The relationship between gas transmission stations and pigging stations

There is no need to build a separate pigging station; pigs are generally installed at the starting station (where a pig launcher is located) and the ending station (where a pig receiver is located). When the pipeline is long, multiple stations can be set up along its length, and pig receiving and sending devices are designed in the appropriate stations as required.

1. Principles for installing pigging devices in long-distance pipelines: x6 b2 V/ I4 @: ? \: y Pigging devices are necessary for pipelines carrying crude oil, refined oil, natural gas, and similar substances. The cleaning of crude oil pipelines is primarily aimed at removing the wax that forms as a result of crude oil degradation during production and operation. In contrast, since refined oil and natural gas are relatively pure, cleaning devices are often used for assisting with cleaning and purging before operations begin, as well as for intelligent cleaning tasks during the later stages of operation. ) \8 R" P. y9 ^& o' } 2. Spacing between pigging stations: % b* F0 w0 b& X4 c4 h. There are no national standards governing the placement of pigging stations; therefore, the density of such stations along crude oil pipelines should be as high as possible. Generally, pigging stations are built together with other types of facilities. There are relatively few pigging stations installed along the entire length of oil product pipelines; for a 600-kilometer pipeline that has been built in China, only one pigging station was installed at 150 kilometers along its length. . [% B n4 s9 H5 R3 T; W( m; x 3. Type of pig: With the advancement of technology, pigs have gradually moved beyond their basic cleaning functions and have come to incorporate features such as intelligent monitoring. For long-distance pipelines, barrel-type ball receiving and sending units are still widely used in China; however, this year cleaning valves have also been applied to short-distance, small-diameter pipelines, with good results as well. 4. Setting of the pigging process: The main process allows flow to enter the station directly, while the pigging process is enabled by switching valves so that the medium enters the station after ball sending and receiving. ) J4 B- _+ o! ^/ u6 ~& L2 h 5. Requirements for the installation of the ball receiving and sending cylinders: They must be designed to facilitate operation by workers and ensure safety; safety valves should be installed on these cylinders, and quick-actuation blind plates must not be positioned in areas where people might be present. 6. Operating procedures and precautions for pigging operations: / U* ?, d8 L& t: U For pigs with larger diameters, receiving and sending devices must also be installed to reduce the workload on workers. 1. Pigging facilities should be installed within the gas transmission station ； 6 X! p$ t, Q5 y8 O- x 2. The pigging process should employ a gas-free, sealed pigging procedure ； 3. The pig passage indicator should be installed on the pipeline sections at the inlet and outlet of the station. Indicators should also be installed on the pipelines outside the station as required for automated pig operation, and the indication signals should be transmitted to inside the station ； 4. The structure of the pig receiving and sending tanks should meet the requirements for passing pigs or plug testers. The design of pig receiving and sending cylinders and quick-opening blind flanges shall comply with the provisions of the current standards **\"Technical Specifications for the Design of Pigging Equipment\" SY/T0533 and \"Quick-Opening Blind Flanges\" SY/T0556** ； 5. The quick-release blind flanges on the pig launcher and receiver should not be positioned directly facing residential areas or buildings/structures within a distance of 60 meters or less. When site conditions prevent the fulfillment of the above requirements, appropriate safety measures should be taken ； 6. The waste removed during pigging operations must be collected and disposed of properly; it shall not be discharged indiscriminately

Pigging stations are usually located together with transfer stations; they simply have the additional equipment of pig receiving and sending cylinders, so no separate installation is required. Generally, it is at the starting and ending stations; if there are pipeline branches, stations may also be set in between.