Introducing and analysis of a hybrid molten carbonate fuel cell-supercritical carbon dioxide Brayton cycle system

Sustainable Energy Technologies and Assessments 18 (2016) 100–106

Contents lists available at ScienceDirect

Sustainable Energy Technologies and Assessments journal homepage: www.elsevier.com/locate/seta

Original article

Introducing and analysis of a hybrid molten carbonate fuel cell-supercritical carbon dioxide Brayton cycle system Mehdi Mehrpooya a,b,⇑, Parimah Bahramian a, Fathollah Pourfayaz a, Marc A. Rosen c a

Renewable Energies and Environment Department, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran Hydrogen and Fuel Cell Laboratory, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran c Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario L1H 7K4, Canada b

a r t i c l e

i n f o

Article history: Received 31 March 2016 Revised 6 October 2016 Accepted 6 October 2016

Keywords: Molten carbonate fuel cell Supercritical CO2 Brayton cycle Hybrid system Exergy

a b s t r a c t A hybrid system is proposed, which integrates a molten carbonate fuel cell, and a supercritical carbon dioxide Brayton cycle. This case deals with waste heat recovery from catalytic burner exhaust gas using a Brayton cycle as a bottoming cycle for additional power production due its very high temperature, which yields high electrical and overall efficiencies. After designing and simulating the process energy and exergy analyses are performed. The greatest exergy destruction is observed in the reformer while the lowest exergy efficiency is attributable to the fuel cell. The main advantage of this kind of hybrid system, in addition to efficiency improvement and cost reduction, is its ability to reduce harmful emissions and negative impacts on the environment. Ó 2016 Elsevier Ltd. All rights reserved.

Introduction Usage of the renewable energies the integrated power plants because of transiente nature of them is one of research aspects in this area [1–4]. Also hybrid systems formed by combining high temperature fuel cells and other types of the power generators such as gas turbines with organic Rankine cycles as bottoming cycles have been investigated extensively over the last decade [5–7]. Improvements in fuel cell technology have increased interest in cogeneration and hybrid systems based on high temperature fuel cells [8–10]. The molten carbonate fuel cell (MCFC) is a high temperature fuel cell that has attracted attention due to its high efficiency, low emissions, and fuel flexibility [11]. In addition the high temperature exhaust gas (600–700 °C) provides the potential for cogeneration or combined cycle applications, which can lead to higher efficiency and/or provide more power output. The exhaust gases contain a considerable amount of heat which can be used to drive a bottoming cycle in order to increase the electrical efficiency of the system. The supercritical carbon dioxide Brayton cycle is a potentially suitable option as bottoming cycle and has attracted much attention as a future power conversion system due to its high efficiency and impact size. The operating ⇑ Corresponding author at: Renewable Energies and Environment Department, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran. E-mail address: [email protected] (M. Mehrpooya). http://dx.doi.org/10.1016/j.seta.2016.10.003 2213-1388/Ó 2016 Elsevier Ltd. All rights reserved.

temperature range of the supercritical carbon dioxide (S-CO2) in such cycles is between 450 and 750 °C [12]. Supercritical fluids undergo no state change during processes, so they have no pinch points and associated limitations on heat transfer efficiency. In addition, conventional gases are subject to high losses during compression but S-CO2 cycles avoid this kind of loss. CO2 is an potentially beneficial working fluid due to its supercritical, thermodynamic and environmental properties. Some analysis work has been reported in this area. Carbon dioxide is proposed as a working fluid for a closed supercritical bottoming cycle linked with high-temperature fuel cells [13]. Also, part-load performance of such a hybrid system has been studied [14] while the S-CO2 cycle is compared with other cycles using hot air as a working fluid [15]. S-CO2 cycles can obtain high thermal efficiency due to their ability to achieve high turbine work at high temperature and low demand for compression power. Performance analysis of a hybrid MCFC cycle is analyzed. The net electrical efficiency is gained 57.8% [14]. MCFC is considered for high efficiency CO2 capture combined cycles [16]. The net electrical efficiency for the cycles discussed in this study is about 58%. MCFC is used in a hybrid system with a supercritical Brayton cycle [17]. In this study the results show that 56.25% electrical efficiency is achievable. By using CO2 as a working fluid near the critical point, low compression work has been shown to be needed [18]. Optimization theory of the thermodynamic cycles are investigated [19–23]. Optimum design of liquid recovery plants by genetic algorithm is investigated [24]. Optimization for a

M. Mehrpooya et al. / Sustainable Energy Technologies and Assessments 18 (2016) 100–106

101

Nomenclature A Deff D0 dp E Eact;an Eact;cat E0 e0i F G h i i0 L P P0 R rp s T T0 Uf V Welec

can cca

area, (m2) effective diffusivity constant (cm2 s
1) average particle diameter thermodynamic voltage (V) activation energy for anode (kJ mol
1) activation energy for cathode (kJ mol
1) thermodynamic voltage at standard condition (V) standard chemical exergy (kj/kg) Faraday constant, 96,485 (C mol
1) Gibbs free energy (kJ mol
1) enthalpy (kj/kg) current density (A cm
2) exchange current density (A cm
2) length, m pressure standard pressure (1 bar) gas constant, 8.314 J mol
1 K
1 average pore radius entropy (kj/kg °C) temperature (K) standard temperature (298 K) fuel utilization voltage (V) electric power (kW) pre-exponential factor for anode (A m
2) pre-exponential factor for cathode (A m
2)

solid oxide fuel cell is reported [25]. An irreversible-closed Intercooled-Recuperated (ICR) gas turbine cycle is optimised considering the ecological function[26]. Exergy analysis is tool which can be used for evaluation of the exergy systems [27–30]. Natural gas liquefaction processes are investigated by exergy method [31– 33]. Cyogenic air separation processes are investigated by exergy analysis method [34,35]. An endoreversible Brayton cycle used in a three generation system is considered by exergoeconomic analysis method [36]. Exergoeconomic analysis of the mixed refrigerant refrigeration cycles is done [37–39]. A CHP system with two-stage intercooled regenerative reheated closed Brayton cycle is introduced and analyzed based on the exergy method [40,41]. Brayton cycles thermodynamic analysis is investigated [42–44]. In this work a supercritical carbon dioxide cycle is coupled with a molten carbonate fuel cell system in order to boost the electrical efficiency of the system by waste heat recovery from the fuel cell

ci e gohmic gact gconc

activity porosity Ohmic loss, (V) activation loss, (V) concentration loss, (V)

Subscripts An anode Cat cathode C cell Act activation E electrolyte (s) solid (g) gas G generation P pressure Abbreviations HHV higher heating value LHV lower heating value SOFC solid oxide fuel cell MCFC molten carbonate fuel cell S/C steam to carbon ratio ST steam cycle GHG greenhouse gas

exhaust gases. Exergy analysis is used to explain the advantages of this proposed system. The objective of this research is to propose a feasible design of a high temperature fuel cell hybrid system which can satisfy the need for electrical power production while reducing the destructive effect of power plants on the environment. One advantage can be seen in Fig. 1, which illustrates the heat recovery process for three different working fluids: pure, zeotropic, and supercritical. With a supercritical fluid, more efficient composite curves are achievable.

Process description A general schematic of the S-CO2 Brayton cycle system is shown in Fig. 2. The system is mainly composed of a MCFC plant and a supercritical carbon dioxide Brayton cycle as the bottoming cycle.

Fig. 1. Heat recovery process with (a) pure fluid, (b) zeotropic fluid, and (c) supercritical fluid [45].

102

M. Mehrpooya et al. / Sustainable Energy Technologies and Assessments 18 (2016) 100–106

and then enters the heat exchanger, where it is preheated by recovering heat from the turbine exhaust stream. That stream next passes to another heat exchanger and the carbon dioxide attains its desired temperature. Next, the carbon dioxide enters the turbine section and produces shaft power which is used to drive the compressor and provide useful energy. The turbine exhaust stream is cooled after exiting the aforementioned heat exchanger and returns to its initial conditions. Fig. 2 illustrates the S-CO2 Brayton cycle process flow diagram. In this study, the inlet temperature for the compressor of S-CO2 Brayton cycle shown in Fig. 2 is assumed to be 35 °C, which is close to the critical point of CO2, while the minimum cycle pressure is fixed at 7.5 MPa. Simulation and computational results Fig. 2. Schematic of S-CO2 Brayton cycle.

Table 1 Natural gas composition. Constituent

Molar breakdown (%)

Methane CO CO2 Nitrogen Oxygen H2O Hydrogen Ethane

92.77 0.81 0.95 1.51 0 0 0.53 3.43

Natural gas, for which the composition is shown in Table 1, is converted to hydrogen in the reformer via the following reactions[46]:
1

DH298 ¼ 206 kJ mol

CH4 þ H2 O $ CO þ 3H2


1

DH298 ¼
41 kJ mol

CO þ H2 O $ CO2 þ H2

ð1Þ

System efficiency

ð2Þ

Based on the first law of thermodynamics, overall thermal efficiency is defined as follows [3,49]:

The mixture of water vapor and natural gas is preheated in the heat exchanger and fed to the reformer. The required heat for the reforming reactions in the reformer is supplied by the catalytic burner which burns the anode outlet in an air stream, which is preheated by part of cathode exhaust gases. The air stream provides the required amount of oxygen for the electrochemical reaction at the cathode side and further combustion of the fuel. The reformer outlet stream preheats the inlet steam and is cooled to the desired temperature, and enters the anode where it takes part in the electrochemical reaction [47]:
H2 þ CO2
3 ! CO2 þ H2 O þ 2e

CO þ

CO2
3




! 2CO2 þ 2e

ð3Þ ð4Þ

The anode outlet gas mixes with air and enters the catalytic burner. The high temperature outlet stream of the burner is a significant source of heat and provides the heat needed to allow the bottom cycle to attain the required performance. After the stream is fed to cathode where the following reaction occurs:


0:5O2 þ CO2 þ 2e !

CO2
3

The process is simulated by Aspen HYSYS software. In this work, the SRK equation of state is chosen for simulation of streams and components. The electrochemical modeling of the fuel cell is coded in Matlab software and the results are used for process simulation in HYSYS. The reformer is simulated by a plug reactor. A conversion reactor is selected for each electrode of the fuel cell. The carbonate ion is produced in the cathode and transferred to the anode. In order to transfer a greater amount of energy to the bottoming cycle, the outlet stream of the catalytic burner is used for heat recovery instead of the cathode outlet stream. This configuration result in a higher energy efficiency and has been shown to be preferable [45]. A process flow diagram of the proposed hybrid process is shown in Fig. 3. The inlet streams are at atmospheric pressure and 20 °C. The process outlet stream exits the process at 101 kPa and 130 °C. The parameter values used in the simulation for the process components are presented in Table 2. Table 3 shows the MCFC parameters and Table 4 presents the operating condition and stack characteristics.

ð5Þ

The carbonate ion produced at the cathode side is transferred to the anode side. The cathode exhaust gases contain a large amount of thermal energy which is used for preheating the inlet air stream and supplying the steam needed by the reformer. The supercritical carbon dioxide Brayton cycle is a closed regenerative cycle. The working fluid is pressurized in the compressor

gov erall;LHV ¼

W net þ Q Recov er heat mfuel  LHV fuel

ð6Þ

Here, W net is the net power produced by the system and ðmfuel  LHV fuel Þ is the fuel input energy based on lower heating value. Another definition of overall thermal efficiency is suggested as follows [49]:

gnetov erall;LHV ¼

W net mfuel  LHV fuel
Q recov er

ð7Þ heat

This relation is preferable since the importance and value of work is recognized. Other kinds of efficiency definitions used in this work and their expressions are presented in Table 5. The effect of addition of the bottoming cycle on electrical efficiency is shown in Fig. 4. The net electrical efficiency is 66% and this value is considerable compared to the efficiency reported for the similar cases. Exergy analysis and efficiency Exergy analysis is an increasingly common method to develop strategies for using energy efficiently. The exergy of a material consists of four components: physical, chemical, kinetic, and potential. In this study, kinetic and potential parts are neglected because changes of speed and elevation are negligible [50]. Physical exergy is defined as the maximum work obtained from system as it interacts with a reference environment at an equilibrium state [51].

103

M. Mehrpooya et al. / Sustainable Energy Technologies and Assessments 18 (2016) 100–106

Fig. 3. Process flow diagram of the MCFC/S-CO2 Brayton cycle.

Table 2 Parameter values for process components utilized in the simulation. Heat exchanger Solution method Simple weighted

Heat loss 0

Compressor Type

Adiabatic efficiency (%)

Centrifugal

85

Tolerance 1  10
4

Maximum iteration 25

Polytropic efficiency (%)

Polytropic method

Friction loss factor (kg m2/s)

Nozzle diameter (m)

86.2

Schults

6  10
6

5  10
2

Turbine Adiabatic efficiency (%)

Polytrophic efficiency (%)

Friction loss factor (kg m2/s)

Nozzle diameter (m)

85

83.9

6  10
6

5  10
2

Recycle Calculation method

Acceleration

Acceleration frequency

Maximum iteration

Iteration count

Flash type

PSD properties

Nested

Wegstein

3

10

0

PT Flash

1  10
3

Table 4 Fuel cell characteristics and input data.

Table 3 MCFC parameters. Parameter Temperature input streams Natural gas Air Water Ambient pressure Adiabatic compressor efficiency Pre-reformer conversion S/C in reformer Pressure drop in fuel cell Pressure drop in reformer

Value 20 15 25 101.3 0.75 40% 3 [48] 0 28.6

Unit °C °C °C kPa – – – kPa kPa

Chemical exergy is related to the chemical composition and its departure from the chemical equilibrium of the reference environment [51]. Specific physical and chemical exergy can be evaluated respectively as follows:

Unit

Value

Input

°C °C – – – °C – Bar °C A cm
2 V cm2 –

20 15 40 3.2 0.9 699.1 21% O2, 79% N2 2.71 134 0.3 1.1 320 215,000

Fuel inlet temperature Air inlet temperature Amount of methane conversion (%) Steam-to-carbon ratio Fuel utilization Nominal cell temperature Air gas inlet composition Pressure Steam temperature Cell current density Cell voltage Active cell area Number of cell

eph ¼ h
h0
T 0 ðs
s0 Þ ech ¼

X

xi e0i þ RT 0

X

xi lnxi ci

ð8Þ ð9Þ

104

M. Mehrpooya et al. / Sustainable Energy Technologies and Assessments 18 (2016) 100–106

The first step of exergy analysis is to calculate the exergy of material streams. This evaluation requires the stream specific enthalpy and entropy values, which are provided by process simulator. Then, exergy balance which is shown in Eq. (10) is written for each component [47]. The thermodynamic data used to evaluate the exergies of the material streams are summarized in Table 6. In order to find out the contribution of each component to the system exergy destruction, the exergy destruction is evaluated next using the following exergy balance.

Table 5 Efficiency of the system based on the various definitions. Parameter

Expression

Value (%)

Net overall thermal efficiency (LHV basis) Electrical efficiency (LHV basis)

W net gnetov erall;LHV ¼ mfuel LHV fuel
Q recov er

MCFC cycle efficiency (LHV basis)

W DC gMCFC;LHV ¼ ðmfuel;in LHV fuel Þ

net gelec;LHV ¼ mfuelWLHV fuel

78 heat

66 35

anode inlet

Note: DC in WDC is abbreviation of direct current.

Exi þ ExQi ¼ Ex0 þ ExQo þ W sh þ I

ð10Þ

where Exi and Exo are the inlet and outlet flow exergy of the material streams, ExQi and ExQo are the inlet and outlet exergies of the thermal energy streams, Wsh is shaft work and I is exergy destruction. Another important parameter is the exergy efficiency. This is evaluated here for the system and its components; in general it differs for each component. The definition for the exergy efficiency of each component is presented in Table 7. A general basis for the recovered exergy efficiency definition is: g ¼ Exergy [47]. The exergy Exergy supplied

analysis results are shown in Table 4. Fig. 5 illustrates the share each component contributes to the system exergy destruction. Also Table 8 presents exergy efficiencies and destruction rates of the process components.

Fig. 4. Effect of bottoming cycle on electrical efficiency.

Table 6 Exergy rates and other properties of material streams. Stream

Total exergy rate (kW)

Physical exergy rate (kW)

Chemical exergy rate (kW)

Enthalpy rate (kW)

Entropy rate (kW/°C)

1 2 3 4 5 6 7 8 9 10 11 12 Air NG Water Steam To reformer Anode inlet Anode outlet Cathode inlet Burner inlet Burner outlet Outlet

343 7200 8382 64,537 3470 2766 23,621 20,349 15,393 14,851 15,819 20,046 14 6870 98 383 7301 8192 69,189 65,973 68,893 69,896 2103

329 232 691 11,766 1579 875 13,551 10,279 5323 4781 5749 9976 0 0 0 285 334 500 11,837 14,136 11,762 18,059 212

14 6967 7691 52,771 1890 1890 10,070 10,070 10,070 10,070 10,070 10,070 14 6870 98 98 6967 7691 57,351 51,837 57,131 51,837 1890

8250
205,106
117,003
30,175
42,773
49,557
364,947
371,230
391,280
398453
396,265
376,215
153
77,229
286356
238,659
197,939
122,523
53,044
36,211
28,613
19,075
58,513

171 188 201 277 196 188 178 179 145 125 126 165 151 185 53 183 203 195 263 250 233 267 171

Table 7 Exergy destruction rates and efficiency definitions for the overall process and its components. Components Compressor Heat exchanger Turbine Separator/mixer Pre-reformer Fuel cell system (overall process)

Exergy destruction _ i
Ex_ 0 ¼ P ðmeÞ _
P ðmeÞ _ i þW _ 0 I_ ¼ Ex P _I ¼ Ex _ i
Ex_ 0 ¼ P ðmeÞ _ i
ðmeÞ _ 0 _ i
Ex_ 0 ¼ P ðmeÞ _
P ðmeÞ _ i
W _ 0 I_ ¼ Ex P _I ¼ Ex _ i
Ex_ 0 ¼ P ðmeÞ _ i
ðmeÞ _ 0 P _ i
Ex_ 0 ¼ P ðmeÞ _ i
ðmeÞ _ 0 I_ ¼ Ex _ i
Ex_ 0 ¼ I_ ¼ Ex

P

_ i
ðmeÞ

P

Exergy efficiency P P _ i
_ 0 ðmeÞ ðmeÞ e¼ _ WPn   Pm   _ DeÞ _ DeÞ ðm ðm e ¼ 1
Pn1 _
Pm1 _ 1

ðmDhÞ

_ W P e ¼ P ðmeÞ _ _
ðmeÞ

P

i

h

1

ðmDhÞ

0

_ ðmeÞ

0 e ¼ P ðmeÞ _

P

i

_ ðmeÞ

0 e ¼ P ðmeÞ _ i

_ 0 ðmeÞ

of desired output ðelectricityÞ e ¼ Total exergyRequired exergy input

c

M. Mehrpooya et al. / Sustainable Energy Technologies and Assessments 18 (2016) 100–106

105

Fig. 5. Breakdown of component exergy losses (components beginning with ‘‘E-” are heat exchangers).

Table 8 Exergy efficiencies and destruction rates of base process components. Component

Exergy efficiency (%)

Exergy destruction rate (kW)

Compressor Heat exchanger E-100 E-101 E-102 E-104 Turbine Reformer Fuel cell system (overall process)

88

126

93 91 96 94 96 87 50

377 347 729 375 130 1082 3512

Conclusions In the present study, a molten carbonate fuel cell-supercritical carbon dioxide Brayton cycle, proposed in order to increase the power production and waste heat recovery, is successfully simulated. The overall thermal efficiency of the system is 78% which suggests the proposed system may be thermodynamically advantageous. Using carbon dioxide as a working fluid not only reduces some of the thermodynamic limitations exhibited by other fluids but also mitigates impact on environment in the form of climate change. This is particularly important since emissions of greenhouse gases, especially CO2, and their role in global warming, are causing most countries/regions to seek ways to lower such emissions and raise process efficiencies. Designs such as the one described in this article are attracting increasing attention in recent years because of their advantages. Further investigation and analysis is merited to further improve understanding of the system, and would be useful to boost public awareness and make this kind of technology more common. References [1] Mehrpooya M, Hemmatabady H, Ahmadi MH. Optimization of performance of combined solar collector-geothermal heat pump systems to supply thermal load needed for heating greenhouses. Energy Convers Manage 2015;97:382–92. [2] Mehrpooya M, Sharifzadeh MMM, Rosen MA. Energy and exergy analyses of a novel power cycle using the cold of LNG (liquefied natural gas) and lowtemperature solar energy. Energy 2016;95:324–45. [3] Aghaie M, Mehrpooya M, Pourfayaz F. Introducing an integrated chemical looping hydrogen production, inherent carbon capture and solid oxide fuel cell biomass fueled power plant process configuration. Energy Convers Manage 2016;124:141–54.

[4] Ahmadi MH, Mehrpooya M, Pourfayaz F. Exergoeconomic analysis and multi objective optimization of performance of a carbon dioxide power cycle driven by geothermal energy with liquefied natural gas as its heat sink. Energy Convers Manage 2016;119:422–34. [5] Massardo FLAF. Eng Gas Turbines Power-Trans ASME 2000;122:27–35. [6] Roberts JBRA, Liese E, Gemmen RS. Eng Gas Turbines Power-Trans ASME 2006;128(128):294–301. [7] Ferrari ELML, Tucker D, Lawson L, Traverso A, Massardo AF. Eng Gas Turbines Power-Trans ASME 2007;129:1012–9. [8] Mehrpooya M, Akbarpour S, Vatani A, Rosen MA. Modeling and optimum design of hybrid solid oxide fuel cell-gas turbine power plants. Int J Hydrogen Energy 2014;39:21196–214. [9] Mehrpooya M, Daviran S. Dynamic modeling of a hybrid photovoltaic system with hydrogen/air PEM fuel cell. Iranica J Energy Environ 2013;4:104–9. [10] Mehrpooya M. Conceptual design and energy analysis of novel integrated liquefied natural gas and fuel cell electrochemical power plant processes. Energy 2016;111:468–83. [11] Mamaghani AH, Najafi B, Shirazi A, Rinaldi F. Exergetic, economic, and environmental evaluations and multi-objective optimization of a combined molten carbonate fuel cell-gas turbine system. Appl Therm Eng 2015;77:1–11. [12] Dostal V. A supercritical carbon dioxide cycle for next generation nuclear reactors. Massachusetts Institute of Technology; 2004. [13] Sánchez D, Chacartegui R, Jiménez-Espadafor F, Sánchez T. A new concept for high temperature fuel cell hybrid systems using supercritical carbon dioxide. J Fuel Cell Sci Technol 2009;6:021306. [14] Sánchez D, Chacartegui R, Muñoz de Escalona JM, Muñoz A, Sánchez T. Performance analysis of a MCFC & supercritical carbon dioxide hybrid cycle under part load operation. Int J Hydrogen Energy 2011;36:10327–36. [15] Sánchez D, Muñoz de Escalona JM, Chacartegui R, Muñoz A, Sánchez T. A comparison between molten carbonate fuel cells based hybrid systems using air and supercritical carbon dioxide Brayton cycles with state of the art technology. J Power Sources 2011;196:4347–54. [16] Campanari S, Manzolini G, Chiesa P. Using MCFC for high efficiency CO2 capture from natural gas combined cycles: comparison of internal and external reforming. Appl Energy 2013;112:772–83. [17] Baronci A, Messina G, McPhail SJ, Moreno A. Numerical investigation of a MCFC (molten carbonate fuel cell) system hybridized with a supercritical CO2 Brayton cycle and compared with a bottoming organic rankine cycle. Energy 2015;93:1063–73. [18] Ma Z, Turchi C. Advanced supercritical carbon dioxide power cycle configurations for use in concentrating solar power systems. In: Proceedings of supercritical CO2 power cycle symposium; 2011. p. 24–5. [19] Chen L, Wu C, Sun F. Finite time thermodynamic optimization or entropy generation minimization of energy systems. J Non-Equilib Thermodyn 1999;24:327–59. [20] Wu C. Recent advances in finite-time thermodynamics. Nova Publishers; 1999. [21] Chen L. Advances in finite time thermodynamics: analysis and optimization. Nova Publishers; 2004. [22] Chen L, Xia S. Generalized thermodynamic dynamic-optimization for irreversible processes. Beijing, China: Science Press; 2016. [23] Ge Y, Chen L, Sun F. Progress in finite time thermodynamic studies for internal combustion engine cycles. Entropy 2016;18:139. [24] Mehrpooya M, Vatani A, Mousavian S. Optimum design of integrated liquid recovery plants by variable population size genetic algorithm. Can J Chem Eng 2010;88:1054–64. [25] Feng H, Chen L, Xie Z, Sun F. Constructal optimization for a single tubular solid oxide fuel cell. J Power Sources 2015;286:406–13. [26] Wang W, Chen L, Sun F. Ecological optimisation of an irreversible-closed ICR gas turbine cycle. Int J Exergy 2011;9:66–79.

106

M. Mehrpooya et al. / Sustainable Energy Technologies and Assessments 18 (2016) 100–106

[27] Tirandazi B, Mehrpooya M, Vatani A, Moosavian SA. Exergy analysis of C+2 recovery plants refrigeration cycles. Chem Eng Res Des 2011;89:676–89. [28] Mehdi Mehrpooya Ã, Gharagheizi F, Vatani A. Thermoeconomic analysis of a large industrial propane refrigeration cycle used in NGL recovery plant. Int J Energy Res 2009;33:960–77. [29] Mehrpooya M, Vatani A, Moosavian SA. Introducing a new parameter for evaluating the degree of integration in cryogenic liquid recovery processes. Chem Eng Process 2011;50:916–30. [30] Mehrpooya M, Hossieni M, Vatani A. Novel LNG-based integrated process configuration alternatives for coproduction of LNG and NGL. Ind Eng Chem Res 2014;53:17705–21. [31] Vatani A, Mehrpooya M, Palizdar A. Advanced exergetic analysis of five natural gas liquefaction processes. Energy Convers Manage 2014;78:720–37. [32] Vatani A, Mehrpooya M, Palizdar A. Energy and exergy analyses of five conventional liquefied natural gas processes. Int J Energy Res 2014;38:1843–63. [33] Vatani A, Mehrpooya M, Tirandazi B. A novel process configuration for coproduction of NGL and LNG with low energy requirement. Chem Eng Process 2013;63:16–24. [34] Mehrpooya M, Sharifzadeh MMM, Rosen MA. Optimum design and exergy analysis of a novel cryogenic air separation process with LNG (liquefied natural gas) cold energy utilization. Energy 2015;90:2047–69. [35] Mehrpooya M, Kalhorzadeh M, Chahartaghi M. Investigation of novel integrated air separation processes, cold energy recovery of liquefied natural gas and carbon dioxide power cycle. J Cleaner Prod 2015. [36] Chen L, Feng H, Sun F. Exergoeconomic performance optimization for a combined cooling, heating and power generation plant with an endoreversible closed Brayton cycle. Math Comput Model 2011;54:2785–801. [37] Mehrpooya M, Ansarinasab H. Exergoeconomic evaluation of single mixed refrigerant natural gas liquefaction processes. Energy Convers Manage 2015;99:400–13. [38] Mehrpooya M, Ansarinasab H. Advanced exergoeconomic evaluation of single mixed refrigerant natural gas liquefaction processes. J Nat Gas Sci Eng 2015;26:782–91. [39] Mehrpooya M, Ansarinasab H. Advanced exergoeconomic analysis of the multistage mixed refrigerant systems. Energy Convers Manage 2015;103:705–16.

[40] Yang B, Chen L, Ge Y, Sun F. Exergy performance analyses of an irreversible two-stage intercooled regenerative reheated closed Brayton CHP plant. Int J Exergy 2014;14:459–83. [41] Yang B, Chen L, Ge Y, Sun F. Exergy performance optimization of an irreversible closed intercooled regenerative Brayton cogeneration plant. Arabian J Sci Eng 2014;39:6385–97. [42] Zhang Z, Chen L, Yang B, Ge Y, Sun F. Thermodynamic analysis and optimization of an air Brayton cycle for recovering waste heat of blast furnace slag. Appl Therm Eng 2015;90:742–8. [43] Chen L, Ni D, Zhang Z, Sun F. Exergetic performance optimization for new combined intercooled regenerative Brayton and inverse Brayton cycles. Appl Therm Eng 2016;102:447–53. [44] Yang B, Chen L, Sun F. Exergetic performance optimization of an endoreversible variable-temperature heat reservoirs intercooled regenerated Brayton cogeneration plant. J Energy Inst 2016;89:1–11. [45] Baronci A, Messina G, McPhail SJ, Moreno A. Numerical investigation of a MCFC (molten carbonate fuel cell) system hybridized with a supercritical CO2 Brayton cycle and compared with a bottoming organic rankine cycle. Energy 2015;93(Part 1):1063–73. [46] Silveira JL, Leal EM, Ragonha LF. Analysis of a molten carbonate fuel cell: cogeneration to produce electricity and cold water. Energy 2001;26:891–904. [47] Yazdanfar J, Mehrpooya M, Yousefi H, Palizdar A. Energy and exergy analysis and optimal design of the hybrid molten carbonate fuel cell power plant and carbon dioxide capturing process. Energy Convers Manage 2015;98:15–27. [48] De Simon G, Parodi F, Fermeglia M, Taccani R. Simulation of process for electrical energy production based on molten carbonate fuel cells. J Power Sources 2003;115:210–8. [49] Mehrpooya M, Dehghani H, Ali Moosavian SM. Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system. J Power Sources 2016;306:107–23. [50] Al-Sulaiman FA, Dincer I, Hamdullahpur F. Exergy analysis of an integrated solid oxide fuel cell and organic Rankine cycle for cooling, heating and power production. J Power Sources 2010;195:2346–54. [51] Ahmadi P, Dincer I, Rosen MA. Exergo-environmental analysis of an integrated organic Rankine cycle for trigeneration. Energy Convers Manage 2012;64:447–53.