase binary mixture of carbon dioxide and toluene has been developed to remove low-molecular-weight components from coal tar pitch, with an ultimate goal of increasing the softening point of the pitch. The mass fraction of coal tar pitch extracted was determined as a function of extraction temperature (25--75 C), pressure (8.7--14.9 MPa), and extractive solvent composition (40--70 wt % toluene) using a factorial experimental design. As much as 44 wt % of the coal tar pitch was removed at these extraction conditions, and softening points greater than 250 C were achieved. The separation is controlled by the temperature and composition of the extractant solvent. This compressed gas/organic solvent extraction process removes low-molecular-weight material from the coal tar pitch using significantly milder solvents and reduced temperatures relative to traditional extractive processes.
- OSTI ID:
- 6106546
- Journal Information:
- Industrial and Engineering Chemistry Research, Vol. 38:9; ISSN 0888-5885
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON DIOXIDE
CARBON FIBERS
COAL TAR
FABRICATION
PITCHES
SOLVENT EXTRACTION
TOLUENE
ALKYLATED AROMATICS
AROMATICS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
EXTRACTION
FIBERS
HYDROCARBONS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SEPARATION PROCESSES
TAR
010402* - Coal
Lignite
& Peat- Purification & Upgrading
010500 - Coal
Lignite
& Peat- Products & By-Products