A. Introduction to Pipeline Integrity Management
Pipeline integrity management (PIM) is a fundamental aspect of modern infrastructure, ensuring the safety, reliability, and efficiency of the pipelines that transport critical resources such as oil, gas, water, and chemicals over vast distances. These pipelines are often the lifeblood of industries, providing the energy and materials necessary for both daily operations and large-scale industrial processes. Managing the integrity of these pipelines involves a complex and multi-disciplinary approach, combining engineering, technology, and risk management practices to protect against potential failures that can have devastating economic, environmental, and public safety consequences.
Pipelines are subjected to a wide array of environmental and operational stresses that can lead to degradation over time, such as corrosion, material fatigue, mechanical damage, and external impacts like ground movement or third-party interference. These factors make maintaining the structural and functional integrity of pipelines a highly challenging task, requiring a proactive and systematic approach. This is where Pipeline Integrity Management comes into play.
At its core, pipeline integrity management is a holistic framework designed to ensure that pipelines operate within their design parameters throughout their entire lifecycle. It involves regular inspection, maintenance, monitoring, and analysis to prevent potential failures before they occur. This process is vital not only for maintaining the continuous and safe flow of materials through the pipeline but also for complying with stringent regulatory standards that govern pipeline safety and environmental protection.
B. The Importance of Pipeline Integrity
Pipelines are often considered the safest and most efficient mode of transporting hydrocarbons and other fluids over long distances. However, due to their exposure to environmental conditions, operational stresses, and potential human error, pipelines face various integrity threats. Pipeline integrity ensures that these systems operate without leaks, ruptures, or failures that could have catastrophic consequences for human safety, the environment, and company operations.
Ensuring pipeline integrity is vital for several reasons:
- Safety: Pipeline failures can result in severe accidents, posing threats to human life and property.
- Environmental Protection: Leakage of harmful substances into the environment can lead to contamination of water, soil, and air.
- Economic Efficiency: Pipeline failures result in costly repairs, fines, and lost revenue from interrupted operations.
1. Pipeline Design and Material Selection
The design and construction phase is the first critical step in ensuring the long-term integrity of a pipeline. A thorough understanding of the operational environment, transported materials, and pressure conditions must guide the selection of appropriate materials and construction techniques.
- Material Selection: Choosing the right materials is essential for pipeline durability. Factors such as the corrosive nature of the transported substance, soil chemistry, and the operating temperature and pressure are key considerations.
- Design Standards: Compliance with international engineering standards, such as those provided by ASME, API, or ISO, ensures that pipelines are designed to withstand expected mechanical stresses and environmental conditions.
A well-designed pipeline with the correct material ensures it can operate efficiently and safely over its expected lifespan, minimizing maintenance and repair costs in the long run.
2. Inspection and Monitoring
Continuous inspection and monitoring of pipelines are at the heart of integrity management. Early detection of flaws or potential threats allows operators to address issues before they become critical.
- In-Line Inspection (ILI): ILI tools, also known as smart pigs, are employed to inspect pipelines from the inside. These tools use technologies like magnetic flux leakage (MFL), ultrasonic testing (UT), and electromagnetic acoustic transducers (EMAT) to detect corrosion, cracks, dents, and metal loss. ILI provides highly accurate and real-time data on pipeline conditions.
- Non-Destructive Testing (NDT): Methods such as ultrasonic testing, radiography, and eddy current testing are used to inspect pipelines externally without damaging the structure. NDT methods are useful in detecting surface cracks, corrosion, or mechanical deformation.
- Continuous Monitoring Systems: Advanced sensors placed along the pipeline route provide real-time data on pressure, temperature, and flow rates. These systems can alert operators to potential leaks, overpressure situations, or mechanical damage.
By leveraging these technologies, operators can maintain a detailed and updated profile of the pipeline's condition, leading to proactive maintenance strategies.
3. Corrosion Control and Cathodic Protection
Corrosion is one of the primary causes of pipeline failure, particularly in pipelines transporting oil, gas, or corrosive materials. To mitigate this risk, effective corrosion control measures must be in place.
- Cathodic Protection (CP): Cathodic protection is one of the most widely used methods for preventing corrosion, particularly in buried or submerged pipelines. CP works by converting the pipeline into a cathode in an electrochemical cell, which prevents the pipe from corroding. This is typically achieved using sacrificial anodes or impressed current systems.
- Coatings and Linings: Protective coatings are applied to the external surface of pipelines to create a barrier between the metal and the environment. Internally, special linings are often used to protect the pipeline from corrosive materials such as sour gas, crude oil, or chemicals.
Implementing effective corrosion control is crucial to extending the lifespan of pipelines and maintaining their operational safety.
4. Risk Assessment and Hazard Identification
Risk assessment is a systematic process used to identify potential hazards, evaluate their likelihood and consequences, and prioritize them based on their impact.
- Failure Mode and Effect Analysis (FMEA): This method involves identifying possible failure modes for each component of the pipeline and assessing their potential impact on overall system performance.
- Quantitative Risk Assessment (QRA): Using mathematical models and historical data, QRA helps to calculate the probability of pipeline failure and the associated consequences, including environmental, safety, and financial impacts.
- Hazard Identification (HAZID): This is an important step in understanding the various threats that could compromise pipeline integrity. HAZID studies assess potential risks such as external impacts, geological movements, or third-party interference.
By conducting thorough risk assessments, operators can implement targeted maintenance and monitoring efforts to minimize the chances of pipeline failure.
Maintenance is a key element of any pipeline integrity management system. Preventive maintenance refers to regular, planned activities that keep the pipeline in good condition, while corrective maintenance addresses specific defects or damage.
- Scheduled Maintenance: Cleaning operations such as pigging are regularly conducted to remove debris, scale, and other deposits that can accumulate inside pipelines, reducing flow efficiency and increasing the risk of corrosion.
- Coating Repair and Replacement: External protective coatings are inspected periodically, and any damaged or degraded sections are repaired or replaced to ensure continued protection against environmental factors.
- Emergency Response and Repair: In the event of a leak or damage, rapid response and repair are crucial to minimizing the impact on the environment and human safety. Temporary fixes like pipeline clamps or sleeves can be used until permanent repairs are made.
- Geographical Information Systems (GIS): GIS tools are often integrated into PIM systems to provide visual representations of pipeline routes, inspection data, and risk areas. These systems allow for better decision-making and resource allocation.
- Integrity Management Plans (IMP): An IMP outlines the processes and procedures used to maintain pipeline integrity over time. This plan includes regular inspections, maintenance schedules, and risk mitigation strategies. Operators must regularly review and update the IMP based on new data and operational conditions.
- Regulatory Audits: Operators are subject to periodic audits to ensure compliance with national and international safety standards. Non-compliance can result in fines, operational shutdowns, and reputational damage.
- Documentation and Reporting: Maintaining thorough documentation of all pipeline activities, including inspection reports, maintenance logs, and risk assessments, is crucial for demonstrating regulatory compliance.
Even with robust preventive measures in place, pipelines are still vulnerable to unforeseen events such as natural disasters, third-party damage, or operational failures. A comprehensive emergency response plan ensures that pipeline operators can quickly and effectively respond to incidents.
- Leak Detection Systems: Rapid detection of leaks is essential for minimizing environmental and safety impacts. Acoustic sensors, fiber optic cables, and pressure monitoring systems are commonly used for real-time leak detection.
- Incident Response Teams: Trained personnel must be on standby to respond to any emergencies. These teams are responsible for isolating damaged sections, containing spills, and making repairs.
- Post-Incident Analysis: After an incident, a thorough investigation is conducted to identify the root cause and implement corrective actions to prevent future occurrences.
D. Corrosion Control and Mitigation
Corrosion is one of the most significant threats to pipeline integrity, often causing leaks, structural failures, and environmental disasters if not properly managed. Pipelines, especially those buried underground or submerged in water, are continuously exposed to various environmental and operational conditions that accelerate corrosion processes. Therefore, controlling and mitigating corrosion is crucial to maintaining the integrity and longevity of pipeline systems.
This section will provide an in-depth exploration of the principles, techniques, and strategies involved in corrosion control and mitigation for pipelines, including various engineering solutions and preventive measures to minimize corrosion risks.
1. Understanding Corrosion: A Pipeline's Enemy
Corrosion is the natural deterioration of metals due to chemical reactions between the metal surface and the environment. In pipelines, corrosion can occur both internally and externally. Understanding the types of corrosion that affect pipelines is the first step toward effectively managing and mitigating its impact.
- External Corrosion: This type occurs when the external surface of the pipeline is exposed to corrosive elements, such as soil moisture, oxygen, or chemical contaminants in the surrounding environment. It is especially prevalent in pipelines buried underground or exposed to marine environments.
- Internal Corrosion: Pipelines transporting oil, gas, or chemicals are vulnerable to internal corrosion due to the presence of water, hydrogen sulfide (H₂S), carbon dioxide (CO₂), or other corrosive substances within the pipeline's flow. This type of corrosion can weaken the internal walls of the pipe, eventually leading to perforations or leaks.
- Galvanic Corrosion: This occurs when two dissimilar metals come into contact, leading to the more reactive metal corroding faster. Pipelines with different metals in their construction are at risk of this form of corrosion.
- Stress Corrosion Cracking (SCC): This is a more complex form of corrosion that occurs when a pipeline is subjected to both a corrosive environment and tensile stress. SCC can cause cracks to form in the metal, compromising its structural integrity.
2. Corrosion Prevention Strategies
Preventing corrosion begins with proper design and material selection during the construction phase, followed by the implementation of engineering techniques and coatings to protect the pipeline throughout its service life.
A. Material Selection and Coatings
The choice of materials for pipeline construction plays a vital role in minimizing corrosion risks. Engineers must select materials that are corrosion-resistant and suitable for the operational environment.
Corrosion-Resistant Alloys: Certain alloys, such as stainless steel, are naturally more resistant to corrosion due to their chemical composition. For pipelines exposed to highly corrosive environments, selecting such materials can extend the pipeline’s life significantly.
Protective Coatings: External coatings are one of the most common methods for preventing corrosion in pipelines. These coatings form a physical barrier between the metal surface and the environment, preventing moisture and chemicals from reaching the metal. Common types of coatings include:
- Fusion-Bonded Epoxy (FBE): A thermosetting powder coating widely used in pipeline protection due to its strong adhesion and resistance to chemicals.
- Polyethylene Coatings: These are highly effective for protecting buried pipelines against soil moisture and corrosive substances.
- Coal-Tar Enamel: A traditional coating that provides excellent protection, though it is being phased out in favor of more environmentally friendly alternatives.
B. Internal Corrosion Control
Pipelines that transport fluids like oil or natural gas with corrosive elements such as water or CO₂ require additional internal protection measures.
- Chemical Inhibitors: These are substances injected into the pipeline flow to react with corrosive agents, neutralizing their effects. For instance, corrosion inhibitors like phosphates or silicates form a protective film on the internal surface of the pipeline, preventing corrosive reactions.
- Dehydration Systems: For gas pipelines, removing moisture from the gas stream is crucial to reducing the risk of internal corrosion. Dehydration systems, such as glycol dehydration or molecular sieve systems, can effectively reduce water content and prevent corrosion.
3. Cathodic Protection (CP)
Cathodic Protection is one of the most effective methods for controlling external corrosion in underground or submerged pipelines. It involves the application of an external current to the pipeline, making it the cathode of an electrochemical cell, which inhibits the corrosion process.
A. Impressed Current Cathodic Protection (ICCP)
In this method, a direct current (DC) power source is used to supply a continuous current to the pipeline, counteracting the natural electrochemical reactions that cause corrosion. This current is supplied by anodes that are buried or submerged near the pipeline.
- Anode Materials: Impressed current systems use durable anodes, such as graphite, mixed metal oxide, or high-silicon cast iron, which can last for several decades.
- Control Systems: ICCP systems are equipped with monitoring and control mechanisms to ensure the correct voltage and current levels are applied to the pipeline. Rectifiers convert AC power to DC, and sensors monitor pipeline conditions in real time.
- Anode Placement: Sacrificial anodes are strategically placed along the pipeline’s length, typically at high-risk areas like joints or bends where corrosion is more likely to occur.
A. In-Line Inspection (ILI)
ILI tools, commonly referred to as smart pigs, are sent through the pipeline to inspect its internal and external conditions. These tools use various technologies to detect corrosion, cracks, and metal loss:
- Magnetic Flux Leakage (MFL): This method uses magnetic fields to detect corrosion and metal loss in pipelines. When the pig passes through the pipeline, changes in the magnetic field indicate areas of corrosion or damage.
- Ultrasonic Testing (UT): UT technology uses high-frequency sound waves to measure the pipeline’s wall thickness. Areas with reduced thickness due to corrosion are easily identified.
- Electromagnetic Acoustic Transducers (EMAT): EMAT generates sound waves that detect cracks or stress corrosion cracking in the pipeline’s walls.
- Radiography: This technique uses X-rays or gamma rays to inspect the pipeline’s external structure. It’s effective for detecting corrosion at joints or weld seams.
- Eddy Current Testing: By inducing electromagnetic fields into the pipeline, eddy current testing detects surface and near-surface defects, such as cracks or corrosion pitting.
5. Corrosion Mitigation in Specific Environments
Different environments pose unique challenges to pipeline corrosion control. Understanding these challenges allows for the implementation of specialized mitigation strategies.
A. Marine Environments
Pipelines submerged in seawater are particularly vulnerable to both external corrosion and biofouling (the accumulation of marine organisms on surfaces). To combat these issues, specialized coatings and cathodic protection systems are employed:
- Polyurethane Coatings: Highly durable and resistant to saltwater, polyurethane coatings protect submerged pipelines from both corrosion and mechanical damage from marine organisms.
- Marine Cathodic Protection: Sacrificial anodes made from aluminum alloys are often used in marine environments due to their high efficiency in saltwater.
B. High-Temperature Environments
Pipelines in high-temperature environments face accelerated corrosion rates due to increased chemical reaction speeds. To mitigate these effects, high-temperature coatings and alloys like Inconel or Hastelloy are often used.
6. Corrosion Control in Pipeline Maintenance Programs
Corrosion control must be a central focus of any pipeline maintenance program. The following activities are essential for preventing and mitigating corrosion:
- Regular Pigging: Pigging operations are conducted to clean out debris, scale, or buildup inside the pipeline that can lead to corrosion.
- Coating Inspections and Repairs: External coatings are periodically inspected for damage, and any compromised areas are repaired or replaced.
- Routine Cathodic Protection System Checks: Both ICCP and SACP systems require regular monitoring to ensure they are functioning properly. Anode replacement and rectifier adjustments may be needed over time.
Modern pipeline integrity management programs use predictive modeling and data integration systems to forecast potential corrosion issues and implement preventive actions before problems occur.
- Corrosion Growth Modeling: Based on historical inspection data and operational parameters, models can predict corrosion growth rates, allowing operators to schedule maintenance activities proactively.
- Data Integration Systems: These systems collect data from multiple sources, such as ILI tools, sensors, and inspection reports, to provide a comprehensive view of the pipeline’s condition. Advanced analytics can identify trends and potential hotspots for corrosion.
E. Monitoring and Data Collection
Effective pipeline integrity management relies heavily on real-time monitoring and data collection. Technological advancements have allowed operators to continuously monitor pipeline systems, ensuring early detection of potential threats.
Types of Monitoring Technologies
- SCADA Systems (Supervisory Control and Data Acquisition): SCADA systems allow operators to monitor pipeline pressure, flow rate, and temperature in real-time, identifying irregularities that may indicate leaks or failures.
- Acoustic Monitoring: Detects changes in sound waves traveling through the pipeline, which can indicate a leak or rupture.
- Fiber Optic Sensors: These are installed along the pipeline and can detect temperature changes, ground movement, and other indicators of potential failure.
1. Classification of Pipeline Defects and Failures
Before selecting an appropriate repair or rehabilitation technique, it is important to classify the type and severity of the pipeline defect. Defects can be classified into the following categories:
- Corrosion Defects: These include both external and internal corrosion, which can manifest as pitting, thinning of the pipe wall, or full penetration leading to leaks.
- Mechanical Damage: Caused by external forces such as excavation activities, impacts, or stress from ground movement, mechanical damage often results in dents, gouges, or cracks.
- Crack Defects: Cracks may develop from welding issues, stress corrosion cracking (SCC), or fatigue, leading to potential ruptures if left unaddressed.
- Leaks and Ruptures: Complete failures where the pipeline experiences a loss of containment, often requiring immediate attention to prevent environmental contamination and product loss.
- Weld Defects: Defects related to faulty welding during installation or maintenance may lead to weaknesses at joints, creating the potential for cracks or leaks.
2. Pipeline Repair Techniques
Several engineering techniques are employed for the repair of pipelines, with the goal of restoring structural integrity without the need for full pipeline replacement. These techniques can be divided into non-invasive (those that do not require pipeline shutdown) and invasive methods (requiring section replacement or major repairs).
A. Sleeve Repairs
Sleeve repair is a common method used to reinforce areas of a pipeline that have experienced thinning or cracks due to corrosion or mechanical damage. Sleeves are steel or composite wraps that are installed over the damaged section to restore the pipe’s strength and pressure integrity.
- Steel Sleeves: These are welded or clamped onto the pipeline, acting as a permanent reinforcement. They are effective for dealing with external corrosion, dents, and cracks. Steel sleeves can be either reinforcing sleeves, which do not fully restore pressure integrity, or full-encirclement sleeves, which are designed to handle the full operating pressure of the pipeline.
- Composite Sleeves: A modern alternative to steel, composite sleeves use materials like fiberglass or carbon fiber, often bonded with resin, to form a durable wrap around the damaged section. Composite sleeves are lightweight and offer high strength, making them suitable for pipelines that require quick repairs with minimal downtime. These are particularly effective for internal corrosion issues when combined with special sealing compounds.
- Temporary Clamps: These are used for emergency repairs, allowing the pipeline to continue operating while a more permanent solution is planned. They are easy to install and do not require the pipeline to be shut down.
- Permanent Clamps: These are designed for long-term use, offering a durable, leak-proof solution without needing to replace the damaged section of pipe.
C. Hot Tapping and Line Stopping
When repairs are needed on live pipelines, hot tapping and line stopping techniques are used to isolate the damaged section without disrupting the entire pipeline system.
- Hot Tapping: This process allows a new branch connection or access point to be created in a live pipeline without shutting down the flow. Hot tapping is often used in repair scenarios where a pipeline bypass is required, or additional equipment needs to be installed.
- Line Stopping: In cases where a segment of the pipeline must be isolated for repair, line stopping involves inserting a plug into the pipeline to temporarily block the flow of product while repairs are made downstream of the stop. This method is highly effective for making repairs while minimizing downtime for the rest of the system.
D. Welded Repairs
Welding remains a fundamental technique for repairing pipelines, particularly in areas with cracks, fractures, or damaged weld seams. There are two primary types of welded repairs:
- Weld Overlay: This method involves applying new weld material over the damaged section, restoring the structural integrity of the pipe. Weld overlays are commonly used to address corrosion pits, cracks, and gouges.
- Sectional Replacement: For severely damaged pipeline sections, cutting out the affected area and replacing it with a new piece of pipe is often the best solution. Welding is used to join the new section to the existing pipeline. While this method is more invasive and requires pipeline shutdown, it offers a complete solution for extensive damage.
E. Epoxy Injection
For pipelines with internal corrosion or pinhole leaks, epoxy injection is an innovative method for sealing small cracks and restoring the internal surface. This process involves injecting a two-part epoxy resin into the pipeline, where it hardens and forms a durable coating that seals leaks and prevents further corrosion. Epoxy injection is often used in combination with internal liners to provide additional protection.
3. Pipeline Rehabilitation Techniques
Rehabilitation techniques are employed when large sections of a pipeline require extensive repair, but complete replacement is not feasible or cost-effective. These techniques aim to extend the service life of pipelines by restoring their structural integrity and preventing further degradation.
A. Slip Lining
Slip lining involves inserting a smaller-diameter pipe, known as a liner, into the existing pipeline. This technique is primarily used for pipelines experiencing internal corrosion or structural degradation. Slip lining restores the pipeline’s pressure capacity and prevents further internal damage.
- Material Selection: The liner can be made from a variety of materials, including HDPE (high-density polyethylene), PVC, or steel. The choice of material depends on the pipeline’s operating environment and the transported fluid.
- Installation Process: The liner is pulled or pushed into the existing pipeline, and the space between the liner and the original pipe is often filled with grout or another sealing material to ensure a tight fit.
Cured-in-place pipe (CIPP) rehabilitation is a trenchless technique where a flexible liner, impregnated with resin, is inserted into the damaged pipeline. The liner is then expanded and cured in place using heat, steam, or UV light, forming a new pipe within the old one.
- Durability: CIPP is highly effective for addressing internal corrosion and cracks. The cured liner is resistant to corrosion and chemical attack, and it significantly enhances the structural integrity of the original pipe.
- Application: CIPP is often used in urban environments or areas where excavation is not possible, minimizing disruption to surrounding infrastructure.
- Process: A bursting tool is inserted into the old pipe, where it fractures the pipe and pushes the fragments outward into the surrounding soil. At the same time, a new pipe (usually made of HDPE or PVC) is pulled into place, creating a brand-new, structurally sound pipeline.
D. Internal Linings and Coatings
For pipelines exposed to corrosive fluids, internal linings and coatings provide an additional layer of protection. These linings are applied to the inside surface of the pipeline to prevent further corrosion and material loss.
- Epoxy Linings: These are commonly used in water and wastewater pipelines, as well as oil and gas pipelines. Epoxy forms a smooth, protective barrier that prevents the transported fluids from contacting the metal surface.
- Cement Mortar Linings: Used in water distribution systems, cement mortar linings provide a highly durable surface that resists corrosion and prevents the buildup of mineral deposits.
- ILI Tools: Smart pigs equipped with ultrasonic, magnetic flux leakage (MFL), or eddy current technologies provide detailed data on the pipeline’s condition. These tools detect internal and external corrosion, cracks, and metal loss.
- NDT Methods: Radiography, ultrasound, and electromagnetic testing are used to assess areas of the pipeline that are difficult to access or cannot be inspected using ILI tools.
5. Formulas for Repair and Rehabilitation
Pipeline repair and rehabilitation often require engineering calculations to ensure that the chosen repair method will restore the pipeline’s structural integrity and pressure capacity. Key engineering formulas used in repair include:
A. Burst Pressure Formula:
Where:
- Pb is the burst pressure,
- D is the outer diameter of the pipe.
- St is the tensile strength of the pipe material,
- t is the wall thickness, and.
- CR is the corrosion rate,
- K is a constant depending on units,
- W1 and W2 are the initial and final weights of the material sample,
- A is the surface area,
- t is the time of exposure, and
- p is the density of the material.
G. Pipeline Integrity Regulations and Standards
Pipeline integrity management is governed by various international and local regulations designed to ensure public safety, environmental protection, and operational reliability.
Key Regulations and Standards
- API 1160: This American Petroleum Institute (API) standard outlines best practices for managing the integrity of pipelines used for liquid hydrocarbons.
- ASME B31.8S: The American Society of Mechanical Engineers (ASME) standard focuses on the integrity management of gas transmission pipelines.
- PHMSA Regulations: In the United States, the Pipeline and Hazardous Materials Safety Administration (PHMSA) sets stringent regulations for pipeline integrity, emphasizing frequent inspections, corrosion control, and emergency preparedness.
H. Formulas for Pipeline Integrity
The structural integrity of pipelines can be assessed using several engineering formulas. These formulas help calculate the stresses acting on the pipeline and evaluate its ability to withstand operational loads.
A. Hoop Stress Formula
Where:
- σh = hoop stress (MPa)
- P = internal pressure (MPa)
- D = outside diameter of the pipe (mm)
- t = wall thickness of the pipe (mm)
B. Von Mises Stress
The Von Mises stress helps in determining whether a pipeline material will yield under a given load:
Where:
𝜎1 and 𝜎2 represent the principal stresses acting on the pipeline.
I. Conclusion
Pipeline integrity management is an essential practice for ensuring the safe and reliable operation of pipeline systems. By combining risk assessments, regular inspections, corrosion control, real-time monitoring, and repair techniques, operators can significantly extend the lifespan of their pipelines while minimizing risks to safety, the environment, and economic efficiency.
Investing in Pipeline Integrity Management ensures compliance with regulatory standards, reduces the likelihood of catastrophic failures, and maintains the trust of stakeholders. With continuous advancements in technology, the future of pipeline integrity promises even more robust and precise solutions to manage risks effectively.
J. Reference
- American Petroleum Institute (API). (2019). API 1160: Managing System Integrity for Hazardous Liquid Pipelines.
- American Petroleum Institute (API). (2019). API 1160: Managing System Integrity for Hazardous Liquid Pipelines.
- ASME B31.8S (2014). Managing System Integrity of Gas Pipelines.
- Mokhatab, S., Poe, W. A., & Mak, J. Y. (2015). Handbook of Natural Gas Transmission and Processing. Gulf Professional Publishing.
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