Using ceramic membranes for the separation of hydrogen produced by dehydrogenation of perhydro-m-terphenyl

Article abstract of DOI:10.1134/S0036024415010100

The efficiency of a variety of ceramic membranes for the purification of hydrogen obtained by dehydrogenation of perhydro-m-terphenyl in a catalytic flow reactor from vapors of initial hydrocarbons and dehydrogenation products is investigated.

Full text of DOI:10.1134/S0036024415010100

ISSN 0036ꢀ0244, Russian Journal of Physical Chemistry A, 2015, Vol. 89, No. 1, pp. 16–18. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © A.N. Kalenchuk, V.I. Bogdan, L.M. Kustov, 2015, published in Zhurnal Fizicheskoi Khimii, 2015, Vol. 89, No. 1, pp. 20–23.
CHEMICAL KINETICS
AND CATALYSIS
Using Ceramic Membranes for the Separation of Hydrogen
Produced by Dehydrogenation of Perhydroꢀmꢀterphenyl
A. N. Kalenchuk, V. I. Bogdan, and L. M. Kustov
Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, 119991 Russia
eꢀmail: lmc@ioc.ac.ru
Received January 4, 2014
Abstract—The efficiency of a variety of ceramic membranes for the purification of hydrogen obtained by
dehydrogenation of perhydroꢀ
mꢀterphenyl in a catalytic flow reactor from vapors of initial hydrocarbons and
dehydrogenation products is investigated.
Keywords: dehydrogenation, perhydroꢀ
DOI: 10.1134/S0036024415010100
mꢀterphenyl, catalysis, ceramic membranes, hydrogen.
INTRODUCTION
formaldehyde resin, LBSꢀ1 grade (GOST 901ꢀ78,
mod. 1–6; 58–60 wt % resin, up to 9.0 wt % free pheꢀ
nol, and no more than 10 wt % water; gelling time, up
to 100 s) was used as a precursor of the carbonized
layer. The carbonized coating was formed by increasꢀ
ing the resin’s capability to adhere to the substrate
under various conditions of drying, thermal stabilizaꢀ
tion, and substrate surface modification, without penꢀ
etrating the structure of the nearꢀsurface layer.
The current trend toward the decentralization of
electric and heat supply networks based on compact,
highly efficient electric power sources is of great interꢀ
est worldwide. Hydrogen fuel elements, which proꢀ
duce pure water and no hazardous substances during
operation, are considered a priority area of power
source development; however, there are very strict
requirements for the purity of their fuel. As is well
known, it is neither convenient nor safe to store and
transport pure hydrogen under the conditions of a
modern metropolis.
Catalytic Experiment
The technique for storing hydrogen described in
1–3], based on reversible cycles of the hydration–
dehydrogenation of organic chemical compounds and
characterized by high hydrogen absorbing capacity
7–7.5 wt %), is completely explosion proof, since
hydrogen is stored in the chemically bonded state and
is separated only under the specific conditions of the
dehydrogenation reaction.
The capability of membranes to separate hydrogen
from hydrocarbon vapors in the dehydrogenation
reaction of perhydroꢀmꢀterphenyl was investigated in
a flow catalytic system [4]. The PHMT dehydrogenaꢀ
tion was conducted continuously for 8 and 25 h in
three different ways: (a) without ceramic membranes;
[
(
(
b) using ceramic membrane (I) with the carbonized
coating on its external surface; and (c) using memꢀ
The aim of this work was to study the possibility of brane (II) without carbonized coating.
separating hydrogen from hydrocarbon vapors in the
The basic criterion for evaluating the capability of
membranes to separate hydrogen was the quantity of
dissolved hydrocarbons in the solvents mixture at the
separator’s outlet.
dehydrogenation reaction of perhydroꢀ
mꢀterphenyl
(
PHMT) in a flow catalytic system using hydrogen
permeable ceramic membranes.
3
Each catalyst sample (6 cm ) was charged into a
steel reactor 10 mm in diameter and 230 mm long. The
EXPERIMENTAL
To study the possibility of separating hydrogen catalyst bed was fixed in the center of the reactor with
from hydrocarbon vapors in dehydrogenation process, a quartz wool. The reactor was placed in an oven and
we used two types of hydrogen permeable membranes heated to the reaction temperature. Liquid perhydroꢀ
based on closed at one end tubular ceramic carriers
m
ꢀterphenyl was supplied to the reactor using an HPP
and a volume
m. Membranes (I) with rate of 1 h . The substrate for the dehydrogenation
and (II) without carbonized coating ~100
m thick on reaction (i.e., perhydroꢀ ꢀterphenyl) was obtained via
the outer surface were provided by the National the full hydration of commercial ꢀterphenyl (99%,
Research Center Kurchatov Institute. Resole phenolꢀ Aldrich) in an Rꢀ201 chemical reactor (Reaction
(
α
ꢀAl O , 120 mm long, 8 mm o.d., 6 mm i.d.) with an 5001 highꢀpressure pump at 90–95°С
2
3
–1
average pore size of up to 0.2
µ
µ
m
m
16

USING CERAMIC MEMBRANES FOR THE SEPARATION OF HYDROGEN
17
Content of gas products from the PHMT dehydrogenation reꢀ of the catalyst were reduced at 320
°C
in a hydrogen
action, %
flow (30 mL/min) for 2 h.
τ
,
h
A
B
C
Chromatographic Analysis
8
0.29
0.37
0.01
0.03
0.12
0.14
The analysis of hydrocarbon reaction products and
of the solvents mixture from the bubbler was perꢀ
formed using a Kristaluxꢀ4000M chromatograph with
ZBꢀ5 capillary column (ZEBRON, United States),
equipped with a flame ionization detector (FID). The
2
5
τ is length of the experiment, (A) no membrane, (B) membrane (I),
and (C) membrane (II).
programmed temperature profile was 70–220°C with
a heating rate of 6 K/min. Some samples of the reacꢀ
tion products were analyzed on a FOCUS DSQ II
Engineering, Inc.). All supply lines were thermostatꢀ
ted at 90–95°С.
Hydrogen and the other reaction products outgoꢀ GCꢀMS instrument equipped with a TRꢀ5ms capilꢀ
lary column for detailed identification of partial
hydrogenation products and byproducts of substrate
dehydrogenation. The purity of the obtained hydrogen
was additionaly controlled by gas chromatography
with thermal conductivity detector on a Porapak Q
column.
ing from the reactor entered a standard metallic satuꢀ
rator designed for the basic separation of liquid reacꢀ
tion products from gases. The saturator’s outlet for liqꢀ
uid products was tightly connected to a receptacle.
The saturator’s gas outlet was connected to one neck
of a twoꢀnecked flask. The investigated membrane was
placed inside the flask and gasꢀtightly glued to the
hydrogen inlet tube at its open end. The hydrogen was
then passed from the output neck of the flask to a bubꢀ
bler filled with a mixture of equal volumes of cyclohexꢀ
RESULTS AND DISCUSSION
The main products of the full dehydrogenation of
ane and benzene with a total volume of 100 mL. The PHMT cycloalkane are
outlet of the bubbler was connected directly to a puriꢀ The partially hydrated
m
m
ꢀterphenyl and hydrogen.
ꢀterphenyls (cyclohexylꢀ
fied gas volume meter (an RG7000 drum gas counter) diphenyl, diphenylcyclohexane and dicyclohexylbenꢀ
via a glass tube. So, after passing through the memꢀ zene) are byproducts of perhydroꢀmꢀterphenyl dehyꢀ
brane, the gas mixture of hydrogen and possible drogenation. The structural features of a flow catalytic
byproducts formed during the dehydrogenation went system ensured an output of hydrogen without byꢀ
product gases. Trace amounts of mꢀterphenyl cracking
first to the flask and then to the bubbler with the solꢀ
vent mixture, where possible organic impurities were
dissolved, and finally to the meter for measuring the
volume of separated gas. For better condensation of
the possible gas products of reaction entering the bubꢀ
bler, it was cooled in water.
products such as diphenyl and benzene were observed
under more hard reaction conditions (higher temperꢀ
ature, minimal substrate flow rate).
The amount of impurities in the gas mixture at the
separator outlet was estimated chromatographically
under the assumption that all boiling phases could be
removed from the reactor zone along with the hydroꢀ
gen. A sample of partially hydrated
4% degree of conversion and 92% selectivity toward
ꢀterphenyl was used. A 0.0003 g sample
as the active component in amounts of 3 wt % disꢀ composed of perhydroꢀ ꢀterphenyl (more than 90%),
persed on the surface of a sibunit carbon carrier was
ꢀterphenyl (6%), and a mixture of partialy hydrogeꢀ
used both for the hydration of
ꢀterphenyl and the nated forms of PHMT with traces of diphenyl (total,
dehydrogenation of perhydroꢀ
ꢀterphenyl. The cataꢀ ~4%) was added to 1 mL of a 50 : 50 cyclohexane–
mꢀterphenyl with a
Catalyst Preparation
9
A heterogeneous Pt/C catalyst based on platinum perhydroꢀ
m
m
m
m
m
lyst was prepared by impregnation with metal precurꢀ benzene (both solvents of analytical grade) mixture
sors aqueous solutions (chloride complexes), followed giving the 300 ppm (0.03%) solution. In a similar
by hydrogen reduction. The initial reagents for platiꢀ manner, samples with concentrations of 1500, 1000,
numꢀbased catalysts were an H PtCl6 solution 500, 150, and 50 ppm were prepared and analyzed on
2
(
(Pt) = 36.3 wt %) of pure grade, prepared from calꢀ a chromatograph.
ω
culated amount of hexachloroplatinic acid
The table presents the results from quantitative
[
(
H PtCl · 6H O] and a 30% formalin solution estimates of the content of gas products from the
2
6
2
2.5 parts per one part of hexachloroplatinic acid). It PHMT dehydrogenation reaction after they were
, and the coated sample was then passed through a 1 : 1 mixture of cyclohexane and benꢀ
impregnated with a 50% KOH solution (300% sample zene with and without membranes (I) and (II). Unforꢀ
weight) at . The resulting mass was heated on a tunately, the sensitivity of the Kristaluxꢀ4000M chroꢀ
water bath at 55–65 for 1 h, then rinsed with disꢀ matograph did not allow us to determine with suffiꢀ
tilled water to a neutral pH, and then placed in a dryꢀ cient accuracy any concentrations below 50 ppm, so
ing oven at 105–110 for 2.5 h [5]. Finally, samples the concentrations for the product peaks registered
was applied at 10°C
5°C
°C
°C
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
Vol. 89
No. 1 2015

18
KALENCHUK et al.
experimentally on the chromatograms with areas of
lower values were calculated by extrapolation. On the
other hand, since benzene and cyclohexane are used as
solvents in this work, only С12 and higher hydrocarꢀ
bons were determined to estimate the ability of memꢀ
branes to separate hydrogen from hydrocarbons.
CONCLUSIONS
Based on a comparison of the results from experiꢀ
ments on the PHMT reaction without ceramic memꢀ
branes (A), using membrane (I) with a carbonized
coating on its outer surface (B), and a membrane (II)
without carbonized layer (C), it was established that at
the estimated volumes of hydrogen separated in
PHMT dehydrogenation, using membrane (I) drastiꢀ
cally reduced the passing of byproducts vapors from
the PHMT dehydrogenation reaction along with
hydrogen. At the same time, the concentration of
impurities in the hydrogen produced by the dehydroꢀ
genation of the organic compound was even lower
than in the technical grade hydrogen used for hydrogeꢀ
nation.
Using membrane (II) without carbonized coating
also reduced the concentration of byproducts of
PHMT dehydrogenation reaction in the mixture of
solvents, but to a lesser degree than membrane (I) with
the carbonized layer. At the same time, there was a
progressive increase in the concentration of dissolved
Analysis of samples of the gas products from the
PHMT dehydrogenation reaction showed that after
they were passed through the mixture of solvents withꢀ
out membranes (A), an additional five peaks belonging
to cisꢀ and transꢀperhydroꢀmꢀterphenyl, mꢀterphenyl,
and two intermediate products of their transformation
into one another appeared on the chromatograms
along with the peaks of the solvents. The total amount
of dissolved substances in the analyzed samples was
~
0.29% (~1000 ppm) after 8 h (sample 1) and ~0.37
after 25 h. The rates of hydrogen evolution were 5.0,
.7, and 4.0 L/h after 2, 8, and 25 h, respectively, with
90% PHMT conversion and >90% selectivity toward
ꢀterphenyl for the first two points. A drop in these
4
>
m
figures and a rise in the content of partially hydrated products of the PHMT dehydrogenation reaction over
reaction products was unfortunately observed at the time. It should be noted that no trace amounts of C12
end of 25 h, due apparently to decrease of catalyst were observed while analysis for C hydrocarbons by
18
activity.
chromatography.
The progress in using chemical composite systems
of hydrogen storage can be attributed to the increased
efficiency of catalyst operation and improvements in
flow catalytic systems that use selective hydrogenꢀperꢀ
meable membranes.
The volumes of the produced hydrogen did not
change during PHMT dehydrogenation reaction (B)
using membrane (I) with a carbonized layer; however,
no C hydrocarbons are seen on the chromatograms,
18
while they are present for samples 1 and 2 in experiꢀ
ment (A). Instead, four other peaks are seen that
belong to PMHT and MT cracking products (dicycloꢀ
hexyl, diphenyl, and intermediate products of their
mutual transformation), and the total amount of disꢀ
solved substances in each analyzed sample did not
exceed 0.03% even after 25 h (sample 4).
REFERENCES
1. L. M. Kustov, A. L. Tarasov, V. I. Bogdan, and
A. L. Kustov, RF Patent No. 2281154 (2004).
2. J. S. Sung, Y. Choo Ko, T. H. Kim, et al., Int. J. Hydroꢀ
gen Energy 33, 2721 (2008).
3
. A. L. Tarasov, O. A. Kirichenko, N. N. Tolkachev, et al.,
Russ. J. Phys. Chem. A 84, 1122 (2010).
In experiment (C) using membrane (II) without
carbonized layer, analysis of the samples of hydrogen
after the dehydrogenation reaction showed that cisꢀ
4
. A. N. Kalenchuk, V. I. Bogdan, A. L. Tarasov, and
L. M. Kustov, in Proceedings of the 3rd International
Symposium on Hydrogen Power (MEI, Moscow, 2009),
p. 175 [in Russian].
and transꢀperhydroꢀ
sample 5) accompanied the solvent peaks on the
chromatograms in a total amount of 0.12% after 8 h,
while cisꢀ and transꢀperhydroꢀ ꢀterphenyl, ꢀterꢀ
mꢀterphenyl and mꢀterphenyl
(
5. N. D. Zelinskii and M. B. TurovaꢀPolyak, in Collection
of Academician N. D. Zelinsky Works (Akad. Nauk
SSSR, Moscow, 1955), Vol. 3 [in Russian].
m
m
phenyl, and two intermediate products of their transꢀ
formation into one other (sample 6) were present in a
total amount of 0.14% after 25 h.
Translated by S. Saveleva
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
Vol. 89
No. 1 2015