Article: Energy, exergy, economic, and environmental analyses and multi-objective optimisation of using turbo-expanders in natural gas pressure reduction stations Journal: International Journal of Exergy (IJEX) 2022 Vol.38 No.2 pp.238 - 266 Abstract: This paper focused on evaluating and multi-objectively optimising the utilisation of turbo-expanders (TEs) in natural gas pressure reduction stations (NGPRSs). To this end, an energy, exergy, economic, and environmental (4E) analysis was conducted, and the NGPRS of the Montazeri Power Plant in Iran was considered and simulated in cycle-tempo and MATLAB®. Then, the exergy efficiency (ηexergy) and the costs of electricity generation (Zelec) were selected as the objective functions and the system was optimised using the genetic algorithm approach. The results of the simulations indicated that approximately 23 MW exergy is lost during the throttling process in case of not using the TEs while using the two TEs saves 18 MW of the referred exergy, leading to the generation of about 121,650 MWh green electricity per year. It further prevents the emission of 65,756 tons of CO2 and facilitates selling an approximate value of 294,640 million rials of electricity. Moreover, the results of the multi-objective optimisation were provided for different TE inlet temperatures, and the value of Tin,TE = 110°C, as the optimum point, could yield the values of ηexergy = 52.2% and Zelec = $0.038/kWh. Inderscience Publishers - linking academia, business and industry through research

Title: Energy, exergy, economic, and environmental analyses and multi-objective optimisation of using turbo-expanders in natural gas pressure reduction stations

Authors: Hossein Haghjoo; Emad Aram; Gholamreza Ahmadi; Davood Toghraie

Addresses: Department of Mechanical Engineering, Islamic Azad University, Khomeinishahr Branch, Khomeinishahr, Iran ' Department of Mechanical Engineering, Islamic Azad University, Khomeinishahr Branch, Khomeinishahr, Iran ' Department of Mechanical Engineering, Islamic Azad University, Khomeinishahr Branch, Khomeinishahr, Iran ' Department of Mechanical Engineering, Islamic Azad University, Khomeinishahr Branch, Khomeinishahr, Iran

Abstract: This paper focused on evaluating and multi-objectively optimising the utilisation of turbo-expanders (TEs) in natural gas pressure reduction stations (NGPRSs). To this end, an energy, exergy, economic, and environmental (4E) analysis was conducted, and the NGPRS of the Montazeri Power Plant in Iran was considered and simulated in cycle-tempo and MATLAB®. Then, the exergy efficiency (η_exergy) and the costs of electricity generation (Z_elec) were selected as the objective functions and the system was optimised using the genetic algorithm approach. The results of the simulations indicated that approximately 23 MW exergy is lost during the throttling process in case of not using the TEs while using the two TEs saves 18 MW of the referred exergy, leading to the generation of about 121,650 MWh green electricity per year. It further prevents the emission of 65,756 tons of CO₂ and facilitates selling an approximate value of 294,640 million rials of electricity. Moreover, the results of the multi-objective optimisation were provided for different TE inlet temperatures, and the value of T_in_,_TE = 110°C, as the optimum point, could yield the values of η_exergy = 52.2% and Z_elec = $0.038/kWh.

Keywords: turbo-expander; NG pressure reduction station; 4E analysis; CO₂ reduction; multi-objective optimisation.

DOI: 10.1504/IJEX.2022.123607

International Journal of Exergy, 2022 Vol.38 No.2, pp.238 - 266

Received: 17 Mar 2021
Accepted: 09 Dec 2021
Published online: 29 Jun 2022 *

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Title: Energy, exergy, economic, and environmental analyses and multi-objective optimisation of using turbo-expanders in natural gas pressure reduction stations

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