A novel method for natural gas pipeline safety online monitoring based on acoustic pulse compression

A novel method based on acoustic pulse-compression and envelope extraction is proposed and discussed to detect and locate hydrate blockage and leak in natural gas pipelines. Linear frequency modulation (LFM) signal rather than single frequency sinusoidal signal is emitted to inspect the pipeline. Reflected signal is firstly processed through a matched filter and then demodulated with Hilbert transform so that the envelope is obtained. By envelope subtraction, the detection and location of hydrate blockage and leak can be achieved. Based on the measurement and signal processing principle, a simulation model has been established with COMSOL which verifies the feasibility of the method. Experimental results demonstrate that the technique can not only locate hydrate blockage and pipeline leak precisely but also monitor the hydrate formation process in real time. Besides, the spatial resolution is improved and the interference of noises is reduced significantly thanks to matched filtering. The novel method has significantly enhanced the performance of existing system and has considerable application prospect in natural gas pipeline safety online monitoring. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.