The hydrogen transfer cycle for coal liquefaction: Process implications
Direct liquefaction of coal involves the conversion of a hydrogen-poor solid to a liquid richer in hydrogen by a complex set of bond ruptures and hydrogen transfer reactions. This study of the hydrogen transfer cycle for coal liquefaction suggests more effective ways to utilize hydrogen. The results of these experiments clearly demonstrate that an excellent coal liquefaction solvent can be produced by reaction of a coal-derived liquid with a H/sub 2//CO/steam mixture at relatively low temperature and pressure. The resulting solvent contains a sufficient concentration of hydroaromatics to be used as the sole source of hydrogen for the liquefaction of coal. Applying these techniques for transfer of hydrogen to coal in a liquefaction process could provide several advantages: First, use of CO/H/sub 2//steam mixtures, instead of purified hydrogen, for the hydrogenation of the solvent would eliminate the need for gas purification units. Second, operation of the solvent production reactor at a lower temperature and pressure would allow reduction of the wall thickness of the reactor vessel, thus reducing vessel cost. Third, the 650 to 770/sup 0/F distillate cut used as a recycle solvent contains significant concentrations of the important three- and four-ring hydroaromatic donor precursors, but does not contain compounds that cause extensive catalyst deactivation. Finally, the requirement for gas-phase hydrogen and high pressure in the thermal liquefaction step would be eliminated. 6 refs., 4 figs., 2 tabs.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6535334
- Report Number(s):
- SAND-87-0374C; CONF-870802-4; ON: DE87008505
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
AROMATICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CHALCOGENIDES
CHEMICAL BONDS
CHEMICAL REACTIONS
CHROMATOGRAPHY
CLEAVAGE
COAL LIQUEFACTION
COAL LIQUIDS
CONDENSED AROMATICS
CONSUMPTION RATES
CRYSTAL STRUCTURE
DEHYDROGENATION
ELEMENTS
FLUIDS
GAS CHROMATOGRAPHY
HYDROCARBONS
HYDROGEN
HYDROGEN TRANSFER
HYDROGENATION
LIQUEFACTION
LIQUID COLUMN CHROMATOGRAPHY
LIQUIDS
MASS SPECTROSCOPY
MICROSTRUCTURE
NONMETALS
ORGANIC COMPOUNDS
ORGANIC SOLVENTS
OXIDES
OXYGEN COMPOUNDS
PHENANTHRENE
POLYCYCLIC AROMATIC HYDROCARBONS
PYRENE
RECYCLING
SEPARATION PROCESSES
SOLVENTS
SPECTROSCOPY
STEAM
TEMPERATURE EFFECTS
THERMOCHEMICAL PROCESSES
YIELDS