Advancing Energy Performance Monitoring of Large Compression Units Using a Thermodynamic Digital Twin

Abstract

Abstract The compression units installed on the sales gas network encounter a diverse range of operating modes due to the fluctuating supply and demand conditions and the corresponding dynamics of the network. Determining the actual performance in such applications creates a significant challenge due to the variability of specific energy consumption. This paper introduces a new and reliable monitoring system that allows for real-time assessment of energy performance in dynamic compression. The system also identifies potential applications for energy conservation. The methodology involved a comprehensive examination of the design and original equipment manufacturer (OEM) data associated to the compression units. This was subsequently followed by an in-depth review of the operating envelope. Afterwards, a comprehensive thermodynamic model was developed for compression units that incorporates all operational modes. The model was then confirmed using real operational data by integrating the OEM's actual performance curves into the thermodynamic digital twin. In order to facilitate the monitoring of compressor performance when the thermodynamic digital twin is not available, an additional mathematical model has been developed alongside the existing thermodynamic model. This supplementary model allows operators to conduct off-line monitoring of the compressors. Conducting a comprehensive performance analysis of centrifugal compressors is imperative in order to accurately assess their operational status and efficiency. A decline in performance can serve as an indicator of internal wear or fouling, which, if left unaddressed, may lead to diminished throughput, increased energy consumption, or unexpected interruptions in operation. Hence, the performance metric encompasses not only energy consumption and operational expenses, but also encompasses critical factors such as reliability. The development of an integrated thermodynamic digital twin for large sales gas compression units, which possess a total throughput capacity exceeding 500 MMSCFD, has facilitated and exhibited efficient energy performance monitoring, even in the presence of varying operating scenarios. The tool enabled the immediate comparison between the actual performance, specifically the energy consumption, and the anticipated performance based on the model. Additionally, it facilitated immediate tracking of polytropic efficiency trends and provided a real-time visualization of potential opportunities for energy savings. The digital twin has demonstrated its efficacy as a cost-effective and dependable tool for real-time prediction of compressor performance across different operational modes. The information obtained from the compression digital twin can be integrated with process simulation models to enhance the optimization of the overall process. The model has the potential to enhance supervisory capabilities, diagnostics, control capabilities, and even aid in the prediction of failures in advance.