Pipeline transportation is a way of transporting fluid goods using pipelines.
I. Characteristics of pipeline transportation
(I) Large transport volume
Because the pipeline can carry on uninterrupted transportation, the transportation continuity is strong, no empty driving occurs, and the transportation volume is large. Such as 529 mm diameter pipeline, the annual transport capacity of up to 10 million tons; Pipe diameter 630 mm pipeline, the annual transport capacity of 15 million tons; Pipeline 720mm pipeline, annual transport capacity of 20 million tons; The 1200mm pipe has an annual capacity of 100 million tons.
(2) Relatively simple pipeline transportation construction projects
Pipeline buried in the ground, in addition to pumping stations, the first and last stations occupy some land, the pipeline occupies less land, construction cycle is short, quick results. At the same time, the pipeline can also pass rivers, lakes, railways, and even over mountains, across the desert, through the sea, etc., easy to take shortcuts, shorten the transport mileage.
(3) Mechanization of dispatching in pipeline transportation
Pipeline transportation of fluid goods, mainly rely on every 60 ~ 70 km of the booster station to provide pressure energy, equipment operation is relatively simple, and easy to local automation and centralized remote control. The advanced pipeline booster station has been completely unmanned. As a result of energy saving and dispatching automation, less personnel, so that transport costs significantly reduced.
- Enabling environmental protection
Pipeline transportation produces no noise, less leakage and pollution of goods. It is not affected by climate and can operate safely and stably for a long time.
(5) Limitations in the application of pipeline transportation
The engineering structure of pipeline transportation itself determines the limitation of its scope of application. Pipeline transportation is suitable for long-term directional and fixed-point transportation. If the range of transportation volume is narrow and the scope of transportation change is too large, the superiority of pipeline is difficult to play.
II. Forms of pipeline transportation
The pipe is named after the medium. Such as transportation of crude oil, called crude oil pipeline, transportation of processed products known as refined oil pipelines, in addition to natural gas pipeline, coal slurry pipeline.
(1) Crude oil pipelines
The extracted crude oil enters the pipeline after oil-gas separation, dehydration, precipitate removal and stabilization. Pipeline transportation, in view of the physical properties of the crude oil (such as specific gravity, viscosity, easy to pour state, etc.), the transportation process.
Crude oil pipeline transportation technology can be divided into heating transportation and non-heating transportation. The dilute crude oil (such as the Middle East crude oil) is transported without heating, while the crude oil in China is easy to pour and high viscosity, so it needs to be transported by heating.
(2) Product oil pipeline
Product oil pipeline is the transportation of fuel oil, such as gasoline, kerosene, jet fuel, diesel oil and liquefied petroleum gas, which is extracted from crude oil refineries. From the most light to heavy fuel oil produced by refining processing, are the finished oil pipeline transportation medium.
Product oil pipeline is isothermal transportation, there is no heating problem along the way. The characteristic of the product oil pipeline is that there are many different oil products, such as kerosene, gasoline, diesel oil, aviation oil and different grades of the same oil, in order to transport, and strict distinction is required to ensure the quality of oil products. Because the product oil pipeline is multi-source and multi-variety sequential transportation, its management complexity is far more complicated than the crude oil pipeline. The refined oil pipeline connects several kerosene plants, and the oil products can enter the same pipeline. At the same time, it can supply the finished oil products directly to the major cities and towns along the pipeline.
(3) Natural gas pipelines
Natural gas pipeline is the natural gas (including the associated gas produced in the oil field), from the production site or treatment plant to the city gas distribution center or enterprise users of the pipeline. Natural gas pipelines are distinguished from gas pipelines in that the gas pipeline uses coal as raw material to convert gas, and the starting pressure is relatively low, while natural gas is produced by gas wells in the gas field and has high pressure, which can be transported long distance by the pressure of gas wells. In the early days, the transportation of natural gas by pipeline depended entirely on the pressure of gas wells. In modern natural gas pipeline transportation, because of the increase of transportation distance and transportation volume, a booster station is commonly set up. The utility model is provided with a gas engine or a gas turbine that uses natural gas as fuel to drive various compressors matched with power.
(4) Coal slurry pipelines
Coal slurry pipeline is a kind of solid slurry pipeline. The solid is broken into powder granules and mixed with an appropriate amount of fluid to make slurry, which is transported in a long distance by pressurized pipeline. The first coal slurry pipeline was a 173 km (254 mm) pipeline built in 1957 by Goodben Coal Company in Ohio. One of the world’s most famous coal slurry pipelines currently in operation is the one that carries coal from the open-pit coal mines in the Black Mesa region of northern Arizona to the Moha Power Plant in Nevada. Completed and put into production in 1970, the total length of 439 kilometers, pipe diameter 457 mm, designed to transport 5 million tons. Besides coal slurry transportation, solid slurry pipeline is also used for hematite, bauxite and limestone. China’s pipeline transportation is largely limited to crude oil, refined petroleum products and natural gas.
III. Composition of oil pipelines
A large oil pipeline consists of two parts: an oil pipeline and an oil station.
(1) Oil Transfer Station
The oil station is an important component of pipeline transportation equipment and link. By pressurizing the transported materials through the oil station, the frictional resistance in the process of operation can be overcome, and the crude oil or its products can be transported to the destination by pipeline. According to their location, the stations can be divided into: - First oil station. The first oil station is close to the mine or the factory, collecting the crude oil and its products along the pipeline, receiving, sorting, measuring and transporting the oil products to the next station. If it is hot oil delivery also equipped with heating equipment.
- Intermediate oil terminal. The intermediate station is responsible for transferring the oil from the previous station to the next station. If it is hot oil transportation, heating through the intermediate oil station, so that the oil temperature is greater than the ring temperature, with a heating function called heat pump station.
- End base. The terminal base receives, measures and stores the oil delivered by the pipeline, and distributes it to the consumption units or transfers it to other means of transport.
- Other major facilities relating to oil filling stations. There are a series of complex structures in the oil transportation station, including pump house, oil pool and valve house. The function of the pump house is to create a certain amount of pressure in order to overcome the resistance produced in the pipeline, the oil to the next station. According to the pressure, a pumping station is set up on the line of each interval distance. There are special oil pools for receiving and sending oil in mines, refineries and oil transmission stations. Oil can be collected from oil producing enterprises or sent out from oil pools by pipelines. The valve house is equipped with a gate valve to control the oil transportation process.
(2) Oil pipelines - Auxiliary oil pipe with inner pipeline. This refers to refineries, oil bases in a variety of line systems, is the transmission and processing of crude oil and filling tank trucks, river and port barges, ocean-going tankers and oil barrels of the pipeline.
- A localized pipeline. This refers to the short-distance field line that carries oil from the mine to the oil base and the first station of the large pipeline.
- Large pipeline or mainline pipeline. This is the main body of the pipeline. The pipeline is a system of its own, forming an independent enterprise unit, whose lines can be hundreds or even thousands of kilometers. In addition to the necessary maintenance work, the oil can be constantly transported throughout the year.
