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The fixed carbon content of the coal is the carbon found in the material which is left after volatile materials are driven off. This differs from the ultimate carbon content of the coal because some carbon is lost in hydrocarbons with the volatiles. Fixed carbon is used as an estimate of the amount of coke that will be yielded from a sample of ...
Coal rank is based on several characteristics of the coal. The fixed carbon content refers to the percentage of the coal that is neither moisture, nor ash, nor volatile matter. When evaluated on a dry, mineral-matter-free basis, the fixed carbon content is the fraction of the coal that is not volatile organic matter. [4]
Lignite mining, western North Dakota, US (c. 1945). Lignite is brownish-black in color and has a carbon content of 60–70 percent on a dry ash-free basis. However, its inherent moisture content is sometimes as high as 75 percent [1] and its ash content ranges from 6–19 percent, compared with 6–12 percent for bituminous coal. [5]
The value of bituminite increases with grade. At high grade, i.e. high maturity, bituminite has high hydrogen to carbon content [citation needed]. A high hydrogen/carbon ratio bituminite indicates a good hydrocarbon source. However, low grades of bituminite vary depending on type, meaning that there is variable hydrogen/carbon ratios. [1]
Bituminous coal has a composition of about 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on a weight basis. [40] The low oxygen content of coal shows that coalification removed most of the oxygen and much of the hydrogen a process called carbonization. [41]
Fossiliferous organic carbon can alI BE sported throughout the modern environment, in rivers, soils, and eventually the oceans. This process occurs over a very large time scale, and acts as one of the major mechanisms for fossiliferous organic carbon to be released back into the environment.
This gives information on the carbon, hydrogen and nitrogen composition of the coal, and determines the type of coal: lignite, bituminous coal, or anthracite. Macerals found in kerogen source rocks are often observed under the microscope to determine the kerogen maturity of the sedimentary formations. This is a vital component of oil and gas ...
Sub-bituminous coal is a lower grade of coal that contains 35–45% carbon. The properties of this type are between those of lignite, the lowest grade of coal, and those of bituminous coal, the second-highest grade of coal. [1] Sub-bituminous coal is primarily used as a fuel for steam-electric power generation.