Exploring the stability and dynamic responses of dual-stage series ORC using LNG cold energy for sustainable power generation

Abstract

Utilizing LNG cold energy for power generation is critical for improving energy efficiency of LNG supply chain. Current studies on power generation systems that use LNG cold energy primarily focus on steady-state simulations and optimizing key parameters. However, there is a notable gap in research regarding dynamic simulations to understand the dynamic behaviors of these systems. To address this, a dynamic model for a dual-stage series ORC system that harnesses LNG cold energy was proposed focusing on its dynamic responses. A comparative analysis of its stability under two different control strategies were conducted identifying the cascade control strategy as the superior method. The effects of various parameters, such as LNG temperature, mass flow, and composition, along with exhaust gas pressure, temperature, and composition, on the stability and dynamic response of the system were investigated. The results indicate that fluctuations in LNG mass flow have the most significant impact on system stability, while exhaust gas pressure has the least. Additionally, most parameters effectively returned to their setpoints after disturbances when managed by the cascaded control strategy. This research provides valuable insights into the operational characteristics of the dual-stage ORC, demonstrating its potential for sustainable power generation by leveraging the recovery of LNG cold energy.