Coal Pipeline

Another method to transport coal is through a slurry pipeline. This connects a mine with a power plant where the coal is used to generate electricity. Coal slurry pipelines use a slurry of water and pulverized coal. The ratio of coal to water is about 1 1. 

Coal slurry pipelines are potentially the least costly available means for transporting coal to any location, measured in economic terms. Whether this is true with reference to any particular pipeline can only be determined by detailed evaluation of the conditions of the route. The current coal transportation scenario does not offer any choices between slurry pipelines and railroad, which undoubtedly will necessarily minimize the cost of transporting coal. In this context, the present times warrant assessment of the potential economic, environmental, and social implications of coal slurry pipeline development and transportation of coal through it. 

However, there is need for caution. The large water and energy requirements for coal slurry pose a significant barrier to further deployment, especially in arid regions of Australia and the western United States. 

The coal log pipeline is another technology for transporting coal in which coal at the mine site is treated and compacted into cylindrical shapes (coal logs) (Liu et al., 1993). Then the coal logs are injected into an underground pipeline filled with water for transportation to destination which may be one or more than one power plants, or to a train station, a barge terminal, or a seaport, for intermodal transportation. 

The coal must have been cleaned and crushed, with a binding agent comprised of coal pitch, bitumen, or wax. The coal mixture is then tightly compressed and compacted as coal logs that are 5%-10% thinner than the transportation pipeline. The logs are injected into a pipeline and pumped 

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Coal pipelines have been built in countries such as France (8.8 km), and Russia (61 km), and pipelines are also used for transporting limestone, copper concentrates, magnetite, and gHsonite in other parts of the world. The first coal pipeline, built in Ohio, led to freight rate reductions. The pipeline stopped operation after introduction of the unit train, used exclusively to transport coal from the mine to an electric power generation station. 

In 1969 Air Products Chemicals began delivering carbon dioxide and hydrogen to customers in the Houston area via pipeline. There was also talk of shipping methanol by pipeline. A 273-mile pipeline was also opened in 1969 to convey 660 tons/hr of slurried coal from Kayenta, Arizona, to a power plant in southern Nevada. A previous coal pipeline in Ohio closed down in the mid-1960s because it proved to be uneconomical when the railroads reduced their rates.5... 

Because of substantial reserves of coal, situated in distant locations from consumers, the limited sources of oil and natural gas, expected growing price of oil and gas a considerable development and progress in the coal pipelining can be expected especially in the USA, in the former Soviet Union and also in other countries in a near future. One of prospective ways of energy transportation, i.e. gas, liquid and also solid fossil fuels transport, seems to be the transport of solidified oil in LNG and pipelining of coal in methanol. 

The world-wide knowledge in design, construction and operation of hydraulic pipeline systems based on experimental investigation and operational experiences as well as on theoretical calculations has shown the efficiency and prospect of the pipeline transport of coal in comparison with other kinds of transport. However, at a level of technical projects a series of weaknesses and/or imperfections in contemporary used systems of the coal pipelining with water used as a carrier liquid have been detected. One of them is a rather difficult, energy consuming and expensive process of dehydration of coal slurry before combustion. Besides, transport of a great quantity of ballast - the carrier water - also requires considerable power inputs and usually also expensive water treatment before reutilization or... 

Because of permanently problematic supply of natural oil and gas, often in consequence with economical and political pressure, the present time brings a new interest to solve the problem of optimisation of pipeline transport of coal. We could pick out three main directions of modem long distance coal pipelining. 

The first way is pipeline transport of concentrated coal-water slurry. It assumes that utilisation of coal particle distribution preparation and/or using the various additives can substantially increase mass concentration of coal-water slurry till 70-80 %. For example, Black Messa Pipeline realised in USA transports 4.8 million tons of coal per year over the distance 439 km from the colliery in North Arizona to power plant Mohave near the border of Nevada and California with mass ratio of coal to water about 1 1, without using any additives, [5]. Recently, in the USA, Italy, China, Russia and other countries several coal pipelines were already realised. Even Oil and gas should be effectively transported as hydrate slurries, [6],... 

The third way of coal pipelining intensification supposes using the carrier liquid different than water. Oil products (crude oil, residual fuel oil, kerosene, fuel or Diesel oil and various mineral oils) or hydrocarbons (methanol, ethanol, carbonic acid, and other liquid organic compositions) can be used as a carrier liquid. 

An annual world production of methanol increased already at present in average about 15%. The majority of methanol is now produced from petroleum or natural gas since it is about 25-50 % cheaper than production from coal. However, according to the economical prediction the difference in prices should be essentially decreased in the near future. Methanol as a carrier liquid for the coal hydrotransport offers the following scheme of the coal pipelining. 

Common carrier pipelining is economically efficient transport. Using the different liquid hydrocarbons as carrier for coal pipelining, as well as common pipeline transport of oil and natural gas or encapsulated (solidified) oil in water, methanol or LNG could be prospective way for future exploitation of distant deposits, especially in arctic conditions. 

For many pipes, C/C is considered by Wasp et al. (1977) to be 0.08 77/from the top of the pipe. Wasp et al. (1977) examined the distribution of concentration of The Consolidation Coal Company s Ohio coal pipeline at a height of 8% from the bottom of the conduit and at 8% from the top of the conduit they reinterpreted the work of IsmaU (1951) and devised the following equation ... 

Coal is an important fuel for power plants. Its transportation in the form of slurry has received considerable attention since the successful construction of the Black Mesa Pipeline (Figure 11-1). In fact, one of the longest slurry pipelines is the ETSl coal pipeline, built in 1979. It spans a distance of 1670 km (1036 miles), uses a 965 mm (38 in) pipe, and transports 23 million metric tons/year (25 US tons/year). In Russia, the Siberian coal pipeline is 260 km (163 mi) long and transports 4 million tons of coal a year from Siberian mines. 

Hughes (1986) described the development of positive displacement pumps for the Siberian coal pipeline Belovo-Novosibirsk. This pipeline is 256 km (160 ml) long. It transports heavily concentrated water-coal slurry. This pipeline features one main pump station and two booster stations. Each pump station features single acting triplex IngersoU Dresser pumps. Special 100 bar (1,470 psi) gate valves were manufactured in sizes of 200 mm (8 in) and 350 mm (14 in). 

Despite all the promise of coal, only one long coal pipeline has been huilt in the United States—the Black Mesa Pipeline. Another long pipeline that transports coal is the Novo-Siberski pipeline in Siberia, Russia. Other minerals such as copper concentrate. 

In the coal-mining industry, more than 300 mines are operated in three coal-mining regions Ukraine produces only 5 5 million tons of its own oil, but the ramified network of oil pipelines supports the operation of 10 petroleum plants. The Ukrainian gas pipelines transport the Russian gas to Central and Western Europe. 

The dominant role of petroleum in the chemical industry worldwide is reflected in the landscapes of, for example, the Ruhr Valley in Germany and the U.S. Texas/Louisiana Gulf Coast, where petrochemical plants coimected by extensive and complex pipeline systems dot the countryside. Any movement to a different feedstock would require replacement not only of the chemical plants themselves, but of the expensive infrastmcture which has been built over the last half of the twentieth century. Moreover, because petroleum is a Hquid which can easily be pumped, change to any of the soHd potential feedstocks (like coal and biomass) would require drastic changes in feedstock handling systems. 

Dry soHds, such as as-rnined ore, emshed ore, and dried concentrates, are transported using tmeks, rail cars, ore passes, conveyor belts (see Conveying), or slurry pipelines (qv) as dictated by the logistics, distances involved, and capacity. Within the mill, conveyor belts are more common, but for fine particles, tailings, and coal, slurry transportation is more typical. 

Coal Slurry Pipelines. The only operating U.S. coal slurry pipeline is the 439-km Black Mesa Pipeline that has provided the 1500-MW Mohave power plant of Southern California Edison with coal from the Kayenta Mine in northern Arizona since 1970. It is a 457-mm dia system that aimuaHy deHvers - 4.5 x 10 t of coal, the plant s only fuel source, as a 48.5—50% slurry. Remote control of slurry and pipeline operations is achieved with a SCADA computer system. In 1992 coal deHvery cost from mine to power plant was calculated to be 0.010/tkm ( 0.015/t-mi) (28). 

The former Soviet Union constmcted a 262-km, 508-mm dia experimental coal slurry line between the Belovo open-pit coal mine in Siberia s Kuznets basin to an electric power plant at Novosibirsk, using technology developed by Snamprogetti. Testing began in late 1989 and tentative plans call for constmction of two much larger slurry pipelines, each 3000-km long, with capacity to move a total of 33 x 10 t/yr to industrialized areas near the Ural Mountains (27,33). 

H. Liu, "Coal Log Pipeline Economics, Water Use, Right-of-Way, and Environmental Impact," presented at The 10thMnnualPittsburgh Coal Conference, Sept. 20—24,1993, Pittsburgh, Pa. 

Coal-tar pitch for other uses is similarly subject to a few national specifications but mainly sold to users specifications. Pitch intended for roofing, dampproofing, and waterproofing is the subject of ASTM specification D450 and Federal specification R-P-381 hot-appHed tar-based coatings (pipeline enamels) are the subject of BSS 4164/1987, amended in 1988, and, in the United States, of American Water Works Association (AWWA) specification C203. 

The usual means of transporting coal are railroad, barge, tmck, conveyer belt from mine to plant, and slurry pipelines (2,4) (see Transportation). In 1988 769 X 10 t of coal was transported to United States destinations of this, 57.5% was shipped by railroad, 16.0% by barge, 12.3% by tmck, and 14.2% by conveyer, slurry pipeline, and other methods (2). Electric utihties consumed 85.83% of the coal transported in the United States in 1988 (2). 

A 437 km slurry pipeline, 46 cm in diameter, was started in 1970 to move coal from Arizona to southern Nevada. The coal is cmshed and ground to the fineness needed for proper viscosity and settiing. About 18—20% is —325 mesh (<44 //m), 35—45% is —100 mesh (<149 //m), and 0—2% is + 14 (<1070 fim) mesh. The soflds content of the slurries has approached 70% using additives to stabilize the mixture. The slurry is dewatered with centrifuges before combustion of the coal. 

Euture large gasification plants, intended to produce ca 7 x 10 m standard (250 million SCE) of methane per day, are expected to be sited near a coal field having an adequate water supply. It is cheaper to transport energy in the form of gas through a pipeline than coal by either rail or pipeline. The process chosen is expected to utilize available coal in the most economical manner. 

P. F. H. Rudolph, "The Lurgi Process—The Route to SNG From Coal," Fourth Synthetic Pipeline Gas Symposium, Chicago, IU., 1972. 

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