Introduction to Pigging in Pipeline

Excerpt

2152020

Pigging in pipeline is a process in pipeline maintenance that involves the use of devices known as pigs, which clean pipelines and are capable of checking pipeline condition without necessarily stopping or interfering with the flow of product in the pipeline.

The primary purpose of pipeline pigs is to make sure that the pipe is clean and free from obstruction. As the pig moves through the pipeline, it can possibly detect and remove any build-ups within the pipe which can often lead to reduced performance, increased energy costs and cause corrosion, which could lead to disastrous leaks and cracks in the pipeline.
Pipeline pigging is used in number of industries including oil & gas, lube oil, chemical plants and hygienic applications such as pharmaceutical or food.

Pipeline Pigging Applications

• Pigs are used to clean solids, scale, wax buildup, and other debris from the pipelines to keep the pipeline flow efficiency high.
• In natural-gas pipelines, pigs are used to manage liquid accumulation and keep the pipeline free of liquids. Water and natural-gas liquids can condense out of the gas stream as it cools, which affects flow efficiency and can lead to enhanced corrosion.
• Pigs are used to empty the pipelines into the product tanks.
• Pigs (also known as smart pigs or inspection pigs) are used to inspect pipelines for detecting leaks and buildups, which could be explosive and dangerous to the environment. Inspection pigs collect information about temperature and pressure, corrosion/metal loss, diameter, bends and curvature, cracks, weld defects, surface pitting and areas of crushing/deformation to verify pipeline integrity.
• Pigs are used to apply internal pipe coatings, such as epoxy coating materials, in operating pipelines.
• Some “smart” pigs have GPS capabilities that can assist in mapping a pipeline. This helps maintenance teams save time and money by pin-pointing exactly where is a pipeline is run, instead of having to excavate a large area to reach a specific location in the line.