Adaptability evaluation of the software for transient process simulation of supercritical CO₂ pipelines

Objective Transient processes like leakage and commissioning in CO₂ pipeline operation pose simulation challenges due to the unique physical properties and phase behavior of CO₂. Currently, there is a deficiency in adaptability evaluation of numerical simulation software for CO₂ pipeline transient processes.

Methods This study utilized two mainstream transient simulation software, OLGA and LedaFlow, to establish a numerical simulation model for transient CO₂ leakage. Testing was conducted on a self-built experimental setup for DN200 high-pressure CO₂ pipeline leakage across different phases, with software adaptability evaluated in terms of pressure, temperature and phase behavior. Furthermore, the adaptability of these software types was verified through a comparison of the simulation results with field data from transient commissioning of a long-distance CO₂ pipeline in China.

Results The comparison of the results from leakage test and software simulations revealed that under two specified leakage conditions, OLGA exhibited average pressure calculation errors of 15.3% and 14.7%, whereas LedaFlow exhibited errors of 16.7% and 18.0%. Consequently, the pressure calculation accuracy of OLGA closely aligns with that of LedaFlow. OLGA underestimated the lowest temperature in the pipe during leakage, with average relative errors of 21.2% and 24.5% at the two measuring points. In contrast, LedaFlow overestimated the lowest temperature with average relative errors of 13.1% and 11.1% at the two measuring points. During the commissioning of a CO₂ pipeline, OLGA exhibited average relative errors of 1.2% for pressure and 6.1% for temperature, whereas LedaFlow exhibited errors of 1.3% and 5.2% for the same parameters. The simulation results from both software packages closely align with the field data.

Conclusion In conclusion, in the process of CO₂ pipeline leakage, OLGA underestimates the lowest temperature during the leakage process, which can enhance the low-temperature safety of the pipeline. OLGA is better suited for predicting pressure, temperature and phase behavior during CO₂ leakage. Both OLGA and LedaFlow are suitable for simulation studies on pressure and temperature in CO₂ pipelines during commissioning.