Natural gas pipeline support related information
The practice of various operations without stopping the flow of products in the pipeline.
The cleanliness of the pipes produced by pigging is lower than that obtained by the blowing method. Usually, the gas supply line leading to the natural gas metering station is cleaned by natural gas purge. It has become more and more common to use blowpipes instead of blowing air in the pipeline to the yard. If the gas supply pipeline leading to the gas field is not blown, the cleanliness of the entire system will be equal, because the residual particles after pigging the trunk line may be transferred to the pipeline downstream of the dosing field.
The cost of pigging is estimated to be roughly the same as that of blowing. However, compared to blowing, this cleaning process requires additional gas line filter cleaning during the initial commissioning. Overall, we estimate that it will take about three to five days to rely on pigging to achieve the same pipe cleanliness as blowing. Due to the increase in filter cleaning frequency, the cost of longer cleaning time should also be considered for additional gas turbine operation under reduced or restricted load.
Assuming that the pigging process is used to clean the gas supply pipeline leading to the gas station, the internal cleanliness of the factory-side pipeline is expected to exceed the internal cleanliness of the supply pipeline. Water washing requires additional pigging to remove excess water from the pipeline system before the pipeline is purged and laid.
The blowing pipe cleaning process uses oil-free high-pressure compressed air to clean the process piping system. This process uses a temporary high-pressure air compressor to pressurize the system and a high-speed safety valve to quickly exhaust the piping system. The natural gas pipeline support repeats the pressurization and decompression cycle until it is determined that the pipeline system is clean.
For gas pipeline cleaning, the efficiency of blowing air is not expected to be very high due to the lack of sufficient storage space upstream of the pipeline system to be cleaned. The method of steam blowing instead of steam blowing for steam line cleaning is to use the boiler as a storage device before the steam piping system. Unfortunately, when blowing into the natural gas supply pipeline, the amount of storage in the pipeline is much less. The duration of the blow is expected to be less than two seconds. Obviously, compared with blowing, blowing will take longer to clean the gas pipeline.
There are basically three main types of pipelines along the transportation route: collection systems, transmission systems, and distribution systems. The collection pipeline system collects raw natural gas from the production well. The natural gas distribution pipeline system is spread across thousands of communities along the coast, and distributes natural gas to our homes and businesses through main lines and service lines.
Except for gas supply lines, the diameters of pipes used in natural gas pipeline systems range from 2 inches to 42 inches. The gas service line is usually ½ inch to 2 inches in diameter. The natural gas collection and transmission pipeline system is constructed of steel pipes. However, the natural gas distribution system is made of many different materials, including cast iron, steel, copper and plastic pipes. Nowadays, plastic pipes are commonly used in gas distribution systems.
Natural gas pipelines can be thousands of kilometers long, and there is usually one compressor station every 200 kilometers. In these positions, the compressor can balance the unavoidable pressure loss to ensure the required pipeline pressure of 75 to 100 bar.