Maede Samani| MEL Candidate |Dec 2024
Mentor:Ysabel Vidal|Solaris MCI
Abstract
Waste heat recovery (WHR) is essential for improving energy efficiency and reducing emissions in the oil and gas sector. To address the untapped potential of thermal energy from natural gas compressor station (NGCS) exhausts, this study evaluates the integration of Organic Rankine Cycle (ORC) technology. Using a PGT25+ gas turbine as the heat source, a thermodynamic model was developed in Aspen HYSYS, optimized with real site-rated d data.
The ORC system produced an average net output of 7.5 MW, generating 70.8 GWh annually, equivalent to $7 million in revenue and reducing CO₂ emissions by 37,000 tonnes per year. The results demonstrate ORC’s suitability for low-to-medium temperature WHR applications, with opportunities for further optimization through advanced designs and control strategies to enhance efficiency and scalability.
Introduction
The oil and gas sector faces mounting pressure to reduce emissions and improve energy efficiency. While renewable energy gets significant attention, waste heat recovery (WHR) remains underutilized. For low-temperature waste heat, technologies like the Organic Rankine Cycle (ORC) are more effective and cost-efficient than traditional methods, offering advantages such as lower maintenance, compact design, and suitability for remote applications, making it a promising solution for sustainable energy recovery.
Methods and Materials
The primary components of this project include:
·Retrofitting ORC Technology
·Thermodynamic Modeling, Optimal Design Identification
·OFF-design Behavior Analysis
This study uses Aspen HYSYS to simulate the ORC technology, Boundary conditions for the gas turbine, are derived from operational data and manufacturer performance curves.
Results
The ORC system simulation in HYSYS shows that the system generates approximately 8 MW of power monthly, with seasonal variations. After accounting for 0.7 MW consumed by the internal pumps, the average net power output is 7.5 MW. Key performance metrics include ORC efficiency, power generation, net output, and specific power recovery.
The specific power recovery varies slightly each month, ranging between 30% and 35%, while the ORC efficiency is calculated to be approximately 24%. These findings demonstrate the ORC system’s capacity for consistent energy recovery across varying conditions, with efficiency and power recovery metrics indicating strong potential for integrating the ORC as a sustainable solution for waste heat recovery in gas turbine applications.
Discussion
The results of this analysis reveal that the ORC system can effectively generate an average of 8 MW of power throughout the year, considering availability of the gas turbine assumed to be around 100%, a total energy production of approximately 70.8 GWh per year is expected from the ORC system under these operating conditions. Furthermore, the environmental impact of the ORC system is substantial. The power generated by this system corresponds to a reduction of approximately 37,000 tonnes of CO₂ emissions annually.
Table 1 – Summary of total performance results of utilizing ORC system
Conclusion
In conclusion, the implementation of an ORC system for waste heat recovery at gas compression stations offers a robust and sustainable means to enhance energy efficiency and reduce carbon emissions. Future recommendations include optimizing ORC component design and exploring advanced control strategies to further improve efficiency, especially under part-load conditions, and maximizing the financial and environmental returns of this technology integration.