what is pigging

Pigging is a process used in pipeline transportation to perform various maintenance operations without stopping the flow of the product. It involves using pipeline inspection gauges or gadgets, devices generally referred to as pigs or scrapers, to clean pipelines and check pipeline conditions. The pig is usually cylindrical or spherical to aid movement and efficient cleaning. As the pig moves through the pipeline, it can remove and possibly detect 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 pipe. Pigging is used to clean large diameter pipelines in the oil industry, but the use of smaller diameter pigging systems is now increasing in many continuous and batch process plants as plant operators search for increased efficiencies and reduced costs. Pigging systems are installed in industries handling products as diverse as lubricating oils, paints, chemicals, toiletries, cosmetics, and foodstuffs. Pigs are used in lube oil or paint blending to clean the pipes to avoid cross-contamination, and to empty the pipes into the product tanks (or sometimes to send a component back to its tank) . Pigging systems are designed so that the pig is loaded into the launcher, which is pressured to launch the pig into the pipeline through a kicker line. In some cases, the pig is removed from the pipeline via the receiver at the end of each run. Pigging is performed throughout the lifecycle of a pipeline from pre-commissioning all the way through to decommissioning. The most common uses of pigging are routine cleaning, maintenance, and inspection of the asset’s internal characteristics.