Experimental Study on Leak Detection and Location for Gas Pipelines Based on Acoustic Waves Using Improved Hilbert–Huang Transform

Abstract

Pipeline systems are a safe method of transporting oil and gas from one place to another, although they suffer from leaks due to external and internal factors and fail to deliver the required products to customers. Many methods have been researched and implemented for gas leakage detection and localization. However, larger leakages can be easily detected while small leakages may not be detected for some time, especially when a pipeline is buried in remote places or under ice. Therefore, lacking real-time small and larger gas leakage wireless sensor detection systems causes financial, environmental, and health problems. In this paper, an experimental study has been conducted for real-time natural gas leakage detection and localization based on acoustic waves. Surface acoustic sensor technology and Hilbert–Huang transform (HHT) processing algorithm were successfully studied both experimentally and numerically to discover their efficiency on leakage detection and localization, and they are proposed and established as the best method for gas pipeline leak detection. A small gas pipe section with 40-m length, 20-mm internal diameter, and two valves as the artificial leaks was used. First, the leakage detection and location method based on an acoustic wave with an improved HHT method and the propagation model were suggested and designed. When the two key points were established, the experiential equipment was constructed on a laboratory scale and the experiments were conducted. The time difference (TD) was calculated, and the propagation model and the leakage localization methods were also verified. Finally, the results of the experiments are discussed and analyses indicate the improved HHT method and the HHT method yield different experimental leak location error maximum absolute values of 0.58% and 13.66%, respectively, showing that an improved HHT method is better than the HHT method for calculating the TD of leakage location; the method based on the amplitude propagation model can be achieved without TD calculation. Therefore, it is concluded that the new method is efficient and can protect and monitor natural gas pipelines.