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Detection of Abnormal Leakage and Its Location by Filtering of Sonic Signals at Petrochemical Plant

비정상 음향신호 필터링을 통한 플랜트 가스누출 위치 탐지기법

  • Yoon, Young-Sam (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Kim, Cheol (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.)
  • 윤영삼 (경북대학교 기계공학부) ;
  • 김철 (경북대학교 기계공학부)
  • Received : 2011.06.09
  • Accepted : 2012.04.04
  • Published : 2012.06.01

Abstract

Gas leakage in an oil refinery causes damage to the environment and unsafe conditions. Therefore, it is necessary to develop a technique that is able to detect the location of the leakage and to filter abnormal gas-leakage signals from normal background noise. In this study, the adaptation filter of the finite impulse response (FIR) least mean squares (LMS) algorithm and a cross-correlation function were used to develop a leakage-predicting program based on LABVIEW. Nitrogen gas at a high pressure of 120 kg/$cm^2$ and the assembled equipment were used to perform experiments in a reverberant chamber. Analysis of the data from the experiments performed with various hole sizes, pressures, distances, and frequencies indicated that the background noise occurred primarily at less than 1 kHz and that the leakage signal appeared in a high-frequency region of around 16 kHz. Measurement of the noise sources in an actual oil refinery revealed that the noise frequencies of pumps and compressors, which are two typical background noise sources in a petrochemical plant, were 2 kHz and 4.5 kHz, respectively. The fact that these two signals were separated clearly made it possible to distinguish leakage signals from background noises and, in addition, to detect the location of the leakage.

심각한 사고를 초래하는 석유화학 플랜트의 가스 누출 여부와 위치를 실시간으로 탐지하기 위하여 주변의 여러 기계소음 등으로부터 비정상적 누출 음향을 분리할 수 있는 기법을 제시하였다. LMS 알고리즘을 이용하여 FIR구조의 적응필터와 누출 탐지용 상호상관함수를 이용하여, LABVIEW를 통하여 누출예측프로그램을 개발하였고 직접 제작한 장비를 이용하여 잔향실에서 실험을 수행하였다. 홀 사이즈, 압력, 거리, 주파수를 인자로 하여 비정상적 누출소음에 대한 실험에서 얻어진 데이터를 분석한 결과, 암소음은 1kHz 대역 이하에서 주로 발생하고 누출에 의한 소음신호는 고주파 대역, 특히 16kHz의 대역에서 가장 잘 발생한다는 것을 알게 되었다. 이런 음향기법의 가능성을 확인하기 위해서 실제로 정유공장에서 소음을 측정한 결과, 펌프와 압축기에서의 소음신호가 각각 2kHz, 4.5kHz로 측정됨으로써 주변 환경 소음과 누출음이 구별 가능하고 누출 위치(거리)의 탐지가 가능함을 밝혔다.

Keywords

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