1070-4272/04/7701-0154C2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 4, 2004, pp. 154 !158. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 4,
2004, pp. 158!162.
Original Russian Text Copyright + 2004 by Kerimov.
OF FOSSIL FUEL
Flash Pyrolysis and Kinetic Parameters of Decomposition
of Oil Shales
Kh. M. Kerimov
Azerbaijan State Petroleum Academy, Baku, Azerbaijan
Received December 6, 2002; in final form, October 2003
Abstract-Flash pyrolysis of oil shales and distribution of the organic matter in the volatile products and solid
residue at various pyrolysis temperatures were studied. The concentrations of aliphatic hydrocarbons and
naphthenes + arenes in the volatile products were determined.
Inevitable exhaustion of traditional power resources
calls for a search for new sources of hydrocarbon raw
materials. Among materials showing promise in this
respect are oil shales .
The assortment of substances produced by shale
processing includes tens of items, without taking into
account wastes that can be processed. From the view-
point of energy production, the most important com-
ponent of shale oils is the organic matter; its base is
kerogen. Kerogen is mainly recovered from the inor-
ganic matrix by pyrolysis. Alternative procedures
(extraction, biochemical methods) are less suitable for
commercial application .
Pyrolytic decomposition of oil shale kerogen in-
volves a set of parallel and consecutive reactions
following the scheme
Kerogen 77 6 gas, bitumen 77 6 gas, tar, coke, (1)
are the rate constants, min
are the activation energies, kJ mol
; and A
are the preexponential terms (min
) of the corre-
Ballice et al. studied decomposition of kerogen
thermogravimetrically  and concluded that the
process occurs in two steps: decomposition of kerogen
proper at 3003375oC and secondary decomposition
and condensation processes at 3753500oC.
The kinetics of thermal decomposition of kerogen
is described by a first-order equation
dx/dt = kf(x), (2)
x = ÄÄÄÄÄÄÄ, (3)
, and m
are the initial, intermediate, and
final sample weights, respectively (mg); k is the rate
; and x is the degree of decomposition.
dlnk/dT = E/RT
and, for first-order reactions, f(x)=13x, Eq. (2) can
be written as follows:
ÄÄÄ ÄÄÄ = A exp (3E/RT)(1 3 x), (4)
ÄÄÄ =(A/b)exp(3E/RT)(1 3 x), (5)
where b =dT/dx.
Integration of Eq. (5) gives
]ln [1/(1 3 x)]} = ln (AR/b) 3 E/RT. (6)
This equation is the Chen3Nuttall equation . The
kinetic parameters of oil shale decomposition can be
determined by the Coats3Redfern graphical method
. The activation energy can be determined from the
slope of the straight line plotted in the coordinates
3ln[3ln(1 3 x)/T
] vs. 1/T .
In this work, to evaluate the kinetic parameters of
decomposition of oil shales from the Dzhangichai
deposit, we used a combination of the above methods.
From the values of x [Eq. (3)] for definite tempera-
tures, we calculated E by the Coats3Redfern method.
These values of E were substituted in Eq. (6), and the
preexponential term was determined.