Process for liquefaction of coal
A coal liquefaction process comprises a liquefaction stage and an extraction stage. In the liquefaction stage the comminuted coal is liquefied with a process-derived solvent under elevated temperature and pressure conditions. In the extraction stage the liquefied coal is extracted with an extraction solvent, which can be derived from the process or initially supplied from external sources, comprising aromatic hydrocarbons having boiling point of up to 400/sup 0/ F., to extract valuable hydrocarbon products from the liquefied coal and to separate the extract phase from ash and undissolved coal under elevated temperature and pressure conditions. The extraction is conducted at supercritical temperature and pressure conditions for the extraction solvent. The temperature and pressure of the extract phase is then decreased, thereby decreasing the dissolution power of the solvent and separating the extract phase into a deashed fraction and a liquid fraction. A portion of the liquid fraction is recycled back to the extractor as the extraction solvent and the remainder of the liquid fraction is subjected to further pressure reduction and is passed to an atmospheric distillation column or stripper. The stripper bottom is a high quality coal extract (solid at ambient temperature and pressure conditions), and the overhead stream is recycled to the extractor as the extract solvent. A portion of the high quality coal extract is recycled to the liquefaction zone as the liquefaction solvent and the remainder thereof is removed from the process as the major product thereof.
- Assignee:
- Mobil Oil Corp.
- Patent Number(s):
- US 4402821
- OSTI ID:
- 5601729
- Country of Publication:
- United States
- Language:
- English
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010405* -- Coal
Lignite
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CARBONACEOUS MATERIALS
COAL
COAL LIQUEFACTION
COAL LIQUIDS
DEASHING
DISTILLATION
ENERGY SOURCES
EXTRACTION
FLUIDS
FOSSIL FUELS
FUELS
LIQUEFACTION
LIQUIDS
MATERIALS
SEPARATION PROCESSES
SOLVENT EXTRACTION
SUPERCRITICAL GAS EXTRACTION
THERMOCHEMICAL PROCESSES