Coal hydrogen between

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. 

Exchange of Hydrogen Between Coal and Naphthalene Incorpora-tion of into tne a and 8 positions of napnthalene-ds as measured by XH NMR spectrometry is shown in Figure 6. Progressively more protium was found to be incorporated into the naphthalene-de solvent as the reaction time was increased. During the first few minutes, the incorporation in both positions occurred more rapidly than later in the reaction. Throughout the measured duration of the reactions, the rate of incorporation of protium into the a position was more rapid than in the 8 position. 

We believe it is important, at this time, to establish a documented historical review of asphaltenes and the separation/characterization procedures used by early petroleum and coal chemists to profile crude oils and the products of coal hydrogenation. We shall explore the most important differences between petroleum- and coal-derived asphaltenes. 

The direct liquefaction of coal is a process that involves the interaction between coal, hydrogen, solvent, and catalysts. 

Medium Heat- Value Gas. Medium heat-value (medium Btu) gas (6,7) has a heating value between 9 and 26 MJ/m (250 and 700 Btu/fT). At the lower end of this range, the gas is produced like low heat-value gas, with the notable exception that an air separation plant is added and relatively pure oxygen (qv) is used instead of air to partially oxidize the coal. This eliminates the potential for nitrogen in the product and increases the heating value of the product to 10.6 MJ /m (285 Btu/fT). Medium heat-value gas consists of a mixture of methane, carbon monoxide, hydrogen, and various other gases and is suitable as a fuel for industrial consumers. 

Table 4 summarizes the yield of soluble pitch for the hydrogenation experiments. Hydrogenation of WVGS 13407 at 350°C increased the pilch yield from about 66 to 84 wt% Although the incremental yield between untreated and hydrogenated coal is only 18 wt%, there were significant differences m the properties of the pitches in terms of their carbonization behavior. 

Much work has been described in the literature on determining which chemical and physical features distinguish coals in terms of reactivity or hydrogenation potential [21]. Coal rank is certainly one of the featiues as shown by the difference between WVGS 13421, which is a medium-volatile bitummous coal, and the lower rank WVGS 13423, which is a high-volatile A bituminous coal. 

In very broad terms, hydrogenation activity in terms of hydrogen utilization increases as coal rank decreases. Thus, in the absence of any other information, one can expect WVGS 13423 to be the more reactive of the two Obviously, generalities about hydrogenation behavior should not be extended to other coals based solely on a limited data set. Nevertheless, important differences between the pitches derived from WVGS 13421 and WVGS 13423 are apparent. 

The major chemical difference between natural gas, crude oil, and coal is their hydrogen-to-carbon ratios. Coal is carbon-rich and hydrogen-poor, so to produce a synthetic liquid or gas from coal requires an increase in the hydrogen-to-carbon ratio. Coal s ratio of about 0.8 has to be raised to 1.4 to 1.8 for a... 

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