Aiming at the difficulty of leak detection of urban hazardous chemical pipelines, this paper proposes a method for locating pipeline leaks based on the complementary ensemble local mean decomposition (CELMD) and maximum correlation kurtosis deconvolution (MCKD) secondary noise reduction. First, white noise with opposite sign was added to the original leak signal in pairs, and the noisy signal was decomposed to obtain a series of product functions (PF). Second, select the PF component containing the main leakage information according to the correlation coefficient, and perform the initial noise reduction. Then, the maximum correlation kurtosis deconvolution (MCKD) was used to perform secondary noise reduction on the filtered PF component; Finally, the PF component obtained after two screening was reconstructed, and the pipeline leakage location was completed by calculating the delay parameters of AE signal by cross-correlation. The experimental results show that compared with the cross-correlation method and the ELMD method, the method has higher recognition accuracy and positioning accuracy.

Aiming at the problems of early leakage monitoring of urban nonmetallic pipelines and the large positioning error, an inverse transient urban nonmetallic gas pipelines leakage location method based on Markov quantitative judgment was proposed. A Markov flow state transition probability matrix was established based on the flow data under different pressures obtained by experiments to quantitatively determine the pipeline leakage status. On this basis, an inverse transient leakage control equation suitable for urban nonmetallic gas pipeline leakage location was constructed according to the actual. The difference between the pressure and the calculated pressure was sought for the objective function. Finally, the objective function was optimized in conjunction with the sequential quadratic programming (SQP) method to obtain the actual leakage parameters and calculate the size and location of the leakage source. The results show that the inverse transient leakage localization method based on Markov’s quantitative judgment can more accurately determine the leakage status of the pipeline and calculate the early leakage parameters and leakage location of the gas pipeline, which improves the positioning accuracy.