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Frontiers in Energy

ISSN 2095-1701

ISSN 2095-1698(Online)

CN 11-6017/TK

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Front. Energy    2017, Vol. 11 Issue (4) : 510-515    https://doi.org/10.1007/s11708-017-0508-0
RESEARCH ARTICLE
Exergy analysis and performance enhancement of isopropanol-acetone-hydrogen chemical heat pump
Min XU, Jun CAI, Xiulan HUAI()
Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
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Abstract

Exergy loss analysis was conducted to identify the irreversibility in each component of the isopropanol-acetone-hydrogen chemical heat pump (IAH-CHP). The results indicate that the highest irreversibility on a system basis occurs in the distillation column. Moreover, the effect of operating parameters on thermodynamic performances of the IAH-CHP was studied and the optimal conditions were obtained. Finally, the potential methods to reduce the irreversibility of the IAH-CHP system were investigated. It is found that reactive distillation is apromising alternative. The enthalpy and exergy efficiency of the IAH-CHP with reactive distillation increases by 24.1% and 23.2%, respectively.
Keywords waste heat reuse      chemical heat pump      exergy analysis      isopropanol     
Corresponding Author(s): Xiulan HUAI   
Just Accepted Date: 28 September 2017   Online First Date: 15 November 2017    Issue Date: 14 December 2017
 Cite this article:   
Min XU,Jun CAI,Xiulan HUAI. Exergy analysis and performance enhancement of isopropanol-acetone-hydrogen chemical heat pump[J]. Front. Energy, 2017, 11(4): 510-515.
 URL:  
https://academic.hep.com.cn/fie/EN/10.1007/s11708-017-0508-0
https://academic.hep.com.cn/fie/EN/Y2017/V11/I4/510
Fig.1  Schematic diagram of isopropanol-acetone-hydrogenchemical heat pump
Contents Specifications
RadFrac (distillation column) Total stages 15
Feed stage 6
Column pressure/MPa 0.1
Distillate flow rate/(mol?s-1) 0.3
Catalyst loading in reboiler/kg 3.1
RPlug (exothermic reactor) Length/m 5
Diameter/m 0.1
Catalyst density/(kg?m-3) 2000
Bed voidage 0.4
Inlet temperature of the reactant/K 453
Pressure/MPa 0.14
Hydrogen to Acetone mole ratio, CH/Cace 1
Inlet temperature of the coolant/K 433
Coolant flow rate/(mol?s-1) 1
Compr(compressor) Isentropic efficiency 0.72
Mechanical efficiency 1
Tab.1  Specificationsand operation conditions of IAH chemical heat pump in simulations
Stream T/K P/MPa Mass flow rate/(kg?h-1) H/(kJ?kg-1) S/(kJ?kg-1?K-1)
1 312.13 0.10 32.45 3121.58 2.99
2 334.77 0.14 32.45 3345.05 3.08
3 453.15 0.14 32.45 3581.69 3.37
4 481.90 0.14 32.45 3766.76 2.77
5 366.40 0.14 32.45 3530.12 3.64
6 433.15 0.50 64.85 13088.21 2.31
7 480.09 0.50 64.85 13180.81 2.51
Tab.2  Property dataof the streams for the IAH-CHP system
Components Exergy loss/kW Performances Value
Distillation column 3.1893 QH (kW) 1.668
Recuperator 0.1174 W (kW) 0.248
Compressor 0.2150 COP 0.086
Exothermic reactor 0.2514 h 0.180
Tab.3  Exergy lossofeach component and the thermodynamic performances for the IAH-CHPsystem
Fig.2  Effect of pressure of distillationcolumn and exothermic reactor on COP and exergy efficiency
Fig.3  Fig.3 Effect of pressure of distillation column on exergyloss in distillation column
Fig.4  Effect of mole content ofisopropanol in distillate
Fig.5  Effect of inlet temperatureof reactant in exothermic reactor on COP and exergy efficiency
Fig.6  Effect of inlet temperatureof reactant in exothermic reactor on exergy loss in distillation column
Fig.7  Profile of distillation columntemperature with and without reactive distillation (the stage No.is counted from the top to bottom including the stages of condenserand reboiler.)
Exergy loss COP h(Exergy efficiency)
Distillation column Recuperator Compressor Exothermic reactor
Without reactive distillation part 1.5104 0.0692 0.2514 0.2282 0.1517 0.3357
With reactive distillation part 1.0287 0.0692 0.2514 0.2282 0.1883 0.4137
Tab.4  Comparison ofthe operating performances between the IAH chemical heat pump withand without reactive distillation part at Pdis = 0.12 MPa, Pexo = 0.12 MPa
C Concentration/(mol?m-3)
COP Coefficient of performance
Ea Activation energy/(kJ?mol-1)
H Enthalpy/(kJ?mol-1)
Iirr Exergy loss/kW
k Chemical rate constant/(mol?gcat-1?h-1)
K Equilibrium adsorption constant
P Pressure/MPa
QC Heat of the condenser/kW
QH Heat released from the exothermicreactor/kW
QL Heat consumed by the endothermicreactor/kW
r Reaction rate/(mol?gcat-1?h-1)
R Gas constant/(J?mol-1?K-1)
S Entropy/(kJ?mol-1?K-1)
T Temperature/K
TH High temperature/K
TL Low temperature/K
T0 Environment temperature/K
W Energy input/kW
x Mole fraction in liquid phase
y Mole fraction in gas phase
Y Exergy destroged
η Exergy efficiency
ace Acetone
C Condenser
d Dehydrogenation
dis Distillation column
exo Exothermic reactor
feed Feed of the distillation column
H High temperature
in Inlet
iso Isopropanol
L Low temperature
out Outlet
  
1 Spoelstra S, Haije  W G, Dijkstra  J W. Techno-economic feasibility of high-temperature high-lift chemical heat pumps for upgrading industrial waste heat. Applied Thermal Engineering, 2002, 22(14): 1619–1630
https://doi.org/10.1016/S1359-4311(02)00077-7
2 Gandia L M, Montes  M. Effect of the design variables on the energy performance and size parameters of a heat transformer based on the system acetone/H2/2-propanol. International Journal of Energy Research, 1992, 16(9): 851–864
https://doi.org/10.1002/er.4440160907
3 Kim T G, Yeo  Y K, Song  H K. Chemical heat pump based on dehydrogenation and hydrogenation of i-propanol and acetone. International Journal of Energy Research, 1992, 16(9): 897–916
https://doi.org/10.1002/er.4440160910
4 Chung Y, Jeong  H K, Song  H K, Park  W H. Modelling and simulation of the chemical reaction heat pump system adopting the reactive distillation process. Computers & Chemical Engineering, 1997, 21: S1007–S1012
https://doi.org/10.1016/S0098-1354(97)87634-X
5 KlinSoda I, Piumsomboon  P. Isopropanol-Acetone-Hydrogen chemical heat pump: a demonstration unit. Energy Conversion and Management, 2007, 48(4): 1200–1207
https://doi.org/10.1016/j.enconman.2006.10.006
6 Esen H, Inalli  M, Esen M ,  Pihtili K . Energy and exergy analysis of a ground-coupled heat pump system with two horizontal ground heat exchangers. Building and Environment, 2007, 42(10): 3606–3615
https://doi.org/10.1016/j.buildenv.2006.10.014
7 OzgenerO, Hepbasli A. A review on the energy and exergy analysis of solar assisted heat pump systems.Renewable & Sustainable Energy Reviews, 2007, 11(3): 482–496 doi:10.1016/j.rser.2004.12.010
8 Xu M, Xin  F, Li X ,  Huai X, Guo  J, Liu H . Equilibrium model and performances of Isopropanol-Acetone-Hydrogen chemical heat pump with reactive distillation column. Industrial & Engineering Chemistry Research, 2013, 52(11): 4040–4048
https://doi.org/10.1021/ie3028872
9 Kato Y, Nakagawa  N, Kameyama H . Study of Chemical heat pump with reaction couple of acetone hydrogenation/2-propanol dehydrogenation: kinetics of the hydrogenation of acetone. Kagaku Ronbunshu, 1987, 13(5): 714–717
https://doi.org/10.1252/kakoronbunshu.13.714
[1] S. NIKBAKHT NASERABAD,K. MOBINI,A. MEHRPANAHI,M. R. ALIGOODARZ. Exergy-energy analysis of full repowering of a steam power plant[J]. Front. Energy, 2015, 9(1): 54-67.
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