Techniques for removing debris from pipelines—pigging

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Techniques for removing debris from pipelines — pigging. Like other transportation systems, long-distance pipelines need to be cleaned before they are put into use, and they also require cleaning at regular intervals during operation to maintain cleanliness inside them. This process of cleaning the inside of pipes is called “pigging”. To maintain cleanliness inside the pipes, it is essential to keep their interiors clean during installation; therefore, before welding the pipes, it is necessary to remove any dust, rust, welding slag, and other debris from the interior of each pipe section. The pipes are welded for a certain distance in the field, and at the end of the day, iron plates are welded to both ends of the pipes to prevent rainwater and mud from getting in, as well as animals from entering. The principle is similar to cleaning the streets; only when the roads are clean can traffic flow smoothly. Before conducting sectional pressure tests after the pipes are connected (with each section spanning 10 to 30 kilometers), it is necessary to clean the pipes. This is done by installing \"pig receiving and sending buckets\" at both ends of each pipe section; a pig, which is composed of several rubber washers connected together, is inserted at the sending end of the pipe. This pig fills the inner diameter of the pipe, and compressed air is applied to its rear to push it along the pipe, at least twice. In this way, any debris or impurities in the pipe are swept into the receiving bucket, leaving the pipe clean. Not only is pigging necessary before commissioning, but a \"pigging station\" is also installed every approximately 200 kilometers along the pipeline. Pigging operations are required again after the pipeline has been in operation for a certain period of time (such as half a year or a year). The pipeline is sealed, so nothing other than the oil or gas being transported can get in. Then why is pipe cleaning necessary? The rationale behind this kind of treatment is similar to that of regular infusions for elderly people with high blood lipid levels, aimed at maintaining smooth blood flow. The media transported through pipelines are not completely pure; for example, crude oil and diesel contain certain waxy components that gradually stick to the inner walls of the pipelines during transportation ； Some impurities present in the transport medium, as well as water, settle in the lower areas of the pipes due to their higher density. All these factors reduce the inner diameter of the pipes, leading to poor flow. Pipe cleaning operations can remove this wax and other impurities, thereby maintaining optimal conditions for transportation. Even more amazing is that “smart pigging devices” can be sent through the pipes on a regular basis. The intelligent pig contains detection and remote control devices; it can \"examine\" the pipeline, checking for corrosion on its inner and outer walls, as well as identifying any areas that are deformed (elliptical in shape or collapsed). It can accurately pinpoint the locations of such problems, and all this data is stored in a computer, allowing for the maintenance of the pipeline based on this information. Pipelines are buried underground and thus invisible and untouchable, but thanks to advanced technologies such as intelligent pipe cleaning, it is possible to monitor their condition, carry out timely maintenance and repairs, and ensure their safe operation.