1-s2.0-S0360319915319571-main

A detailed reaction mechanism for hydrogen
production via hydrogen sulphide (H2S)
thermolysis and oxidation
Tay Yu Cong a,b
, Abhijeet Raj a,*
, Jirawan Chanaphet a,c
,
Shabin Mohammed a
, Salisu Ibrahim a
, Ahmed Al Shoaibi a
a
Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, United Arab Emirates
b
Department of Chemical Engineering, Universiti Teknologi Petronas, Perak, Malaysia
c
Department of Chemical Engineering, King Mongkut's University of Technology Thonburi, Thailand
a r t i c l e i n f o
Article history:
Received 27 December 2015
Received in revised form
5 March 2016
Accepted 9 March 2016
Available online 3 April 2016
Keywords:
H2S
Thermolysis
Reaction mechanism
H2 yield
Synergistic effect
a b s t r a c t
Hydrogen production from the thermolysis of undesirable hydrogen sulphide (H2S) rep-
resents a viable means of extracting energy from it while enhancing the efficiency of Claus
process, which is a widely used technology for sulphur recovery from H2S laden streams of
oil and gas industries. This paper examines the thermolysis of H2S for direct hydrogen and
sulphur production. A detailed reaction mechanism is proposed that captures the chem-
istry involved in its high temperature decomposition. The simulation results obtained
using the proposed mechanism is compared with a wide range of experimental data from
plug flow and stirred reactors, premixed laminar flames, and shock tubes, and a satisfac-
tory agreement between them is found. Significant improvements in model predictions are
obtained with the proposed mechanism when compared to previously published mecha-
nism. After its validation, the mechanism is then used to investigate the major reactions
involved in hydrogen production. It is shown through simulations under adiabatic condi-
tions that the addition of small amount of oxygen in the inlet H2S gas stream exhibits a
synergistic effect in H2 yield, and can significantly enhance the production of hydrogen.
The results reported herein provide design guidelines and viable means of seeking cost
effective methods of hydrogen production from industrial waste streams containing H2S.
Copyright © 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights
reserved.
Introduction
Hydrogen sulphide (H2S) is often produced as a by-product
from various chemical processes such as amine extraction
[1], hydrodesulphurisation of hydrocarbons [2], upgrading of
heavy oils [3], bitumen [4], and other available methods for oil
and natural gas desulphurization [5]. It is highly toxic and
corrosive [6,7], due to which it cannot be emitted to the
environment in high concentrations. In chemical processes
involving noble metal catalysts, the presence of H2S in the gas
stream leads to catalyst poisoning [8]. Though it is a flam-
mable gas, its combustion products are also harmful for living
* Corresponding author. Tel.: þ971 2 6075738.
E-mail address: abgupta@pi.ac.ae (A. Raj).
Available online at www.sciencedirect.com
ScienceDirect
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i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 4 1 ( 2 0 1 6 ) 6 6 6 2 e6 6 7 5
http://dx.doi.org/10.1016/j.ijhydene.2016.03.053
0360-3199/Copyright © 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

beings, environment, and industrial equipment [9]. For
example, H2S combustion results in SO2 production that is
very corrosive, and causes acid rain [10,11]. Due to these
harmful effects of H2S, the environmental enforcement
agencies worldwide have imposed stringent emission regu-
lations on H2S and other sulphurous compounds [12]. This
makes it imperative to reduce the sulphur content of oil and
gas streams to acceptable levels before further processing.
The most common process used for H2S removal from natural
gas is amine extraction [13e19]. The by-product of amine
extraction process, consisting of H2S, CO2, mercaptans and
aromatic compounds, is further processed to hinder its health
and environmental hazards.
Claus process is a widely used technology to process gas
streams containing H2S to recover Sulphur [20e25]. In this
process, H2S undergoes partial oxidation in air in the thermal
reactor to form SO2 and H2O [5]. Elemental sulphur is produced
by the pyrolysis of H2S and by the reaction between unreacted
H2S with SO2. Thereafter, the unreacted H2S reacts with SO2 in
the presence of catalyst to produce more sulphur [24,26e29].
The global reactions involved in this process are shown below
as (R1)e(R3) [30,31]:
H2S þ 1:5O2/SO2 þ H2O (R1)
2H2S þ SO2/3S þ 2H2O (R2)
Combining the two reactions:
2H2S þ O2/2S þ 2H2O (R3)
Though sulphur produced from Claus process is a
marketable product, it does not allow full exploitation of H2S
as its hydrogen content is wasted as low grade steam [32e34].
As the energy demand increases worldwide, an efficient uti-
lization of available natural resources is needed [35].
Therefore, the direct decomposition of H2S is desired so as
to obtain not only sulphur, but also valuable hydrogen, which
is a desired energy source because of its promising charac-
teristics such as cleanliness [36,37] and highest energy content
and energy conversion efficiency [38]. It is also used in
hydrotreating processes such as hydro-isomerisation to
convert n-paraffins into iso-paraffins, and de-aromatisation to
hydrogenate aromatics into cyclo-alkanes [39,40].
Various decomposition methods of H2S have been sug-
gested in the literature, including thermochemical, electro-
chemical, photochemical and plasma methods [33,34,41e48].
Apparently, most of the hydrogen production processes from
H2S have not been realized in large scale due to economic or
technical feasibility [33]. In general, the simplest and direct
method that can be used is catalytic or non-catalytic thermal
decomposition, following the reaction given below [33,49]:
2H2S/2H2 þ S2 (R4)
In this method, sufficient heat is supplied to break down
H2S into H2 and S2. The reaction is highly endothermic and,
therefore, more favourable at high temperatures. Galuszka
et al. [34] predicted a conversion of 20% at 1273 K and 38% at
1473 K, based on thermodynamic equilibrium calculations.
They reported that temperatures above 1648 K are required to
obtain H2S conversion above 50%. During this process, the
product gases (H2 and S2) must be passed through quenching
zone to prevent the recombination reactions.
The requirement of high temperatures for non-catalytic
decomposition of H2S has motivated several experimental
studies in the search of catalysts for its low-temperature
decomposition with high H2 yield. In Refs. [50e53], the use of
MoS2 was suggested to achieve about 95% conversion of H2S to
H2. In Ref. [54], metal catalysts were proposed for the low-
temperature decomposition of H2S, where about 15% con-
version of H2S to H2 and S2 was achieved at room temperature.
The conversion, however, decreased with increasing tem-
perature. The use of metal oxides as catalysts was suggested
in Ref. [55], where H2S decomposition was studied in the
temperature range of 500e900
C. The production of H2
through the partial oxidation of H2S over alumina catalyst was
studied by Clark et al. [56], where H2S conversion of 64.6% was
achieved at 400
C, and less than 0.5% of H2S was converted to
SO2. In Ref. [57], the use of cobalt sulphide as a catalyst for H2S
decomposition was demonstrated through a kinetics study. A
recent study [58] discusses the application of perovskite cat-
alysts for H2S decomposition, where about 15% of H2S was
shown to decompose at 800
C.
The thermal decomposition often also includes catalytic
H2S oxidation process [59,60]. For instance, sulphur is formed
from H2S oxidation in the presence of stoichiometric amount
of oxygen over the TiO2 catalyst in the mobile direct oxidation
process [61,62]. Kalinkin et al. investigated the kinetics of H2S
oxidation with V2O5 as catalyst at 423e523 K with initial H2S
concentrations up to 3 vol% and O2:H2S ratio above 4 [63].
Zhou et al. also studied the oxidation of H2S in a flow reactor
under atmospheric condition at a temperature range of
950e1150 K in fuel-lean conditions, catalysed by silica surface
although the silica's catalytic effect is suppressed by a coating
of B2O3 [64].
There is still a need to explore efficient means of enhancing
H2 production from H2S thermal (non-catalytic) decomposi-
tion due to lower capital cost requirements as compared to
catalytic methods. This requires a reliable kinetic model based
on a detailed reaction mechanism that can be used to seek
optimum reactor conditions to enhance H2 production from
H2S with minimal environmental burden.
Several studies have examined the thermal decomposition
mechanism of H2S, and proposed global reaction rate ex-
pressions for it. Monnery et al. [30] experimentally investi-
gated the pyrolysis of H2S, including the reactions of H2 and S2
re-association. It was observed that the decomposition of H2S
was insignificant at temperatures below 1273 K, while at
temperatures above 1273 K, the conversion rate reached 68%.
It was conjectured that temperatures greater than 1323 K and
residence time greater than 0.5 s are favourable operating
conditions for H2S thermolysis. A new rate of reaction was
proposed to predict H2S cracking and re-association as shown
below:
r ¼ 5260e
À45:0
RT PH2SP0:5
S2
À 14e
À23:6
RT PH2SPS2
Kaloidaset al. [65] studied the kinetics of thermal decom-
position of H2S in a non-isothermal flow reactor over a tem-
perature range of 873e1133 K and pressures of 1.3e3 atm with
specific flow rates of 3.4e3.6 mol/m2
s. Their results showed
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 4 1 ( 2 0 1 6 ) 6 6 6 2 e6 6 7 5 6663

that the conversion of H2S decreases with increasing molar
flow rate. A reaction mechanism, as shown below, was also
developed to explain the experimental observations and
trends.
H2S/SH þ H (R5)
H2S þ H/H2 þ SH (R6)
SH þ SH/H2S þ S (R7)
S þ S/S2 (R8)
Karan et al. [66] studied the reaction kinetics for thermal
decomposition of H2S using a quartz tubular reactor at
different temperatures and initial H2S concentrations. The
results showed that, below 1473 K, the decomposition is
highly dependent on temperature, while H2S conversions are
close to equilibrium above 1473 K, even within a short resi-
dence time of 200 ms. The data also showed that H2S con-
version was independent of the change in the initial
concentration of H2S for all the studied cases. Through
regression analysis, the decomposition of H2S was found to be
first-order with respect to H2S concentration with a rate con-
stant of k ¼ ð1:68±0:86Þ Â 1011
expðÀð28940±840Þ=TÞ. However,
the above rate expression did not fit experimental data under
a wide temperature range. Therefore, they proposed another
rate expression, k ¼ ð1:12±0:11Þ Â 1011
expðÀð28360±200Þ=TÞ
that matched the experimental data under low and high
temperature condition (1073e3373 K).
Adesina et al. [41] examined H2S decomposition over a
temperature range of 1040e1084 K in a tubular flow reactor,
and also found the overall reaction rate to be first-order with
respect to H2S partial pressures. This agrees with the conclu-
sions of Reymont [67,68]. However, Darwent and Roberts [69]
conducted kinetic experiments in static reactor within a
temperature range of 773e923 K, and reported a second-order
kinetics with respect to H2S concentration for its pyrolysis.
Tesner et al. [69,70] assumed that H2S decomposition was
first-order with respect to H2S concentration, and interpreted
their experimental data based on this assumption, even
though they could not to verify this assumption through a
systematic study. It is important to note that Darwent and
Roberts measured the rate of H2 formation, while Tesner et al.
measured the rate of S2 formation. The H2S concentrations
were not directly measured in either of these studies, even
though the rate constant for the H2S decomposition reaction
was reported. As evident, these studies have failed to provide
unified description of the reaction mechanism of H2S thermal
decomposition.
In the light of these conflicting results on rate expressions
and reaction order, a detailed reaction mechanism for H2S
pyrolysis was proposed by Binoist and co-workers [71]. They
also conducted kinetic experiments at temperatures of
1073e1323 K and residence times of 0.4e1.6 s in a perfectly
mixed quartz reactor. They proposed a detailed (22 reactions)
and a reduced (9 reactions) reaction mechanism, whose rate
constants were obtained by fitting the simulation results
through their experimental data. Their kinetic model did not
match the experimental data very well at high temperatures
(above 1223 K). Manneti et al. [32] then proposed a revised
mechanism of 20 reactions for H2S pyrolysis. It showed
10e20% improvement over Binoist et al.'s mechanism [71],
depending on the operating conditions when compared
quantitatively. Despite this improvement, the revised mech-
anism predicted poorly the experimental data at tempera-
tures above 1223 K. Moreover, both Binoist and Manneti did
not validate their mechanism over different experimental
conditions. Therefore, modifications to the existing kinetic
models are required to improve model predictions under high
temperature conditions such as those encountered in Claus
process. It is also desirable to validate kinetic mechanisms
with experimental data obtained under different sets of con-
ditions and reactor types for its reliability.
The objective of this paper is to develop a detailed and reli-
able reaction mechanism for the high temperature pyrolysis of
H2S to form H2 and S2 under different operating conditions. The
developed mechanism is then validated using a wide range of
experimental data available in the literature. The effect of ox-
ygen addition to H2S feed on the production of H2 is also
examined through the profiles of important species involved in
H2S thermolysis under different reactor operating conditions.
Reaction mechanism development
In order to develop a complete and detailed mechanism for
the decomposition of H2S, the elementary reactions involved
in it were derived from recent works [32,64,72e74]. This
section provides the details on the base mechanisms that
were selected from the literature for mechanism develop-
ment. The mechanism is categorized according to the spe-
cies, H2S, H, H2, S, S2, SH, HSS, HSSH, HS2, H2S2. The reactions
of HSS and HSSH are derived from Refs. [32,72] with an
exception of the reaction, HSSH þ M ¼ 2SH þ M, which is
extracted from the work of Zhou [64]. Some reactions take
place through their collision with a molecule present in the
gas phase. The term “M” represents any molecule present in
the gas phase. In the rate expressions, the mixture concen-
tration is used to represent its concentration [75]. The re-
actions involving HS2 and H2S2 are adopted from Ref. [73].
The thermodynamic properties of the species were adopted
from Refs. [74,76]. The resulting reaction mechanism for the
thermal decomposition of H2S is presented in Table 1. To
investigate the role of O2 in H2 production from H2S, the H2S
oxidation reactions were also included. The complete
mechanism consists of 432 reactions and 89 species, and is
provided in the Supporting Information.
Results and discussion
This section presents the validation of the developed reaction
mechanism and the effects of O2 addition to H2S feed stream
on H2 production. The reaction pathways involved in the
thermolysis of H2S in the presence and absence of O2 are also
discussed. All the simulations and reaction path analyses re-
ported in this study have been conducted using LOGEsoft
software [77]. This software provides a sophisticated numer-
ical tool to simulate zero and one-dimensional reactors

(homogeneous reactors, flames, engine models, and catalytic
converters) with detailed reaction mechanism in a reasonable
computational time. It also allows post-processing of the
simulation results to obtain the reaction pathways that lead to
major product formation through the analysis of the rate of
production of chemical species.
The H2S conversion and H2 and S2 yields are calculated
using the following formula:
H2S conversion ð%Þ ¼
moles of H2S at inlet À moles of H2S at outlet
moles of H2S at inlet
*100%
Table 1 e Rate constants of reactions involved in H2S pyrolysis, expressed in the form of k ¼ ATn
exp (¡E/RT). The rate
coefficient format is detailed in Ref. [86]. The units are in cal, K, mol, cm and s. The low-pressure limit rate constants and
Troe falloff parameters [87] are also provided for some reactions.
Reactions A n E References
H2S ¼ SH þ SH 7.63Eþ14 0 82155 [32,88]
H2S þ M ¼ SH þ H þ M 1.76Eþ14 0 64000 [83]
H2S þ M ¼ H2 þ S þ M
N2/1.5/SO2/10/H2O/10/
(Enhanced collision efficiencies [86])
2.00Eþ14 0 66000 [89]
H2S þ S ¼ SH þ SH 8.30Eþ13 0 2052.689 [32,72e74,90e92]
H2S þ S ¼ H2 þ S2 6.02Eþ12 0 4968.03 [73]
H2S þ S ¼ HS2 þ S2 2.00Eþ13 0 7400.06 [73,74,92]
H þ H þ M ¼ H2 þ M 1.87Eþ18 À1 0 [73,90]
H2 þM ¼ H þ H þ M
H2O/12/H2/2.5/Ar/0/He/0/
4.58Eþ19 À1.4 104380 [64]
H2 þ Ar ¼ H þ H þ Ar 5.84Eþ18 À1.1 104380 [64]
H2 þ He ¼ H þ H þ He 5.84Eþ18 À1.1 104380 [64]
S þ H þ M ¼ SH þ M 6.20Eþ16 À0.6 0 [32,72,90]
S þ H2 ¼ SH þ H 1.40Eþ14 0 19275.97 [32,72e74,90e93]
S þ S þ M ¼ S2 þ M 1.20Eþ17 À1 0 [32,88]
S2 þ M ¼ 2S þ M 4.80Eþ13 0 77103.87 [32,72e74,90e92]
S2 þ H þ M ¼ HSS þ M 1.15Eþ25 À2.84 1665 [72]
S2 þ H þ M ¼ HS2 þ M
N2/1.5/SO2/10/H2O/10/
1.00Eþ16 0 0 [73,74,90e92]
SH þ S ¼ S2 þ H 3.32Eþ12 0.5 À29 [64]
SH þ SH ¼ S2 þH2 3.01Eþ10 0 0 [88]
SH þ SH ¼ H2S þ S 1.00Eþ14 0 430 [89]
SH þ SH þ M ¼ HSSH þ M 8.70Eþ15 À0.76 0 [90]
SH þ SH (þM) ¼ HSSH (þM)
Low pressure limit rate constant:
Troe falloff parameters [86,87]:
3.46Eþ12
2.33Eþ31
1.00Eþ00
0.2
À4.94
254
À1432
1990/
2373/
[64]
HSS þ H ¼ SH þ SH 9.72Eþ07 1.62 À1030 [32,72,90]
HSS þ H ¼ H2 þ S2 4.19Eþ08 1.6 472 [64]
HSS þ H ¼ H2S þ S 4.41Eþ13 0 6326 [32,72,90]
HSS þ S ¼ S2 þ SH 4.17Eþ06 2.2 À600 [32,72,90]
HSS þ SH ¼ H2S þ S2 6.27Eþ03 3.05 À1105 [32,72,90]
HSS þ HSS ¼ HSSH þ S2 9.56Eþ00 3.37 À1672 [32,72,90]
HSSH þ M ¼ SH þ SH þ M 1.40Eþ15 1 57030 [32]
HSSH þ M ¼ 2SH þ M 2.31Eþ14 1 57030 [72]
HSSH þ H ¼ HSS þ H2 4.99Eþ07 1.93 À1408 [32,72,90]
HSSH þ H ¼ H2S þ SH 3.66Eþ08 1.72 467 [72]
HSSH þ S ¼ HSS þ SH 2.85Eþ06 2.31 1204 [32,72,90]
HSSH þ SH ¼ H2S þ HSS 6.40Eþ03 2.98 À1480 [32,72,90]
HS2 þ H ¼ S2 þ H2 1.20Eþ07 2.1 700.33 [73,74,91,92]
HS2 þ S ¼ S2 þ SH 8.30Eþ13 0 7352.69 [73,74,91,92]
HS2 þ H þ M ¼ H2S2 þ M
N2/1.5/S02/10/H2O/10/
1.00Eþ16 0 0 [73,74,91,92]
H2S2 þ H ¼ HS2 þ H2 1.20Eþ07 2.1 715.4 [73,74,91,92]
SH þ NH ¼ SN þ H2 1.00Eþ14 0 0 [74]
N þ SH ¼ SN þ H 6.31Eþ11 0.5 8009.56 [74]
N þ SN ¼ N2 þ S 6.30Eþ11 0.5 0 [74]
S þ NH ¼ SH þ N 1.00Eþ13 0 0 [74]
N2 þ M ¼ N þ N þ M
N/5/O/2.2/
1.00Eþ28 À3.3 225000 [94]

H2 yieldð%Þ ¼
moles of H2 produced
*100%
S2 yieldð%Þ ¼
moles of S2 produced
*100%
Mechanism validation
The experimental data from the literature for different reactor
configurations and operating conditions were used to validate
the developed mechanism to ensure its reliability.
Perfectly stirred reactor
In Ref. [71], Binoist et al. conducted experiments on the py-
rolysis of H2S in isothermal perfectly stirred reactor for resi-
dence times of 0.4e1.6 s in the temperature range of
1073e1373 K at 1 atm pressure. The feed stream with a
composition of 5 mol% H2S and 95 mol% Ar was used. Fig. 1
provides a comparison of the computed profiles with the
experimental observations on H2S conversion, and H2 and S2
yields. The computed profiles using the mechanism proposed
by Binoist et al. are also presented in the figure. As evident, the
profiles predicted by the proposed mechanism are in reason-
able agreement with the experimental data at all the tem-
peratures. The mechanism showed remarkable
improvements over the previously published kinetic model by
(a)
(b)
(c)
0
10
20
30
40
50
60
0.0 0.3 0.6 0.9 1.2 1.5
H2SConversion(%)
Time (s)
1123K 1213K 1243K 1273K 1323K
1123 K
1213 K
1243 K
1273 K
1323 K
0.0
0.5
1.0
1.5
2.0
2.5
0.0 0.3 0.6 0.9 1.2 1.5
H2molfraction(mol%)
Time (s)
1123 K
1213 K
1243 K
1273 K
1323 K
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0 0.3 0.6 0.9 1.2 1.5
S2molfraction(mol%)
Time (s)
1323 K
1273 K
1243 K
1213 K
1123 K
Fig. 1 e Predicted and experimentally observed (a) H2S conversion, (b) H2 mol fraction, and (c) S2 mol fractionfor feed containing
5 mol% H2S in Ar at 1 atm pressure and different temperatures. Points are experimental data from Ref. [71], dotted lines
represent computed profiles from Binoist et al. model [71], and solid lines are computed profiles using our mechanism.

Binoist et al. [71]. It is noteworthy that the data from H2S py-
rolysis at temperatures above 1273 K could not be adequately
captured by the Binoist kinetic mechanism (and the modified
version of their mechanism proposed by Manenti et al. [32],
which is not shown in this figure), but our proposed kinetic
mechanism could satisfactorily capture the complex chem-
istry involved in the high temperature thermolysis of H2S.
With increasing temperature and residence time in the
reactor, the conversion of H2S and the yields of H2 and S2
increased due to the endodermic nature of the reactions. At
1323 K, the predicted and observed maximum H2S conversion
were around 50%, which amounted to the mole fractions of
approximately 2.44 mol% and 1.2 mol% (and yields of 48.8%
and 24%) for H2 and S2, respectively. Ideally, for 50% conver-
sion, the yields of H2 and S2 should be 50% and 25%, respec-
tively. The marginally lower yields for H2 and S2 than their
ideal values are due to the formation of minor species such as
HS2, HSSH and H2S2 from H2S. The reaction path analysis was
conducted to find the reactions responsible for the formation
of H2 and S2 from H2S that are shown in Figs. 2 and 3. The
intermediate species responsible for H2 and S2 formation were
SH, HS2, H and S. Out of all the reactions presented in these
figures, the most significant reactions involved in the forma-
tion and consumption of H2 and S2 are listed below as
(R9)e(R14).
H2S þ S4H2 þ S2 (R9)
H2S þ H4SH þ H2 (R10)
H2S þ S þ M4HSSH þ M (R11)
H2S þ SH4HSSH þ H (R12)
SH þ SH4H2S þ S (R13)
SH þ SH4H2 þ S2 (R14)
The production of H2 mainly occurred by the direct
decomposition of H2S through (R9) and (R10), and through the
recombination of SH radicals (R14). Sulphur production
mainly occurred through the reactions (R13) and (R14). The
reactions (R11) and (R12) were responsible for HSSH formation
that decomposed to form SH radicals (involved in (R13) and
(R14)).
Plug flow reactor
In Ref. [78], Hawboldt et al. conducted experiments in an
isothermal plug flow reactor under Claus process condition on
H2S thermal decomposition. The reactor was operated within
a temperature range of 1123e1473 K and residence times of
0.05e1.5 s. The feed stream consisted of 97.5 mol% N2 and
2.5 mol% H2S at 1 atm pressure. Fig. 4 presents the comparison
between the model predictions and the experimental data on
H2S conversion at different temperatures and residence times.
Fig. 2 e Reaction pathways for H2 formation from H2S.

Overall, the mechanism predicted the experimental data
reasonably well except for the reactor temperature of
1423 K at low residence times. Below 1223 K, the maximum
amount of H2S conversion is below 20%, but as the reactor
temperature increases to 1423 K, the maximum conversion of
H2S increases to nearly 67%. Also, at a high temperature of
1423 K, the model predicts a fast decomposition of H2S, where
H2S conversion reaches its steady state value after a residence
time of 0.3 s.
In another study [30], Monnery et al. reported experimental
data from a plug ﬂow reactor under isothermal condition and
maintained at 1 atm pressure with feed containing0.3e4 mol%
SO2 and 0.25e3 mol% H2S in N2. The H2S/SO2 ratio was kept
near 2 for most of the test conditions, the reactor temperature
was varied from 850 to 1150 K, and the residence time was
maintained between 0.05 and 1.2 s. Fig. 5 compares the
simulation results and the experimental data on H2S conver-
sion for a feed containing 1.5 mol% SO2, 3 mol% H2S and
95.5 mol% N2. The model predictions agree very well with the
experimental values for most of the temperatures tested,
where the maximum difference between the two is found to
be about 10%.
The proposed mechanism was also used to predict the
experimental data reported by Karan et al. [66], where the
thermal decomposition of H2S using a coiled quartz tubular
reactor with diameter of 0.005 m and lengths of 3.2 m, 6.4 m
and 16 m was studied for different residence times in between
0.2 and 2.0 s under isothermal condition. The feed stream
consisted of different concentrations of H2S in diluted nitro-
gen over a temperature range of 1073e1523 K. The inlet
pressure varied from 110 kPa to 165 kPa. The effects of reactor
lengths and initial H2S concentration on H2S decomposition
0
10
20
30
40
50
60
70
80
0.00 0.20 0.40 0.60 0.80 1.00 1.20
H2Sconversion(%)
Time(s)
Sim 1123K
Sim 1223K
Sim 1273K
Sim 1323K
Sim 1423K
Exp 1123K
Exp 1223K
Exp 1273K
Exp 1323K
Exp 1423K
Fig. 4 e Comparison between experimental data (exp) [78] and simulation results (sim) on H2S conversion for a feed
containing 2.5 mol% H2S and 97.5 mol% N2 at pressure of 1 atm.
Fig. 3 e Reaction pathways for S2 formation from H2S.

were illustrated, as shown in Fig. 6. The model predicted the
experimental data satisfactorily, especially for the reactor
lengths of 6.4 m and 16 m, though small differences between
the simulated and experimental data could be seen for the
data from 3.2 m long reactor. Smaller reactors had shorter
residence times that resulted in lower H2S conversions for a
given temperature. The experimental trend showing near-
independence of H2S conversion on the initial H2S concen-
tration at temperatures of 900 and 1000
C was successfully
captured with the mechanism.
Premixed laminar flames
Levy et al. [79e81] have conducted several experimental
studies on the oxidation of H2S by O2 in premixed laminar
flames at atmospheric and sub-atmospheric pressures, and
have reported concentration profiles for several species such
as H2S, O2, SO2, H2 and H2O at different heights above the
burner. The species profiles were measured at different
equivalence ratios using a mass spectrometric-flame sam-
pling technique, while the temperature profiles were
measured using thermocouples. To validate the oxidation
chemistry of H2S in the proposed mechanism, the experi-
mentally observed species profiles in a premixed laminar H2S
flame were compared to the simulated profiles, as shown in
Fig. 7. The figure shows a good agreement between the
experimental and the predicted profiles. The further valida-
tion of the H2S oxidation chemistry is provided in our previous
work [82]. Such a validation was necessary to ensure that the
role of O2 in the decomposition of H2S to form H2, as demon-
strated in the following section, is reliably predicted.
0
10
20
30
40
50
60
70
80
90
100
0 0.2 0.4 0.6 0.8 1 1.2 1.4
H2SConversion(%)
Residence time (s)
850K 950K 1050K 1150K
Fig. 5 e H2S conversion vs residence time at different temperatures at atmospheric pressure with inlet streams of 1.5% SO2,
3% H2S and remaining N2. Lines are simulation results and points are experimental data from Ref. [30].
)b()a(
0
10
20
30
40
50
60
70
80
90
100
800 900 1000 1100 1200
H2Sconversion(%)
Temperature (oC)
Sim (3.2m)
Exp (3.2m)
Sim (6.4m)
Exp (6.4m)
Sim (16m)
Exp (16m)
0
10
20
30
40
50
60
0 0.5 1 1.5 2
H2Sconversion(%)
H2S concentration (mol %)
Sim 900 C (16m)
Exp 900 C (16m)
Sim 1000 C (16m)
Exp 1000 C (16m)
Fig. 6 e (a) Comparison between experimental data (exp) [66] and the simulation results (sim) on H2S conversion at different
reactor lengths (3.2 m, 6.4 m, and 16 m) at temperatures in between 800 and 1200
C and at a pressure of 1 atm with feed
containing 1 mol% H2S and 99 mol% N2. (b) Comparison between experimental data [66] and simulation results on the effect
of initial H2S concentration (in N2) on H2S conversion at 900 and 1000
C and at a pressure of 1 atm.

Shock tubes
The ignition delay times for H2S have been studied at different
temperatures, pressures and H2S concentrations in the liter-
ature using shock tubes [83,84] The advantage associated with
shock tubes is the possibility of performing high-temperature
reaction kinetics experiments without wall surface catalytic
effects that are often observed with silica in flow reactors [84].
These ignition delay measurements provide crucial data to
validate kinetic models [84]. While most of the shock tube
studies have focused on low H2S concentrations ([84] and refs.
therein), Frenklach et al. [83] have carried out ignition delay
measurements at relatively higher concentrations of up to 22
vol% H2S. Shock tube can be modelled as a homogeneous and
isobaric zero-dimensional reactor. Fig. 8 provides a compari-
son between the experimental and the computed ignition
delay times for H2S. A satisfactory match between the two can
be seen in this figure. A slight over-prediction of ignition delay
at low temperatures can be observed. This is expected because
the modelling assumption of constant pressure in shock tubes
Fig. 7 e Experimental and computed profiles of major
species in a premixed H2S flame [79].
Fig. 8 e Experimental and computed ignition delay times
for H2S at different pressures and concentrations.
Experimental data in (a) is from Ref. [95], and in (b) is from
Ref. [83].

becomes less valid at low temperatures [85], and the experi-
mental data on pressure variation is generally not available.
Role of O2 in H2 production from H2S
As presented earlier, a significant amount of work on the ef-
fects of residence time, temperature and initial concentration
of H2S on H2 yield during thermal decomposition of H2S is
available in the literature. In this study, in an attempt to find
optimum conditions for H2S decomposition to maximize H2
production, simulations have been carried out in an adiabatic
plug flow reactor with feed streams containing H2S with
different amount of O2 and Ar. The purpose of these simula-
tions was to study the effect of O2 on H2 production from H2S.
The inlet gas pressure was 1 atm, while the inlet gas tem-
perature was varied from 873 to 1673 K to assess the effect of
initial temperature on H2 production. A residence time of 1.5 s
was maintained in the reactor. The typical residence time for
H2S-rich feed in Claus furnace is about 1.5e2 s. This is why,
many literature-based studies [30,66,71] have presented their
experiments or simulation results on H2S decomposition at
residence times near or below 2.0 s.
Fig. 9 presents the effects of inlet temperature
(873e1673 K), initial H2S concentration (10e40 mol%), and
initial O2 concentration (0e50 mol%) on H2 yield at the reactor
outlet. A synergistic effect can be observed in all the sub-
figures, where H2 yield increased with increasing O2 concen-
tration, and after reaching a maximum value, it decreased
with further O2 addition. For example, with 20% H2S in the
feed diluted in Ar (Fig. 9b) at inlet temperature of 873 K, the H2
yield increased to a maximum value with the addition of
about 20% O2 into the H2S inlet stream, but above this amount
of O2, H2 yield decreased. The important reactions responsible
for the observed trends were examined. At low O2
(a)
(b)
(c)
(d)
0
10
20
30
40
50
60
0 10 20 30 40 50
H2yield(%)
873K 973K
1073K 1173K
1220K 1273K
1373K 1473K
1573K 1673K
0
10
20
30
40
50
0 10 20 30 40 50
H2yield(%)
0
10
20
30
40
50
0 10 20 30 40 50
H2yield(%)
0
10
20
30
40
50
0 10 20 30 40 50
H2yield(%)
Initial O2 concentration (mol%)
873 K
1673 K
Increasing T
1673 K
873 K
873 K
1673 K
1673 K
Increasing T
Increasing T
873 K
Increasing T
Fig. 9 e H2 yield vs initial O2 concentration (mol%) at different initial gas temperatures with a residence time of 1.5 s at
atmospheric pressure under adiabatic condition with feed containing(a) 10% H2S in Ar, (b) 20% H2S in Ar, (c) 30% H2S in Ar,
and (d) 40% H2S in Ar.

concentrations (before the maximum H2yield is attained), it
was found that the direct decomposition of H2S and recom-
bination of SH radicals contributed mostly to the formation of
H2 through reactions (R9), (R10) and (R14).
As the O2 concentration in feed is increased, its presence
enhanced the radical pool, and stimulated recombination re-
actions to promote H2 production. It was observed that the
increase in H2 yield to a maximum value was attributed to the
occurrence of additional reactions (R15) and (R16). However, at
higher concentrations of O2, the decrease in H2 yield was
mainly due to more favourable oxidation reactions of H2S to
form oxygenated radicals and species such as reactions (R17)
and (R18), and the oxidation of H2 to form H2O.
HS2 þ H4H2 þ S2 (R15)
SH þ H4H2 þ S (R16)
H2S þ O4HSO þ H (R17)
H2S þ OH4SH þ H2O (R18)
Fig. 9 also reveals the effect of varying the concentrations
of H2S in the inlet feed stream in the range of 10e40%. At all
the inlet temperatures, it was observed that a higher amounts
of O2 is required to reach the maximum yield of H2, as the
concentration of H2S in the inlet feed stream is increased.
To further elucidate the effect of O2 addition on the con-
centration profiles of the radical species responsible for H2
formation (that are H, S, SH and HS2), simulations results with
inlet streams containing 20% H2S/80% Ar and 20% H2S/10% O2/
70% Ar at 1073 K in an adiabatic flow reactor were analysed.
The H2 yields from these two feed streams can be seen in
Fig. 9b, where O2 addition increased H2 yield by about 25%.
Figs. 10 and 11 present the profiles of the important radical
species for the two feed conditions. In the absence of O2, HS2
and SH were the main radicals species formed in the reactor,
while H and S concentrations were very low. In the presence
of O2 in the feed stream, at low residence times, when H2S
oxidation by O2 has not taken place, the profiles of all the four
radicals (H, S, SH and HS2) were found to be similar to the
previous (anaerobic) case. However, as the H2S oxidation takes
1.E-11
1.E-10
1.E-09
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
0.00 0.02 0.04 0.06 0.08 0.10
Concentration(mol%)
Time (s)
H S SH HS2
Fig. 10 e Concentration (mol %) vs time (s) for species involved in H2formation at 1 atm pressure under adiabatic condition
for feed containing 20% H2S and 80% Ar at 1073 K.
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
0.00 0.02 0.04 0.06 0.08 0.10
Concentration(mol%)
Time (s)
H
S
SH
HS2
Fig. 11 e Concentration (mol %) vs time (s) for species involved in H2 formation at 1 atm pressure under adiabatic condition
for feed containing 20% H2S, 10% O2 and 70%Arat 1073 K.

place at about 0.025 s, a high amount of these radicals are
formed through the thermal and chemical decomposition of
H2S. The combustion of H2S increased the gas temperature
from its initial value of 1073 K to 1980 K that enhanced the
radical pool in the reactor to form H2 through the chemical
reactions listed before. In this manner, partial H2S combustion
assists in increasing H2 yield.
In these figures, the effect of residence times on radical
concentrations (and the concentration of H2 that forms from
them) can be seen. The species profiles were found to vary
minimally after 0.04 s, which is indicative of thermodynamic
equilibrium in the reactor.
While the extent of the synergistic effect exhibited by H2
yield upon O2 addition to H2S feed stream needs to be verified
through controlled experiments in the future, the results
presented here provide an insight into viable means of
enhancing H2 production while minimizing environmental
burden arising from releasing H2S-containing waste streams
of oil and gas refineries in air.
Conclusions
To examine the production of H2 through H2S thermolysis, a
detailed reaction mechanism that captures the complex
chemistry of high temperature decomposition and oxidation
of H2S was proposed. The reaction mechanism was validated
by comparing the experimental data on H2S conversion, H2
and S2 yields, and species concentrations, obtained from
different types of reactors under varied operating conditions,
with the simulations results. A satisfactory agreement be-
tween the simulated and experimental profiles was obtained
for the tested reactor conditions. The reaction pathways for
the decomposition of H2S to form H2 and S2 were also deter-
mined through reaction path analysis. The detailed mecha-
nism was then used to investigate the role of O2 on the
formation of H2 from H2S. It was observed that an addition of
small amount of O2 to H2S feed increased the H2production,
while higher O2 concentrations caused the oxidation of the
produced H2, thus reducing its yield at the reactor outlet. The
role of the radicals H, S, SH, and HS2, in the production of H2
was highlighted. It was observed that the addition of O2
significantly enhanced the formation of S, H, SH and HS2,
which improved H2 production. The well-validated H2S
mechanism presented in this study is expected to facilitate
the design and optimization of cost effective reactors for
enhanced energy, H2 and S2 recovery from H2S.
Acknowledgements
The authors acknowledge the financial support from the Pe-
troleum Institute Research Centre, Abu Dhabi, UAE.
Appendix A. Supplementary data
Supplementary data related to this article can be found at
http://dx.doi.org/10.1016/j.ijhydene.2016.03.053.
r e f e r e n c e s
[1] Jianwen Z, Da L, Wenxing F. Analysis of chemical disasters
caused by release of hydrogen sulfide-bearing natural gas.
Procedia Eng 2011;26:1878e90.
[2] Arrowsmith, R. T., Frederick, F. J., and George, A. D..
“Desulphurization of hydrocarbons using oxidative and
hydro-treatments,” ed: Google Patents; 1967.
[3] Clark PD, Hyne JB, Tyrer JD. Chemistry of organosulphur
compound types occurring in heavy oil sands: 1. High
temperature hydrolysis and thermolysis of
tetrahydrothiophene in relation to steam stimulation
processes. Fuel 1983;62:959e62.
[4] Thimm H. Hydrogen sulphide measurements in SAGD
operations. In: Canadian international Petroleum
conference; 2000.
[5] Palma V, Vaiano V, Barba D, Colozzi M, Palo E, Barbato L,
et al. H 2 production by thermal decomposition of H 2 S in the
presence of oxygen. Int J Hydrogen Energy 2015;40:106e13.
[6] Stanek J, Gift J, Woodall G, Foureman G. Hydrogen sulfide:
integrative analysis of acute toxicity data for estimating
human health risk. In: Nriagu JO, editor. Encyclopedia of
environmental health. Burlington: Elsevier; 2011. p. 124e39.
[7] Guidotti T. Hydrogen sulphide. Occup Med 1996;46:367e71.
[8] Ma G, Yan H, Shi J, Zong X, Lei Z, Li C. Direct splitting of H 2 S
into H 2 and S on CdS-based photocatalyst under visible light
irradiation. J Catal 2008;260:134e40.
[9] Bongartz D, Ghoniem AF. Chemical kinetics mechanism for
oxy-fuel combustion of mixtures of hydrogen sulfide and
methane. Combust Flame 2015;162:544e53.
[10] Ibrahim S, Al Shoaibi A, Gupta AK. Role of toluene in
hydrogen sulfide combustion under Claus condition. Appl
Energy 2013;112:60e6.
[11] Nagase Y, Silva ECD. Acid rain in China and Japan: a game-
theoretic analysis. Regional Sci Urban Econ 2007;37:100e20.
[12] Chou C. Hydrogen sulfide: human health aspects. 2003.
[13] Sibeud, J. P.and Ruff, C. D., “Process for the removal of
hydrogen sulfide and mercaptans from liquid and gaseous
streams,” ed: Google Patents; 1977.
[14] Jou FY, Mather AE, Otto FD. Solubility of hydrogen sulfide and
carbon dioxide in aqueous methyldiethanolamine solutions.
Industrial Eng Chem Process Des Dev 1982;21:539e44.
[15] Huang HY, Yang RT, Chinn D, Munson CL. Amine-grafted
MCM-48 and silica xerogel as superior sorbents for acidic gas
removal from natural gas. Industrial Eng Chem Res
2003;42:2427e33.
[16] Morris, J., “Method and system for removing hydrogen
sulfide from sour oil and sour water,” ed: Google Patents;
2014.
[17] Thonsgaard, J. E., “Method and apparatus for removing
aromatic hydrocarbons from a gas stream prior to an amine-
based gas sweetening process,” ed: Google Patents; 2001.
[18] Yan R, Liang DT, Tsen L, Tay JH. Kinetics and mechanisms of
H2S adsorption by alkaline activated carbon. Environ Sci
Technol 2002;36:4460e6. 2002/10/01.
[19] Farha Jr., F. E.and Gardner, L. E., “Hydrodesulfurization of
organic sulfur compounds and hydrogen sulfide removal
with incompletely sulfided zinc titanate materials,” ed:
Google Patents; 1982.
[20] Pujare NU, Tsai KJ, Sammells AF. An electrochemical Claus
process for sulfur recovery. J Electrochem Soc
1989;136:3662e78.
[21] Goar B. Sulfur recovery technology. New York, NY: American
Institute of Chemical Engineers; 1986.
[22] Manenti F, Papasidero D, Bozzano G, Pierucci S, Ranzi E,
Buzzi-Ferraris G. Total plant integrated optimization of
sulfur recovery and steam generation for Claus processes

using detailed kinetic schemes. In: Andrzej K, Ilkka T,
editors. Computer aided chemical engineering, vol. 32.
Elsevier; 2013. p. 811e6.
[23] Fischer, H., “Production of sulfur from Claus process waste
gas,” ed: Google Patents; 1978.
[24] Elsner MP, Menge M, Mu¨ ller C, Agar DW. The Claus
process: teaching an old dog new tricks. Catal Today
2003;79:487e94.
[25] Woo Chun S, Yeol Jang J, Won Park D, Chul Woo H, Shik
Chung J. Selective oxidation of H2S to elemental sulfur over
TiO2/SiO2 catalysts. Appl Catal B Environ 1998;16:235e43.
[26] Selim H, Gupta AK, Al Shoaibi A. Effect of reaction
parameters on the quality of captured sulfur in Claus
process. Appl Energy 2013;104:772e6.
[27] Lagas J, Borsboom J, Berben P. Selective-oxidation catalyst
improves Claus process. Oil Gas J 1988;86 (United States).
[28] Nguyen P, Edouard D, Nhut JM, Ledoux MJ, Pham C, Pham-
Huu C. High thermal conductive b-SiC for selective oxidation
of H2S: a new support for exothermal reactions. Appl Catal B
Environ 2007;76:300e10.
[29] Zagoruiko AN, Matros YS. Mathematical modelling of Claus
reactors undergoing sulfur condensation and evaporation.
Chem Eng J 2002;87:73e88.
[30] Monnery WD, Hawboldt KA, Pollock A, Svrcek WY. New
experimental data and kinetic rate expression for the Claus
reaction. Chem Eng Sci 2000;55:5141e8.
[31] Sammells AF, Patel J, Osborne J, Cook RL. Intermediate
temperature electrochemical Claus process for sulphur
recovery. Gas Sep Purif 1992;6:141e7.
[32] Manenti F, Papasidero D, Ranzi E. Revised kinetic scheme for
thermal furnace of sulfur recovery units. Chem Eng Trans
2013;32:1185e290.
[33] Zaman J, Chakma A. Production of hydrogen and sulfur from
hydrogen sulfide. Fuel Process Technol 1995;41:159e98.
[34] Galuszka J, Iaquaniello G, Ciambelli P, Palma V, Brancaccio E.
Membrane-assisted catalytic cracking of hydrogen sulphide
(H2S). In: Membrane reactors for hydrogen production
processes. Springer; 2011. p. 161e82.
[35] Outlook E. International energy outlook. 2010.
[36] Yildiz B, Kazimi MS. Efficiency of hydrogen production
systems using alternative nuclear energy technologies. Int J
Hydrogen Energy 2006;31:77e92.
[37] Winter C-J. Hydrogen energydAbundant, efficient, clean: a
debate over the energy-system-of-change. Int J Hydrogen
Energy 2009;34:S1e52.
[38] Rodrigue J-P, Comtois C, Slack B. The geography of transport
systems. Routledge; 2013.
[39] Calemma V, Peratello S, Perego C. Hydroisomerization and
hydrocracking of long chain n-alkanes on Pt/amorphous
SiO2eAl2O3 catalyst. Appl Catal A General 2000;190:207e18.
[40] Ali SA, Siddiqui MA. Dearomatization, cetane improvement
and deep desulfurization of diesel feedstock in a single-stage
reactor. React Kinet Catal Lett 1997;61:363e8.
[41] Adesina A, Meeyoo V, Foulds G. Thermolysis of hydrogen
sulphide in an open tubular reactor. Int J Hydrogen Energy
1995;20:777e83.
[42] Chivers T, Hyne J, Lau C. The thermal decomposition of
hydrogen sulfide over transition metal sulfides. Int J
[43] Chivers T, Lau C. The thermal decomposition of hydrogen
sulfide over alkali metal sulfides and polysulfides. Int J
[44] Kiuchi H, Iwasaki T, Nakamura I, Tanaka T. Thermochemical
decomposition of H2S with metal sulfides or metals. In: ACS
symposium series; 1980. p. 349e57.
[45] Dokiya M, Kameyama T, Fukuda K. Thermochemical
hydrogen preparationdPart V. A feasibility study of the
sulfur iodine cycle. Int J Hydrogen Energy 1979;4:267e77.
[46] Mao Z, Anani A, White RE, Srinivasan S, Appleby A. A
modified electrochemical process for the decomposition of
hydrogen sulfide in an aqueous alkaline solution. J
Electrochem Soc 1991;138:1299e303.
[47] Chaudhari NS, Bhirud AP, Sonawane RS, Nikam LK,
Warule SS, Rane VH, et al. Ecofriendly hydrogen production
from abundant hydrogen sulfide using solar light-driven
hierarchical nanostructured ZnIn2S4 photocatalyst. Green
Chem 2011;13:2500e6.
[48] Traus I, Suhr H. Hydrogen sulfide dissociation in ozonizer
discharges and operation of ozonizers at elevated
temperatures. Plasma Chem Plasma Process 1992;12:275e85.
1992/09/01.
[49] Woiki D, Roth P. Kinetics of the high-temperature H2S
decomposition. J Phys Chem 1994;98:12958e63.
[50] Fukuda K, Dokiya M, Kameyama T, Kotera Y. Catalytic
decomposition of hydrogen sulfide. Industrial Eng Chem
Fundam 1978;17:243e8. 1978/11/01.
[51] Weiner, J. G.and William, L. C., “Process for production of
hydrogen and sulfur,” ed: Google Patents; 1961.
[52] Sugioka M, Aomura K. A possible mechanism for catalytic
decomposition of hydrogen sulfide over molybdenum
disulfide. Int J Hydrogen Energy 1984;9:891e4.
[53] Kaloidas VE, Papayannakos NG. Kinetic studies on the
catalytic decomposition of hydrogen sulfide in a tubular
reactor. Industrial Eng Chem Res 1991;30:345e51. 1991/02/01.
[54] Startsev AN, Kruglyakova OV, Chesalov YA,
Ruzankin SP, Kravtsov EA, Larina TV, et al. Low
temperature catalytic decomposition of hydrogen sulfide
into hydrogen and diatomic gaseous sulfur. Top Catal
2013;56:969e80.
[55] Reshetenko TV, Khairulin SR, Ismagilov ZR, Kuznetsov VV.
Study of the reaction of high-temperature H2S
decomposition on metal oxides (g-Al2O3,a-Fe2O3,V2O5). Int J
Hydrogen Energy 2002;27(4):387e94.
[56] Clark PD, Dowling NI, Huang M. Production of H2 from
catalytic partial oxidation of H2S in a short-contact-time
reactor. Catal Commun 2004;5(12):743e7.
[57] Meeyoo V, Adesina AA, Foulds G. The kinetics of H2s
decomposition over precipitated cobalt sulphide catalyst.
Chem Eng Commun 1996;144:1e17. 1996/02/01.
[58] Guldal NO, Figen HE, Baykara SZ. New catalysts for hydrogen
production from H2S: preliminary results. Int J Hydrogen
Energy 6/29/2015;40:7452e8.
[59] Marshneva V, Mokrinskii V. Catalytic activity of metal oxides
in hydrogen sulfide oxidation by oxygen and sulfur dioxide.
Kinet Catal Engl Transl 1989;29 (United States).
[60] Batygina M, Dobrynkin N, Kirichenko O, Khairulin S,
Ismagilov Z. Studies of supported oxide catalysts in the
direct selective oxidation of hydrogen sulfide. React Kinet
Catal Lett 1992;48:55e63.
[61] Kettner R, Liermann N. New Claus tail-gas process proved in
German operation. Oil Gas J 1988;86 (United States).
[62] Chopin, T., Hebrard, J.-L., and Quemere, E., “Monolithic
catalysts for converting sulfur compounds into SO2,” ed:
Google Patents; 1994.
[63] Kalinkin P, Kovalenko O, Khanaev V, Borisova E. Direct
oxidation of hydrogen sulfide over vanadium catalysts: I.
Kinetics of the reaction. Kinet Catal 2015;56:106e14.
[64] Zhou CR, Sendt K, Haynes BS. Experimental and kinetic
modelling study of H 2 S oxidation. Proc Combust Inst
2013;34:625e32.
[65] Kaloidas V, Papayannakos N. Kinetics of thermal, non-
catalytic decomposition of hydrogen sulphide. Chem Eng Sci
1989;44:2493e500.
[66] Karan K, Mehrotra AK, Behie LA. On reaction kinetics for the
thermal decomposition of hydrogen sulfide. AIChE J
1999;45:383e9.

[67] Reymont MED. The thermal decomposition of hydrogen
sulphide. AB, Canada: Ph.D., University of Calgary Calgary;
1974.
[68] Reymont MED. Hydrocarbon processing. 1975. p. 177e9.
[69] Darwent B d B, Roberts R. The photochemical and thermal
decompositions of hydrogen sulphide. Proc R Soc Lond Ser A,
Math Phys Sci 1953;216:344e61.
[70] Tesner P, Nemirovskii M, Motyl D. Kinetics of the thermal
decomposition of hydrogen sulfide at 600-1200
C. Kinet Catal
1990;31:1081e3.
[71] Binoist M, Labegorre B, Monnet F, Clark PD, Dowling NI,
Huang M, et al. Kinetic study of the pyrolysis of H2S.
Industrial Eng Chem Res 2003;42:3943e51.
[72] Sendt K, Jazbec M, Haynes B. Chemical kinetic modeling of
the H/S system: H 2 S thermolysis and H 2 sulfidation. Proc
Combust Inst 2002;29:2439e46.
[73] Sassi M, Amira N. Chemical reactor network modeling of a
microwave plasma thermal decomposition of H 2 S into
hydrogen and sulfur. Int J Hydrogen Energy 2012;37:
10010e9.
[74] Leeds University Sulphur Mechanism, version 5.2. Available:
http://www.chem.leeds.ac.uk/Combustion/sox.html/.
[75] Atkins P, De Paula J, Walters V. Physical chemistry:
Macmillan higher education. 2006.
[76] Burcat A, Ruscic B. Third millennium ideal gas and
condensed phase thermochemical database for combustion
with updates from active thermochemical tables. Argonne,
IL: Argonne National Laboratory; 2005.
[77] 2014). LOGEsoft. Available: http://loge.se/Products/LOGE_
Products.html.
[78] Hawboldt KA, Monnery WD, Svrcek WY. New experimental
data and kinetic rate expression for H2S pyrolysis and re-
association. Chem Eng Sci 2000;55(3):957e66.
[79] Levy A, Merryman EL. The microstructure of hydrogen
sulphide flames. Combust Flame 1965;9(9):229e40.
[80] Merryman EL, Levy A. Kinetics of sulfur-oxide formation in
Flames: II. Low pressure H2S flames. J Air Pollut Control
Assoc 1967;17:800e6. 1967/12/01.
[81] Merryman EL, Levy A. Disulfur and the lower oxides of sulfur
in hydrogen sulfide flames. J Phys Chem 1972;76:1925e31.
1972/07/01.
[82] Mohammed S, Raj A, Al Shoaibi A, Sivashanmugam P.
Formation of polycyclic aromatic hydrocarbons in Claus
process from contaminants in H2S feed gas. Chem Eng Sci 12/
1/2015;137:91e105.
[83] Frenklach M, Lee JH, White JN, Gardiner Jr WC. Oxidation of
hydrogen sulfide. Combust Flame 1981;41:1e16.
[84] Mathieu O, Deguillaume F, Petersen EL. Effects of H2S
addition on hydrogen ignition behind reflected shock waves:
experiments and modeling. Combust Flame
2014;161(1):23e36.
[85] Pang GA, Davidson DF, Hanson RK. Experimental study and
modeling of shock tube ignition delay times for
hydrogeneoxygeneargon mixtures at low temperatures.
Proc Combust Inst 2009;32:181e8.
[86] 2nd March 2016). GRI-Mech. Available: http://combustion.
berkeley.edu/gri_mech/data/k_form.html.
[87] Burcat A, Gardiner WCJ, Dixon-Lewis G, Frenklach M,
Hanson RK, Salimian S, et al. Combustion chemistry. New
York: Springer; 2012.
[88] Petherbridge JR, May PW, Shallcross DE, Harvey JN, Fuge GM,
Rosser KN, et al. Simulation of HeCeS containing gas
mixtures relevant to diamond chemical vapour deposition.
Diam Relat Mater 2003;12:2178e85.
[89] Gargurevich IA. Hydrogen sulfide Combustion: relevant
issues under Claus furnace conditions. Industrial Eng Chem
Res 2005;44:7706e29. 2005/09/01.
[90] Cerru FG, Kronenburg A, Lindstedt RP. Systematically
reduced chemical mechanisms for sulfur oxidation and
pyrolysis. Combust Flame 2006;146:437e55.
[91] Alzueta MU, Bilbao R, Glarborg P. Inhibition and sensitization
of fuel oxidation by SO2. Combust Flame 2001;127:2234e51.
[92] Gimenez-Lopez J, Martıńez M, Millera A, Bilbao R,
Alzueta MU. SO2 effects on CO oxidation in a CO2
atmosphere, characteristic of oxy-fuel conditions. Combust
Flame 2011;158:48e56.
[93] Rasmussen CL, Glarborg P, Marshall P. Mechanisms of radical
removal by SO2. Proc Combust Inst 2007;31:339e47.
[94] Mevel R, Javoy S, Lafosse F, Chaumeix N, Dupre G,
Paillard CE. Hydrogenenitrous oxide delay times: shock tube
experimental study and kinetic modelling. Proc Combust
Inst 2009;32:359e66.
[95] Bradley JN, Dobson DC. Oxidation of hydrogen sulfide in
shock waves. II. The effect of added hydrogen on the
absorption of OH and SO2. J Chem Phys 1967;46:2872e5.

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