Experimental Research On Non-intrusive Gas Pipeline Leak Detection

Gas piping system,such as gas,steam pressure pipeline,has been widely used in electric power, petroleum, chemical, natural gas and other industrial sectors. The working environment of those gas pipelines are usually very poor, which may result in corrosion,cracking and fatigue damage easily, even leading to pipeline leakage that could be great damage to people's lives,property safety and survival,especially when flammable, explosive or toxic gases are involved. How to make sure the accuracy and timeliness in leak detection and location is a major problem in gas pipeline leak monitoring.Most of the existing methods of gas pipeline leak detection tend to use intrusive instruments as sensing module,which may not only affect the measurement,but also easy to introduce security risks because of the welding quality or other reasons. Even though there are some portable non-intrusive equipments of the gas pipeline leak detection that has a good sensitivity, they can not be widely used due to their limited measurement range. Aiming at these problems above, a non-intrusive gas pipeline leak detection method is proposed:piezoelectric acoustic sensors were used,by pasting on the metal gas pipe outer wall,to measure the low-frequency acoustic leakage signal which was propagated by the gas flowing in the pipeline. The build method of the experimental platform is described and the feasibility of this method is showed through experiments. It is found from the analysis of the leakage signal that the piezoelectric signal maximum amplitude change (within a certain time interval) and the signal power spectrum (0.4Hz or less) can be used as characteristic parameters in non-intrusive leak detection,and there is a monotonic relationship between the former one and the gas leak rate. The adoption of relevant technology to determine the leak location, according to the relational model between the characteristic parameter and gas leak rate, the size of the leakage can be determined. The non-intrusive gas pipeline leak detection method provides a new technological means for dangerous gas pipeline leak detection.