A systematic optimization approach of an actual LNG plant: Power savings and enhanced process economy

Abstract

Developing a cost-effective LNG liquefaction cycle could significantly enhance the process's economic feasibility, improve the production rate and reduce GHG emissions. In this work, the power consumption of the C3MR system integrated with NGL recovery, HeXU, and NRU has been optimized within the process limitations and critical operational constraints. The study fills a gap in the literature by analyzing and optimizing the propane cycle using real-world plant data. Results revealed that increasing the NG pre-cooling temperature and pressure from the base-case values of −27 and 54.9 bar to ∼ -4 °C and 59 bar reduced the power requirement by 2.6% (123–119.8 MW). The optimized C3MR process showed power savings of 3.1 MW that could be translated into a saving of 0.092 MTPA of LNG corresponding to annual revenue of 28.5 million $. The cycle compression power was dramatically decreased from 44.3 MW to 18.5 MW resulting in a 15.6% (122.9 MW–105.5 MW) reduction in the total energy demand (TED). Systematic optimization of HeXU and NRU units saved power that could be utilized to produce an additional 13,873 TPD LNG. The proposed optimization approach reduced the TED of the LNG plant, increased production, and enhanced process economy.