pipelines

Pipeline Transport

Pipeline Transport is a transportation of goods through a pipe. Most commonly, liquid and gases are sent, but pneumatic tubes that transport solid capsules using compressed air have also been used.

As for gases and liquids, any chemically stable substance can be sent through a pipeline. Therefore sewage, slurry, water, or even beer pipelines exist; but arguably the most important are those transporting oil and natural gas.

The idea was first brought up by Dmitri Mendeleev in 1863. He suggested a method of using a pipe for transporting Petroleum. He explained how it should be done and why it should be done.

An elevated section of the Alaska Pipeline

Oil & Natural Gas Pipelines

A Pig launcher/receiver, belonging to the natural gas pipeline in Switzerland.

There is some argument as to when the first real oil pipeline was constructed. Some say pipeline transport was pioneered by Vladimir Shukhov and the Branobel Company in the late 19th century. Others say oil pipelines originated when the Oil Transport Association first constructed a 2-inch (51 mm) wrought iron pipeline over a 6-mile (9.7 km) track from an oil field to Pennsylvania to a rail road station in Oil Creek, in the 1860s. Regardless of this, pipelines are generally the most economical way to transport large quantities of oil or natural gas over land. Compared to railroad, they have lower cost per unit and also higher capacity. Although pipelines can be built under the sea, that process is economically and technically demanding, so the majority of oil at sea is transported by tanker ships.

Oil pipelines are made from steel or plastic tubes with inner diameter typically from 10 to 120 cm (about 4 to 48 inches). Most pipelines are buried at a typical depth of about 1 - 2 meters (about 3 to 6 feet). The oil is kept in motion by pump stations along the pipeline, and usually flows at speed of about 1 to 6 m/s. Multi-product pipelines are used to transport two or more different products in sequence in the same pipeline. Usually in multi-product pipelines there is no physical separation between the different products. Some mixing of adjacent products occurs, producing interface. This interface is removed from the pipeline at receiving facilities and segregated to prevent contamination.

Crude oil contains varying amounts of wax, or paraffin, and in colder climates wax buildup may occur within a pipeline. Often these pipelines are inspected and cleaned using pipeline inspection gauges pigs, also known as, scrapers or Go-devils [1]. These devices are launched from pig-launcher stations and travel through the pipeline to be received at any other station down-stream, cleaning wax deposits and material that may have accumulated inside the line.

For natural gas, pipelines are constructed of carbon steel and varying in size from 2 inches (51 mm) to 56 inches (1,400 mm) in diameter, depending on the type of pipeline. The gas is pressurized by compressor stations and is odorless unless mixed with a Mercaptan odorant where required by the proper regulating body.

 

 

Pipeline Components

Pipeline networks are composed of several pieces of equipment that operate together to move products from location to location. The main elements of a pipeline system are:

Pipeline Schematic

 Initial Injection Station

Known also as Supply or Inlet station, is the beginning of the system, where the product is injected into the line. Storage facilities, pumps or compressors are usually located at these locations.

Compressor/Pump Stations

Pumps for liquid pipelines and Compressors for gas pipelines, are located along the line to move the product through the pipeline. The location of these stations is defined by the topography of the terrain, the type of product being transported, or operational conditions of the network.

Partial Delivery Station

Known also as Intermediate Stations, these facilities allow the pipeline operator to deliver part of the product being transported.

Block Valve Station

These are the first line of protection for pipelines. With these valves the operator can isolate any segment of the line for maintenance work or isolate a rupture or leak. Block valve stations are usually located every 20 to 30 miles (48 km),

Sometimes it depends on the type of pipeline. Even though it is not a design rule, it is a very usual practice in liquid pipelines. The location of these stations depends exclusively on the nature of the product being transported, the trajectory of the pipeline and/or the operational conditions of the line.

Regulator Station

This is a special type of valve station, where the operator can release some of the pressure from the line. Regulators are usually located at the downhill side of a peak.

Final Delivery Station

Known also as Outlet stations or Terminals, this is where the product will be distributed to the consumer. It could be a tank terminal for liquid pipelines or a connection to a distribution network for gas pipelines.

Types of Pipelines

In general, pipelines can be classified in three categories depending on purpose:

1.   Gathering Pipelines

Group of smaller interconnected pipelines forming complex networks with the purpose of bringing crude oil or natural gas from several nearby wells to a treatment plant or processing facility. In this group, pipelines are usually short, couple of hundred meters, and with small diameters. Also sub-sea pipelines for collecting product from deep water production platforms are considered gathering systems

2.   Transportation Pipelines

Mainly long pipes with large diameters, moving products (oil, gas, refined products) between cities, countries and even continents. These transportation networks include several compressor stations in gas lines or pump stations for crude and multiproducts pipelines.

3.   Distribution Pipelines

Composed of several interconnected pipelines with small diameters, used to take the products to the final consumer. Feeder lines to distribute gas to homes and businesses downstream. Pipelines at terminals for distributing products to tanks and storage facilities are included in this group.

Pipeline Operation

When a pipeline is built, the construction project not only covers the civil work to lay the pipeline and build the pump/compressor stations, it also has to cover all the work related to the installation of the field devices that will support remote operation.

Field devices are instrumentation, data gathering units and communication systems. The field Instrumentation includes flow, pressure and temperature gauges/transmitters, and other devices to measure the relevant data required. These instruments are installed along the pipeline on some specific locations, such as injection or delivery stations, pump stations (liquid pipelines) or compressor stations (gas pipelines), and block valve stations.

The information measured by these field instruments is then gathered in local Remote Terminal Units (RTU) that transfer the field data to a central location in real time using communication systems, such as satellite channels, microwave links, or cellular phone connections.

Pipelines are controlled and operated remotely, from what is usually known as The Main Control Room. In this center, all the data related to field measurement is consolidated in one central database. The data is received from multiple RTU’s along the pipeline. It is common to find RTU’s installed at every station along the pipeline.

SCADA System for Pipelines

The SCADA system at the Main Control Room receives all the field data and presents it to the pipeline operator through a set of screens or SCADA/Human Machine Interface, showing the operational conditions of the pipeline. The operator can monitor the hydraulic conditions of the line, as well as send operational commands (open/close valves, turn on/off compressors or pumps, change set points, etc.) through the SCADA system to the field.

To optimize and secure the operation of these assets, some pipeline companies are using what is called Advanced Pipeline Applications, which are software tools installed on top of the SCADA system, that provide extended functionality to perform leak detection, leak location, batch tracking (liquid lines), pig tracking, composition tracking, predictive modeling, look ahead modeling, operator training and more.

Leak Detection Systems

Since oil and gas pipelines are an important asset of the economic development of almost any country, it has been required either by government regulations or internal policies to ensure the safety of the assets, and the population and environment where these pipelines run.

Pipeline companies face government regulation, environmental constrains and social situations. Pipeline companies should comply with government regulations which may define minimum staff to run the operation, operator training requirements, up to specifics including pipeline facilities, technology and applications required to ensure operational safety. As an example, in the State of Washington, it is mandatory for pipeline operators to be able to detect and locate leaks of 8 percent of maximum flow within 15 minutes or less.

The social situation also affects the operation of pipelines. In third world countries, product theft is a problem for pipeline companies. It is often to find unauthorized extractions in the middle of the pipeline. In this case, the detection levels should be under 2 percent of maximum flow, with a high expectation for location accuracy.

Different types of technologies and strategies have been implemented, from walking the lines, up to satellite surveillance. The most common technology to protect these lines from occasional leaks is known as Computational Pipeline Monitoring Systems or CPM. CPM takes information from the field related to pressures, flows and temperatures to estimate the hydraulic behavior of the product being transported. Once the estimation is done, the results are compared to other field references to detect the presence of an anomaly or unexpected situation, which may be related to a leak.

The American Petroleum Institute has published several articles related to the performance of CPM in liquids pipelines, the API Publications are:

- API 1130 – Computational pipeline monitoring for liquids pipelines

- API 1155 – Evaluation methodology for software based leak detection systems

- API 1149 – Pipeline variable uncertainties & their effects on leak detect ability.

Accidents

Pipelines conveying flammable or explosive material, such as natural gas or oil, pose special safety concerns.

• 1982 - A logic bomb inserted by the CIA into the control system software for the Soviet Trans-Siberian Pipeline caused one of the largest non-nuclear explosions in history.
• June 4, 1989 - sparks from two passing trains detonated gas leaking from an LPG pipeline near Ufa, Russia. Up to 645 people were reported killed.
• October 17, 1998 - at Jesse in the Niger Delta in Nigeria, a petroleum pipeline exploded killing about 1,200 villagers, some of whom were scavenging gasoline - the worst of several similar incidents in this country.
• June 10, 1999 - a pipeline rupture in a Bellingham, Washington park led to the release of 277,200 gallons of gasoline. The gasoline was ignited, causing an explosion that killed two children and one adult.
• August 19, 2000 - natural gas pipeline rupture and fire near Carlsbad, New Mexico this explosion and fire killed 12 members of the same family. The cause was due to severe internal corrosion of the pipeline.
• July 30, 2004 - a major natural gas pipeline exploded in Ghislenghien, Belgium near Ath (thirty kilometers southwest of Brussels), killing at least 23 people and leaving 122 wounded, some critically.
• May 12, 2006 - an oil pipeline ruptured outside Lagos, Nigeria. Up to 200 people may have been killed. See Nigeria oil blast.
• November 1, 2007 - a propane pipeline exploded near Carmichael, Mississippi, about 30 miles (48 km) south of Meridian, Mississippi. Two people were killed instantly and an additional four were injured. Several homes were destroyed and sixty families were displaced. The pipeline is owned by Enterprise Products Partners LP, and runs from Mont Belvieu, Texas, to Apex, North Carolina, according to an Enterprise spokesman.

Hydrogen pipeline transport

Hydrogen pipeline transport is a transportation of hydrogen through a pipe as part of the hydrogen infrastructure. Hydrogen pipeline transport is used to connect the point of hydrogen production or delivery of hydrogen with the point of demand, with transport costs similar to CNG, the technology is proven. Most hydrogen is produced at the place of demand with every 50 to 100 miles (160 km) an industrial production facility. As of 2004 there are 900 miles (1450 km) of low pressure hydrogen pipelines in the USA and 930 miles (1,500 km) in Europe.

Pipelines for other liquids

 

Biobutanol

Biobutanol can be transported using existing pipelines

Water pipelines

Two millennia ago the ancient Romans made use of large aqueducts to transport water from higher altitudes by building the aqueducts in graduated segments that allowed gravity to simply push the rushing water along until it reached its intended destination. Hundreds of these were built throughout Europe and elsewhere, and along with flour mills were considered the lifeline of the Roman Empire. The ancient Chinese also made use of channels and pipe systems for public works. The infamous Han Dynasty court eunuch Zhang Rang (d. 189 AD) once ordered the engineer Bi Lan to construct a series of square-pallet chain pumps outside the capital city of Luoyang. These chain pumps serviced the imperial palaces and living quarters of the capital city as the water lifted by the chain pumps were brought in by a stoneware pipe system.

Pipelines are useful for transporting water for drinking or irrigation over long distances when it needs to move over hills, or where canals or channels are poor choices due to considerations of evaporation, pollution, or environmental impact.

The 530 km (360 mile) Goldfields Water Supply Scheme in Western Australia using 760 mm (30 inch) pipe and completed in 1903 was the largest water supply scheme of its time.

Examples of significant water pipelines in South Australia are the Morgan - Whyalla (completed 1944) and Mannum - Adelaide [3] (completed 1955) pipelines.

There are two Los Angeles, California aqueducts, the First Los Angeles Aqueduct (completed 1913) and the Second Los Angeles Aqueduct (completed 1970) which also include extensive use of pipelines.

The Los Angeles Aqueduct in Antelope Valley.

Lacks of Pipeline

Pipelines can be the target of vandalism, sabotage, or even terrorist attacks. In war, pipelines are often the target of military attacks, as destruction of pipelines can seriously disrupt enemy logistics.

Besides, the construction of pipeline is enormously expensive and mostly only rich nation/company could afford it.

Barriers in political and economical regulation also have become one of disadvantage factors in pipeline.