Coal production

X 10 J/kg(10.4 X 10 Btu/lb) in 1990. The shift in coal production toward western coal deposits also reflects the shift in coal utilization patterns (Table 7). Electric utiUties are increasing coal consumption on both absolute and percentage bases, whereas coke plants, other industrial operations, and residential and commercial coal users are decreasing use of this soHd fossil fuel. 

Environmental considerations also were reflected in coal production and consumption statistics, including regional production patterns and economic sector utilization characteristics. Average coal sulfur content, as produced, declined from 2.3% in 1973 to 1.6% in 1980 and 1.3% in 1990. Coal ash content declined similarly, from 13.1% in 1973 to 11.1% in 1980 and 9.9% in 1990. These numbers clearly reflect a trend toward utilization of coal that produces less SO2 and less flyash to capture. Emissions from coal in the 1990s were 14 x 10 t /yr of SO2 and 450 x 10 t /yr of particulates generated by coal combustion at electric utiUties. The total coal combustion emissions from all sources were only slightly higher than the emissions from electric utiUty coal utilization (6). 

Rates of production of lignite have continued to increase since 1960. In 1980 374 x 10 tons of coal equivalent (tee) were produced. One tee is the amount of energy available from combustion of a metric ton of coal having a heat content of 29.3 GJ, ie, 29.3 MJ/kg (12, 600 Btu/lb) (3). In 1989 this figure had risen to 460 x 10 tee. This 23% increase is somewhat less than the 28% increase in hard coal production during this period (see Coal). In 1990 the 1130 X 10 metric tons of lignite produced worldwide represented 24% of the total coal production. 

Hard coal is more important ia most of the western European countries with the exception of Austria and Italy. No lignitic coal production was iadicated ia 1989 for the Netherlands, Denmark, Belgium, Sweden, Norway, and the United Kingdom (24). 

Goal Production. In 1860 world coal production was 122 x 10 t/yr. Production increased to 1140 x 10 t in 1913, giving a 4.2% aimual average rate of increase. The rate has slowed and been erratic since that time. Statistical data on world coal production from 1860 to 1960 is given in Reference 81. World coal and lignite production rose to about 4.7 x 10 t in 1988 (1). 

The demand for energy is continually increasing and the highest energy consumption in the world occurs in the United States. In 1989 consumption totaled 8.6 x 10 MJ (81.3 x 10 Btu) or 11.7 metric tons of coal-equivalent per capita (85). World recoverable reserves were about 120 times the annual coal production in 1988 and about 10 times that for the additional reserves beheved to be in place (1). Estimated coal consumption reduces the known recoverable reserves at about 1%/yr. Whereas the use of bituminous coal is expected to continue to increase in terms of tonnage, the percentage of coal used in the United States has stabilized as shown in Table 11. 

In 1990 coal production in the United States reached 0.9 biUion metric tons (2) and worldwide production was estimated to be over four biUion metric tons. In 1982 it was estimated that at least 50% of the world coal production was cleaned in some manner before use (3). As higher quaUty coal reserves are depleted and more stringent environmental regulations on pollutants, particularly sulfur oxides, are enacted, this percentage is expected to increase. 

Flotation. The appfication of flotation (qv) to coal cleaning is a relatively new development iu the United States. In 1960, only 0.6% of the clean coal produced came from flotation. However, by 1983 flotation accounted for about 5% of the clean coal production (Table 2). Utilization of the flotation process is expected to grow rapidly because more fine size coal is produced as a result of beneficiation schemes that require significant size reduction of the taw coal prior to cleaning to enhance the fiberation of pyrite and ash minerals. 

The flotation process usually iuvolves three steps (/) the conditioning of the coal surface iu a slurry with reagents, (2) adhesion of hydrophobic coal particles to gas bubbles, and (J) the separation of the coal-laden bubbles from the slurry. In the conventional flotation process, when the coal particles become attached to air bubbles, the particles ate allowed to rise to the top of the flotation cell and form a stable froth layer (9). A mechanical scraper is used to remove the froth layer and separate the clean coal product from the refuse-laden slurry. 

New Mexico s San Juan Gas Plant is one of the United States newest and largest natural gas liquids recovery plant. Commissioned in November 1986, its levels of productivity are high by industry standards. Located near Bloomfield, New Mexico, just south of tlie Colorado border, the plant is jointly owned by Conoco Inc. (then a subsidiary of the DuPont Company) and Tenneco Inc., both of Houston. It is operated by Conoco and is named after its location in the San Juan basin, an area of oil, gas, and coal production. 

Table 13. Ash content in WVGS coals and coal products...

Table 16. Ash content of raw coal and their hydrogenated coal products, wt%...

The chemical process industry is vast and varied. The value of chemicals and chemical products in 1993 was 0.5 trillion for the Ll.S," involving 67,000 chemical engineers, 98,000 chemists. There were 5.5 non-fatal occupational injuries per 100 employees in 1995 involving chemical and allied products, and 4.8 per 100 workers in petroleum and coal products, There were 101 fatalities due to exposure to caustic, noxious or allergenic substances and 208 deaths from fires and explosions in 1995. 

Kohlen-wasserstoffol, n. hydrocarbon oil. -wasserstoffverbindtmg, /. hydrocarbon, -wertstoff, m. coal product (esp., a by-product). -wertstoffbetrieb, m., -wertstoffge-winnungsanlage, /. coal by-product plant, -ziegel, m. coal briquet. 

After 1930, four other energy sources began to contribute significantly, as wood use continued its slow decline and coal production was relatively flat. These four were oil, natural gas, nuclear power (beginning in the 1950s), and hydroelectricity. The... 

See also Coal, Production of Coal, Transportation and Storage of Environmental Problems and Energy Use Fossil Fuels. 

Coal is the most abundant and most economical fossil fuel resource in the world. Proven coal reseiwes exceed 1 trillion tons, and indicated reserves are estimated at 24 trillion tons. Coal is found in eveiy continent of the world, including Antarctica, although the largest quantities of coal are in the Northern Hemisphere. Coal is mined in some sixty countries in nineteen coal basins around the world, but more than 57 percent of the world s total recoverable reserves are estimated to be in the United States, and China, which together account for more than two-thirds of the world s coal production. 

See also Coal, Consumption of Coal, Production of Locomotive Technology Transportation, Evolution of Energy Use and. 

See also Catalysts Coal, Production of Conservation of Energy Explosives and Propellants Heat T ransfer. 

United States and the world (Figure 1), despite perceptions that it has been replaced by other sources. In 1997 production ofboth coal (23.2 quadrillion Btus, or about 4.6 billion barrels of oil) and natural gas (19.5 quadrillion Btus, or about 3.9 billion barrels of oil) on an energy equivalent basis exceeded U.S. domestic oil production (13.6 quadrillion Btus, equivalent to about 2.7 billion barrels, or 3.1 billion barrels of oil if natural gas liquids are included). Coal production in the United States nearly doubled from 1970 to 2000 (from about 600 million tons to about 1 billion tons produced annually). Meanwhile, petroleum consumption at 18.6 million barrels of oil per day is near the all-time high of 18.8 million barrels of oil per day in 1978. Net U.S. petroleum imports (8.9 million barrels of oil per day) in 1997 were worth 67 billion and exceeded U.S. petroleum production (8.3 million... 

Programs were instituted to preserve coal production in Western Europe and Japan. Every involved country (Britain, Germany, France, Spain, Belgium, and Japan) transferred taxpayers money to the coal industry. The programs started in the period between the end of World War II and the resurgence of the oil supply in the late 1950s. 

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