The Design Of Dangerous Chemical Pipeline Leak Detection System

The detection of dangerous chemical pipeline is the guarantee for safety in production. On account of the properties of highly corrosive、 flammable、explosive、toxic、radioactive in dangerous chemical, the system of dangerous chemical pipeline leak detection should fast time response、highly sensitivity、accurately location, and it also requires simple and convenient in operation and maintenance, but there is almost none dangerous chemical pipeline leak detection system based on acoustic method. Therefore, the design and application of dangerous chemical pipeline leak detection system is necessary promise in safety production of dangerous chemical area.This paper selected the dangerous chemical pipeline as research object, this paper improved the operability by designing a remote monitoring system of adjustable gain instrument, established the feature extraction method based on double moving window and power spectrum comparison to improve effectiveness of feature extraction, and also put forward none leak signal dangerous chemical transport pipeline detection model based on SVDD method to solve the problem of none real " simulated leak signal" in dangerous chemical transport pipeline, through all of this, this paper reduced false alarm, and eliminated missing alarm.The same acoustic sensors output the same signals in different transport pipeline, this paper analyzed the normal dynamic pressure signal and the leak dynamic pressure signal of gas transport pipeline from the same type of piezoelectric pressure sensor, compared the normal dynamic pressure signal and the leak dynamic pressure signal from the aspect of frequency domain, found the differences of power spectrum, explored and identified the method of double moving window feature extraction based on power spectrum. This paper applied the feature extraction method in dangerous chemical transport pipeline. Then, this paper proposed a none leak signal diagnose model based on SVDD.In dangerous chemical pipeline leak detection system, first, this paper designed adjustable gain instrument which integrating a MCU, the instrument amplified the signal from acoustic sensors and output standard industrial signal (4-20mA), and also received adjustment command from embedded Remote Terminal Unit(RTU); second, this paper designed an embedded Remote Terminal Unit(RTU) which integrating the RS-485bus, the embedded Remote Terminal Unit(RTU) sample the signal from field instrument, transport the sampling data to the Monitoring Server, and also receive the adjustment command from the Monitoring Server, then send the adjust command to the field instrument.This paper selected liquid nitrogen as the experimental object in liquid chlorine pipeline, test the system by simulating with nitrogen, and the system all made the right alarm. The continuous operation showed that the dangerous chemical transport pipeline leak detection system can effectively guarantee the dangerous chemicals pipeline safety in production.