A variety of conditions can make it difficult for Gas Distribution operators to pig their pipelines for cleaning, maintenance, or inline inspection (ILI), leading them to believe that their system is unpiggable. In reality, any system can be modified and made piggable. And with expanding regulatory requirements for inline inspection – and the fact that pigging can contribute to pipeline productivity and profitability – improving piggability is essential.
Pigging is often impeded by pipeline design characteristics – including tight, mitered, or forged bends, certain types of welds and connections, and dual- and multi-diameter pipe sections. Some valves, particularly older gate valves, obstruct pig passage; in fact, valves are the leading cause of stuck pigs and other pigging problems.
In the case of pipeline acquisitions, absent or incomplete records can lead to piggability concerns. And of course, systems without pig launchers and receivers cannot be pigged at all.
Conditions inside the pipeline – such as internal damage and the build-up of debris, sediment, and other flow-restricting materials – also cause pigging challenges. Because pigs are pushed along by product pressure inside the pipeline, low flow rates may cause stopping and starting, preventing the pig from performing effectively. Conversely, pigs running in high velocity product streams can also be less effective.
TDW helps operators improve piggability for:
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The installation of pig launchers and receivers is one key to making a system piggable. TDW offers Gas Distribution operators both conventional launchers and receivers and automated pigging systems that enable pigging access without interrupting flow.
In addition, TDW provides cleaning pigs that remove liquids and debris to maximize throughput and mitigate corrosion growth.
Launchers and receivers:
Technical assistance is available from TDW subject matter experts for special circumstances or if the path to a solution requires consultation.
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Hot tapping and plugging (HT&P) technology allows Gas Distribution market pipeline owners and operators to complete pipeline replacements and modifications – from making lines piggable to line lowering to relocations – all while their line is in service. TDW equipment and services are engineered for safety and efficiency, allowing operators to better protect their employees and the surrounding community.
The HT&P process incorporates a low pressure pipeline fitting , valve, tapping machine, and isolation equipment, all working together to provide a safe and proven isolation solution. Once the area of pipeline that needs work has been safely isolated and evacuated, the line modification can be performed.
The full suite of isolation solutions offered by TDW plays a critical role in this process. The TDW STOPPLE® Train isolation system, for example, uses double block and bleed technology to help increase efficiency and safety during pipeline modification. The system only requires a single pipeline tap – reducing costs associated with fittings, valves, welding, and inspection services. The bleed port affixed on the line ensures that any product that bypasses the first seal is captured and evacuated through the bleed port, which creates a safe zone in high-consequence areas.
Whether operators are purchasing equipment to perform their own HT&P jobs or turning to TDW to execute the service for them, they can rely on the broad line of equipment and consumables by TDW. The company engineers and manufactures nearly every component needed for an HT&P project, and TDW tapping and isolation equipment is considered the industry standard.
TDW can also partner with operators before the work begins, providing consulting services to help them make optimum use of TDW products and services. TDW application engineers are recognized industry experts, ready to assist operators through each project phase – from start to finish.