Definition - What does Ice Pigging mean?
Ice pigging is a method used to clean the inside of a pipeline and involves the use of an ice slurry. The ice slurry is forced through a section of the pipeline and retrieved at the end of the section. Undesirable materials are scrapped off the inner wall and flushed out as the ice pig moves through the pipeline. Because it is not a completely solid object, an ice pig can move through pipeline bends and diameter changes with relative ease.
Corrosionpedia explains Ice Pigging
Ice pigging is performed by forcing the ice through a valve at the desired location of the pipeline. Additives such as salt are frequently added to the ice pigging material to ensure that it remains effective throughout its journey through the pipeline. The ice pig continues to move through the pipeline until it is allowed to leave via valves and hydrants at the desired exit point. As the ice pig exits the system, so too do the contaminants it gathered along the way.
Ice pigging is a widely used pipeline cleaning process. It combines two of the other most common cleaning processes:
- Flushing only uses water that is injected at a high speed into the pipeline to force out contaminants. While it is an effective method, flushing may fail to remove all undesirable materials from the inside of the pipeline, especially those adhering to the inside wall.
- Regular pigging involves the use of a solid object. This often requires that a portion of the pipeline be excavated so the pig can be inserted and removed. The solid object can also cause damage to the inner wall or become stuck. An ice pig does not run into this problem because even if it becomes stuck, it will eventually melt and continue moving through the pipeline.