Pneumatic Pipelines

Pneumatic pipelines, also called pneumo transport, transport solid particles using air as the carrier medium. Because air is free and exists everywhere, and because it does not wet or react chemically with most solids, pneumo transport is preferred to hydro transport for most cargoes wherever the transportation distance is short. Owing to high energy consumption and abrasiveness to pipe and materials, pneumatic pipelines are usually adopted for distances not more than a few hundred feet or meters. Large-diameter pneumatic pipelines can be used economically for longer distances, sometimes more than a mile or a kilometer.

Pneumatic pipelines are employed extensively throughout the world in bulk materials handling, and hundreds of different cargoes have been transported successfully. Common applications include the loading of grain from silos or grain elevators to trucks or trains parked nearby, transport of refuse from collection stations to processing plants or from processing plants to disposal sites, transport of cement or sand to construction sites, and transport of coal from storage bins to boilers within a power plant.

There are two general types of pneumatic pipelines. The first employs suction lines, which create a suction or vacuum in the pipe by placing the compressor or blower near the down- stream end of the pipe. The line operates like a vacuum cleaner. The second type is pressure lines, which have compressors or blowers located near the upstream end. This creates a pressure in the line that drives the air and the solids through the pipe. Pressure lines are used for longer distances and in places where solids concentrated at one location are trans- ported to several separate locations using a single blower or

compressor. In contrast, suction lines are more convenient for shorter distances and in places where solids from several locations are to be transported to a common destination by means of a common blower or compressor.

In addition to the pipe and blower, a pneumatic pipeline system also must have a tank or hopper connected near the pipeline inlet to feed solid particles into the pipeline and a tank near the pipeline outlet to separate the transported solids from the airstream. The exhaust air also must be filtered to prevent air pollution.

Combustible solids such as grain or coal transported pneumatically through pipe, if handled improperly, can cause fire or even explosion. This is due to the accumulation of electric charges on fine particles transported pneumatically. Prevention of such hazards can be accomplished by using metal rather than plastic pipes; by grounding the pipe, valves, and other fixtures that accumulate charges; by cleaning the interior of the pipe to rid it of dust; and by increasing the moisture of the air used for pneumatic transport.

Capsule Pipelines

Capsule pipelines transport freight in capsules propelled by a fluid moving through a pipeline. When the fluid is air or another gas, the technology is called pneumatic capsule pipeline (PCP), and, when water or another liquid is used, it is termed hydraulic capsule pipeline (HCP). Owing to the low density of air, capsules in PCP cannot be suspended by air at ordinary speeds. Instead, the capsules are wheeled vehicles rolling through pipelines. In contrast, because water is heavy, the capsules in HCP do not require wheels. They are both propelled and suspended by water under ordinary operational speeds. HCP sys- tems are operated normally at a speed of 6 to 10 feet per second (1.8 to 3 meters per second), whereas the operational speed of PCP is normally much higher—20 to 50 feet per second. Owing to high frictional loss at high velocity, PCP consumes more energy in operation than HCP.

PCP has been in use since the 19th century for transporting mail, printed telegraph messages, machine parts, cash receipts, books, blood samples (in hospitals), and many other products. Since 1970, large wheeled PCP systems have been developed for transporting heavy cargo over relatively long distances. The largest PCP in the world is LILO-2 in the republic of Georgia, which has a diameter of 48 inches and a length of 11 miles. The system was built for transporting rock.

In contrast to the long history of PCP, the technology of HCP is still in its infant stage. HCP was first considered by the British military for transporting war materiel in East Asia during World War II. The concept received extensive investigation in Canada at the Alberta Research Council during 1958-1975. Interest in this new technology soon spread to many other nations. In 1991, the United States established a Capsule Pipeline Research Center at the University of Missouri in Columbia, jointly funded by industry and government.

A new type of HCP being developed is coal-log pipeline (CLP), which transports compressed coal logs. The system eliminates the use of capsules to enclose coal and the need for having a separate pipeline to return empty capsules. Compared with a coal-slurry pipeline of the same diameter, CLP can »transport more coal using less water.

Capsule pipelines of large diameter (greater than seven feet) can be used to transport most of the cargoes normally carried by trucks or trains. In both Europe and the United States, large-diameter capsule pipelines (mostly PCPs) have been proposed for intercity freight transport in the 21st century. Proponents of such projects point out that such underground freight pipeline systems not only allow land surface to be used for other purposes but also reduce the number of trucks and trains needed, which in turn reduces air pollution, accidents, traffic jams, and damage to highway and rail infrastructures caused by the high traffic volume.

Odesa-Brody Pipeline

The usage and direction of Odesa-Brody pipeline is believed to be of considerable geopolitical significance and has thus been the subject of both political disagreement and international pressure. The pipeline was originally intended to reach Gdansk in order to transfer oil from the Caspian Sea (mainly from Kazakhstan) to the Polish Baltic Sea port and from there to the rest of Europe. The Pivdenny maritime terminal in Odesa and the pipeline between Odesa and Brody were built in 2001 and the state oil transport company Ukrtransnafta was established to develop the commercial attractiveness of the Odesa-Brody pipeline. However, the pipeline remained unused until 2004.

A sufficient capacities of oil supplies were not agreed, on 5 July 2004 the Ukrainian cabinet accepted proposal of Russian oil companies to reverse the pipeline flow, and thus making it transfer Russian oil southwards to the Black Sea and from there to Mediterranean destinations. Currently the oil is shipped to the pipeline from the junction of the southern branch of Druzhba pipeline.

Technical features. The current length of the pipeline is 674 kilometers (419 mi). The pipeline is operated by Ukrtransnafta, and the oil is shipped by TNK-BP. In 2006 TNK-BP pumped 3.42 million tons of oil through the pipeline. In 2007, this volume was exceeded as already during seven month in January-July almost 5.3 million tons of oil were pumped and transported.

Offshore Pipelines

Oil from many offshore fields can be pumped directly into pipelines that are laid on the bottom of the ocean. This is often the most efficient and safest way to get the oil ashore. A large pipeline may bring oil or gas ashore from several platforms and smaller gathering lines collect it to one point. Pipelines are made up of long sections of high-quality steel pipe welded together in a continuous string. Protective coating is applied and often a concrete cover is added to protect against damage and to provide more weight under water. Pressure pumps and compressors are placed along the line at

intervals to maintain a constant flow of gas or oil. In shallow water near shore, at depths less than 200 feet, trenches are dug to contain the pipe- line. A special trenching barge is used. A jetting sled is lowered to straddle the pipe. As it moves along the pipe, powerful jets of air and water flush out the bottom mud and sand, thereby forming a trench into which the pipeline settles.

This operation disrupts plant and animal habitats. Spoil accumulates on either side of the pipeline ditch, extending to 50 m. or more to either side. Most organisms in the disturbed sediments are smothered or uprooted. Studies in Chesapeake Bay show that dredging destroys about 70% of the bottom organisms in the disturbed area. Primary productivity in the water column is temporarily reduced by the increased turbidity caused by suspended materials. Recovery of the bottom organisms takes at least two years. Pipelines are thoroughly tested before oil or gas is put through them. Periodically a pipeline may be cleaned by using a plug or scraper that has blades, disks, or bristles and is pulled through the line. Deep- sea divers may inspect the line, or automatic equipment can be used to test for any problems. Pipelines are being laid at depths up to 2000 feet. Accidents will occur, but, in general, pipelines for offshore oil have proved to be extremely reliable and environmentally safe.