Carbonized coal

The recorded chronology of the coal-to-gas conversion technology began in 1670 when a clergyman, John Clayton, in Wakefield, Yorkshire, produced in the laboratory a luminous gas by destmctive distillation of coal (12). At the same time, experiments were also underway elsewhere to carbonize coal to produce coke, but the process was not practical on any significant scale until 1730 (12). In 1792, coal was distilled in an iron retort by a Scottish engineer, who used the by-product gas to illuminate his home (13). 

Coke oven charging Hydrocarbons, carbon, coal dust Aspiration systems to draw pollutants into oven, venturi scrubbers... 

Still A method for increasing the yield of fight oil formed in the carbonization of coal. Some of the gas produced is passed through the partially carbonized coal in a cooler part of the bed. Developed by C. Still and used in Recklinghausen, Germany in the 1930s for producing motor fuel. See also Carl Still. 

Miller, V. R., E. L. Wehry, and G. Mamantov, Photochemical Transformation of Pyrene Vapor Deposited on Eleven Subfractions of a High-Carbon Coal Stack Ash, Environ. Toxicol. Chem., 9, 975-980 (1990). 

Shao, L., Jones, T., Gayer, R., Dai, S., Li, S. Jiang, Y. 2003. Petrology and geochemistry of the high-sulphur coals from the Upper Permian carbonate coal measures in the Hesham Coalfield, southern China. International Journal of Coal Geology, 55, 1 -26. 

CASH CBM CBO CBPC CC CCB CCM CCP CDB CEC CFBC CFC CFR CMM COP CSH CT Calcium aluminosilicate hydrate Coal bed methane Carbon burn-out Chemically-bonded phosphate ceramics Carbonate carbon Coal combustion byproducts Constant capacitance model Coal combustion product Citrate-dithionate-bicarbonate Cation exchange capacity Circulating fluidized bed combustion Chlorofluorocarbon Cumulative fraction Coal mine methane Coefficient of performance Calcium silicate hydrate Collision theory... 

Figs. 07 and 08 represent a coking fumaco in use in liolgium for carbonizing coal. In these figures, the... 

Coal Derivatives. In attempting to extend this investigation to coal products, it was evident that not many isomeric analyses have been carried out. In the case of low temperature tar the predominant species reported have been normal olefins and normal alkanes. Branched alkane isomers are probably very low in concentration. However, limited data for high temperature coal tar (10) and for coal hydrogenation products (7, 12) indicate a close comparison of C7 alkanes with those from crude oil and the values predicted by the Fischer-Tropsch equation (Table III, top). A close comparison is notable also in the bottom part of Table III, which gives data for the Co and C7 naphthenes from high temperature coal carbonization, coal hydrogenation, and a crude oil. 

Exothermic reactions culminate at about 640°C. (point F), reflecting both accelerated oxidation and crystallite ordering. The down slope of the exothermic peak after 640°C. suggests that Combustible volatiles have been depleted, and reactive surface area has been reduced. The trace then tends to reflect the general endothermic character of carbonized coals. Smothers and Chiang (34) have demonstrated that this exotherm (F) is caused mainly by... 

Table III shows that values for the percent yield of methane (including small amounts of ethane reported as methane) in the bituminous range (C = 81-90% on dmf basis) are largely the same and may be put at 7000 500 cc. at NTP, although strictly speaking the yield tends to decrease somewhat between 88 and 90% carbon coal. However, when the yield is expressed as...

Figure 7 shows carbonized coal particles of the sieve fraction 5 to 3 mm. It can be seen that for all types of coals practically all particles display devolatilization pores. This result, obtained by counting, is particularly interesting for the low volatile bituminous coal (No. 6 in Figure 7) because in high temperature cokes produced under normal conditions from another coal of the same rank, the particles of carbonized coal show no pores and will be found as so-called unmelted particles in the coke. 

It was established in the early stages of this investigation that on carbonization, coal-tar and petroleum-tar pitches and some other substances behaved like the vitrinite of a coking coal. For pitch, the sequence of events was exactly the same as for vitrinite, except that the temperature range over which the changes occurred was wider and the absolute temperatures were lower. 

Table VII. Analytes of Some of the Soots from 802 Coal Together with the Analyses of Carbonized Coals of Similar Carbon Content...

Since metallurgical coke for use in blast furnaces is the prime product of coal carbonization, coal tar production is tied closely io the demand for... 

Some methane is manufactured hv the distillation of coal. Coal is a combustible nick formed from the remains of decayed vegetation. Ii is ihe only rock containing significant amounls of carbon. The elemental composition of coal varies between 60% and 95% carbon. Coal also contains hydrogen and oxygen, with small concentrations of nitrogen, chlorine, sulfur, and several metals. Coals are classified by the amount of volatile material they contain, that is. by how much of Ihe mass is vaporized when the coal is healed to about 900 C in the absence of air. Coal that contains more than 15% volatile material is called bituminous coal. Substances released from bituminous coal when it is distilled, in addition to methane, include water, carbon dioxide, ammonia, benzene, toluene, naphthalene, and anthracene In addition, the distillation also yields oils, tars, and sulfur-containing products. The non-volatile component of coal, which remains after distillation, is coke. Coke is almost pure carbon and is an excellent fuel, However, it may contain metals, such as arsenic and lead, which can he serious pollutants if ihe combustion products are released into the atmosphere. 

The biorefinery approach is the most sound in terms of truly exploiting the potential of an aquatic biomass, and this concept is now becoming accepted on a worldwide basis. In the biorefinery approach, the economic and energetic value of the biomass is maximized, although it must be emphasized that fluctuations in the prices of fossil carbon (coal, oil, gas) raises uncertainty regarding the opportunity to produce biodiesel from aquatic biomass. For example, when the oil price is below US 120 per barrel it is uneconomic to produce biodiesel in this way. On the other hand, an aquatic biomass demonstrates an excellent potential for use as a source of specialty chemicals, with some components also having added value as animal feeds or fertilizers. 

Carbon dioxide is considered to be an inert molecule since, with water, it is the end product of any combustion process, including biological cellular oxidation reactions. Although it is produced by all living organisms, whether animal or vegetable (for example, an adult man emits about 0.9kg C02 per day), by far the main source of C02 is the combustion of fossil carbon (coal, oil, gas) used for the production of energy. 

One particular test method (ASTM D-1756) covers the determination of carbon dioxide in coal in any form, such as mineral carbonate, from which carbon dioxide is released by action of mineral acids (e.g., hydrochloric acid). The method can be applied to high- and low-carbonate coals. The determination of carbon dioxide is made by decomposing with acid a weighed quantity of the sample in a closed system and absorbing the carbon dioxide in an absorbent (e.g., such as sodium... 

Coal with more than 85% w/w carbon have usually been shown to exhibit a greater degree of hydrophobic character than the lower-rank coals, with the additional note that the water density may be substantially lower than the helium density for the 80 to 84% carbon coals, there is generally little, if any, difference between the helium and water densities. However, the hydrophobicity of coal correlates better with the moisture content than with the carbon content and better with the moisture/carbon molar ratio than with the hydrogen/carbon or oxygen/carbon atomic ratios. Thus, it appears that there is a relationship... 

An additional noteworthy trend is the tendency for the density of coal to exhibit a minimum value at approximately 85% w/w carbon. For example, a 50 to 55% w/w carbon coal will have a density of approximately 1.5 g/cm3, and this will decrease to, say, 1.3 g/cm3 for an 85% carbon coal followed by an increase in density to about 1.8 g/cm3 for a 97% carbon coal. On a comparative note, the density of graphite (2.25 g/cm3) also falls into this trend. 

As already noted with respect to coal density (Figure 6.1), the porosity of coal decreases with carbon content (Figure 6.3) (King and Wilkins, 1944 Berkowitz, 1979) and has a minimum at approximately the 89% w/w carbon coals followed by a marked increase in porosity. The nature of the porosity also appears to vary with carbon content (rank) for example, the macropores are usually predominant in the lower carbon (rank) coals whereas higher carbon (rank) coals contain predominantly micropores. Thus, pore volume decreases with carbon content (Figure 6.4) and, in addition, the surface area of coal varies over the range 10 to 200 m2/g and also tends to decrease with the carbon content of the coal. 

The refractive index of coal can be determined by comparing the reflectance in air with that in cedar oil. A standard test method (ASTM D-2798) covers the microscopic determination of both the mean maximum reflectance and the mean random reflectance measured in oil of polished surfaces of vitrinite and other macerals in coal ranging in rank from lignite to anthracite. This test method can be used to determine the reflectance of other macerals. For vitrinite (various coals), the refractive index usually falls within the range 1.68 (58% carbon coal) to 2.02 (96% carbon coal). 

Early work on a series of carbonized coals gave 3 x 1019 free radicals per gram (1 free-radical per 1600 carbon atoms). It was also established that the free-radical content of coal at first increases slowly (in the range 70 to 90% carbon) (Ladner and Wheatley, 1965), rises markedly (90 to 94% w/w C), and then decreases to limits below detectability. Thus, in a coal having 70% carbon, there is one radical per 50,000 carbon atoms, but this is increased to one radical per 1000 carbon atoms in coal with 94% w/w carbon. 

There is a relationship between yield of the extract and the saturation sorption or imbibition of solvent that is independent of the rank coal or the particular amine solvent (Dryden, 1951). An adsorption isotherm for ethylenediamine vapor on an 82% carbon coal exhibited three main features (1) chemisorption up to 3 to 6% adsorbed, (2) a fairly normal sorption isotherm from the completion of chemisorption up to a relative pressure of at least 0.8, and (3) a steeply rising indefinite region near saturation that corresponded to observable dissolution of the coal. 

Cornelissen, G., Gustafsson, O., Bucheli, T.D., Jonker, M.T.O., Koelmans, A.A., van No-ort, P.C.M., 2005. Extensive sorption of organic compounds to black carbon, coal, and kerogen in sediments and soils Mechanisms and consequences for distribution, bioaccumulation, and biodegradation. Environ. Sci. Technol. 39, 6881-6895. 

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