Liquid Transmission Pipelines Research Articles

Two-Leak Case Diagnosis Based on Static Flow Model for Liquid Transmission Pipelines.

The article deals with a diagnosis of multiple leaks from liquid transmission pipelines using analytical methods. Such solutions, based on advanced mathematical models of pipeline flow dynamics, usually turn out to be very complex and time-consuming. However, under certain operating conditions, a simpler approach may also be useful. Such an idea is presented in this paper, proposing two simplified methods for diagnosing double leakages. In principle, these methods apply to both simultaneous and non-simultaneous leaks. The first one uses a static model of a pipeline involving two leaks and takes advantage of the minimization of the objective function defined as the squared deviation of the modeled pressures from the pressures measured on the pipeline. The second method uses a pipeline flow model of a static type in combination with a gradient indicator aimed at detecting leaks and employing algorithms assigned to determining the location and size of leaks. The results of methods' validation, based on tests carried out with the use of measurement data obtained from an experimental water pipeline, were also presented. The outcomes of the performed tests proved the methods' effectiveness in terms of detection, isolation, localization, and intensity estimation of both simultaneous and non-simultaneous double leakages.

Flow Improvers and Pipeline Internal Coating Benefits and Limitations with Respect to Pipeline Capacity Enhancement

This article illustrates the outcome of a theoretical examination of applying internal coating and flow improver to gas and liquid pipeline systems. A test case of a 12-inches, 18-inches, 24-inches, 30-inches, 36-inches, and 42-inches diameter gas and liquid transmission pipelines evaluates hypothetically, synergistic use of pipeline internal coating with flow improver to enhance flow rate of a pipeline and minimize internal friction. The improvements in pipeline hydraulics are recognized and the enhancement of pipeline capacity calculated over a broad range of parameters. The hydraulic benefits are presented as percentage increase in pipeline capacity using flow equations. Analysis shows that internal coating of pipelines plus injection of flow improver is hydraulically and economically viable for both gas and liquid pipelines with a typical capacity increase greater than 116%. Corrosion protection and safety is improved with low operating cost.

An integrated risk prediction model for corrosion-induced pipeline incidents using artificial neural network and Bayesian analysis

In onshore hazardous liquid transmission pipelines, corrosion-induced incidents are potentially significant hazard to people, property and environment. Therefore, several statistical data analysis methods have been developed to analyze their risks. These existing models utilize only a few attributes from a wide incident database and generally assume failure rates as homogeneous or constant over time which is not true. There is also a lack of frameworks to predict risk by utilizing the current condition of pipelines and historical incident data simultaneously. This article presents an integrated risk prediction model which leverages rich incident database of Pipeline Hazardous Material Safety Administration (PHMSA) and utilizes nonhomogeneous failure rates derived from data. From incident data for 2010–2019, 70 attributes are selected based on their significance to corrosion-induced pipeline incidents, and artificial neural network (ANN) models are developed for the prediction of causes and consequences of incidents. Next, the probability of incident is predicted using Bayesian analysis with nonhomogeneous failure rates. Here, ANN models employ current conditions of pipelines and Bayesian analysis utilizes historical incident data simultaneously. The predicted consequences and probability are multiplied to predict risk of corrosion-induced incidents. The effectiveness of the proposed framework is demonstrated using the PHMSA database.

Accuracy and Uncertainty of Gradient Based Leak Localization Procedure for Liquid Transmission Pipelines.

This paper describes issues of leakage localization in liquid transmission pipelines. It focuses on the standard leak localization procedure, which is based on the calculation of pressure gradients using pressure measurements captured along a pipeline. The procedure was verified in terms of an accuracy and uncertainty assessment of the resultant coordinate of a leak spot. An important aim of the verification was to assess the effectiveness of the procedure in the case of localization of low intensity leakages with a level of 0.25–2.00% of the nominal flow rate. An uncertainty assessment was carried out according to the GUM convention. The assessment was based on the metrological characteristics of measuring devices and measurement data obtained from the laboratory model of the pipeline.

An exploration on the machine learning approaches to determine the erosion rates for liquid hydrocarbon transmission pipelines towards safer and cleaner transportations

Erosion is commonly found in pipelines with existence of interactions between solid particles, fluid product transported and the surrounding materials. Erosion may lead to material degradation in pipeline and may eventually cause pipeline failure. This failure may cause catastrophic consequence to the surrounding health, property and the environment. Therefore, a better estimation on the pipeline erosion rate is critical for the pipeline engineers to maintain a safer, more cost-effective and sustainable operating condition. In this study, two erosion rate models were used to create an erosion rate database and three machine-learning approaches were developed to help pipeline engineers evaluate the optimal flow velocity. The major results of this study are threefold: First, a purely visual approach was used to present critical information to decision makers. Second, three machine learning approaches (classification tree, artificial neural network and Bayesian network) were established for the erosion rate determination. Third, the benefits and limits of each approach were discussed and evaluated. As novel methodologies to estimate pipeline erosion rate, the machine learning approaches can serve as simple or comprehensive tools to address the various pipeline operating scenarios, with certain or uncertain information. This study provides innovative, intuitive and cost-effective tools for the pipeline operators to predict the erosion rate under various operating conditions and handles the uncertainty via a probabilistic approach, aiming to build safer and more environmental-friendly pipelines.

Corrosion Resistance of Transmission Pipeline Steel Coated with Five Types of Enamels

Corrosion is one of the main causes of incidents occurred in hazardous liquid and gas transmission pipelines in the USA, resulting in a loss of over $12 billion per year. In this study, the corrosion resistance of pipeline steel coated with five types of enamel was investigated in 3.5 wt% NaCl solution with linear polarization resistance and electrochemical impedance spectroscopy tests. Steel coupons were cut from API 5L X65 pipeline steel and coated with five types of enamels using the wet process. The microstructures of all enamel samples were examined by scanning electron microscopy. Experimental results indicate that all enamel coatings increase the corrosion resistance of pipeline steel, and pure enamel PE2, mixed enamels ME1 and ME2 have higher corrosion resistances than pure enamel PE1 and mixed enamel ME3.

An Investigation of the Gathering System Options for a Hypothetical Field with Uniformly Distributed Production Wells

The gathering systems in the production wells are very crucial in the transportation of produced liquids from production wells to collection points such as the processing plant or central processing facilities. Liquid transmission pipelines are a part of the energy industry which involves the transportation of natural crude oil through pipelines. In this research the pipeline costs, material costs are proportional to pipeline diameter, whilst construction and design costs are approximately constant. The research shows that the bigger the length of the flow line, the bigger the total pressure drop, per unit length of the flow line for a given size and the type of pipe, the total pressure drop increases with length, whilst the pressure increases from 100 kpa to 250 kpa, and the length of the flow lines increases from 5.4 km to 12.5 km. The inlet pressure of 600 psig was used, as maximum inlet pressure with a design pressure of 1215 psig, with the assumption that protection against closed in tubing head pressure (CITHP) was protected. The investigation shows that a single flow line or trunk lines are not economical in transporting the fluids from the production wells, due to high -pressure drop in the flowline segments and it can affect pipeline diameters since pressure drop can lead to excess inlet pressure to push the liquid through the flow line and the operating costs can be excessive and result in insufficient pressure to pump or transport the fluids to the central processing facility. The modeling of the pressure drop in the flowline at different rates and for different sizes of nominal pipeline in the gathering systems was achieved.

Leak detection in liquid transmission pipelines using simplified pressure analysis techniques employing a minimum of standard and non-standard measuring devices

This paper deals with issues of detecting leaks in liquid transmission pipelines. It presents solutions of procedures (algorithms) applied to both negative pressure wave and gradient methods. These algorithms are aimed at achieving a satisfactory level of efficiency of a single leakage diagnosis. The methods are evaluated in terms of their implementation with a minimum number of measuring devices. In the case of the negative pressure wave method, apart from the standard pressure transmitters to measure the pipeline pressure, also the use of non-standard measuring devices, conventionally the so-called correctors, is considered. The signals generated by the correctors are characterized by good correspondence of the measured signal representing a change in the pressure to measurement noise level and the overall pressure transmitter range. All this, in combination with the developed algorithm, which apart from detecting a leak, is aimed at precise identification of a change in the signal related to the wave pressure front, i.e. the so-called inflection point, provides a high efficiency of leak detection. This has been proven by carrying out a number of experimental tests on a laboratory water pipeline. The tests involved simulations of both sudden as well slow leakages.

Building hazard resilience through collaboration: the role of technical partnerships in areas with hazardous liquid and natural gas transmission pipelines

Although long-term planning can be improved by full stakeholder participation that generates consensus, there are some planning problems that lack interest from a large and diverse group of stakeholders. For these low-interest yet substantively important issues, such as hazard mitigation, technical collaboration has been suggested as a precursor to processes that involve full stakeholder participation. However, there has been only limited research evaluating the role of technical collaboration in practice. In this study I analyze how technical collaboration influences hazard mitigation capacity for communities at risk from hazardous liquid and natural gas transmission pipeline accidents. Semistructured interviews were conducted with forty-five emergency managers and planning directors located in the Greensboro-Winston-Salem, North Carolina (USA) metropolitan area whose communities had hazardous liquid and natural gas transmission pipelines. On the basis of these interview data, I classified technical collaborations into three categories: loose alliances, full partnerships, and hierarchically cooperative groups. Using this typology of technical collaboration, I found that the type of collaboration (1) influenced local knowledge about pipelines; (2) impacted how transmission pipeline hazards were addressed within a mitigation agenda; and (3) affected a community's long-term capacity to mitigate pipeline hazards and build resilience against potential disasters. Leadership, access to resources, and continuity of the collaboration affected the function of technical collaborations. The research illustrated the inconsistencies in hazard resilience outcomes produced by the three types of technical collaboration. Collectively, the results illustrate how some planners and emergency managers can overcome deficits in knowledge about transmission pipeline hazards or about hazard mitigation planning tools in order to improve hazard resilience. Practitioners from jurisdictions of various sizes can use this research to facilitate their use of existing relationships to achieve hazard mitigation goals or to address critical issues that may have limited stakeholder support.

Using Land-Use Planning Tools to Mitigate Hazards

Critical infrastructure such as hazardous liquid and natural gas transmission pipelines has received little attention by planning scholars even though local development management decisions have far-reaching consequences for homeland security, environmental damage, and human exposure. Using a survey of planning directors in North Carolina, the article identifies frequently used tools for mitigating pipeline hazards and examines factors associated with tool adoption. Despite the risks associated with pipeline rupture, most localities use few mitigation tools, and adoption of regulatory and informational tools appear associated with divergent factors. Whereas stakeholder participation, commitment, capacity, and community context were associated with total tool and information tool use, only stakeholder participation and capacity factors were associated with regulatory tool use.

Improving the Efficiency of Diagnosing of Leaks from Liquid Transmission Pipelines by Using the New Diagnostic Information – The Signals of Weak Interactions between Objects

A new method for the diagnosing of leaks from liquid transmission pipelines is proposed in this paper. The solution consists in the acquiring of the new diagnostic information (i.e. the new diagnostic signals). These signals result from the operation of special testing objects joined to a tested pipeline. This paper presents the results of the application of the proposed method upon the laboratory pipeline. During experimental tests it has been determined that thanks to the use of these new diagnostic signals improving the efficiency of diagnosing of leaks is possible.

Flexible piezopolymer ultrasonic guided wave arrays

Ultrasonic guided wave technology is being applied to a variety of gas and liquid transmission pipeline inspection applications. There are a variety of promising transduction techniques used to excite longitudinal, torsional, and flexural modes in pipe. Some of the more common methods include electromagnetic-acoustic, magnetostrictive, and piezoceramic array transducers. The objective of the work presented in this paper was to develop an array design that is simpler to manufacture and attach to pipelines compared to the current piezoceramic design. The design considerations for a flexible piezopolymer-based array are discussed in this paper along with the basic principles behind the selection of the array element width and spacing. The performance of a piezoceramic and piezopolymer array, with identical element spacing and width, are compared at four different frequencies. Tests were undertaken on a carbon steel pipe with a simulated defect. Evaluation of the different arrays was performed in terms of the defect response, in terms of amplitude, of the lower-order axisymmetric modes. It is shown that while the piezopolymer array provides comparable sensitivity to the piezoceramic array, the amplitude of the signals reflected from the simulated defect are 30 dB lower compared to those generated using the piezoceramic array.