Acoustic Leak Detection Technology Assessment

2012 ◽  
Author(s):  
Augusto Garcia-Hernandez ◽  
Shane Siebenaler
Keyword(s):  
Speed Of Sound ◽  
Linear Trend ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Initial Pressure ◽  
Leak Detection ◽  
Hydraulic Modeling ◽  
Pressure Waves ◽  
Signal Attenuation ◽  
Detection Systems

Leak detection systems are a vital part of a pipeline integrity management program. For liquid hydrocarbon pipelines, these leak detection systems can take the form of measuring conditions inside the pipeline (internal detection) or by use of hardware installed outside of the pipe (external detection). One internally-based technology is acoustic leak detection, sometimes known as rarefaction-wave monitoring. This technology is based on detecting transient pressure waves that are generated when a sudden leak occurs. Acoustic pressure waves travel in the pipeline at the speed of sound of the fluid that is being transported and can be detected by dynamic pressure sensors. Various filters and algorithms can be used to identify this disturbance and distinguish it from other pressure events on the pipeline. This architecture can even be used for noise and for signal pattern recognition to allow for automatic alarming of potential leak events. Each manufacturer of such technology applies unique algorithms or processing methods to capture and analyze the pressure signals that are used to later predict leaks and their locations. This paper presents a comprehensive review of the technical basis and methodology employed by acoustic leak detection systems in order to further understand their capabilities and limitations. This work included a vast amount of hydraulic modeling aimed at understanding the physics of wave propagation caused by leak events. Diverse parameters, such as initial pressure wave amplitude, signal attenuation, flow and pressure dependence, speed of sound effects, and sensor locations were evaluated. This modeling was conducted for a variety of simulated fluids. A proportional relationship between leak rate and the initial pressure disturbance caused by a leak was obtained. This linear trend can be used in combination with an attenuation model to calculate sensor location limitations. The work determined that the uncertainty in the speed of sound for a pipeline fluid segment significantly impacts the error bands of leak location. The modeling was used to generate correlations for signal attenuation over distance as a function of pipeline conditions.

Field Testing of Negative-Wave Leak Detection Systems

2014 ◽  
Author(s):  
Shane Siebenaler ◽  
Eric Tervo ◽  
Paul Vinh ◽  
Chris Lewis
Keyword(s):  
Response Times ◽  
Dynamic Pressure ◽  
User Interaction ◽  
Field Testing ◽  
Leak Detection ◽  
Operating Conditions ◽  
Negative Wave ◽  
Oil Pipeline ◽  
Detection Systems ◽  
The Cost

The pipeline industry is improving its ability to detect and locate leaks through emerging technologies. There has been a variety of research in recent years aimed at further development of sensor-based technologies for leak detection. A key obstacle to retrofitting existing pipelines with leak detection technologies is the cost and risk of installing hardware, particularly those sensors that require excavation near the pipe. There are many advantages to employing leak detection systems that can leverage existing instrumentation access locations. One such technology may be negative-wave leak detection systems. Negative-wave technologies work by measuring dynamic pressure changes in the pipe. It should be noted that some negative-wave systems require line modifications to accommodate multiple transmitters. While such systems have been on the market for many years, there is insufficient data available about their performance under various pipeline operating conditions for widespread adoption. In an effort to close many information gaps on the performance envelope of negative-wave technologies, a PRCI-funded field test was performed on a 41-kilometer segment of a 30-inch diameter heavy crude oil pipeline. Products from three suppliers were installed at either end of the test segment. Actual commodity withdrawals were conducted at a remote valve site approximately 21 kilometers into the segment during various operations to test the systems’ abilities to detect the withdrawals without direct user interaction. These test points included withdrawals during steady-state flowing, pump startup, and shutdown conditions. Data were collected from each system to determine their abilities to detect leaks under various conditions, abilities to locate the leak, false alarm rates, and response times. This test provided significant insight into the performance of such systems over the range of conditions tested. The key focus of this paper is the approach for conducting such multi-vendor commodity withdrawals. This project required some unique considerations for its execution. Such considerations are also documented to provide input to others who are considering such a test.

TRENDS IN PIPELINE LEAK DETECTION SYSTEMS USING SONIC TECHNOLOGY

2008 ◽  
Vol 2008 (1) ◽  
pp. 211-215
Author(s):  
Jairo A. Prezzi
Keyword(s):  
New Technology ◽  
Digital Signal ◽  
Leak Detection ◽  
Hydraulic Modeling ◽  
Detection Systems ◽  
Acoustic Signatures ◽  
Physical Forces ◽  
Multivariate Systems ◽  
Software Filtering ◽  
New Generation

ABSTRACT Acoustic sensing is a relatively well known method for detecting leaks, particularly in transport pipelines. This methodology is based on the rarefaction phenomenon which occurs around the leak spot as a result of a sudden rupture of the pipe wall. The physical forces involved in the phenomenon generate a pressure disturbance that propagates through the fluid, upstream and downstream the pipe. The key feature behind acoustic technology, when applied to LDS, is the systems capability to monitor pressure disturbances and accurately recognize and pinpoint characteristic “leak waveforms” superimposed on the background noise. This is usually achieved by a combination of mechanical, hardware and software filtering techniques. Although real applications have demonstrated the effectiveness of acoustic technology over a quite broad range of scenarios, it has experienced few innovations along the past years. The relative technological stagnation and the experience achieved in several LDS installations in Brazil, encouraged Aselco, a Brazilian company focused on LDS applications, to invest in developing new strategies around the classical acoustic concept. The R&D project started in early 2006 jointly with NETeF, Thermal and Fluids Engineering Centre, at University of São Paulo at São Carlos. A 1. 2Km pipeline was built at NETeF'S lab in order to simulate leaks under mono or multiphase flow conditions. Among the project goals was the development of a new generation of systems dedicated to leak detection encompassing more elaborated algorithms to identify leak acoustic signatures. The core R&D is still centered on the acoustic concept, but under a different approach such as DSP-Digital Signal Processing, pattern recognition through neural network analysis. Another line of development is toward multivariate systems, which bring together both acoustic and hydraulic modeling algorithms running on the same platform. The experimental data obtained, proposed system architecture and characteristics are hereby discussed. Also, the prospective aspects and application of the new technology are objects of analysis.

COMPARATIVE ANALYSIS OF WATER LEAK DETECTION SYSTEMS AND METHODOLOGIES

2016 ◽  
Vol 15 (9) ◽  
pp. 2063-2074
Author(s):  
Pedro Rosas Quiterio ◽  
Florencio Sanchez Silva ◽  
Ignacio Carvajal Mariscal ◽  
Jesus Alberto Meda Campana
Keyword(s):  
Comparative Analysis ◽  
Leak Detection ◽  
Detection Systems ◽  
Water Leak

scholarly journals Experimental Study on Dynamic Combustion Characteristics in Swirl-Stabilized Combustors

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1609
Author(s):  
Donghyun Hwang ◽  
Kyubok Ahn
Keyword(s):  
Experimental Study ◽  
Heat Release ◽  
Dynamic Pressure ◽  
Combustion Instability ◽  
Flame Structure ◽  
Pressure Sensors ◽  
Necessary Condition ◽  
Rayleigh Criterion ◽  
Pressure Oscillations ◽  
Geometric Conditions

An experimental study was performed to investigate the combustion instability characteristics of swirl-stabilized combustors. A premixed gas composed of ethylene and air was burned under various flow and geometric conditions. Experiments were conducted by changing the inlet mean velocity, equivalence ratio, swirler vane angle, and combustor length. Two dynamic pressure sensors, a hot-wire anemometer, and a photomultiplier tube were installed to detect the pressure oscillations, velocity perturbations, and heat release fluctuations in the inlet and combustion chambers, respectively. An ICCD camera was used to capture the time-averaged flame structure. The objective was to understand the relationship between combustion instability and the Rayleigh criterion/the flame structure. When combustion instability occurred, the pressure oscillations were in-phase with the heat release oscillations. Even if the Rayleigh criterion between the pressure and heat release oscillations was satisfied, stable combustion with low pressure fluctuations was possible. This was explained by analyzing the dynamic flow and combustion data. The root-mean-square value of the heat release fluctuations was observed to predict the combustion instability region better than that of the inlet velocity fluctuations. The bifurcation of the flame structure was a necessary condition for combustion instability in this combustor. The results shed new insight into combustion instability in swirl-stabilized combustors.

A New Approach to Pipeline Leak Detection Using Electromagnetic Sensing

2016 ◽  
Author(s):  
Chris Dawson ◽  
Stuart Inkpen ◽  
Chris Nolan ◽  
David Bonnell
Keyword(s):  
Leak Detection ◽  
False Alarms ◽  
Detection Accuracy ◽  
Minimal Risk ◽  
Detection Systems ◽  
Acoustic Signatures ◽  
Cost System ◽  
Trade Offs ◽  
In Situ Sensors ◽  
Operational Range

Many different approaches have been adopted for identifying leaks in pipelines. Leak detection systems, however, generally suffer from a number of difficulties and limitations. For existing and new pipelines, these inevitably force significant trade-offs to be made between detection accuracy, operational range, responsiveness, deployment cost, system reliability, and overall effectiveness. Existing leak detection systems frequently rely on the measurement of secondary effects such as temperature changes, acoustic signatures or flow differences to infer the existence of a leak. This paper presents an alternative approach to leak detection employing electromagnetic measurements of the material in the vicinity of the pipeline that can potentially overcome some of the difficulties encountered with existing approaches. This sensing technique makes direct measurements of the material near the pipeline resulting in reliable detection and minimal risk of false alarms. The technology has been used successfully in other industries to make critical measurements of materials under challenging circumstances. A number of prototype sensors were constructed using this technology and they were tested by an independent research laboratory. The test results show that sensors based on this technique exhibit a strong capability to detect oil, and to distinguish oil from water (a key challenge with in-situ sensors).

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