Kinetics of catalytic hydrogenation of pyrene: implications for direct coal-liquefaction processing

Conference · Sat Jan 01 04:00:00 EST 1983

OSTI ID:6085988

Stephens, H P; Chapman, R N

Although recycling heavy solvents has recently re-emerged as a key to cutting the cost of direct coal liquefaction, little data for the hydrogenation of heavy-solvent donors have been reported. This study addresses the kinetic and thermodynamic aspects of catalytic hydrogenation of pyrene, a donor-solvent precursor thought to play an important role in coal-liquefaction processes that use heavy recycle solvents. Thirty-six batch hydrogenation experiments were performed with solutions of 9.1 wt % pyrene in n-hexadecane, which approximated the concentrations found in integrated two-stage liquefaction recycle solvents. Reactions were performed over a range of conditions: temperatures of 348, 374 and 394/sup 0/C, pressures of 500, 1250 and 2000 psig, and catalyst/pyrene weight ratios of 0.05, 0.15 and 0.45. Several experiments performed without catalyst confirmed that contributions of homogeneous reactions and reactor wall effects were insignificant. In addition, several catalyzed experiments performed with hexahydropyrene proved the existence of reversible reaction steps. Two generalizations may be made regarding hydrogen supplied by the dihydropyrene component of donor solvents: (1) increasing hydrogen partial pressure increase both the rate at which H/sub 2/Py is formed and the equilibrium concentration of H/sub 2/Py. Therefore, pyrene rehydrogenation should be done at as high a pressure as is cost effective; and (2) although an increase in temperature favors the rate of attainment of equilibrium between Py and H/sub 2/Py, the position of the equilibrium is shifted toward pyrene. Temperature must therefore be adjusted to achieve an optimum trade-off between rate of formation and maximum possible concentration of H/sub 2/Py.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6085988
• Report Number(s): SAND-83-0418C; CONF-830814-6; ON: DE83010027
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
010600 -- Coal
Lignite
& Peat-- Properties & Composition
AROMATICS
ARRHENIUS EQUATION
CATALYSTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL LIQUEFACTION
CONDENSED AROMATICS
DATA
ELEMENTS
ENTHALPY
EQUATIONS
EXPERIMENTAL DATA
HYDROCARBONS
HYDROGEN
HYDROGENATION
INFORMATION
KINETICS
LIQUEFACTION
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC SOLVENTS
PARTIAL PRESSURE
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
PYRENE
REACTION KINETICS
SOLVENTS
STRUCTURAL MODELS
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
THERMODYNAMIC PROPERTIES
TSL PROCESS