Work

The shielding effect in turboexpander-equipped natural gas pressure reduction stations: an advanced exergoeconomic analysis

Year: 2026

Type: article

Abstract: Natural gas pressure reduction stations dissipate exergy when gas pressure is throttled from transmission to distribution levels. Turboexpanders recover part of this energy, but their expansion requires preheating to prevent hydrate formation, and the preheater-turboexpander coupling governs station performance. Previous studies examined thermodynamic and economic aspects separately. This study presents a conventional and advanced exergoeconomic analysis of a pressure reduction station with a preheater and turboexpander under three scenarios: winter (10 °C, 500 psi), mild (21 °C, 600 psi), and summer (30 °C, 900 psi). The advanced analysis partitions exergy destruction, investment cost, and exergy destruction cost into endogenous/exogenous and avoidable/unavoidable parts. Three findings emerge. First, the turboexpander's inefficiency shields the preheater by lowering required preheat, reducing its exergy destruction by up to 1596 kJ/kmol and generating a negative exogenous investment cost. Second, the preheater's avoidable exogenous exergy destruction changes sign with inlet temperature, from +624 to −236 kJ/kmol between winter and summer, as its specific unavoidable exergy destruction ratio varies. Third, the preheater's low product exergy in winter amplifies the turboexpander's exergy destruction cost to 0.865 $/s, despite the smallest physical exergy destruction. Ideal-point optimization gives a preheater thermal efficiency that is always optimal at 0.95, while the turboexpander isentropic efficiency is optimal at 0.80 when operating costs dominate and at 0.75 when capital and operating costs are weighted equally. This work is the first coupling analysis of the preheater and turboexpander within an advanced exergoeconomic framework and identifies the preheater as the primary economic bottleneck.

Source: Applied Thermal Engineering

DOI: 10.1016/j.applthermaleng.2026.133569

Authors: Mohammad Olfati, Farzad Veysi, Shoaib Khanmohammadi

Institutions: Razi University, Kermanshah University of Technology

Language: English

Topic: Thermodynamic and Exergetic Analyses of Power and Cooling Systems

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Affordable and clean energy, Industry, innovation and infrastructure, Climate action

Open Access status: hybrid

Estimated APC paid: $3,660