international journal of hydrogen energy xxx (xxxx) xxx

Available online at www.sciencedirect.com

ScienceDirect

journal homepage: www.elsevier.com/locate/he

An energy-efficient and cleaner production of

hydrogen by steam reforming of glycerol using
Aspen Plus

Md Alquma Haider, Nitin Dutt Chaturvedi*

Department of Chemical and Biochemical Engineering, Indian Institute of Technology Patna, Bihta, Patna, 801106
(Bihar) India

highlights graphical abstract

To develop an energy-efficient H2
production model by steam
reforming of glycerol.

Maximum H2 production with
minimum reformer heat duty is
found by thermodynamic feasi-
bility of stoichiometric data.

Reformer duty reductions show
substantial potential for improving
glycerol steam reforming
efficiency.

The model also incorporates CO2
capture, resulting in cleaner H2
production.

article info abstract

Article history: Hydrogen (H2) is produced in an efficient and sustainable manner using steam reforming of
Received 17 May 2023 glycerol in this work. Two models are used to provide anticipation about how efficiently H2
Received in revised form can be produced: Model 1, a stoichiometric model, and Model 2, a thermodynamic model.
7 September 2023 Model 1 helps determine the water/glycerol molar input ratio and reaction pathway. The
Accepted 9 September 2023 thermodynamic feasibility of Model 1 is examined using Model 2, which then determines
Available online xxx the optimum conditions for maximal H2 generation. Model 2 produced 1275 kmol/h of H2
with an H2 mole fraction of 0.49 at 658  C and 1 atm of pressure. The reactor's net heat load
Keywords: is greatly reduced through heat integration in this study. The energy required is reduced by
Hydrogen 29.5% as compared to when no heat integration is used. The process of separating and

* Corresponding author.
E-mail address: nitind@iitp.ac.in (N.D. Chaturvedi).
https://doi.org/10.1016/j.ijhydene.2023.09.089
0360-3199/© 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Please cite this article as: Haider MA, Chaturvedi ND, An energy-efficient and cleaner production of hydrogen by steam reforming of
glycerol using Aspen Plus, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2023.09.089
2 international journal of hydrogen energy xxx (xxxx) xxx

Glycerol eliminating CO2 is accomplished by employing the principles of mass and energy balance
Steam reforming in the Aspen Plus.
Stoichiometry © 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Thermodynamics

CeO2 [23], Ni/Al2O3 [24], NiO/NiAl2O4 [25], Ni/Fly-ash [26],

1. Introduction among others [27]. The production of biodiesel involves the
utilization of a technique known as trans-esterification,
In recent times, there has been a growing trend among which results in the formation of glycerol (C3H8O3) as a
various nations to declare their intentions to transition their byproduct. Glycerol is also called glycerine or 1,2,3-propane
transportation and energy infrastructures towards more tri-ol [28].
environmentally friendly fuel sources [1]. The phenomenon Several ways to make H2 have been thought of, including
commonly referred to as the “global energy transition” is steam reforming (SR) [29], partial oxidation [30], dry reforming
rapidly gaining momentum. There is a growing global trend [31], water phase reforming [32], and autothermal reforming
towards the adoption of cleaner fuels as viable substitutes for [33]. The SR process has been identified as a highly efficient
conventional fossil fuels [2]. The utilization of cleaner fuels is technique for H2 production, owing to its superior perfor-
essential in the continuous effort to reduce carbon emissions, mance in this regard and its relatively low environmental
reduce global warming, and promote sustainable develop- impact when compared to alternative methodologies [34]. The
ment [3]. Renewable energy sources, such as solar power, SR method is basically a chemical change of hydrocarbons
wind power, hydroelectric power, and geothermal energy, as and steam into H2 and carbon oxides. It has three main steps:
well as biofuels and hydrogen (H2), have emerged as promi- reforming or making synthesis gas (syngas), water-gas shift
nent alternatives to fossil fuels and are experiencing (WGS), and methanation or cleaning the gas [35]. In the
increasing levels of public interest [4]. H2 is considered a context of glycerol steam reforming (GSR), it has been postu-
viable fuel option for various sectors, such as transportation lated that the reaction between water vapor and glycerol
and electricity generation, due to its clean and carbon-free yields primarily carbon monoxide (CO), carbon dioxide (CO2),
characteristics [5]. In other words, H2 is regarded as a prom- and H2. The process described above is considered the most
ising fuel due to its versatile applications, including its po- efficient pathway for conversion, as it leads to increased
tential as an energy source, energy storage medium, fuel for selectivity and yield of the final product by directly removing
combustion, and as a means to mitigate carbon emissions [6]. H2 from water [36]. The topic of interest in recent years has
H2 is often considered to be the most promising energy car- been the valorisation of glycerol through the process of GSR
rier, especially as a fuel for fuel cell technologies [7]. Addi- [37]. The primary reaction occurring in the process involves
tionally, H2 finds extensive utilization in industrial processes, the decomposition of glycerol, while the WGS reaction is a
including but not limited to petroleum refining [8], ammonia secondary reaction [38]. The aforementioned process occurs
production [9], methanol synthesis [10], and steel under conditions of elevated operating temperatures and at-
manufacturing [11]. Researchers are currently working in mospheric pressure, and is commonly referred to as an
efforts to enhance the performance characteristics of the endothermic reaction [39]. The process of vaporizing reactants
subject, which encompass a high energy density, significant necessitates a substantial amount of energy, thereby reducing
capacity, extended lifespan, and convenient storage and the overall energy efficiency of the process. The variables that
transmission capabilities [12,13]. H2 can be produced using influence the efficiency of H2 production through the GSR
various methods, such as electrochemical, thermochemical, process include temperature, pressure, water to glycerol feed
photochemical, photocatalytic, and photoelectrochemical ratio (WGFR), feed reactants to inert gas ratio, and feed gas
processes [14]. Coal and natural gas, along with alternative rate [40]. In the last ten years, a lot of research has been done
sources such as solar, nuclear, and biomass, have the po- on GSR using different catalysts, such as transition metals
tential to serve as viable feedstocks for the production of H2 (like Co and Ni) and noble metals (like Pt, Rh, and Ru) based on
[15]. In order to effectively mitigate environmental impacts, it different oxides [41]. Ni-based catalysts have been studied a
is essential to ensure the eco-friendly production of H2, lot in the past few years [42]. They were found to be the most
particularly through the utilization of renewable feedstocks popular choice in the literature. Using a NieCueAl catalyst in
[16]. The rapid expansion of the biodiesel industry has a continuous flow fixed-bed reactor at 500e600  C and normal
resulted in a significant increase in the production of crude pressure, Dou et al. (2014) found that 54.3e70.4% H2 could be
glycerol [17,18]. Although the cosmetics, food, and pharma- made from GSR [43]. Based on a study, sorption-enhanced GSR
ceutical industries utilize purified glycerol, there is too much was found to be a good way to increase the quality of H2 to
of it on the market for biodiesel producers to use, and the cost more than 90% and reduce the amount of CO2. The effect of
of purification is considerable [19,20]. One potential approach temperatures between 400 and 700  C on the selectivity of the
involves the utilization of crude glycerol as a precursor for the product is strong. As the temperature goes up, the H2 selec-
production of H2 [21,22]. Pure glycerol is utilized by numerous tivity goes up [44]. A study by Buffoni et al., 2009 shows that
researchers in conjunction with various catalysts such as Ni/ nickel catalysts are active and selective, with a strong

Please cite this article as: Haider MA, Chaturvedi ND, An energy-efficient and cleaner production of hydrogen by steam reforming of
glycerol using Aspen Plus, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2023.09.089
 international journal of hydrogen energy xxx (xxxx) xxx 3

relationship between the reaction temperature and the Aspen Plus software. The process begins with the identifica-
gaseous products made from glycerol. This showed that the tion of the raw materials and their corresponding reactions.
lowest temperature needed to get H2 with a high sensitivity is Two Aspen Plus simulation models, namely RStoic and
550  C [45]. The findings of the study indicate that optimal RGibbs, serve as the basis for the model's development.
conditions for H2 production involve a temperature exceeding Additionally, different input parameters are incorporated into
900 K and a molar ratio of 9:1 between water and glycerol. In the simulation models.
the given circumstances, the generation of methane is effec-
tively suppressed, and the thermodynamic principles prevent 2.1. Materials used
the accumulation of carbon. According to the literature, the
maximum amount of H2 that can be produced per mole of Pure glycerol and water are the raw materials that are used to
glycerol is 6, whereas the maximum amount predicted by make H2. Glycerol is a sticky liquid that is thick when it is
stoichiometry is 7 [46]. When the temperature is raised to cold, has no smell or colour, and tastes sweet. Because it has
350  C and a feed containing 10% weight glycerol is used, the three hydroxyl groups, it can take water from the air because
Pt/SiO2 catalyst exhibits a H2 yield of 60% [47]. When it is hygroscopic. Glycerol is slightly thicker than water.
employing a WGFR of 3:1 and operating within a temperature Three hydrophilic hydroxyl groups in the liquid glycerol are
range of 500e600  C, the utilization of ZrO2/Ni/Al2O3 catalyst what give it its hygroscopic properties and water solubility
results in a yield of 70% [48]. At a temperature of 650  C and a [50].
WGFR of 6:1, the resulting yield of H2 is 65.64% [49]. H2 production via GSR is a high-temperature process that
The aforementioned studies conclude that GSR is an converts glycerol to synthesis gas, a H2-rich gaseous product.
effective method for producing H2. However, the production of The chemical reaction (Eq. (1)) involved in the GSR into syngas
steam is an energy-intensive process because GSR as a whole is well understood and has already been described in the
is endothermic. So, the heat load of the reactor has to be kept literature [51].
as low as possible. The decomposition of glycerol at higher
 
temperatures also reduces the amount of H2 that can be pro- C3 H8 O3 4 3CO þ 4H2 DH0r ¼ þ 250 kJ mol (1)
duced. It is clear that a GSR model is needed that directly The overall reaction for GSR is represented by the following
addresses these two problems. The developed model offers a equation [52].
way to produce H2 that uses less energy. The model is devel-

 
oped using Aspen Plus software, which incorporates carbon C3 H8 O3 þ 3H2 0 / 3CO2 þ 7H2 DH0r ¼ þ 128 kJ mol (2)
capture and storage (CCS) advancements. Here are some of
CO is converted to CO2 as a result of an excess of vapor in
the unique features and improvements that the proposed
the process, which also results in the release of more H2 gas.
model offers.
Since the reaction is reversible, both species exist in dynamic
chemical equilibrium. This reaction is known as the WGS [53]:
➢ The energy required in this model is much less than in

 
models available in the literature; CO þ H2 O 4 CO2 þ H2 DH0r ¼  41 kJ mol (3)
➢ The developed stoichiometry-based model can be applied
to unknown kinetics; Since GSR reactions are conducted at extremely high
➢ This work allows to give a relationship between conversion temperatures, there is a significant chance of glycerol
and temperature for H2 production. decomposition (Eq. (4)) into oxygenates with lower molecular
➢ This model also incorporates CCS, making it an environ- weights and lighter hydrocarbons such as CH4, C2H6, etc. [54].
mentally friendly production model. C3 H8 O3 / Cx Hy Oz þ Carbon þ GasesðH2 ; CO; CO2 ; CH4 ; Cx Hxþ2 Þ
(4)
The rest of this work is put together in the following way:
The procedure for creating the GSR process simulation model Coke formation occurs in the system at high temperatures,
in Aspen Plus is outlined in Section 2. In Section 3, the model is which can result in depositions on the catalyst surface and
initially validated by comparing it with previously published subsequent inactivation. Carbon deposition is a very severe
literature. Several effects on H2 production have been re- problem in heterogeneous catalyst-based catalytic SR systems
ported. Model 1 first examines the impact of the water/glyc- [55].
erol molar feed ratio. The optimal value determines whether
reactions are conducted in parallel or in series. Model 2 then 2.2. Methodology and detailed process scheme
verifies the feasibility of Model 1's results and establishes a
relationship between the two models regarding conversion Fig. 1 presents the GSR process model developed by Aspen
and temperature. Afterward, the reduction of reformer heat Plus based on stoichiometry. The simulation's numerous
duty is compared to the literature based on possible results. components include glycerol (C3H8O3), water (H2O), oxygen
Finally, Section 4 gives the conclusion of this study in detail. (O2), hydrogen (H2), carbon dioxide (CO2),2-methoxyethanol
(C3H8O2), propane (C3H8), ethane (C2H6), methane (CH4), car-
bon monoxide (CO), and carbon (C). These components are
2. Materials and methodology regarded as typical components with well-known chemical
formulas. UNIFAC has been chosen as the property method
The present section delineates the procedural steps entailed [56]. Rather than relying on molecular contributions, UNIFAC
in formulating the GSR process simulation model within the (UNIversal Functional Activity Coefficient) is based on group

Please cite this article as: Haider MA, Chaturvedi ND, An energy-efficient and cleaner production of hydrogen by steam reforming of
glycerol using Aspen Plus, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2023.09.089
4 international journal of hydrogen energy xxx (xxxx) xxx

Fig. 1 e The process flowsheet for H2 production based on stoichiometry (Model 1).

contributions. “UNIFAC” can forecast activity coefficients

using a small set of group parameters and group-group
Table 1 e Description of blocks of the given flowsheet.
interaction parameters. The “UNIFAC” model is highly pre-
dictive because it is a group-contribution model. At low Blocks Description
pressure (below 10 atm), it is utilized to represent severely B1 Mixer (combines an arbitrary number
nonideal liquid mixtures [57]. In this procedure, two feed of input streams and produces a single
stream by simple material balance)
streamsdpure glycerol and waterdwere fed into a mixer
B2 Stoic reactor (used when the reaction
(MIX) before being fed to the reformer. Before entering the
stoichiometry is known but kinetics is
reformer, the mixed stream was heated up to a temperature unknown.)
calculated based on optimization of heat exchanger size using B3 SEP (use to the assignment of the flow
one of the product streams that is available at product tem- rates or componential split fraction of
perature. At ambient temperatures (25  C and 1 atm), glycerol each component)
and water were given in a specific molar ratio [56]. A block B4 HeatX (use to heat mixed stream in
order to reduce reactor heat duty)
designated as a stoichiometric reactor (RStoic) was the steam
reformer. RStoic can simulate parallel or series reactions.
Additionally, RStoic has estimations for product selectivity
Consequently, the amount of component i that enters the
and heat of reaction. Stoichiometry reactor models' calcula-
block Fi can be determined by Eq. (5) [60].
tions are based on equations for the material and energy
balances [58]. The aforementioned GSR reactions occur at at- X
l

mospheric pressure and temperatures between 400 and 750  C Fi ¼ fik (5)
k¼1
and follow the stoichiometry specified in Eqs (2) and (4). The
reformer temperature range was selected in accordance with Eq. (6) provides the relationship between the split fraction
j
research that was conducted for the GSR process [59]. The ai of a specific component i in stream j and the quantity of
j
reactor's output is routed to Block B3, which allows for the component i leaving the block in stream j, Si [60].
assignment of flow rates or componential split fractions for
j j
each component in each of the (n - 1) product streams based Si ¼ ai Fi (6)
on the inputs' combined feeds. B3 generates three streams: S6, The captured CO2 is transferred to a heat exchange pro-
PRO1; S7, PRO2; and S8, PRO3. S6, PRO1 is pure H2, S8, PRO3 is cess with S3, MIX. This process aims to raise the temperature
CO2, and S7, PRO2 is a combination of all other components. In of S3, MIX to a maximum value determined through the
order to lower the reformer's heat load, the S8, PRO3 product sensitivity analysis of B4. When the temperature of S3, MIX
stream is being utilized to heat up the S3, MIX stream. When increases, it is subsequently transferred to the reformer as S4.
S4 is heated, it goes into B2 (Refer Table 1 for block descrip- It should be noted that S5, PRO can be directed toward a CCS
tion). To achieve enhanced energy efficiency and promote system, which can be accomplished through processes such
environmentally friendly production practices, it is impera- as absorption/stripping, cryogenic separation, membrane
tive to implement measures for the capture of CO2 and the separation, and pressure swing adsorption, among others.
minimization of reformer heat duty. The separation of CO2 However, current research focuses on H2 production, so SEP is
from S5, PRO can be achieved by employing the split fraction currently used for CO2 separation (Refer Table 2 for streams
method. The subsequent equations are employed to perform description).
the process of splitting fractions into products. The variable fik Process Assumptions The following assumptions were
denotes the quantity of component i present in feed stream k. considered in the development of the model.

Please cite this article as: Haider MA, Chaturvedi ND, An energy-efficient and cleaner production of hydrogen by steam reforming of
glycerol using Aspen Plus, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2023.09.089
 international journal of hydrogen energy xxx (xxxx) xxx 5

value is employed to assess whether reactions are conducted

Table 2 e Description of streams of the given flowsheet.
in a parallel or series manner. The verification of the feasibility
Streams Description of the results obtained from Model 1 is conducted through the
S1, FEED1 Pure glycerol (25  C and utilization of Model 2. This subsequent analysis establishes a
atmospheric pressure) relationship between the two models in relation to the vari-
S2, FEED2 Water (25  C and atmospheric ables of conversion and temperature. Subsequently, an anal-
pressure)
ysis is conducted to compare the reduction of reformer heat
S3, MIX Mixed stream (cold)
duty achieved in this study with existing literature, yielding
S4 Mixed stream (hot)
S5, PRO Products from B2 promising and viable results.
S6, PRO1 H2 (pure)
S7, PRO2 Mixed products from B2 3.1. Model validation
S8, PRO3 CO2 using as heating medium
S9 CO2 after losing heat Table 4 presents a comparative analysis of the mole fraction of
H2 values derived from GSR, lined up with relevant literature

The process occurs under steady-state conditions. studies. The majority of GSR in the literature was done

Pre-treatment of feed is not required since pure glycerol is experimentally. In the few simulation studies that have been
taken as feed instead of crude glycerol. published, the impact of temperature is typically examined.

Negligible pressure drops in B1. Below is a summary of the values found in the literature.

Vapor phase is only valid in B2. It should be noted that Model 1 is based on the principles of

Shortcut method is used in HeatX. stoichiometry, thus necessitating the verification of its results
for thermodynamic feasibility. This verification process is
The results of Model 1 are based on stoichiometric analysis, carried out in Model 2.
which should be verified by thermodynamic analysis. In
Model 2 use RGibbs in place of RStoic as B2. All other variables 3.2. Effect of water/glycerol molar feed ratio
have the same notation as Model 1.
Several factors, like the amount of H2 gas production, can The effect of the water-to-glycerol feed ratio on the rate of H2
affect how well the GSR process works. The GSR operating production is examined and depicted in Fig. 2. The entire feed
conditions chosen for the Aspen Plus simulation of the pro- rate is assumed to be 1000 kmol/h. The molar quantity ratio
cess model are listed in Table 3. For both model, molar feed fluctuates between 0.11 and 9. As glycerol molar flowrate
ratio of water and glycerol is varied. For Model 1, the conver-
sion of glycerol in Eqs (2) and (4) were varied to see how they
affected the production of H2. For example, if the conversion Table 4 e Comparison of conversion values with those in
of glycerol in Eq. (2) is 90%, then the conversion in Eq. (4) is set the literature.
to 10%. For Model 2, temperature of reformer is varied from
Reaction H2 fraction Reference
400 to 750  C and then up to 900  C for better analysis. temperature (0C)
400 0.65 [61]
727 0.45 [62]
3. Results and discussions 700 0.60 [54]
600 0.28 [63]
This section presents a comprehensive analysis of the diverse 750 0.26 [64]
factors influencing the production of H2. Firstly, the model is 658 0.49 (Model 2 This study
validated by comparing it with other existing literature on H2 reformer: RGibbs)
N.A 0.66 (Model 1 This study
production. The investigation of the impact of the molar feed
reformer: RStoic)
ratio of water to glycerol is conducted in Model 1. The optimal

Table 3 e Model's equipment and input stream conditions (only manually entered variables were filled; values left for
Aspen to calculate are denoted by a – symbol).
Blocks/streams Temperature (0C) Pressure (atm) Vapor fraction Split fraction Flowrate (kmol/hr)
S1 25 1 100e900
S2 25 1 900e100
B1 e 1
B2 e 1 1
B3 e e H2 ¼ 1 for S6,PRO1
CO2 ¼ 1 for S8,PRO3
B4 –(outlet temperature e
of cold stream is
calculated via
optimization)
S8,PRO3 1

Please cite this article as: Haider MA, Chaturvedi ND, An energy-efficient and cleaner production of hydrogen by steam reforming of
glycerol using Aspen Plus, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2023.09.089
6 international journal of hydrogen energy xxx (xxxx) xxx

Fig. 2 e H2 production flowrate vs. water/glycerol molar input ratio.

increases from 100 to 300 kmol/h and water molar flowrate slower rate of increase. If both R1 and R2 occur in parallel
decreases from 900 to 600 kmol/h, H2 production increases fashion, then H2 production will first increase and then
and reaches a maximum, but further increases in glycerol decrease. Table 5 displays H2 production data for a few
flowrate and decreases in water flowrate result in a decrease representative positions. Fig. 3 shows that R1 has a quicker
in H2 production. Reportedly, the optimal molar feed ratio is reaction time compared to R2. This is because when XA1 ¼ 1,
2.33. indicating total conversion in R1, H2 production increases.

3.3. Effect of conversion of glycerol in parallel reaction 3.4. Effect of conversion of glycerol in a series reaction

In a parallel reaction, many reactions take place concurrently, The occurrence of a series of reactions can result in the for-
typically with the same reactants but distinct end products. mation of a particular distribution of products. The final
How much time is spent on each pathway depends on the product is determined by both the order in which the re-
rates of the parallel reactions. The supply of reactants for actions take place and the relative rates at which each step
slower reactions will decrease as faster reactions use more of proceeds. The reaction conditions and kinetics of each step
them. The major reaction (R1) leading to the formation of H2 is have an influence on the selectivity and yield of the desired
the GSR, which is Eq. (2). The decomposition of glycerol (R2) is products. The present study focuses on the modelling of
represented by Eq. (4). Fig. 3 shows the results of running both product formation and distribution, with a particular
reactions in parallel. As the value of XA1 increases from 0 to 1, emphasis on the conversion of reactions. The reformer uti-
there is a rapid increase in the production of H2. Conversely, lized in Model 1 operates based on the fundamental principle
when XA2 rises from 0 to 1, the production of H2 exhibits a of stoichiometry. Fig. 4 illustrates the results of the simulation

Fig. 3 e Effect of conversion of glycerol in parallel reaction for Model 1.

Please cite this article as: Haider MA, Chaturvedi ND, An energy-efficient and cleaner production of hydrogen by steam reforming of
glycerol using Aspen Plus, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2023.09.089
 international journal of hydrogen energy xxx (xxxx) xxx 7

Table 5 e H2 production flowrate for both reactions when

running in parallel for some selected conversion.
XA1 XA2 H2 production (kmol/h)
0 1 450
0.1 0.9 615
0.2 0.8 780
0.3 0.7 945
0.4 0.6 1110
0.5 0.5 1275
0.6 0.4 1440
0.7 0.3 1605
0.8 0.2 1723.33
0.9 0.1 1678.33
1 0 1633.33

Continuously as XA2 ranges fro m 0 to 1, and when XA1 ¼ 0.9,

indicating incomplete conversion, H2 production increases first,
reaches a maximum at XA2 ¼ 0.9, and then drops further.

Fig. 5 e Comparison of series and parallel reactions for

Model 1.

Fig. 5 analyzes the maximal H2 generation flow rate for both

parallel and series configurations of the reactions. More H2 is
generated in a parallel configuration than in a series config-
uration. Under both extreme conditions, the production of H2
is equivalent for both the parallel and series configurations.
According to the findings presented in Fig. 5, it can be identi-
fied that when complete conversion is achievable, any
configuration can be utilized. However, in scenarios of
incomplete conversion, the parallel configuration is preferred.

3.6. Effect of temperature on RGibbs reactor

The temperature of reactor varies from 400 to 900  C at at-

mospheric pressure, and is shown in Fig. 6. It is found that as
Fig. 4 e Effect of conversion of glycerol in a series reaction temperature increases from 400 to 658  C, H2 production goes
for Model 1. on increasing and reaches its maximum at 658  C, decreasing
with further increases in temperature.

conducted for both reactions in a series manner. The findings

indicate that an increase in XA1 from 0 to 1 led to a substantial
rise in H2 production. However, when XA2 increases from 0 to
1, the increase in H2 production is comparatively lower in in-
dependent reactions and even lower in series reactions for
both R1 and R2. It is evident that under the extreme condition
where XA2 is equal to zero and XA1 ranges from 0 to 1, the
production of H2 varies from 0 to 1633.3 kmol/h. Under
different extreme conditions, specifically when XA2 is equal to
1 and XA1 ranges from 0 to 1, the production of H2 exhibits a
variation ranging from 450 to 1633.3 kmol/h. Fig. 4 illustrates
various conversion combinations, elucidating the relationship
between H2 production and the variables XA1 and XA2.

3.5. Comparison of parallel and series reactions

Both series and parallel configurations are possible for re-

actions, depending on how the pathways are linked. The re-
action kinetics and product distribution can be drastically Fig. 6 e Effect of reformer temperature on H2 production for
altered by whether the reactions occur in parallel or series. Model 2.

Please cite this article as: Haider MA, Chaturvedi ND, An energy-efficient and cleaner production of hydrogen by steam reforming of
glycerol using Aspen Plus, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2023.09.089
8 international journal of hydrogen energy xxx (xxxx) xxx

molar feed ratio of water to glycerol is determined by sys-

Table 6 e Thermodynamically feasible results of Model 1.
tematically varying the quantities of water and glycerol while
XA1 XA2 H2 flowrate Reactor H2 fraction maintaining a feed basis of 1000 kmol/h. The optimal molar
(kmol/h) temperature (0C)
feed ratio of water to glycerol was determined to be 2.33.
0 1 450 474.6 0.22 Subsequently, an investigation is conducted to determine the
0.1 0.9 615 515.3 0.28 reaction pathway that yields a higher production of H2, spe-
0.2 0.8 780 551.4 0.34
cifically examining the parallel and series pathways. Research
0.3 0.7 945 586.4 0.40
has demonstrated that the parallel configuration of reactions
0.4 0.6 1110 620.6 0.45
0.5 0.5 1275 658 0.49 yields a higher production of H2 when compared to the series
configuration. It is found that a H2 production rate of
1723.3 kmol/h can be attained with a glycerol conversion rate
of 0.8, accompanied by a corresponding H2 mole fraction of
0.66. Given that Model 1 is founded upon the principles of
Table 7 e Effect of conversion on net heat duty reduction
(%). stoichiometry, it is imperative to conduct additional research
to ascertain its thermodynamic viability. At a temperature of
XA1 XA2 Net heat Net heat Energy
658  C and a pressure of 1 atm, the RGibbs model yielded a
duty (kW) duty (kW) reduction (%)
(Without B4) (With B4) production rate of 1275 kmol/h of H2 with a H2 mole fraction of
0.49. The investigation involves comparing the H2 production
0 1 46254.1 27783.6 39.9
values of Model 2 and Model 1 across a temperature range of
0.1 0.9 43888.3 27081.3 38.3
0.2 0.8 41522.5 26379.0 36.5 400e900  C, while keeping atmospheric pressure constant at
0.3 0.7 39156.5 25676.6 34.4 standard levels. The empirical observation demonstrates that
0.4 0.6 36790.5 24974.3 32.1 a H2 fraction of 0.49 is associated with a conversion rate of 50%
0.5 0.5 34424.4 24271.9 29.5 for both reactions. In Model 1, a total of 62.5 kmol/h of carbon
is generated through parallel reactions, with each reaction
achieving a 50% conversion rate. Conversely, Model 2 does not
yield any carbon production at a temperature of 658  C. The
3.7. Relationship between two models
current investigation demonstrates that the inclusion of heat
integration in the model results in a noteworthy decrease in
Thermodynamic feasibility of Model 1 is done in Model 2, and
the net heat duty of the reactor. When XA1 and XA2 are both
results are tabulated in Table 6. Model 2 is run for a temper-
equal to 0.5, a reduction of 29.5% is observed. Future research
ature range of 400e900  C at atmospheric pressure and com-
efforts are focused on the assessment and enhancement of H2
pares H2 production values with Model 1. It is found that
generation models that utilize a variety of feedstocks in a
Model 1 is feasible only up to a 50% conversion of both re-
manner that is both energy-efficient and environmentally
actions in parallel fashion. Model 1 produces 62.5 kmol/h of
sustainable. The upcoming research efforts will focus on
carbon at 50% conversion of both reactions in parallel fashion,
examining the kinetic parameters relevant to the current
while model 2 produces zero kmol/h of carbon at 658  C
study along with conducting a thorough analysis of the cata-
because optimum conditions are applied.
lyst's activity.
3.8. Effect of conversion on reactor duty

Here, the percentage reduction of the reactor's net heat duty is

Declaration of competing interest
calculated for both the proposed model and the literature
The authors declare that they have no known competing
model [56]. It is found that, if this model is used, the reactor's
financial interests or personal relationships that could have
net heat duty will be significantly reduced because this model
appeared to influence the work reported in this paper.
integrates heat. At XA1 ¼ 0.5 and XA2 ¼ 0.5, 29.5% less energy
is consumed for maximum H2 generation. Table 7 presents the
impact of conversion on the reduction of net heat duty. The references
presented table provides an overview of the energy savings
achieved through the implementation of heat integration
techniques. [1] Lowe RJ, Drummond P. Solar, wind and logistic substitution
in global energy supply to 2050eBarriers and implications.
Renew Sustain Energy Rev 2022 Jan 1;153:111720.
4. Conclusions [2] Abe JO, Popoola AP, Ajenifuja E, Popoola OM. Hydrogen
energy, economy and storage: review and recommendation.
Int J Hydrogen Energy 2019 Jun 7;44(29):15072e86.
The present study employs GSR combined with Aspen Plus
[3] Lagioia G, Spinelli MP, Amicarelli V. Blue and green hydrogen
software to a devise H2 production process characterized by energy to meet European Union decarbonisation objectives.
optimal energy utilization. Two putative models may be used An overview of perspectives and the current state of affairs.
to conduct thermodynamic and stoichiometric evaluations. Int J Hydrogen Energy 2023 Jan 12;48(4):1304e22.
Stoichiometric principles form the basis of Model 1, while [4] Alsaffar MA, Ghany MA, Mageed AK, Ali JM, Ayodele BV.
thermodynamics form the basis of model 2. The optimal Competitiveness of hydrogen production by glycerol

Please cite this article as: Haider MA, Chaturvedi ND, An energy-efficient and cleaner production of hydrogen by steam reforming of
glycerol using Aspen Plus, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2023.09.089
 international journal of hydrogen energy xxx (xxxx) xxx 9

reforming in fixed-bed reactor: an overview of the catalytic [23] Gallegos-Sua
rez E, Guerrero-Ruiz A, Ferna

ndez-Garcı́a M,
performance, product distribution and reactant conversions. Rodrı́guez-Ramos I, Kubacka A. Efficient and stable NieCe
Mater Today Proc 2023. https://doi.org/10.1016/j. glycerol reforming catalysts: chemical imaging using X-ray
matpr.2023.04.578. electron and scanning transmission microscopy. Appl Catal
[5] Yue M, Lambert H, Pahon E, Roche R, Jemei S, Hissel D. B Environ 2015 Apr 1;165:139e48.
Hydrogen energy systems: a critical review of technologies, [24] Suffredini DF, Thyssen VV, de Almeida PM, Gomes RS,
applications, trends and challenges. Renew Sustain Energy Borges MC, de Farias AM, Assaf EM, Fraga MA, Branda ~ o ST.
Rev 2021 Aug 1;146:111180. Renewable hydrogen from glycerol reforming over nickel
[6] Acar C, Dincer I. Review and evaluation of hydrogen aluminate-based catalysts. Catal Today 2017 Jul
production options for better environment. J Clean Prod 2019 1;289:96e104.
May 1;218:835e49. [25] Ni Y, Wang C, Chen Y, Cai X, Dou B, Chen H, Xu Y, Jiang B,
[7] Demirci UB, Akdim O, Andrieux J, Hannauer J, Chamoun R, Wang K. High purity hydrogen production from sorption
Miele P. Sodium borohydride hydrolysis as hydrogen enhanced chemical looping glycerol reforming: application
generator: issues, state of the art and applicability upstream of NiO-based oxygen transfer materials and potassium
from a fuel cell. Fuel Cell 2010 Jun;10(3):335e50. promoted Li2ZrO3 as CO2 sorbent. Appl Therm Eng 2017 Sep
[8] Manna J, Jha P, Sarkhel R, Banerjee C, Tripathi AK, Nouni MR. 1;124:454e65.
Opportunities for green hydrogen production in petroleum [26] Bepari S, Pradhan NC, Dalai AK. Selective production of
refining and ammonia synthesis industries in India. Int J hydrogen by steam reforming of glycerol over Ni/Fly ash
Hydrogen Energy 2021 Nov 8;46(77):38212e31. catalyst. Catal Today 2017 Aug 1;291:36e46.
[9] Ozturk M, Dincer I. An integrated system for ammonia [27] Lin YC. Catalytic valorization of glycerol to hydrogen
production from renewable hydrogen: a case study. Int J and syngas. Int J Hydrogen Energy 2013 Feb
Hydrogen Energy 2021 Jan 29;46(8):5918e25. 27;38(6):2678e700.
[10] Bampaou M, Haag S, Kyriakides AS, Panopoulos KD, [28] Gu Y, Je
ro
^ me F. Glycerol as a sustainable solvent for green
Seferlis P. Optimizing methanol synthesis combining chemistry. Green Chem 2010;12(7):1127e38.
steelworks off-gases and renewable hydrogen. Renew [29] Charisiou ND, Papageridis KN, Siakavelas G, Sebastian V,
Sustain Energy Rev 2023 Jan 1;171:113035. Hinder SJ, Baker MA, Polychronopoulou K, Goula MA. The
[11] Liu W, Zuo H, Wang J, Xue Q, Ren B, Yang F. The production influence of SiO2 doping on the Ni/ZrO2 supported catalyst
and application of hydrogen in steel industry. Int J Hydrogen for hydrogen production through the glycerol steam
Energy 2021 Mar 8;46(17):10548e69. reforming reaction. Catal Today 2019 Jan 1;319:206e19.
[12] Bicer Y, Dincer I. Comparative life cycle assessment of [30] Wang W. Thermodynamic analysis of glycerol partial
hydrogen, methanol and electric vehicles from well to wheel. oxidation for hydrogen production. Fuel Process Technol
Int J Hydrogen Energy 2016;42:3767e77. 2010 Nov 1;91(11):1401e8.
[13] Ozawa A, Kudoh Y, Kitagawa N, Muramatsu R. Life cycle CO2 [31] Harun N, Abidin SZ, Osazuwa OU, Taufiq-Yap YH,
emissions from power generation using hydrogen energy Azizan MT. Hydrogen production from glycerol dry
carriers. Int J Hydrogen Energy 2019;44:11219e32. reforming over Ag-promoted Ni/Al2O3. Int J Hydrogen Energy
[14] Balat M. Possible methods for hydrogen production. Energy 2019 Jan 1;44(1):213e25.
Sources, Part A Recovery, Util Environ Eff 2008 Dec [32] Morales-Marı́n A, Ayastuy JL, Iriarte-Velasco U, Gutie
rrez-
2;31(1):39e50. Ortiz MA. Nickel aluminate spinel-derived catalysts for the
[15] Qureshi F, Yusuf M, Pasha AA, Khan HW, Imteyaz B, aqueous phase reforming of glycerol: effect of reduction
Irshad K. Sustainable and energy efficient hydrogen temperature. Appl Catal B Environ 2019 May 5;244:931e45.
production via glycerol reforming techniques: a review. Int J [33] Liu SK, Lin YC. Generation of syngas through autothermal
Hydrogen Energy 2022;47(98):41397e420. partial oxidation of glycerol over LaMnO3-and LaNiO3-
[16] Narayanan D, Vinithkrishna N, Rajkumar S, Thangaraja J, coated monoliths. Catal Today 2014 Nov 15;237:62e70.
Sivagaminathan M, Devarajan Y, et al. Techno-economic [34] Kaiwen L, Bin Y, Tao Z. Economic analysis of hydrogen
review assessment of hydrogen utilization in processing the production from steam reforming process: a literature
natural gas and biofuels. Int J Hydrogen Energy review. Energy Sources B Energy Econ Plann 2018 Feb
2022;48(55):21294e312. 1;13(2):109e15.
[17] Qureshi F, Yusuf M, Khan MA, Ibrahim H, Ekeoma BC, [35] Nikolaidis P, Poullikkas A. A comparative overview of
Kamyab H, Rahman MM, Nadda AK, Chelliapan S. A state-of- hydrogen production processes. Renew Sustain Energy Rev
the-art review on the latest trends in hydrogen production, 2017 Jan 1;67:597e611.
storage, and transportation techniques. Fuel 2023 May [36] Roslan NA, Abidin SZ, Ideris A, Vo DV. A review on glycerol
15;340:127574. reforming processes over Ni-based catalyst for hydrogen and
[18] Johnson DT, Taconi KA. The glycerin glut: options for the syngas productions. Int J Hydrogen Energy 2020 Jul
value-added conversion of crude glycerol resulting from 17;45(36):18466e89.
biodiesel production. Environ Prog 2007 Dec;26(4):338e48. [37] Soares RR, Simonetti DA, Dumesic JA. Glycerol as a source for
[19] Olson AL, Tune
r M, Verhelst S. A concise review of glycerol fuels and chemicals by low-temperature catalytic
derivatives for use as fuel additives. Heliyon 2023 Jan processing. Angew Chem 2006 Jun 12;118(24):4086e9.
18:p13041. [38] Van Bennekom JG, Venderbosch RH, Assink D, Heeres HJ.
[20] Quispe CA, Coronado CJ, Carvalho Jr JA. Glycerol: production, Reforming of methanol and glycerol in supercritical water. J
consumption, prices, characterization and new trends in Supercrit Fluids 2011 Aug 1;58(1):99e113.
combustion. Renew Sustain Energy Rev 2013 Nov [39] Avasthi KS, Reddy RN, Patel S. Challenges in the production
1;27:475e93. of hydrogen from glycerolea biodiesel byproduct via steam
[21] Silva JM, Soria MA, Madeira LM. Challenges and strategies for reforming process. Procedia Eng 2013 Jan 1;51:423e9.
optimization of glycerol steam reforming process. Renew [40] Bepari S, Pradhan NC, Dalai AK. Selective production of
Sustain Energy Rev 2015 Feb 1;42:1187e213. hydrogen by steam reforming of glycerol over Ni/Fly ash
[22] Moklis MH, Cheng S, Cross JS. Current and future trends for catalyst. Catal Today 2017 Aug 1;291:36e46.
crude glycerol upgrading to high value-added products. [41] Roslan NA, Abidin SZ, Ideris A, Vo DV. A review on glycerol
Sustainability 2023 Feb 7;15(4):2979. reforming processes over Ni-based catalyst for hydrogen and

Please cite this article as: Haider MA, Chaturvedi ND, An energy-efficient and cleaner production of hydrogen by steam reforming of
glycerol using Aspen Plus, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2023.09.089
10 international journal of hydrogen energy xxx (xxxx) xxx

syngas productions. Int J Hydrogen Energy 2020 Jul [52] Slinn M, Kendall K, Mallon C, Andrews J. Steam reforming of
17;45(36):18466e89. biodiesel by-product to make renewable hydrogen. Bioresour
[42] Cichy M, Dobosz J, Borowiecki T, Zawadzki M. Glycerol steam Technol 2008 Sep 1;99(13):5851e8.
reforming over calcium deficient hydroxyapatite supported [53] Smith RJB, Loganathan M, Shantha MS. A review of the water
nickel catalysts. React Kinet Mech Catal 2017 Oct;122:69e83. gas shift reaction kinetics. Int J Chem React Eng 2010 Jun
[43] Dou B, Wang C, Song Y, Chen H, Xu Y. Activity of NieCueAl 30;8(1).
based catalyst for renewable hydrogen production from [54] Dave CD, Pant KK. Renewable hydrogen generation by steam
steam reforming of glycerol. Energy Convers Manag 2014 Feb reforming of glycerol over zirconia promoted ceria supported
1;78:253e9. catalyst. Renew Energy 2011 Nov 1;36(11):3195e202.
[44] Dou B, Dupont V, Rickett G, Blakeman N, Williams PT, [55] Dieuzeide ML, Amadeo N. Thermodynamic analysis of
Chen H, Ding Y, Ghadiri M. Hydrogen production by glycerol steam reforming. Chem Eng Technol: Industrial
sorption-enhanced steam reforming of glycerol. Bioresour Chemistry-Plant Equipment-Process Engineering-
Technol 2009 Jul 1;100(14):3540e7. Biotechnology. 2010 Jan;33(1):89e96.
[45] Buffoni IN, Pompeo F, Santori GF, Nichio NN. Nickel catalysts [56] Unlu D, Hilmioglu ND. Application of aspen plus to
applied in steam reforming of glycerol for hydrogen renewable hydrogen production from glycerol by steam
production. Catal Commun 2009 Jul 25;10(13):1656e60. reforming. Int J Hydrogen Energy 2020 Jan 29;45(5):3509e15.
[46] Adhikari S, Fernando S, Gwaltney SR, To SF, Bricka RM, [57] Al-Malah KI. Aspen plus: chemical engineering applications.
Steele PH, Haryanto A. A thermodynamic analysis of John Wiley & Sons; 2022 Oct 12.
hydrogen production by steam reforming of glycerol. Int J [58] Haydary J. Chemical process design and simulation: aspen
Hydrogen Energy 2007 Sep 1;32(14):2875e80. plus and aspen hysys applications. John Wiley & Sons; 2019
[47] Sad ME, Duarte HA, Vignatti CH, Padro
CL, Apesteguia CR. Jan 23.
Steam reforming of glycerol: hydrogen production [59] Adhikari S, Fernando SD, Haryanto A. Hydrogen production
optimization. Int J Hydrogen Energy 2015 May from glycerol: an update. Energy Convers Manag 2009 Oct
18;40(18):6097e106. 1;50(10):2600e4.
[48] Singh S, Bahari MB, Abdullah B, Phuong PTT, Truong QD, [60] Schefflan R. Teach yourself the basics of aspen plus. John
Vo DVN, et al. Bi-reforming of methane on Ni/SBA-15 Wiley & Sons; 2016 Sep 26.
catalyst for syngas production: influence of feed [61] Giwa AG. Application of aspen plus to hydrogen production
composition. Int J Hydrogen Energy 2018;43:17230e43. from alcohols by steam reforming: effects of reactor
[49] Yusuf M, Farooqi AS, Keong LK, Hellgardt K, Abdullah B. temperature. Int J Eng Res Technol 2013;2:648e57.
Contemporary trends in composite Ni-based catalysts for [62] Jimmy U, Mohamedali M, Ibrahim H. Thermodynamic
CO2 reforming of methane. Chem Eng Sci 2021;229:116072. analysis of autothermal reforming of synthetic crude
[50] Quispe CA, Coronado CJ, Carvalho Jr JA. Glycerol: production, glycerol (SCG) for hydrogen production. ChemEngineering
consumption, prices, characterization and new trends in 2017 Jul 19;1(1):4.
combustion. Renew Sustain Energy Rev 2013 Nov [63] Chattanathan SA. Hydrogen production from renewable bio-
1;27:475e93. based sources. Doctoral dissertation, Auburn University; 2014.
[51] Pompeo F, Santori G, Nichio NN. Hydrogen and/or syngas [64] Kumar MA, Venumadhav C, Sagar TV, Surendar M, Lingaiah N,
from steam reforming of glycerol. Study of platinum Rao GN, Prasad PS. Catalytic tri-reforming
catalysts. Int J Hydrogen Energy 2010 Sep 1;35(17):8912e20. of glycerol for hydrogen generation. Indian J Chem 2014:530e4.

Please cite this article as: Haider MA, Chaturvedi ND, An energy-efficient and cleaner production of hydrogen by steam reforming of
glycerol using Aspen Plus, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2023.09.089