Genetic algorithm optimization of two natural gas liquefaction methods based on energy, exergy, and economy analyses: the case study of Shahid Rajaee power plant peak-shaving system

Document Type : Research Article


1 Department of Mechanical Engineering, West Tehran Branch, Islamic Azad University, Tehran, Iran

2 Department of Mechanical Engineering, Imam Khomeini International University, Qazvin, Iran


Power plants have problems  supplying fuel in the cold season due to the high domestic demand for natural gas. Therefore, they use alternative fuels such as diesel and fuel oil, which reduce the plant's efficiency and cause environmental problems. Fuel peak-shaving is a solution that means liquefaction and storage of natural gas in hot seasons and then using it in cold seasons. Two cycles of the PRICO and LIMUM3 liquefaction methods, which are the two most peak-shaving cycles in natural gas liquefaction, have been studied and optimized for the case study Shahid Rajaee power plant in Qazvin city, Iran. By performing energy, exergy, and economy analyses, these two cycles are compared. A genetic algorithm is used to optimize and find the appropriate values of the key parameters. Using optimization, the SEC value in PRICO and LIMUM3 cycles experienced +0.15 and +0.12 improvement, respectively. PRICO with SEC value of 0.268 performed better than the other cycle with a value of 0.317. The annual capital expenditure (CAPEX) of the PRICO cycle was 9.12 million $, which is higher than the other cycle by 7.58 million $. The annual cost of operation (OPEX) is saved in the PRICO cycle due to the lower SEC and power consumption. The annual total cost of PRICO is 23.81 million $, which is 6.1% less than that of the LIMUM3 cycle. Finally, by comparing the results, the PRICO cycle was found to be more suitable than LIMUM3 for the peak-shaving of the Shahid Rajaee power plant.


Aslambakhsh, A. H., Moosavian, M. A., Amidpour, M., Hosseini, M., & AmirAfshar, S. (2018). Global cost optimization of a mini-scale liquefied natural gas plant. Energy, 148, 1191-1200.
Cardella, U., Decker, L., & Klein, H. (2018). Large-scale hydrogen liquefaction by means of a high pressure hydrogen refrigeration cycle combined to a novel single mixed-refrigerant precooling: Google Patents.
Couper, J., Hartz, D., & Smith, F. (2008). Process Economics.-Section 9.-53 P. in «Perry’s Chemical Engineer’s Handbook»: McGraw-Hill Co.–US.-2008.
Couper, J. R., Hertz, D. W., & Smith, F. L. (2008). Process economics: McGraw-Hill.
Couper, J. R., Penney, W. R., Fair, J. R., & Walas, S. M. (2005). Chemical process equipment: selection and design: Gulf professional publishing.
Fazlali Serkani, A., & Mafi, M. (2020). Sensitivity Analysis of Simple Expander– Nitrogen and Two Expander –Nitrogen Liquefaction Processes of Natural Gas. Gas Processing Journal, 8(1), 49-68. doi:10.22108/gpj.2020.120038.1070
Fratzscher, W. (1997). The exergy method of thermal plant analysis. International Journal of Refrigeration, 5(20), 374.
Ghorbani, B., Ebrahimi, A., Moradi, M., & Ziabasharhagh, M. (2020). Energy, exergy and sensitivity analyses of a novel hybrid structure for generation of Bio-Liquefied natural Gas, desalinated water and power using solar photovoltaic and geothermal source. Energy Conversion and Management, 222, 113215.
Ghorbani, B., Ebrahimi, A., Rooholamini, S., & Ziabasharhagh, M. (2020). Pinch and exergy evaluation of Kalina/Rankine/gas/steam combined power cycles for tri-generation of power, cooling and hot water using liquefied natural gas regasification. Energy Conversion and Management, 223, 113328.
Ghorbani, B., Ebrahimi, A., & Ziabasharhagh, M. (2020). Novel integrated CCHP system for generation of liquid methanol, power, cooling and liquid fuels using Kalina power cycle through liquefied natural gas regasification. Energy Conversion and Management, 221, 113151.
Ghorbani, B., Javadi, Z., Zendehboudi, S., & Amidpour, M. (2020). Energy, exergy, and economic analyses of a new integrated system for generation of power and liquid fuels using liquefied natural gas regasification and solar collectors. Energy Conversion and Management, 219, 112915.
Ghorbani, B., Mehrpooya, M., Aasadnia, M., & Niasar, M. S. (2019). Hydrogen liquefaction process using solar energy and organic Rankine cycle power system. Journal of Cleaner Production, 235, 1465-1482.
Ghorbani, B., Miansari, M., Zendehboudi, S., & Hamedi, M.-H. (2020). Exergetic and economic evaluation of carbon dioxide liquefaction process in a hybridized system of water desalination, power generation, and liquefied natural gas regasification. Energy Conversion and Management, 205, 112374.
Ghorbani, B., Roshani, H., Mehrpooya, M., Shirmohammadi, R., & Razmjoo, A. (2020). Evaluation of an Integrated Cryogenic Natural Gas Process with the Aid of Advanced Exergy and Exergoeconomic Analyses. Gas Processing Journal, 8(1), 17-36. doi:10.22108/gpj.2019.117170.1056
Ghorbani, B., Shirmohammadi, R., Mehrpooya, M., & Hamedi, M.-H. (2018). Structural, operational and economic optimization of cryogenic natural gas plant using NSGAII two-objective genetic algorithm. Energy, 159, 410-428.
He, T., & Lin, W. (2020). Design and analysis of dual mixed refrigerant processes for high-ethane content natural gas liquefaction. Chinese Journal of Chemical Engineering.
Hojajizadeh, M. (2015). Investigation of environmental and health effects of fuel oil consumption in Shahid Rajaei power plant in Qazvin. Paper presented at the The Second National Conference on Environmental Health, Health and Sustainable Environment, Hamedan.
Katal, F., & Fazelpour, F. (2018). Multi-criteria evaluation and priority analysis of different types of existing power plants in Iran: An optimized energy planning system. Renewable Energy, 120, 163-177.
Khan, M. S., Lee, S., & Lee, M. (2012). Optimization of single mixed refrigerant natural gas liquefaction plant with nonlinear programming. Asia‐Pacific Journal of Chemical Engineering, 7, S62-S70.
Khodaee, M., Ashrafizadeh, A., & Mafi, M. (2017). Optimization of propane and butane gas liquefaction cycle considering compressor technical limitations using genetic algorithm. Modares Mechanical Engineering, 17(2), 315-324.
Khorrammanesh, M., Amidpour, M., & Nasr, M. (2007). Application of process decomposition in multi-stream plate fin heat exchangers design to use in heat recovery networks. Chemical Engineering and Processing-Process Intensification, 46(10), 941-954.
Lee, S., Long, N. V. D., & Lee, M. (2012). Design and optimization of natural gas liquefaction and recovery processes for offshore floating liquefied natural gas plants. Industrial & Engineering Chemistry Research, 51(30), 10021-10030.
Lin, W., Xiong, X., & Gu, A. (2018). Optimization and thermodynamic analysis of a cascade PLNG (pressurized liquefied natural gas) process with CO2 cryogenic removal. Energy, 161, 870-877.
Marmolejo-Correa, D., & Gundersen, T. J. E. (2012). A comparison of exergy efficiency definitions with focus on low temperature processes. 44(1), 477-489.
Mazyan, W., Ahmadi, A., Ahmed, H., & Hoorfar, M. (2016). Market and technology assessment of natural gas processing: A review. Journal of Natural Gas Science and Engineering, 30, 487-514.
Mehrpooya, M., & Ansarinasab, H. (2015). Exergoeconomic evaluation of single mixed refrigerant natural gas liquefaction processes. Energy Conversion and Management, 99, 400-413.
Mehrpooya, M., Sadaghiani, M. S., & Hedayat, N. (2020). A novel integrated hydrogen and natural gas liquefaction process using two multistage mixed refrigerant refrigeration systems. International Journal of Energy Research, 44(3), 1636-1653.
Mirjalili, S. (2019). Genetic algorithm Evolutionary algorithms and neural networks (pp. 43-55): Springer.
Moradi, A., Mafi, M., & Khanaki, M. (2015). Sensitivity analysis of peak-shaving natural gas liquefaction cycles to environmental and operational parameters. Modares Mechanical Engineering, 15(6).
Moran, M. J., Shapiro, H. N., Boettner, D. D., & Bailey, M. B. (2010). Fundamentals of engineering thermodynamics: John Wiley & Sons.
Morosuk, T., Tesch, S., Hiemann, A., Tsatsaronis, G., & Omar, N. B. (2015). Evaluation of the PRICO liquefaction process using exergy-based methods. Journal of Natural Gas Science and Engineering, 27, 23-31.
Nguyen, T.-V., Rothuizen, E. D., Markussen, W. B., & Elmegaard, B. (2018). Thermodynamic comparison of three small-scale gas liquefaction systems. Applied Thermal Engineering, 128, 712-724.
Pérez, S., & Díez, R. (2009). Opportunities of monetising natural gas reserves using small to medium scale LNG technologies. Paper presented at the IGU 24th world gas conference.
Rehman, A., Qyyum, M. A., Ahmad, A., Nawaz, S., Lee, M., & Wang, L. (2020). Performance Enhancement of Nitrogen Dual Expander and Single Mixed Refrigerant LNG Processes Using Jaya Optimization Approach. Energies, 13(12), 3278.
Serio, L., Bremer, J., Claudet, S., Delikaris, D., Ferlin, G., Pezzetti, M., . . . Wagner, U. (2015). CERN experience and strategy for the maintenance of cryogenic plants and distribution systems. Paper presented at the IOP Conference Series: Materials Science and Engineering.
Tan, H., Shan, S., Nie, Y., & Zhao, Q. (2018). A new boil-off gas re-liquefaction system for LNG carriers based on dual mixed refrigerant cycle. Cryogenics, 92, 84-92.
Thome, J. R. (2010). The New 3rd Edition of the ALPEMA Plate-Fin Heat Exchanger Standards: Taylor & Francis.
Wang, Q., Song, Q., Zhang, J., Liu, R., Zhang, S., & Chen, G. (2019). Experimental studies on a natural gas liquefaction process operating with mixed refrigerants and a rectifying column. Cryogenics, 99, 7-17.
Watson, H. A., Vikse, M., Gundersen, T., & Barton, P. I. (2018). Optimization of single mixed-refrigerant natural gas liquefaction processes described by nondifferentiable models. Energy, 150, 860-876.
Won, W., & Kim, J. (2017). Bi-level optimizing operation of natural gas liquefaction process. Computers & Chemical Engineering, 96, 87-102.
Yin, L., & Ju, Y. (2020). Process optimization and analysis of a novel hydrogen liquefaction cycle. International Journal of Refrigeration, 110, 219-230.
Zhang, J., Meerman, H., Benders, R., & Faaij, A. (2020). Comprehensive review of current natural gas liquefaction processes on technical and economic performance. Applied Thermal Engineering, 166, 114736.