#pipeline

What are pipeline pigs?
In pipeline transportation, pigging is the practice of using pipeline inspection gauges, devices generally referred to as pigs or scrapers, to perform various maintenance operations. This is done without stopping the flow of the product in the pipeline.
Pipe pigs are used for performing following types of tasks -
1. Cleaning of pipeline and displacement of sludge
2. Separation between batches of different products in the same pipeline
3. Inspection tool for the pipeline
Pipe pig types
1. Utility Pipe Pigs
These pig tools are used for cleaning and product separation. Based on the utility or the purpose of the pig tool, these are classified into 'cleaning pig tools' used for cleaning and 'sealing or separation pig tool' used for separation between two products. Based on the pig structure, utility pig tools are further classified as, 'foam pigs', 'mandrel pigs' and 'spherical pigs'. Foam pigs are capsule shaped and made out of polymer foam. Mandrel pigs are dumbbell shaped with a central tube called 'mandrel'. Different kinds of components can be attached to this mandrel to customize the pig tool to suit different operations.
2. Inspection Pig Tool
They are also known as 'intelligent pig tool' or 'smart pig tool'. They are used for inspection of the condition of the pipe and/or its contents. These pig tools are equipped with sensors for gathering various kinds of data, as the pig tool travels through the pipeline. The electronics and sensors on an intelligent pig tool are powered by batteries on the pig. Surface pitting, corrosion of inner walls, cracks and weld defects in pipelines are often detected using magnetic flux leakage (MFL) pigs. Other intelligent pig tools use electromagnetic acoustic transducers to detect pipe defects. Caliper pigs can measure the roundness of the pipeline to determine areas of crushing or other deformations.
3. Gel Pig Tool
Gel pigs are a series of gelled liquid systems which have been developed for use in pipeline operations, either during initial commissioning, or as a part of a continuing maintenance program. Most pipeline gels are water-based, but a range of chemicals, solvents, and even acids can be gelled. Some chemicals can be gelled as the bulk liquid and others only diluted in a carrier. Gelled diesel is commonly used as a carrier of corrosion inhibitor in gas lines. As a liquid, although highly viscous, the gel can be pumped through any line which will accept liquids. Gel pigs can be used alone (in liquid lines), in place of batching pigs, or in conjunction with various types of conventional pigs. When used with conventional pigs, gelled pigs can improve overall performance while almost eliminating the risk of sticking a pig. Gel pigs do not wear out in service like conventional pigs. They can, however, be susceptible to dilution and gas cutting.
#pipeline #maintenance #transportation #inspection #ndtinspection #pigging #oilandgasindustry