ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 2, pp. 212!217. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + Kh.Kh. Gil’manov, A.A. Lamberov, E.V. Shatokhina, E.V. Dement’eva, 2008, published in Zhurnal Prikladnoi Khimii,
2008, Vol. 81, No. 2, pp. 223!228.
OF SYSTEMS AND PROCESSES
Transformation of the Phase Structure of an Iron Oxide
Catalyst for Dehydrogenation of Methyl Butenes
under Industrial Exploitation Conditions
Kh. Kh. Gil’manov, A. A. Lamberov, E. V. Shatokhina, and E. V. Dement’eva
Nizhnekamskneftekhim Open Joint-Stock Company, Nizhekamsk, Tatartstan, Russia
Kazan State University, Kazan, Tatarstan, Russia
Received August 6, 2007
Abstract-X-ray phase, differential-thermal, and elemental analyses were used to study the transformation of
the phase structure of an iron oxide catalyst for dehydrogenation of methyl butenes after exploitation.
Isoamylenes are dehydrated in a flow-through adi-
abatic reactor in a fixed bed of an iron oxide catalyst
at a temperature of 6003 640oC in the presence of
steam . Industrial exploitation of the catalyst under
severe conditions (low dilution of raw materials with
steam, high temperature) leads to its gradual deac-
tivation , with the result that the basic catalytic
parameters of the catalyst fall in 132 years. Accord-
ingly, its reloading and utilization becomes necessary
after this period of time.
It is known  that the main reason for the irre-
versible deactivation of the iron oxide catalyst is
the loss of potassium promoter. However, there are no
data on the distribution of potassium along the height
and diameter of the catalyst bed. Issues associated
with the efficiency of the regeneration performed and
with the uniform operation of the whole catalyst bed
The goal of this study was to examine the trans-
formation of the phase structure of the iron oxide
catalyst for dehydrogenation of methyl butenes under
industrial conditions to determine the efficiency of
its operation in high-power adiabatic reactors.
As objects of study served fresh and spent (8000 h)
samples of the domestic KDO catalyst , taken at
different places along the height and diameter of
the adiabatic reactor.
An X-ray phase analysis (XPA) of all the samples
was performed on a modified automatic X-ray dif-
fractometer based on a standard DRON-2 instrument,
with independent rotation of a sample and the count-
er and with Cu
radiation. A graphite monochromator
was used in the diffracted beam. The angles 2q were
recorded in the range 53 60o with a step of 0.5o.
The X-ray diffraction patterns were recorded at 30 kV
and 15 mA with an exposure time of 3 s. The av-
erage size of the coherent-scattering region (CSR)
was found from the broadening of diffraction
The thermal behavior and thermal transformations
under nonisothermal conditions were studied on
a Netzsch CTA-409 PC Luxx synchronous thermal
analyzer (Germany) in air in the temperature range
2531100oC at a heating rate of 103 40 deg min
The accuracy of determining the loss of mass was
An analysis for the content of carbon was made on
a HORIBA EMIA-510 instrument with a heat-con-
ductivity detector by the ASTM method, with a 1-g
catalyst sample burnt at 1450oC in the course of
The elemental composition of the catalyst (iron,
calcium, magnesium, potassium, and cerium oxides)
was determined on a Hitachi Z-6100 atomic-absorp-
tion spectrometer with an acetylene3air flame by
the method of a calibration plot.