CO₂LeakTrace: Oppdag og spore CO₂ lekkasje fra gass rørledning

Background
Acoustic emission monitoring is a technology that can be used to detect and track leaks from pipelines. This technology is already used for monitoring oil pipelines, but not in the commercial market for CO₂ gas pipelines. When a leak occurs in a gas pipeline, it can create strong turbulence due to gas moving from high pressure to the low-pressure atmosphere through a narrow opening. This turbulence generates stress waves, and acoustic emission technology measures these stress waves and converts them into electrical signals for diagnostics using specially designed piezo elements. The use of acoustic emission for gas leak detection has major advantages, for example: 1) it is a non-destructive monitoring method, 2) it has a wide frequency range (20 kHz to 2.5 MHz), 3) it can also localize the leak. In this project, “CO₂LeakTrace,” we will develop a new solution for monitoring CO₂ gas leaks in pipelines, in order to detect, localize, and quantify the leakage.

Goal
The objective of the project is to assess whether acoustic emission is economically sustainable for condition monitoring of CO₂ pipelines. To achieve this objective, NORCE will:
• Conduct a feasibility study in the NORCE laboratory on pipelines using acoustic emission monitoring.
• Perform a preliminary analysis of acoustic emission data to detect and track CO₂ leaks.
• Investigate the detection range of an acoustic emission sensor for identifying CO₂ leaks from pipelines.
• Estimate the potential cost savings from detecting CO₂ leaks using acoustic emission, compared with the cost of CO₂ leakage per hour without monitoring.

Activities
– Workshop/meeting for planning the test facility, experiment design, and data collection
– Testing and data collection
– Data analysis
– Overall analysis and conclusions
– Project management, final report, and reporting

Results
This study investigated the use of the AE sensors to monitor CO₂ leak from the 6 meter pipeline. The main observation from this study are as follows:
• Using AE feature like RMS, bandpower, power spectral density, mean frequency and median frequency it is possible to monitor leak from the pipeline irrespective of the leak location. The lowest possible leak monitored from the pipeline was 43 L/min.
• Using AE feature like RMS, bandpower, and power spectral density, it is possible to monitor leak from the valve as low as 0.5L/min.
• Leak localization on pipeline using energy-based method provided error less than 10% at most of the AE sensor locations.
• From the cost-benefit analysis, it was observed AE sensor can offer substantial financial benefits by saving from few hundred thousand to millions of dollars annually while also reducing greenhouse emission and avoiding regulator penalties.

This study presents a strong basis for the industries and R&D institutes to identify leak from the pipeline and valves using AE sensor.

Further Work
From the study conducted we also observed the cost is not the only factor that is preventing its extensive implementation in the O&G industry to monitor leaks from pipelines and valves. Factors such as pipeline length, buried pipelines, gas flow in super critical state, continuous data acquisition and processing, retrofitting in existing infrastructure, battery power limitations, and communication in sub-sea environment are known to impact its wider use. In conclusion, further research should be directed at addressing the technical and operational barriers to enable broader application of AE sensor for leak detection and localization of the CO₂ transport systems in the O&G industry.

Publications
Shanbhag. V. V, Schlanbusch. R, Belbachir. N, “Economic Feasibility of Acoustic Emission Monitoring in CO₂ Pipelines: An Experimental Study”. (Article is ready. Will be communicated to journal very soon)