Simulation and Optimization of Rankine Power Generation Cycle Purposing the Efficiency of Liquefied Natural Gas Cold Exergy

Document Type : Research Article

Authors

1 Imam Khomeini international university, Qazvin, Iran

2 Imam Khomeini International University

Abstract

Liquefied natural gas is obtained by cooling the natural gas to −162℃ at the atmospheric pressure. Methane is the major chemical component of liquefied natural gas which varies between 87.0–99.8% for different sources. The cryogenic power generation cycle using liquefied natural gas as its heat sink is known to be one of the considerable ways for the liquefied natural gas exergy recovery. A double-stage Rankine power generation cycle using the single component working fluid in each stage for liquefied natural gas cold exergy recovery is used as a base case in the present study. To improve the recovery of liquefied natural gas cold exergy, a three-stage Rankine power generation cycle has been proposed using mixture working fluid. Optimization is done using the particle swarm algorithm. The performance of the three-stage Rankine power generation cycle is studied regarding the effects of thermal efficiencies, exergy efficiencies, overall heat transfer coefficient of condensers and natural gas distribution pressure. Specific power production of the cycle is 100.45, thermal efficiency is 12.76%, and exergy efficiency is 27.92%. By decreasing the total coefficient of heat transfer, the condensers of different stages of the cycle reduce the maximum output power of the cycle with different trends. The results show that by decreasing the distribution pressure of natural gas, specific power production, thermal efficiency and exergy efficiency increases. So that their optimal values at 6 bar are 290.87, 25.63% and 39.12%, respectively.
 

Keywords

Main Subjects


[1]   B.B. Kanbur, L. Xaing, S. Dubey, F.H. Choo, F. Duan, Cold utilization systems of LNG: A review, Renewable and Sustainable Energy Reviews, 79 (2017) 1171–1188.
[2]   A. Atienza-Márquez, J.C. Bruno, A. Coronas, Cold recovery from LNG-regasification for polygeneration applications, Applied Thermal Engineering, 132 (2018) 463-478.
[3]   G. R. Gómez, R. F. Garcia, J. R. Gómez, J. C. Carril, Review of thermal cycles exploiting the exergy of liquefied natural gas in the regasification process, Renewable and Sustainable Energy Reviews, 38 (2014) 781–795.
[4]   Z. Sun, F Xu, S. Wang, J. Lai, K. Lin, Comparative study of Rankine cycle configurations utilizing LNG cold energy under different NG distribution pressures, Energy, 139 (2017) 380-393.
[5]   M. Badami, J.C. Bruno, A. Coronas, G. Fambri, Analysis of different combined cycles and working fluids for LNG exergy recovery during regasification, Energy, 159 (2018) 373-384.
[6]   H. Sun, H. Zhu, F. Liu, H. Ding, Simulation and optimization of a novel Rankine power cycle for recovering cold energy from liquefied natural gas using a mixed working fluid, Energy, 70 (3) (2014) 317-324.
[7]   U. Lee, A. Mitsos, Optimal multi component working fluid of organic Rankine cycle for exergy transfer from liquefied natural gas regasification, Energy, 127 (2017) 489-501.
[8]   Z. Sun, J. Lai, S. Wang, T. Wang, Thermodynamic optimization and comparative study of different ORC configurations utilizing the exergies of LNG and low-grade heat of different temperatures, Energy, 147 (2018) 688-700
[9]   T. Sung, K.C. Kim, Thermodynamic analysis of a novel dual-loop organic Rankine cycle for engine waste heat and LNG cold, Applied Thermal Engineering, 100 (2016) 1031-41.
[10]           I.H. Choi, S. Lee, Y. Seo, D. Chang, Analysis and optimization of cascade Rankine cycle for liquefied natural gas cold energy recovery, Energy, 61 (2013) 179–95.
[11]           R.F. García, J.C. Carril, J.R. Gomez, M.R. Gomez, combined cascaded Rankine and direct expander-based power units using LNG (liquefied natural gas) cold as heat sink in LNG regasification, Energy, 105 (2016) 16-24.
[12]           P.A. Ferreira, I. Catarino, D. Vaz, Thermodynamic analysis for working fluids comparison in Rankine-type cycles exploiting the cryogenic exergy in Liquefied Natural Gas (LNG) regasification, Applied Thermal Engineering, 121 (2017) 887-96.
[13]           F. Xue, Y. Chen, Y. Ju, Design and optimization of a novel cryogenic Rankine power generation system employing binary and ternary mixtures as working fluids based on the cold exergy utilization of liquefied natural gas (LNG), Energy, 138 (2017) 706-720.
[14]           J. Bao, Y. Lin, R. Zhang, N. Zhang, G. He, strengthening power generation efficiency utilizing liquefied natural gas cold energy by a novel two-stage condensation Rankine cycle (TCRC) system, Energy Convers Manag, 143 (2017) 312-25.
[15]           K. Kim, U. Lee, C. Kim, C. Han, Design and optimization of cascade organic Rankine cycle for recovering cryogenic energy from liquefied natural gas using binary working fluid, Energy, 88 (2015) 304-313.
[16]           G. Venkatarathnam, Cryogenic Mixed Refrigerant Processes, New York, Springer, 2013.
[17]           H. Yu, D. Kim, T. Gundersen, A study of working fluids for Organic Rankine Cycles (ORCs) operating across and below ambient temperature to utilize Liquefied Natural Gas (LNG) cold energy, Energy, 167 (2019) 730-739.
[18]           J. Bao, R. Zhang, Y. Lin, N. Zhang, X. Zhang, G. He, Simultaneous optimization of system structure and working fluid for the three-stage condensation Rankine cycle utilizing LNG cold energy, Applied Thermal Engineering, 140 (2018) 120–130.
[19]           J. Pospíšila, P. Charvátb, O. Arsenyevac, L. Klimeša, M. Špiláčeka, J. J. Klemeša, Energy demand of liquefaction and regasification of natural gas and the potential of LNG for operative thermal energy storage, Renewable and Sustainable Energy Reviews, 99 (2019) 1–15.
[20]           A. Sadeghi, M.K. Parpinchi, S.A. Sadatsakak, M. Khanaki, Optimization of the two stage Rankine power generation cycle by using mixed working fluid for the use of cold energy liquefied natural gas, third national conference on air conditioning and thermal and refrigerating installations, (2017). (In Persian)
[21]           A. Moradi, M. Mafi, M. Khanaki, Sensitivity analysis of peak-shaving natural gas liquefaction cycles to environmental and operational parameters, Modares Mechanical Engineering, 15 (2015) 287-298. (In Persian)
[22]           M. Mehrpooya, M. Ashouri, A. Mohammadi, Thermoeconomic analysis and optimization of a regenerative two-stage organic Rankine cycle coupled with liquefied natural gas and solar energy, Energy,126 (2017) 899-914.
[23]           A. Sadreddini, M.A. Ashjari, M. Fani, A. Mohammadi, Thermodynamic analysis of a new cascade ORC and transcritical CO2 cycle to recover energy from medium temperature heat source and liquefied natural gas, Energy Conversion and Management, 167 (2018) 9–20.
[24]           J. Kennedy, R. Eberhart, Particle Swarm Optimization, Proceedings of IEEE International Conference on Neural Networks IV, (1995) 1942–1948.