Pipeline Transport
Pipeline Transport is the transportation of
goods or material through a pipe. The latest data
in 2014, gives a total of slightly less than
2,175,000 miles ( 3,500,000 km ) of pipeline
in 120 countries of the world.
Liquids and gases are transported in pipe-
lines and any chemically stable substance can be
sent through a pipeline. Pipelines exist for the
transport of crude and refined petroleum, fuels
- such as oil, natural gas and biofuels – and other
fluids including sewage, slurry, water, and beer.
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. Pneumatic tubes using compressed air can be used to transport solid capsules.
Oil pipelines are made from steel or plastic tubes which are usually buried. The oil is moved through the
pipelines by pump stations along the pipeline. Natural gas (and similar gaseous fuels) are lightly pressurized into
liquids known as Natural Gas Liquids (NGLs). Natural gas pipelines are constructed of carbon steel. Highly
toxic ammonia is theoretically the most dangerous substance to be transported through long-distance pipelines,
but accidents have been rare. Hydrogen pipeline transport is the transportation of hydrogen through
a pipe. District heating or teleheating systems use a network of insulated pipes which transport heated
water, pressurized hot water or sometimes steam to the customer.
Pipelines conveying flammable or explosive material,
such as natural gas or oil, pose special safety concerns and there
have been various accidents. Pipelines can be the target
of vandalism, sabotage, or even terrorist attacks. In war,
pipelines are often the target of military attacks.
Pipelines are generally the most economical way to
transport large quantities of oil, refined oil products or natural
gas over land.
Natural gas (and similar gaseous fuels) are lightly
pressurized into liquids knows as Natural Gas Liquids (NGLs).
Small NGL processing facilities can be located in oil fields so the
butane and propane liquid under light pressure of 125 pounds
per square inch (860 kPa), can be shipped by rail, truck or
pipeline. Propane can be used as a fuel in oil fields to heat
various facilities used by the oil drillers or equipment and trucks
A ”Pig” launcher/receiver, natural gas used in the oil patch.
Growth of Market market size for oil and gas pipeline
construction experienced tremendous growth prior to the
economic downturn in 2008. After faltering in 2009,
demand for pipeline expansion and updating increased
the following year as energy production grew.
Construction and Operation
Oil pipelines are made from steel or plastic
tubes with inner diameter typically from 4 to 48
inches (100 to 1,220 mm). Most pipelines are
typically buried at a depth of about 3 to 6 feet. Gas pipe in the dry region of Chile.
To protect pipes from impact, abrasion, and corrosion, a variety of methods are used. These can
include wood lagging (wood slats), concrete coating, rock shield, high-density polyethylene, imported sand
padding, and padding machines.
Crude oil contains varying amounts of paraffin wax and in colder
climates wax buildup may occur within a pipeline. Often these pipelines
are inspected and cleaned using pigging, the practice of using devices
known as "pigs" to perform various maintenance operations on a
pipeline. The devices are also known as "scrapers" or "Go-devils". "Smart
pigs" (also known as "intelligent" or "intelligence" pigs) are used to
detect anomalies in the pipe such as dents, metal loss caused by
corrosion, cracking or other mechanical damage.
For natural gas, pipelines are constructed of carbon steel and vary in size from 2 to 60 inches (51 to
1,524 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 a regulating authority.
Ammonia
Highly toxic ammonia is theoretically the most dangerous substance to be transported through long-
distance pipelines.
Alcohol Fuels
The main problems related to the transport of ethanol by pipeline are its corrosive nature and tendency
to absorb water and impurities in pipelines, which are not problems with oil and natural gas.
Coal and Ore
Slurry pipelines are sometimes used to transport coal or ore from mines. The material to be transported
is closely mixed with water before being introduced to the pipeline; at the far end, the material must be dried.
Hydrogen
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. Most hydrogen is produced at the place of demand with every 50 to 100
miles (160 km) an industrial production facility.
Water
Two millennia ago, the ancient Romans made use of large aqueducts to transport water from higher
elevations by building the aqueducts in graduated segments that allowed gravity to push the water along until it
reached its destination. Hundreds of these were built throughout Europe and elsewhere, and along with flour
mills were considered the lifeline of the Roman Empire.
Other Systems
District Heating
District heating or teleheating systems consist of a network of insulated feed and return pipes which
transport heated water, pressurized hot water or sometimes steam to the customer. While steam is hottest and
may be used in industrial processes due to its higher temperature, it is less efficient to produce and transport due
to greater heat losses. Heat transfer oils are generally not used for economic and ecological reasons.
District heating pipelines are normally installed underground, with some exceptions. Within the
system, heat storage may be installed to even out peak load demands. Heat is transferred into the central
heating of the dwellings through heat exchangers at heat substations, without mixing of the fluids in either
system.
Marine Pipelines
In places, a pipeline may have to cross water expanses, such as small seas, straits and rivers. In many
instances, they lie entirely on the seabed. These pipelines are referred to as "marine" pipelines (also, "submarine"
or "offshore" pipelines). They are used primarily to carry oil or gas, but transportation of water is also important.
Functions
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- a couple hundred metres- and with small diameters. Sub-sea pipelines for collecting product from
deep water production platforms are also 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 multi-products 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.
Development and Planning
When a pipeline is built, the construction project not only covers the civil engineering 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.
The pipeline is routed along what is known as a "right of way". Pipelines are generally developed and
built using the following stages:
1. Open season to determine market interest. This stage lasts up to two months.
2. Route (right of way) selection
3. Pipeline design: The design process may take up to six months.
4. Obtaining approval: The process can last up to 18 months for pipelines in multiple states.
5. Surveying the route
6. Clearing the route
7. Trenching - Main Route and Crossings (roads, rail, other pipes, etc.)
8. Installing the pipe
9. Installing valves, intersections, etc.
10. Covering the pipe and trench
11. Testing: Once construction is completed, the new pipeline is subjected to tests.
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.
Pipelines are controlled and operated remotely, from what is usually known as the "Main Control Room".
Technology & Its 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:
1.) 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.
2.) 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.
3.) Partial Delivery Station
Known also as "intermediate stations", these facilities allow the pipeline operator to deliver part of the
product being transported.
4.) 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), depending on the type of pipeline.
5.) 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.
6.) 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.
7.) 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.
Various technologies and strategies have been implemented for monitoring pipelines, from physically
walking the lines to satellite surveillance. Once the estimation is completed, 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.
8.) Implementation. As a rule pipelines for all
uses are laid in most cases
underground. However, in some cases it is
necessary to cross a valley or a river on
a pipeline bridge. Pipelines for centralized
heating systems are often laid on the ground or
overhead.
9.) Maintenance. Maintenance of pipelines
includes checking cathodic protection (a simple
method of protection connects the metal to
be protected to a more easily corroded
"sacrificial metal" to act as the anode) levels for
the proper range, surveillance for construction,
erosion, or leaks by foot, land vehicle, boat, or
air, and running cleaning pigs, when there is
anything carried in the pipeline that is corrosive.
