Product manufacturers and distributors often use pipelines in the process, and pipeline pigging can ensure that the lines run smoothly with pig pipe cleaning. Slow transmission, cracks, flaws and plugging can have disastrous consequences in a manufacturing plant. Similarly, plants that produce more than one liquid product using the same infrastructure, can suffer contamination unless the pipes are thoroughly cleaned on the inside before a new product is inserted.
Pipeline pigs are maintenance tools that are introduced into pipelines by means of a 'pig trap', which consists of a launcher and receiver. The pig can be used without causing any flow disruptions, and it can be forced through either product flow, or by being towed by a cable or other device.
Why Call it Pipeline Pigging?
After all, a pipeline pig is not an animal...The one hypothesis is that 'pig' is short for Pipeline Intervention Gadget and another - more far-fetched - theory is that a leather pig was sent through a pipeline when the method was started, and it made a squeaking sound as it scraped along the walls of the pipes, much like an actual farm pig.
What is Pipeline Pigging?
The pipeline pig is usually a spherical or cylindrical device that sweeps the inner walls of the pipes, scraping the sides as it pushes debris through towards the exit point. Not only does it clean the pipes, but it can also be used to inspect the integrity of the pipe interiors.
As technology continues to evolve, pipeline pigging has evolved to perform different functions.
Utility pigs (solid cast pigs, foam pigs and mandrel pigs) are used to clean pipeline, much like you would clean a plumbing line. Over time, construction debris can start accumulating inside the pipeline and that's why it is so important that lines are cleared before production commences. The utility pig will scrape away debris. While a sealing pig removes liquids from the pipe, it can also act as a separator between different products using the same pipeline.
Inspection pigs (inline inspection pigs) can gather information about the temperature, pressure, bends, diameter, curvature, corrosion, and metal loss from inside the pipes. Using ultrasonic sounds, a utility pig can measure the thickness of the pipe wall from the inside.
Specialty pigs can isolate a section of the pipeline in order for the team to perform maintenance work. The plugging pig stops up the pipeline on either side of the area where remedial work needs to be performed, thus keeping up the pressure inside the pipe.
Gel pigs have various uses. They can be inserted by themselves, or in conjunction with another type of pig. When a gel pig is pushed through a pipeline, it can help with hydrotesting, condensate removal and dewatering, or debris removal. Companies wishing to separate two types of product in the same pipeline, can also do so using a gel pig.
Pipes are available in a variety of diameters, but the good news is that the pipeline pigging industry caters to all of them by making available pipeline pigs in dual and multi-diameter sizes.
Safe Pipeline Pigging Procedures
Pipeline pigging is a method used all around Canada and the rest of the world as an effective method of cleaning, inspecting and maintaining industrial pipes. While pipeline pigging offers the advantage of not interrupting production processes, it can be a high-risk procedure, unless it is facilitated by a qualified operator.
Any type of pipeline pigging requires extensive planning, and professional assistance for either the pig manufacturers or a qualified pipeline cleaning service company. The key to safe operation is to eliminate or at least minimize ILI tool sensor liftoff. Proper application ensures maximum results for companies, whether they require mechanical dry pigging or liquid pipeline pigging with mechanical pigs.
The process involves launcher and receiving station, which is generally a vessel that is connected parallel to the pipeline that will be cleaned or inspected. This method enables the operator to launch and receive the pipeline pig, using the normal operating pressure of the pipeline to propel it forward without stopping production or interrupting the flow of the liquid product.
The launcher or receiver vessel has a closure door for safe operation, and the process involves a sequence of valve operations combined with opening and closing of the door. A mistake during this operation could have dire consequences.
Pipeline Pigging Launcher and Receiver Station Operation
Safe operation of the pipeline pigging closure door requires that the operator follows certain safety procedures before opening the closure:
- Drain and depressurize the vessel.
- Isolate the vessel from the process pipeline.
- If drain systems or vent headers are present, the vessel must first be isolated.
- The vessel should not contain any toxic gasses, such as H2S.
- The vessel must be isolated when the door is open.
- The closure must be shut tightly before the launching or receiving process commences.
- Production may be interrupted if the throttle is not opened fully before the operator isolates the launcher or receiver station and that's why it is so important to prevent opening the doors when the system is under pressure.
Pipeline pigging inspections ensure that your system is operating as it should. The pig will measure a range of variables from the inside, including the volume, pressure and wall thickness. Again, this process should be handled by a professional pipeline pigging operator who is trained to administer the pig and interpret the results.
When buying a pipeline pigging system, be sure to deal with a reputable ILI company who is able to offer the support needed for best results.