Thermoeconomic assessment of a natural gas expansion system integrated with a co-generation unit

► A system with CHP-based preheating and 2-stage natural gas expansion is analyzed. ► The system achieves 0.895 performance ratio and 49.2% exergy efficiency. ► 2nd Law and thermoeconomic analyzes allow to point out possible system improvements. ► The highest exergy losses are due to irreversible heat transfer from exhaust gases. ► Integration with low-temperature waste heat is the recommended system improvement.