InGenio Journal
Revista de Ciencias de la Ingeniería de la Universidad Técnica Estatal de Quevedo
https://revistas.uteq.edu.ec/index.php/ingenio
e-ISSN: 2697-3642 - CC BY-NC-SA 4.0
InGenio Journal
Revista de Ciencias de la Ingeniería de la Universidad Técnica Estatal de Quevedo
https://revistas.uteq.edu.ec/index.php/ingenio
e-ISSN: 2697-3642 CC BY-NC-SA 4.0
Volumen 7 | Número 2 | Pp. 1–17 | Julio 2024 Recibido (Received): 2024/04/09
DOI: https://doi.org/10.18779/ingenio.v7i2.873 Aceptado (Accepted): 2024/06/18
Simulation and conceptual design of an aniline
production process from catalytic hydrogenation of
nitrobenzene in ChemCAD
(Simulación y diseño conceptual de un proceso de producción de anilina
a partir de la hidrogenación catalítica del nitrobenceno en ChemCAD
)
Amaury Pérez Sánchez
, Yerelis Pons García
,
Lennis Leidy Basulto Cruz
, Maria Isabel
La Rosa Veliz
University of Camagüey, Camagüey, Cuba
amaury.perez84@gmail.com, yerelis.pons@reduc.edu.cu, lennis.basulto@reduc.edu.cu,
maria.rosa@reduc.edu.cu
Abstract: Aniline is a very important compound in organic chemistry, mainly used to
synthesize polyurethane and its precursors. In the present work, the simulation and
conceptual design of an aniline production process through the catalytic hydrogenation
route of nitrobenzene was carried out using ChemCAD
simulator. The simulated aniline
production process consisted of a fired heater, a tubular reactor, several heat exchangers, a
phase separator, a decanter, as well as two distillation columns. By means of the simulation,
the temperatures, pressures, mass flowrates and enthalpies of the main intermediate and
final streams were known, as well as the main operating and design parameters of some
equipment. About 1.743 kg/h of aniline with a purity of 99,78 % are produced at the top
stream of the second distillation column, while about 49.881 kg/h of hydrogen are obtained
as a by-product in the phase separator. In this work a first-of-its-kind ChemCAD
simulation model was obtained in this work, which can be utilized for further optimization
studies and tasks involving the increment of aniline purity, yields and productivity.
Keywords: aniline, nitrobenzene, ChemCAD
, catalytic hydrogenation, conceptual design.
Resumen: La anilina es un compuesto importante en la química orgánica, usado
principalmente para sintetizar poliuretano y sus precursores. En el presente trabajo se llevó
a cabo la simulación y diseño conceptual de un proceso de producción de anilina a partir de
la ruta de la hidrogenación catalítica del nitrobenceno usando el simulador ChemCAD
. El
proceso de producción de anilina simulado consistió de un calentador quemador, un reactor
tubular, varios intercambiadores de calor, un separador de fases, un decantador así como
dos columnas de destilación. Por medio de la simulación se conocieron las temperaturas,
presiones, caudales másicos y entalpias de las principales corrientes intermedias y finales,
así como los principales parámetros de operación y diseño de algunos equipos. Alrededor
de 1.743 kg/h de anilina con una pureza de 99,78 % se producen por la corriente del tope de
la segunda columna de destilación, mientras que se obtienen alrededor de 49.881 kg/h de
hidrógeno como subproducto en el separador de fases. En este trabajo se obtuvo un modelo
de simulación de ChemCAD primero de su tipo, el cual puede utilizarse para estudios
posteriores de optimización y tareas que involucren el incremento de la pureza, rendimiento
y productividad de la anilina.
Palabras clave: anilina, nitrobenceno, ChemCAD
, hidrogenación catalítica, diseño
conceptual.
Volumen 7 | Número 2 | Pp. 158–175 | Julio 2024
DOI: https://doi.org/10.18779/ingenio.v7i2.873
Recibido (Received): 2024/04/09
Aceptado (Accepted): 2024/06/18
Simulation and conceptual design of an aniline
production process from catalytic hydrogenation of
nitrobenzene in ChemCAD
®
(Simulación y diseño conceptual de un proceso de producción de anilina
a partir de la hidrogenación catalítica del nitrobenceno en ChemCAD
®
)
Amaury Pérez Sánchez
, Yerelis Pons García
, Lennis Leidy Basulto Cruz
, Maria Isabel La
Rosa Veliz
InGenio Journal, 7(2), 158–175 159
InGenio Journal, 7(2), 1–18
| 2
1. INTRODUCTION
Aniline is an organic compound consisting of a phenyl group bonded to an amino group,
being a typical aromatic amine. The amino group gives aniline a unique reactivity, making it a
very important intermediate compound from an industrial point of view. It is a flammable liquid
slightly soluble in water.
Most of the aniline produced is used to manufacture methylene-diphenyl-isocyanate, which
is used to prepare polyurethane foams and insulation for refrigerators, freezers and buildings. It
is also used in various industries such as polymers, rubber, pigments, agrochemicals, varnishes,
explosives and dyes [1].
Aniline production reached 8 million tons per year in 2021, and is expected to reach 10
million tons per year by 2027, which could contribute to the development of more efficient and
innovative aniline synthesis production processes [2].
Aniline is produced in both gas and liquid phases. In the case of gas phase production, the
catalytic hydrogenation process of nitrobenzene is used at temperatures of 300-475 ºC and
pressures of 1-10 bar in fixed-bed multitubular reactors provided with cooling systems due to
the highly exothermic nature of the reactions [3]. The production of aniline form catalytic
hydrogenation of nitrobenzene in liquid phase has been studied by several authors [4], [5] as
well as the conversion of nitrobenzene to aniline by means of a semi-continuous
bioelectrochemical system using a microbially catalyzed cathode [6].
There is a report [7] where the production of aniline from nitrobenzene in liquid phase was
described. This aniline production process was divided into three main steps: hydrogenation of
nitrobenzene, dehydration and purification, obtaining aniline with a purity of 99,95 % in the
distillate of the last distillation column. The aniline production capacity of this study was
350.000 MT/year, and the total fixed capital of a plant of this capacity using this production
technology was estimated to be around USD $ 200 million in the first quarter of 2015.
The production of aniline by the catalytic hydrogenation route of nitrobenzene has been
studied primarily in terms of the catalysts to be applied, specifically mono- and bi-metallic
nickel catalyst containing hypercrosslinked polystyrene [2]; Pd/AlO
3
catalyst [4], [8];
Pd/layered double hydroxide (LDH) catalyst [9]; Au/ZrO
2
catalyst [10]; Cu/SiO
2
catalyst [11];
Ni/bentonite catalyst [12] and industrial copper catalyst promoted by chromium and nickel and
supported in kieselguhr [13].
The integration of a process using Aspen Plus
simulator and Aspen Dynamics
to
simultaneously produced aniline by the hydrogenation of nitrobenzene together with the
dehydrogenation of methyl cyclohexane to produce toluene has also been investigated [3]. This
study proposed to carry out both reactions coupled in a tubular adiabatic reactor instead of a
multi-tubular reactor, thus not needing to complex arrangement of the hydrogenation reaction
and the high amounts of hydrogen required preventing the occurrence of irreversible deviations.
Furthermore, in [14] the production of syngas from the steam reforming process using the
nitrobenzene hydrogenation reaction to produce aniline as a heat source was investigated and
simulated in MATLAB
. A coupled recuperative reactor was employed in this study where the
steam reforming reactions occur inside the tubes, while the nitrobenzene hydrogenation reaction
occurs in the shell. The reactor performance was evaluated and analyzed based on methane
conversion, hydrogen yield and nitrobenzene conversion. Also, in [15] the catalytic
dehydrogenation reaction of ethylbenzene to produced styrene was coupled with the catalytic
hydrogenation of nitrobenzene to produce aniline in a simulated integrated reactor consisting of
two fixed beds separated by a hydrogen selective membrane, where both hydrogen and heat are
transferred across the surface of the membrane tubes. In this study, both countercurrent and
cocurrent operation were investigated and the results obtained by simulation were compared
InGenio Journal, 7(2), 158–175 160
InGenio Journal, 7(2), 1–18
| 3
with the corresponding predictions for an industrial adiabatic fixed-bed reactor operated under
the same feed conditions. Other authors [11] studied the catalytic hydrogenation of gas-phase
nitrobenzene over Cu/SiO
2
catalyst in both a single-stage and two-stage fluidized bed reactor at
513-553 K and atmospheric pressure, obtaining as main result that the nitrobenzene conversion
and aniline production selectivity increased in the two-stage fluidized bed reactor compared to
those results obtained in the single-stage fluidized bed reactor.
Chemical process simulation consists of the computerized representation of one or multiple
interconnected unit operations contained in a given chemical plant. It is applied in different
fields of process engineering, either to analyze an existing process (assessment), synthesis of
new chemical processes (design), or as training for operators and supervisor. In recent years, it
has become a basic tool in the field of chemical engineering, mainly to perform the conceptual
design of different chemical, petrochemical and biotechnological processes as an important area
for research and development [16].
Among the simulators used today is ChemCAD
(Chemstations Inc.). ChemCAD
is a
simulator programmed to perform calculations and simulation of chemical processes commonly
found in chemical, petrochemical, pharmaceutical and environmental technology, which
provides and alternative for carrying out large-scale continuous process simulations. It contains
an extensive database of both pure substances and binary mixtures and several thermodynamic
model packages in order to model the chemical process under study in an easy, efficient,
feasible way, as well as a palette of equipment usually found in the chemical industry.
This simulator has been extensively used in recent years to carry out the modeling,
simulation, optimization and sensitivity analysis of different industrial chemical processes.
Among these processes we can mention the design and comparison of different chemical
processes for fuel generation using syngas as a feedstock [17]; the conceptual design of an
acetone production process form the dehydrogenation of isopropyl alcohol for industrial
applications [18]; the simulation of an olive pit pyrolysis plant using a rotary kiln [19]; the
implementation of a separation process of an acetol/acetic acid mixture to design the flowsheet
[20]; the thermal design of a shell and tube heat exchanger used as a cooler and based on the
calculation algorithm of CC-THERM integrated module [21]; and the modeling, simulation and
control of a reactive distillation column for the production of ethyl acetate from acetic acid and
ethanol [22].
Specifically, the authors of this article have used ChemCAD
simulator to simulate various
chemical processes, among which we can mention the production of styrene [23]; acrylic acid
[24]; cumene [25]; maleic anhydride [26] and ethylene oxide [27].
It is of interest for an investment company to erect an aniline production plant by means of
the catalytic hydrogenation of nitrobenzene, since there is a secure, stable market for this
product and the economic, financial and logistic conditions for such a project are available.
Therefore, the conceptual design of a plant of this type is desired in order to know its
productivity, performance and operation, as one of the first stages of the development of a
project in the chemical industry [28].
In this context, in the present work an aniline production process from the gas-phase
catalytic hydrogenation of nitrobenzene was simulated using ChemCAD
simulator 7.1.2, in
order to know the mass composition, temperature, pressure and enthalpy of the main
intermediate and final streams, the productivity of the production process, the operational and
design parameters of the main equipment, the operating parameters of the heat exchangers, and
the preliminary purchase and installed cost of various equipment.
InGenio Journal, 7(2), 158–175 161
InGenio Journal, 7(2), 1–18
| 4
2. MATERIALS AND METHODS
2.1. Physicochemical properties of aniline
Table 1 shows the main physicochemical properties of aniline, according to [1]:
Table 1. Main physicochemical properties of aniline.
Property Value
Other names
Aminobenzene, Phenylamine
Molecular formula
C
6
H
7
N
Molecular weight
98,16 g/mol
Solubility
Miscible in water, ethanol, ethylether,
benzene and acetone.
Melting point
- 6 ºC
Boiling point
184 ºC
Flash point
76 ºC
Density
1.022 g/mL at 27 ºC
2.2. Description of the aniline production process by catalytic hydrogenation of
nitrobenzene
Initially, 2.500 kg/h of liquid nitrobenzene are vaporized to a temperature of 310 ºC using a
shell and tube heat exchanger (Preheater 1) against the hot gaseous mixture coming from the
tubular reactor, as will be discussed later. In another section of the plant, 50,000 kg/h of
hydrogen are preheated (hydrogen/nitrobenzene ratio of 20:1 [14]) from 25 ºC to 310 ºC in a
fired heater, to then mix the preheated hydrogen with the vaporized nitrobenzene. A high
hydrogen/nitrobenzene ratio is employed to avoid reaction run-away and decontrol [3]. The
resulting gaseous mixture, which is at 309 ºC, is compressed to 5 bar in a centrifugal
compressor. Because the compressed gaseous stream exiting the compressor is at 750 ºC, it is
cooled to 340 ºC in a shell and tube heat exchanger (Cooler 1) that uses cooling water at 2 ºC as
the heat exchange agent. The cooled gaseous stream is then sent to the tubular reactor, which is
already loaded with Cu/Ni catalyst [3], [14]. In this tubular reactor, a temperature and pressure
of 320-340 ºC and 2-5 bar, respectively, are maintained during the course of the chemical
reaction, where the temperature control is performed by circulating a special oil as a cooling
agent, since the catalytic reaction is highly exothermic. Once the chemical reaction is
completed, the hot gas mixture leaving the tubular reactor is sent to a shell and tube heat
exchanger (Preheater 1), where it gives part of its heat content to the nitrobenzene feed stream
in order to vaporize it. The hot gaseous mixture leaving the Preheater 1, which is at 337 ºC, is
sent to another shell and tube heat exchanger (Cooler 2), where its temperature is reduced to 30
ºC by means of cooling water at 2 ºC, to then send this cooled stream to a phase separator,
where hydrogen is separated from the liquid phase (aniline, nitrobenzene, water). Subsequently,
the liquid phase leaving the phase separator is sent to a decanter where a certain amount of
water is separated from the rest of the components (aniline and nitrobenzene). The liquid water
is obtained at the bottom stream while the aniline/nitrobenzene/water liquid mixture is obtained
at the top stream of this decanter. Both the phase separator and decanter operate at 30 ºC. The
top stream coming from the decanter is preheated to 110 ºC in a shell and tube heat exchanger
(Preheater 2) which uses saturated steam at 152 ºC and 5 bar as the heating agent, and then this
preheated stream is sent to a first sieve tray distillation column (Water Column) to separate the
water (top stream) from the aniline/nitrobenzene mixture (bottom stream). The bottom stream of
the Water Column, which is at a temperature of 186 ºC, is cooled in a shell and tube heat
exchanger (Cooler 3) to 110 ºC, which uses cooling water at 2 ºC. Finally, this stream at 110 ºC
is fed to a second sieve tray distillation column (Aniline Column), where aniline is separated
from nitrobenzene, thus obtaining about 1.740 kg/h of liquid aniline with a purity of 99,7 % in
InGenio Journal, 7(2), 158–175 162
InGenio Journal, 7(2), 1–18
| 5
the top stream, while about 72 kg/h of liquid nitrobenzene are obtained at the bottom stream
with a purity of 43,7 %, being aniline the main impurity found in this stream. Figure 1 shows
the flow diagram of the aniline production process described above.
Figure 1. Flow diagram of the aniline production process from the catalytic hydrogenation of
nitrobenzene.
2.3. Chemical reaction occurring in the tubular reactor, and its conversion, kinetics and
catalyst properties
According to [8], the reaction of aniline production from the catalytic hydrogenation of
nitrobenzene has the following stoichiometry:
(1)
The conversion of this reaction is 97 % [3] with a ∆H
298
= - 443,0 kJ/mol [14], [15] while
the catalyst used (Cu/Ni) presents the following properties [14], [15]:
• Density: 1.400 kg/m
3
.
• Diameter of the catalyst particle: 4,7x10
-3
m.
• Void fraction: 0,46.
The kinetics of the catalytic hydrogenation reaction of nitrobenzene is described by the
following rate equation [14], [15]:
( )
2
22
22
'
'1
'''
'
HHNBNB
HNBHNB
pK p K
pp K K k
r
⋅+⋅+
⋅⋅⋅ ⋅
=
(2)
In this case, the reaction rate constant (
'k
) is defined as:
⋅
−⋅ =
TR
E
Ak
'
ex
p''
(3)
Where:
'A
= 0,186;
'E
= 10,0 kJ/mol;
2H
K
= 4,427x10
-3
Pa
-0,5
;
NB
K
= 1,510x10
-5
Pa
-1
.
InGenio Journal, 7(2), 158–175 163
InGenio Journal, 7(2), 1–18
| 6
2.4. Selection of the thermodynamic model
The selected thermodynamic model was PSRK with vapor phase association of Hayden
O’Connell, while it was considered the global phase option of vapor/liquid/liquid/solid and the
global enthalpy models of latent heat. Finally, the chosen ideal gas heat capacity was DIPPR
and the selected steam table was of IAPWS-IF97.
2.5. Equipment design parameters
Table 2 shows the design parameters considered for each of the main equipment involved in
the simulation of the aniline production process, which were set taking into account the
suggestions and recommendations reported in [29], [30], [31], [32] and [33].
Table 2. Main design parameters of the equipment included in the aniline production process
simulated in ChemCAD
.
Equipment Design parameters
Fired heater
Type: Vertical, cylindrical.
Tube material: Stainless steel 316.
Thermal efficiency: 0,75.
Compressor
Type: centrifugal.
Driver type: Variable speed drive coupling.
Motor type: Explosion proof.
Motor RPM: 3600.
Cooler 1
Type: Shell and tube.
Exchanger type: Fixed head.
Material: Stainless steel 316.
Area: 30 m
2
.
Preheater 1
Type: Shell and tube.
Exchanger type: U Tube.
Material: Stainless Steel 304.
Area: 40 m
2
.
Reactor
Type: Tubular, fixed bed.
Material: Stainless steel 304.
Diameter: 4,0 m.
Length: 7,0 m.
Tubes: 700 2-inch diameter tubes 5,5 m
long.
Cooler 2
Type: Shell and tube.
Exchanger type: Fixed head.
Material: Stainless steel 304.
Area: 30 m
2
.
Phases separator
Type: Cylindrical tank.
Material: Carbon steel.
Diameter: 2,5 m.
Height: 4,0 m.
InGenio Journal, 7(2), 158–175 164
InGenio Journal, 7(2), 1–18
| 7
Decanter
Type: Cylindrical tank.
Material: Carbon steel.
Diameter: 3,0 m.
Height: 5,0 m.
Preheater 2
Type: Shell and tube.
Exchanger type: U Tube.
Material: Stainless Steel 316.
Area: 40 m
2
.
Water column
Type: Cylindrical.
Material: Carbon steel.
Diameter: 2,0 m.
Tray type: Sieve.
Cooler 3
Type: Shell and tube.
Exchanger type: Fixed head.
Material: Carbon steel.
Area: 20 m
2
.
Aniline column
Type: Cylindrical.
Material: Carbon steel.
Diameter: 1,5 m.
Tray type: Sieve.
2.6. Purchase and installed costs of various equipment
The purchase and installed costs of various equipment involved in the simulated production
process were determined using the “Costing” option contained in ChemCAD
software.
Accordingly, the purchase and installed cost contained in the software was updated to
November 2023 using the cost index of Chemical Engineering magazine [34].
Figure 2 shows the flowsheet of the aniline production process by the catalytic
hydrogenation route of nitrobenzene simulated in ChemCAD
.
Figure 2. Flowsheet of the aniline production process by the catalytic hydrogenation of
nitrobenzene obtained by the simulation in ChemCAD
.
InGenio Journal, 7(2), 158–175 165
InGenio Journal, 7(2), 1–18
| 8
3. RESULTS AND DISCUSSION
3.1. Simulation parameters of the intermediate and final streams
Table 3 displays several parameters of the main intermediate and final streams, which were
obtained by simulating the production process in ChemCAD
simulator. For the values of these
parameters, according to the stream number, refer to Figure 2.
Table 3. Simulated parameters of the main intermediate and final streams.
Parameter
Stream number (refer to Figure 2)
7
26
2
9
Temperature (ºC)
310,74
340
340
30
Pressure (bar)
1
5
5
2
Vapor fraction
1
1
1
0.999
Enthalpy (MJ/h)
209.413
231.370
222.042,7
-4.467,28
Mass flowrate (kg/h)
Nitrobenzene
2.500
2.500
74,99
74,99
Hydrogen
50.000
50.000
49.880,88
49.880,88
Aniline
-
-
1.834,42
1.834,42
Water
-
-
709,71
709,71
Total flow (kg/h)
52.500
52.500
52.500
52.500
Table 3. Continued…
Parameter
Stream number (refer to Figure 2)
10
11
17
16
Temperature (ºC)
30
30
30
110
Pressure (bar)
1
1
1
1
Vapor fraction
1
0
0
0.184
Enthalpy (MJ/h)
3.670,13
-10.601,21
-8.430,17
-1.559,54
Mass flowrate (kg/h)
Nitrobenzene
-
74,99
-
74,99
Hydrogen
49.880,88
-
-
-
Aniline
-
1.834,42
-
1.834,42
Water
-
709,71
532,28
177,43
Total flow (kg/h)
49.880,88
2.619,12
532,28
2.086,84
Table 3. Final.
Parameter
Stream number (refer to Figure 2)
19
20
21
22
Temperature (ºC)
99,60
187,00
186,43
194,51
Pressure (bar)
1
1
1
1
Vapor fraction
1
0
0
0
Enthalpy (MJ/h)
-2.357,52
1.298,46
1.206,01
92,83
Mass flowrate (kg/h)
Nitrobenzene
-
74,99
3,75
71,25
Hydrogen
-
-
-
-
Aniline
-
1.834,42
1.742,68
91,72
Water
177,43
0,001
0,001
-
Total flow (kg/h)
177,43
1.909,41
1.746,43
162,97
InGenio Journal, 7(2), 158–175 166
InGenio Journal, 7(2), 1–18
| 9
According to the results of Table 3, the outlet stream of the tubular reactor (stream 2 in
Figure 2) is composed of 3,49 % aniline, being hydrogen the chemical compound with the
highest presence in this stream (95,01 %).
Of the 2,500 kg/h of nitrobenzene fed to the tubular reactor, approximately 75 kg/h
remained unreacted for a conversion rate of 97 % with respect to this compound, which is
consistent with that reported by [3]. In addition, the amount of hydrogen that reacted was
119,12 kg/h and the amount of aniline formed was 1.834,42 kg/h, thus agreeing with the results
reported by [35].
In the phase separator, all the hydrogen contained in the inlet stream fed to this equipment
(49,880.88 kg/h) is separated at the top stream (stream 10), which can be recovered, purified
and conditioned to be recirculated to the aniline production process, or used as raw material in
other chemical processes. Thus, it is recommended to carry out further studies to implement
steps and operations to recover, purify and condition this important flowrate of hydrogen.
The liquid stream coming from the bottom of the phase separator (stream 11) contains
70,04 % aniline, in addition to water (27,09 %) and nitrobenzene (2,86 %), while 532,28 kg/h of
water are discharged from the bottom stream of the decanter (stream 17), for a separation
percentage of 75 % regarding this compound in this equipment. This water can be treated and
reused in the production plant for the cleaning of equipment, areas and other operations where it
is needed.
In the first distillation column (Water Column), almost all the inlet water is separated, which
is obtained in the top stream (19) with a flowrate of 177,43 kg//h, while a liquid mixture
consisting of aniline (96,07 %) and nitrobenzene (3,93 %) is contained in the bottom stream.
The percentage of water separation in this column is almost 100%.
In the second distillation column, the separation of aniline from nitrobenzene is carried out,
obtaining 1.742,68 kg/h of aniline with a purity of 99,78 % at the top stream of this equipment
(stream 21), being nitrobenzene the main impurity found on this stream. The bottom stream of
this Aniline Column (stream 22) is composed of nitrobenzene (43,72 %) and aniline (56,28 %).
It is recommended to evaluate the possible recycle of this bottom stream to the aniline
production process to recover the quantities of both chemicals, thus improving the productivity
and profitability of the simulated plant.
3.2. Operating parameters of equipment
Shown below are several operating and design parameters calculated by ChemCAD
simulator for several equipment involved in the simulated aniline production process.
Reactor:
• Calculated heat of reaction: - 464,28 kJ/mol.
Fired heater:
• Heat absorbed: 206,55 GJ/h.
Centrifugal compressor:
• Theoretical power: 245.929 MJ/h.
• Actual power: 327.905 MJ/h.
• Cp/Cv: 1,393
Cooler 1:
• Log Mean Temperature Difference (LMTD): 486,305 ºC.
• LMTD Correction factor: 0,976.
• Calculated overall heat transfer coefficient: 5.966 W/m
2
.K.
Preheater 1
• LMTD: 120,463 ºC.
InGenio Journal, 7(2), 158–175 167
InGenio Journal, 7(2), 1–18
| 10
• LMTD Correction factor: 0,987.
• Calculated overall heat transfer coefficient: 120,97 W/m
2
.K.
Cooler 2:
• LMTD: 106,029 ºC.
• LMTD Correction factor: 1,00.
• Calculated overall heat transfer coefficient: 19.600 W/m
2
.K.
Preheater 2:
• LMTD: 75,022 ºC.
• LMTD Correction factor: 1,00.
• Calculated overall heat transfer coefficient: 75,47 W/m
2
.K.
Cooler 3:
• LMTD: 109,989 ºC.
• LMTD Correction factor: 1,00.
• Calculated overall heat transfer coefficient: 42,21 W/m
2
.K.
Water column:
• Condenser duty: - 500,97 MJ/h.
• Reboiler duty: 1.001,45 MJ/h.
• Minimum stages: 27.
• Reflux ratio, minimum: 1,643.
Aniline column:
• Condenser duty: - 1.877,7 MJ/h
• Reboiler duty: 2.212,41 MJ/h.
• Minimum stages: 10.
• Reflux ratio, minimum: 0,891.
According to the results shown above, the value of calculated heat of reaction in the tubular
reactor was – 464,28 kJ/mol, which is very similar to the value reported in [14], [15] for this
type of chemical reaction.
The heat absorbed in the fired heater was 206,55 GJ/h, which is within the range reported by
[33] for this type of equipment (11-210 GJ/h).
Regarding the calculated overall heat transfer coefficients (U), in case of the Cooler 1 and
Cooler 2 the calculated values of U (5.966 W/m
2
.K and 19.600 W/m
2
.K, respectively) are higher
than the range suggested by [28] of 20-300 W/m
2
.K for this type of heat exchange service. In
the case of Preheater 2, the calculated value of U (75,47 W/m
2
.K) is within the range reported
by [28] of 60-450 W/m
2
.K. Finally, the calculated value of U for Cooler 3 (42,21 W/m
2
.K) is
within the range described by [28] of 30-300 W/m
2
.K. In this case, Cooler 2 presents the highest
value of U while Cooler 3 has the lowest value of U among all the shell and tube heat exchanger
used in the simulation.
The calculated actual power of the centrifugal compressor (327.905 MJ/h ≅ 91 MW) is
within the range reported by [36] of 75 kW-97 MW for this compressor type, while the
theoretical power had a value of 245.929 MJ/h (≈ 68 MW).
The Water Column will have a minimum number of stages of 27, a condenser and reboiler
duty of – 500,97 MJ/h and 1.001,45 MJ/h respectively, and a minimum reflux ratio of 1,643.
Likewise, the Aniline Column will have a minimum number of stages of 10, a condenser and
reboiler duty of - 1.877,7 MJ/h and 2.212,41 MJ/h respectively, and a minimum reflux ratio of
0,891. That is, more stages are needed in the Water Column to separate the water from the
aniline/nitrobenzene mixture, requiring in turn a lower duty in the condenser which is due to the
fact that the condenser selected in this column was of partial type, while the condenser selected
in the Aniline Column was of total type. The Aniline Column required fewer stages because of
InGenio Journal, 7(2), 158–175 168
InGenio Journal, 7(2), 1–18
| 11
the significant difference existing between the boiling points of aniline and nitrobenzene, being
aniline more volatile than nitrobenzene.
3.3. Heat duty of the heat exchangers
Figure 3 displays the heat duty values calculated by ChemCAD
simulator for each of the
heat exchangers used in the production process.
Figure 3. Calculated heat duty for each heat exchanger used in the production process.
The heat duty of Cooler 1 has the highest value of all (305.948 MJ/h) mainly because it is in
this equipment where the cooling of the nitrobenzene/hydrogen gaseous mixture is carried out
from 753 ºC to the reaction temperature (340 ºC), i.e. there is a high temperature difference (∆T
= 413 ºC), in addition to handling a high flowrate of gaseous compounds (52.500) kg/h).
On the other hand, Cooler 2 also has a high heat duty (224.437 MJ/h), which is basically due
to the fact that it is the heat exchanger where the gaseous outlet stream of the reactor is cooled
from 337 ºC to 30 ºC, i.e. it has the second highest ∆T (307 ºC) while it also handles a gaseous
mixture stream composed of several chemicals with a high flowrate.
Finally, Cooler 3 has the lowest value of the heat duty (343,33 MJ/h) because its ∆T is the
lowest (77 ºC), i.e. the outlet liquid stream coming from the bottom of the Water Column,
composed of aniline and nitrobenzene, is cooled from 187 ºC to 110 ºC before being fed to the
Aniline Column. It also should be noted that it is the heat exchanger that handles the lowest
flowrate of all the heat exchangers, with 1.909,41 kg/h.
3.4. Heat curves of the heat exchangers
Figure 4 presents the heat curves for each of the heat exchangers included in the production
process, which were obtained using the “Heat Curves” option included in ChemCAD
simulator.
InGenio Journal, 7(2), 158–175 169
InGenio Journal, 7(2), 1–18
| 12
a)
b)
c)
d)
e)
Figure 4. Heat curves of all the heat exchangers included in the production process:
a) Cooler 1.
b) Preheater 1.
c) Cooler 2.
d) Preheater 2.
e) Cooler 3.
The heat curve of Cooler 1 (Figure 4a) shows two linear trends for both the cooling water
stream and stream 8 (nitrobenzene and hydrogen gaseous mixture). This indicates that both
streams do not undergo phase change, i.e. the cooling water is heated from 2 ºC to 80 ºC without
vaporization, while the gaseous stream is cooled from 753 ºC to 340 ºC without condensing.
In the case of the heat curve of Preheater 1 (Figure 4b), stream 2 shows a linear behaviour,
indicating that this stream cools from 340 to 337 ºC while the nitrobenzene stream shows and
ascending linear behaviour up to the 35 % length of the heat exchanger and at a temperature of
approximately 195 ºC, to then undergo a phase change (vaporization) between the 35 % and
InGenio Journal, 7(2), 158–175 170
InGenio Journal, 7(2), 1–18
| 13
84 % length of the equipment, to finally gain sensible heat from 225 ºC to 310 ºC. It is worth
noting that, according to the simulation results, the nitrobenzene has a vapor fraction equal to
zero before being fed to Preheater 1, while its vapor fraction is equal to one at the exit of this
heat exchanger, which confirms that this pure nitrobenzene stream is totally vaporized in this
heat exchanger.
Considering the heat curve of Cooler 2 (Figure 4c), both stream 3 and cooling water stream
present a linear tendency, suggesting that none of these streams undergo phase change in this
equipment. Stream 3 is cooled from 340 ºC to 30 ºC without condensing, while the cooling
water stream is heated from 2 ºC to 70 ºC without vaporization.
In the heat curve of Preheater 2 (Figure 4d), the stream of saturated steam does not undergo
phase change at the temperature and pressure fed to this heat exchanger (152 ºC and 5 bar,
respectively), which is corroborated by verifying that the vapor fraction of the inlet and outlet
streams of steam to the Preheater 2 is equal to one, that is, it does not condense. Stream 18 is
heated from 30 ºC to 100 ºC (up to length 50%) without phase change, and then vaporization
occurs for certain fraction of components from 100 ºC to the outlet temperature (110 ºC). This is
confirmed by noting that the value of the vapor fraction of the outlet stream of Preheater 2
(stream 16) is 0,18, i.e. a two-phase gas-liquid mixture is obtained at the outlet of this heat
exchanger.
Finally, in the heat curve of Cooler 3 the cooling water stream is heated from 2 ºC to 75 ºC
without vaporization considering the increasing linear trend of its heat curve, while stream 20 is
cooled without occurring condensation from a temperature of 187 ºC to 110 ºC, considering the
decreasing linear tendency of the heat curve. This is confirmed by observing that the vapor
fraction of both stream 20 and stream 23 is equal to zero.
3.5. Purchase and installed cost of various equipment
Table 4 shows the purchase and installed cost of various equipment included in the
simulated production process, which were determined using the “Costing” option contained in
the ChemCAD
simulator. The total amount of both cost items is also shown. The purchase and
installed costs of the reactor, phase separator, decanter and distillation columns were not
determined because the simulator does not have this option.
Table 4. Purchase and installed cost of several equipment included in the simulated aniline
production process.
Equipment
Purchase cost (USD $)
Installed cost (USD $)
Fired heater
6,9719x10
6
9,06347x10
6
Centrifugal compressor
3,26058x10
7
4,73061x10
7
Cooler 1
33.282
66.564,1
Preheater 1
35.368,3
70.736,5
Cooler 2
26.290,7
52.581,4
Preheater 2
33.282
66.564,1
Cooler 3
11.883,4
23.766,8
Total
39.717.806,4
∼ 39.720.000
56.649.782,9
∼ 56.700.000
The equipment with the highest acquisition cost is the centrifugal compressor with USD $
3,26x10
7
, while the equipment with the lowest cost is Cooler 3 (USD $ 11.883,4). A total
amount of USD $ 39,72 million and USD $ 56,70 million will be required to purchase and
install the equipment listed in Table 4.
InGenio Journal, 7(2), 158–175 171
InGenio Journal, 7(2), 1–18
| 14
In general, the purchase costs of all the individual equipment included in Table 4 agree with
those reported in [29] and are lower than those reported in [28].
4. CONCLUSIONS
The simulation and conceptual design of an aniline production process by the catalytic
hydrogenation route of nitrobenzene was carried out in this work using ChemCAD
simulator.
Through the simulation, the temperature, pressure, mass flowrate, enthalpy and vapor fraction of
the main intermediate and final streams of the simulated production process were known, as
well as the main operating and design parameters of some equipment, the heat duty and heat
curves of the shell and tube heat exchanger used, in addition to the purchase and installed costs
of several equipment.
Cooler 1 was the heat exchanger that had the highest calculated heat duty, with 305.948
MJ/h, and a value for the overall heat transfer coefficient (U) of 5,966 W/m
2
.K, which is higher
than the value reported by [28]. Cooler 3 had the lowest value of the heat duty with 343,33 MJ/h
and a value for U of 42,21 W/m
2
.K, which is within the range reported by [28]. In this case,
Cooler 2 presented the highest value of U 19.600 W/m
2
.K) while Cooler 3 had the lowest value
of U (42,21 W/m
2
.K) among all the shell and tube heat exchanger employed in the production
process.
The calculated heat of reaction for the tubular reactor (- 464,28 kJ/mol) agrees with what is
reported in the literature [14], [15], while the heat absorbed in the fired heater was 206,55 GJ/h,
which is within the range reported by [33].
The heat curves obtained in this study show that the two process streams do not undergo
phase change in three of the heat exchangers (Cooler 1, Cooler 2 and Cooler 3), which is
verified by the linear trend observed for both streams in the corresponding heat curves. On the
other hand, the heat curve obtained for Preheater 1 indicates that the nitrobenzene stream
experienced total vaporization; while the heat curve obtained for Preheater 2 shows that the
Stream 18 undergoes partial vaporization, thus obtaining a two-phase gas-liquid mixture at the
heat exchanger’s outlet, with a vapor fraction of 0,18 in Stream 16.
The first distillation column (Water Column) had a minimum number of stages of 27, and a
heat duty for the condenser and reboiler of – 500,97 MJ/h and 1.001,45 MJ/h respectively.
Similarly, the second distillation column (Aniline Column) had a minimum number of stages of
10, while the values of the heat duty for the condenser and reboiler were - 1.877,7 MJ/h and
2.212,41 MJ/h respectively. The Aniline Column needed less number of stages due to relatively
significant difference existing between the boiling points of aniline and nitrobenzene, where
aniline is more volatile than nitrobenzene.
The purchase and installed cost of certain equipment included in the process flowsheet
amounted USD $ 39,72 million and USD $ 56,7 million respectively, being the centrifugal
compressor the equipment with the highest calculated purchase cost (USD $ 3,26x10
7
)
The simulated production plant produces 1.742,68 kg/h of aniline with a purity of 99,78 %
at the top stream of the second distillation column. Also, 49.880,88 kg/h of hydrogen are
obtained at the top stream of the phase separator, which is recommended to be recovered,
conditioned and possibly recycled as raw material in the aniline production process. Likewise,
the bottom stream of the second distillation column contains 43,72 % nitrobenzene and 56,28 %
aniline; therefore it is suggested to recycle this stream to the production process as raw material,
to increase its productivity and profitability.
The main contribution of this work is that a simulation model of an aniline production
process through the catalytic hydrogenation of nitrobenzene was obtained for the first time
using ChemCAD
simulator, which could be utilized for supplementary tasks involving the
InGenio Journal, 7(2), 158–175 172
InGenio Journal, 7(2), 1–18
| 15
increment of aniline yields and throughput, sensitivity analysis and optimization studies of key
operating parameters.
REFERENCES
[1] H. J. Patel, Handbook of Chemical Process Industries. Boca Raton, USA: CRC Press, 2024.
[2] R. V. Brovko, L. S. Mushinsky, A. R. Latypova, M. G. Sulman, V. G. Matveeva, and V. Y.
Doluda, "Evaluation of Nitrobenzene Hydrogenation Kinetic Particularities Over Mono and
Bimetallic Ni Containing Hypercrosslinked Polystyrene", Chemical Engineering
Transactions, vol. 86, pp. 883-888, jun. 2021. [Online]. Available:
https://doi.org/10.3303/CET2186148
[3] A. Javaid and C. S. Bildea, "Design and Control of an Integrated Toluene-Aniline
Production Plant a Preliminary Study", International Journal of Chemical Engineering and
Applications, vol. 8, no. 4, pp. 267-271, aug. 2017. [Online]. Available:
https://www.ijcea.org/index.php?m=content&c=index&a=show&catid=88&id=1050#:~:text
=10.18178/ijcea.2017.8.4.668
[4] S. Couto, L. M. Madeira, C. P. Nunes, and P. Araújo, "Hydrogenation of Nitrobenzene over
a Pd/Al
2
O
3
Catalyst – Mechanism and Effect of the Main Operating Conditions", Chemical
Engineering and Technology, vol. 38, no. 9, pp. 1625-1636, jul. 2015. [Online]. Available:
https://doi.org/10.1002/ceat.201400468
[5] Q. Zhang et al., "Highly Efficient Hydrogenation of Nitrobenzene to Aniline over Pt/CeO
2
Catalysts: The Shape Effect of the Support and Key Role of Additional Ce
3+
Sites", ACS
Catalysis, vol. 10, pp. 10350-10363, aug. 2020. [Online]. Available:
https://doi.org/10.1021/acscatal.0c02730
[6] A.-J. Wang et al., "Efficient Reduction of Nitrobenzene to Aniline with a Biocatalyzed
Cathode", Environmental Science and Technology, vol. 45, no. 23, pp. 10186-10193, 2011.
[Online]. Available: https://doi.org/10.1021/es202356w
[7] Scott, J. "Aniline Production from Nitrobenzene (Liquid-Phase)", Chemical Engineering,
vol. 123, no. 3, p. 48, mar. 2016. [Online]. Available:
https://www.proquest.com/openview/2e7ce4678de36dadbbf7bb3973bb5d11/1.pdf?pq-
origsite=gscholar&cbl=41910
[8] C. G. A. Morisse et al., "Toward High Selectivity Aniline Synthesis Catalysis at Elevated
Temperatures", Industrial & Engineering Chemistry Research, vol. 60, no. 49, pp. 17917-
17927, dec. 2021. [Online]. Available: https://doi.org/10.1021/acs.iecr.1c03695
[9] J. Wang, C. Du, Q. Wei, and W. Shen, "Two-Dimensional Pd Nanosheets with Enhanced
Catalytic Activity for Selective Hydrogenation of Nitrobenzene to Aniline", Energy Fuels,
vol. 35, no. 5, pp. 4358-4366, feb. 2021. [Online]. Available:
https://doi.org/10.1021/acs.energyfuels.0c02952
[10] S. Gómez, C. Torres, J. L. García, C. P. Apesteguía, and P. Reyes, "Hydrogenation of
Nitrobenzene on Au/ZrO2 catalysts", J. Chil. Chem. Soc., vol. 57, no. 2, pp. 1194-1198,
mar. 2012. [Online]. Available: http://dx.doi.org/10.4067/S0717-97072012000200029
InGenio Journal, 7(2), 158–175 173
InGenio Journal, 7(2), 1–18
| 16
[11] S. Diao, W. Qian, G. Luo, F. Wei, and Y. Wang, "Gaseous catalytic hydrogenation of
nitrobenzene to aniline in a two-stage fluidized bed reactor," Applied Catalysis A: General,
vol. 286, pp. 30-35, may. 2005. [Online]. Available:
https://doi.org/10.1016/j.apcata.2005.02.026
[12] Y. Jiang, X. Li, Z. Qin, and H. Ji, "Preparation of Ni/bentonite catalyst and its applications
in the catalytic hydrogenation of nitrobenzene to aniline," Chinese Journal of Chemical
Engineering, vol. 24, no. 9, pp. 1195-1200, sep. 2016. [Online]. Available:
https://doi.org/10.1016/j.cjche.2016.04.030
[13] L. Petrov, K. Kumbilieva, and N. Kirkov, "Kinetic Model of Nitrobenzene Hydrogenation
to Aniline over Industrial Copper Catalyst Considering the Effects of Mass Transfer and
Deactivation," Applied Catalysis, vol. 59, no. 1, pp. 31-43, mar. 1990. [Online]. Available:
https://doi.org/10.1016/S0166-9834(00)82185-5
[14] Z. A. Aboosadi, M. R. Rahimpour, and A. Jahanmiri, "A novel integrated thermally coupled
configuration for methane-steam reforming and hydrogenation of nitrobenzene to aniline",
International Journal of Hydrogen Energy, vol. 36, no. 4, pp. 2960-2968, feb. 2011.
[Online]. Available: https://doi.org/10.1016/j.ijhydene.2010.12.005
[15] N. S. Abo-Ghander, J. R. Grace, S. S. E. H. Elnashaie, and C. J. Lim, "Modeling of a novel
membrane reactor to integrate dehydrogenation of ethylbenzene to styrene with
hydrogenation of nitrobenzene to aniline", Chemical Engineering Science, vol. 63, no. 7, pp.
1817-1826, apr. 2008. [Online]. Available: https://doi.org/10.1016/j.ces.2007.12.007
[16] Z. A. Abdel-Rahman and O. S. Latef, "Process simulation of benzene separation column of
linear alkyl benzene (lab)plant usign ChemCAD," Tikrit Journal of Eng. Sciences, vol. 15,
no. 1, pp. 17-29, mar. 2008. [Online]. Available: https://tj-
es.com/ojs/index.php/tjes/article/view/627/653
[17] L. Petrescu, A. Imre-Lucaci, and C. I. Berci, "Modelling and simulation of fules production
from syngas" STUDIA UBB CHEMIA, vol. 62, no. 4, pp. 231-240, 2017. [Online].
Available:
https://go.gale.com/ps/i.do?id=GALE%7CA526440884&sid=googleScholar&v=2.1&it=r&l
inkaccess=abs&issn=12247154&p=AONE&sw=w&userGroupName=anon%7E20a33f99&
aty=open-web-entry
[18] B. Kökdemir and N. Acarali, "A novel study on CHEMCAD simulation of isopropyl
alcohol dehydrogenation process development", Journal of the Indian Chemical Society,
vol. 98, no. 3, p. 100035, mar. 2021. [Online]. Available:
https://doi.org/10.1016/j.jics.2021.100035
[19] E. Benanti, C. Freda, V. Lorefice, G. Braccio, and V. k. Sharma, "Simulation of olive puits
pyrolysis in a rotary kiln plant", Thermal Science, vol. 15, no. 1, pp. 145-158, jan. 2011.
[Online]. Available: http://dx.doi.org/10.2298/TSCI090901073B
[20] C. Chilev, F. Lamari, and P. Langlois, "Numerical Simulation of a Valorisation-Oriented
Hybrid Process for the Bio-Oil-Related Separation of Acetol and Acetic Acid",
ChemEngineering, vol. 8, no. 1, 2024. [Online]. Available:
https://doi.org/10.3390/chemengineering8010005
InGenio Journal, 7(2), 158–175 174
InGenio Journal, 7(2), 1–18
| 17
[21] S. Dibyo, I. D. Irianto, S. Bakhri, and M. Pancoko, "Thermal design of cooler in the fuel
handling pneumatic system of RDE," IOP Conf. Series: Materials Science and Engineering,
vol. 830, p. 022018, 2020. [Online]. Available: http://dx.doi.org/10.1088/1757-
899X/830/2/022018
[22] N. Amenaghawon and S. E. Ogbeide, "Modelling, simulation and control of ethyl acetate
reactive distillation column using ChemCAD," Journal of Engineering and Applied
Sciences, vol. 4, pp. 16-33, mar. 2012. [Online]. Available:
https://www.cenresinjournals.com/wp-content/uploads/2020/02/Page-16-33-640.pdf
[23] Pérez, E. J. Pérez, and R. M. Segura, "Simulation of the styrene production process via
catalytic dehydrogenation of ethylbenzene using CHEMCAD
®
process simulator," Tecnura,
vol. 21, no. 53, pp. 15-31, sep. 2017. [Online]. Available:
https://doi.org/10.14483/udistrital.jour.tecnura.2017.3.a01
[24] Pérez, E. J. Pérez, and R. M. Segura, "Simulation of the acrylic acid production process
through catalytic oxidation of gaseous propylene using ChemCAD
®
simulator," Ingeniare.
Revista chilena de ingeniería, vol. 27, no. 1, pp. 142-150, 2019. [Online]. Available:
https://www.scielo.cl/pdf/ingeniare/v27n1/0718-3305-ingeniare-27-01-00142.pdf
[25] A. Pérez, E. Ranero, E. J. Pérez, y N. Liaño, "Simulación del proceso de producción del
cumeno mediante el simulador ChemCAD
®
," RECyT, vol. 33, no. 1, pp. 38–46, 2020.
[Online]. Available: https://doi.org/10.36995/j.recyt.2020.33.006
[26] A. Pérez, E. Ranero, y E. J. Pérez, "Simulación del proceso de producción de anhídrido
maleico mediante el simulador ChemCAD
®
", Revista Mutis, vol. 11, no. 2, pp. 8-21, may.
2021. [Online]. Available: https://doi.org/10.21789/22561498.1752
[27] Pérez, J. G. Baltá, J. R. Montalván, E. Ranero, and E. J. Pérez, "Simulation of the ethylene
oxide production process in ChemCAD
®
simulator," RECyT, vol. 24, no. 37, pp. 15-24,
may. 2022. [Online]. Available: https://doi.org/10.36995/j.recyt.2022.37.002
[28] R. Sinnott and G. Towler, Chemical Engineering Design, 6th ed. Oxford, United Kingdom:
Butterworth-Heinemann, 2020.
[29] S. M. Walas, Chemical Process Equipment Selection and Design. Boston, USA:
Butterworth-Heinemann, 1990.
[30] N. P. Cheremisinoff, Handbook of Chemical Processing Equipment. Boston, USA:
Butterworth-Heinemann, 2000.
[31] M. S. Peters, K. D. Timmerhaus, and R. E. West, Plant Design and Economics for Chemical
Engineers, 5th ed. New York, USA: McGraw-Hill, 2003.
[32] J. R. Couper, W. R. Penney, J. R. Fair, and S. M. Walas, Chemical Process Equipment
Selection and Design, 3rd ed. Oxford, U.K.: Butterworth-Heinemann, 2012.
[33] D. W. Green and M. Z. Southard, Perry's Chemical Engineers' Handbook, 9th ed. New
York, USA: McGraw-Hill Education, 2019.
[34] S. Jenkins, "Economic Indicators," Chemical Engineering, vol. 131, no. 3, p. 48, 2024.
InGenio Journal, 7(2), 158–175 175
InGenio Journal, 7(2), 1–18
| 18
[35] P. H. Nayak, Proposed new project for Manufacturing of Aniline and Nitro Benzene.
Ahmedabad, India: Satva Environ Consultancy, 2018.
[36] S. M. Hall, Rules of Thumb for Chemical Engineers, 6th ed. Oxford, United Kingdom:
Elsevier, 2018.
OREM
Copyright (2023) ©
Amaury Pérez Sánchez, Yerelis Pons García, Lennis Basulto Cruz, Maria Isabel La Rosa Veliz.
Este texto está protegido bajo una licencia internacional
Creative Commons 4.0.
Usted es libre para compartir, copiar y
redistribuir el material en cualquier medio o formato. También podrá adaptar: remezclar, transformar y construir sobre
el
material.
