To accelerate the flow of gas Natural gas is highly pressurized as it travels through an interstate pipeline. Compression of the natural gas occurs periodically along the pipe to ensure that the natural gas flowing through any one pipeline remains pressurized. Compressor stations are used to accomplish this. These Compressor stations are usually placed at 40 to 100 mile intervals along the pipeline. The natural gas is compressed at the compressor station by a turbine, motor, or engine. Turbine compressors achieve their energy by using up a small amount of the natural gas that they compress.
The turbine itself serves to operate a centrifugal compressor. The turbine contains a type of fan that compresses and pumps the natural gas through the pipeline. An electric motor is used at some compressor stations to turn the same type of centrifugal compressor. Any of the natural gas from the pipe is not required in this type of compression. However, it does need that a reliable source of electricity be located nearby. Reciprocating natural gas engines are also used to power some compressor stations.
These engines resemble very large automobile engines, and natural gas from the pipeline is used. Pistons get power by the combustion of the gas outside of the engine, which serve to compress the natural gas. Some type of liquid separator are also used compressor stations for compressing natural gas, much like those used to dehydrate natural gas during its processing. Usually these separators consist of scrubbers and filters that capture any liquids or undesirable particles from the natural gas in the pipeline.
Although natural gas in pipelines is considered a dry gas, it is not uncommon for a certain amount of water and hydrocarbons to condense out of the gas stream while in transit. The liquid separators, present at compressor stations ensure that the natural gas in the pipeline is as pure as possible, and usually filter the gas prior to compression. Compressor stations are powered by compressors that are each rated at several thousand horsepower (hp). The stations contain valves, pipes, and control systems that monitor the functioning and operating parameters of the system.
Most compressor stations are fully automated. The compressors are typically housed in a metal building with pipe appurtenances and other critical elements above ground. All electrical fittings within the metal building are explosion-proof. “Natural Gas Compressor Station along an Interstate Pipeline” A metal building is used for the housing of the Reciprocating compressor along the pipeline. These stations are monitored or controlled by supervisory control and data acquisition (SCADA) systems.
The average size of an interstate compressor station in the western states is around 13,000 hp, with large variations in size found throughout the western region. 15 to 22 acres of land is needed for the Compressor station include an all-weather gravel access road, the compressor building, cooling fans, a control building, and possibly two or three small auxiliary buildings. The compressor building as well as the piping and equipment are acoustically designed to keep noise to a minimum and are constructed using explosion-proof electrical fittings. Continuous Noise generates at a natural gas compressor station during operations.
Natural gas piping, both aboveground and belowground, associated with the installation of the interconnections, metering stations, and pigging facilities at a compressor station are installed and pressure-tested using methods similar to those used for the main pipeline. After testing is successfully completed, the piping is tied into the main pipeline. Metering Stations Metering stations are located periodically along interstate natural gas pipelines. These stations permit pipeline and local distribution companies to observe, handle, and account for the natural gas in their pipes.
These metering stations calculate the flow of gas along the pipeline, allowing pipeline companies to track natural gas as it flows along the pipeline. Specialized meters are used at the Metering stations to measure the natural gas as it flows through the pipeline without impeding its movement. In essence, the metering station is the company’s “cash register. ” “Typical Metering Station” City Gate Stations The natural gas for a large number of distribution systems is received from transmission pipelines and fed through one or more city gate stations, sometimes called town border or tap stations.
to meter the gas and reduce its pressure these stations are used. The latter operates at a much lower pressure (reduced from approximately 500–1,400 psig to about 0. 25–300 psig). Figure shows a city gate station. To protect it from the weather it should be covered with a fiberglass enclosure or metal building. Metering devices are used by the most city gate stations to measure the gas flow. Pressure of the natural gas is reduced with the help of pressure regulators. These devices control the rate of gas flow and/or pressure through the station and maintain the desired pressure or flow level in the distribution system.
“City Gate Gas Measurement and Regulation Station” Valves A great number of valves along their entire length are present in Interstate pipelines. We can also call these valves gateways because they work like a gateway. They are usually open and permit natural gas to flow freely, but they can be used to stop gas flow along a certain section of pipe. “Aboveground Valve on Natural Gas Pipeline” Pig Launching/Receiving Facilities Pigging facilities consist of pig launching or receiving equipment and allow the pipeline to accommodate a high-resolution internal inspection tool.
Pigs are devices that are placed into a pipeline to execute definite functions. Some are used to clean the inside of the pipeline or to monitor its internal and external condition. Launchers and receivers are facilities that enable pigs to be placed into or removed from the pipeline. A pigging facility is usually smaller than a typical compressor station site, but is typically twice the size of a valve site. SCADA Centers Customers are present on the both ends of the pipeline.
The producers and processors that enter gas into the pipeline and the consumers and local distribution companies those obtain gas out of the pipeline. Sophisticated control systems are required to control the natural gas that enters the pipeline and ensure that all customers obtain timely delivery of their section of this gas and to watch the gas as it travels through all sections of a potentially very lengthy pipeline network. To complete the task of monitoring and controlling the natural gas that is traveling through the pipeline supervisory control and data acquisition (SCADA) systems are used.
Centralized gas control stations assemble, assimilate, and manage the data received from monitoring city gate stations and compressor stations all along the pipeline. Mainly of the data that is received by a control station is provided by supervisory control and data acquisition (SCADA) systems. These systems are basically sophisticated communications systems that take measurements and gather data along the pipeline (generally in metering or compressor stations and valves) and transmit the data to the centralized control station.
Flow rate throughout the pipeline, operational status, pressure, and temperature readings may all be used to assess the status of the pipeline at any one time. This information permits pipeline engineers to identify accurately what is happening along the pipeline at all times, which permits fast reactions to equipment malfunctions, leaks, or any other unusual activity along the pipeline, as well as to monitoring load control.
Access Roads Pipeline companies normally try to use existing roads to give access to the construction ROW. The access roads are used on a temporary basis to transport personnel, equipment, vehicles, heavy trucks, and materials to project work areas. Some of these roads may not support heavy construction equipment and, therefore, would be used only for light truck traffic (e. g. , pickup trucks).Sample Essay of Paperial.com