Title: Techno-economic analysis of power generation by turboexpanders in natural gas pressure reduction stations

Authors: Bijan Hejazi; Ahmad Rafiee

Addresses: Chemical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, 9177948944, Iran ' Chemical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, 9177948944, Iran

Abstract: The objective of this paper is to perform a techno-economic feasibility study of recovering pressure energy of natural gas stream through installing turboexpanders in a pressure reduction station and selling the generated electrical power to the national grid. As a case study, the operating and real conditions of a major pressure reduction station in Iran is collected throughout the years 2015, 2016 and 2017. To account for the effects of the inherently variable operating conditions, a thermodynamic model based on exergy analysis estimates off-design turboexpander isentropic efficiency, size and cost estimate as well as minimum preheating temperature required to avoid hydrate formation due to the expansion process. The detailed economic analysis shows that for the project to be economically feasible, an electricity purchase price of > $0.08/kWh is required. Furthermore, the results of this study are useful for designing automatic preheating temperature control system.

Keywords: natural gas; pressure reduction station; exergy recovery; turboexpander; variable operating conditions; computer-aided process design.

DOI: 10.1504/IJEX.2021.113849

International Journal of Exergy, 2021 Vol.34 No.3, pp.360 - 384

Received: 21 Jan 2020
Accepted: 02 Aug 2020
Published online: 31 Mar 2021 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article