Coal mixtures, complexity

In 1984, the Ube Ammonia Industry Co. began operating the largest Texaco coal gasification complex to date. This faciUty is located in Ube City, Japan, and has a rated gasification capacity of 1500 t/day of coal, and production capacity of 1000 t/day of ammonia. The plant has successfully gasified coals from Canada, AustraUa, South Africa, and China. At the present time the plant uses a mixture of petroleum coke and coal (43). 

The heat and pressure breaks the chemical bonds in coal s complex molecular structure with the steam and oxygen forming a gaseous mixture of hydrogen and carbon monoxide. Gasification may be one of the better ways to produce hydrogen. 

Sasser LB, Lundstrom DL, Zangar RC, et al. 1989. Elevated blood pressure and heart rate in rats exposed to a coal-derived complex organic mixture. J Appl Toxicol 9 (l) 47-52. 

Coal tar is the condensation product obtained by cooling to approximately ambient temperature, the gas evolved in the destmctive distillation of coal. It is a black viscous Hquid denser than water and composed primarily of a complex mixture of condensed ring aromatic hydrocarbons. It may contain phenoHc compounds, aromatic nitrogen bases and their alkyl derivatives, and paraffinic and olefinic hydrocarbons. Coal-tar pitch is the residue from the distillation of coal tar. It is a black soHd having a softening point of 30—180°C (86—359°F). 

Simple aromatic hydrocarbons come from two main sources coal and petroleum. Coal is an enormously complex mixture made up primarily of large arrays of benzene-like rings joined together. Thermal breakdown of coal occurs when it is heated to 1000 °C in the absence of air, and a mixture of volatile products called coal for boils off. Fractional distillation of coal tar yields benzene, toluene, xylene (dimethylbenzene), naphthalene, and a host of other aromatic compounds (Figure 15.1). 

About eight gallons of coal tar are obtained from a ton of coal. Coal tars are very complex mixtures over 200 different carbon compounds have been isolated from them. While the great value of coal to mankind has been as a fuel, a source of energy, the many substances in coal gas and coal tar make coal also an important source of chemical raw materials. 

Aromatic hydrocarbons, which originally got their name from the distinctive odors many of them have, are called arenes. They all contain an aromatic ring, usually the six-membered ring of benzene, which was introduced in Sections 2.7, 3.7, and 3.12. An abundant source of arenes is coal, which is a very complex mixture of compounds, many of which consist of extensive networks containing aromatic rings (Section 18.10). 

FIGURE 18.16 A highly schematic representation of a part of the structure of coal. When coal is heated in the absence of oxygen, the structure breaks up and a complex mixture of products—many of them aromatic—is obtained. 

The recovery of petroleum from sandstone and the release of kerogen from oil shale and tar sands both depend strongly on the microstmcture and surface properties of these porous media. The interfacial properties of complex liquid agents—mixtures of polymers and surfactants—are critical to viscosity control in tertiary oil recovery and to the comminution of minerals and coal. The corrosion and wear of mechanical parts are influenced by the composition and stmcture of metal surfaces, as well as by the interaction of lubricants with these surfaces. Microstmcture and surface properties are vitally important to both the performance of electrodes in electrochemical processes and the effectiveness of catalysts. Advances in synthetic chemistry are opening the door to the design of zeolites and layered compounds with tightly specified properties to provide the desired catalytic activity and separation selectivity. 

The open-column technique is commonly applied in the case of crude oils (being the least complex geochemical organic mixtures). MPLC, high-pressure liquid chromatography (HPLC), and PTLC are more often applied to more complex samples, especially those dominated by more polar compounds, such as hydrothermal bitumens or samples showing terrestrial organic matter input, such as extracts or pyroly-sates of coals of various ranks. 

Complex Mixture of PAHs from Coal Tar PAHs (12) PAHs (18)... 

Traditionally, iron-based catalysts have been used for FT synthesis when the syngas is coal derived, because of their activity in both FTS and WGS reactions. Complex mixtures of straight-chain paraffins, olefins, and oxygenate (in substantial proportions) compounds are known to be formed during iron-based FTS. Olefin selectivity of iron catalysts is typically greater than 50% of the hydrocarbon products at low carbon numbers, and more than 60% of the produced olefins are a-olefins.13 For iron-based catalysts, the olefin selectivity decreases asymptotically with increasing carbon number. 

Seacoke A process for making tar and coke by carbonizing mixtures of coal and petroleum residuum. The tar would be used in an oil refinery and the coke would be used for generating electricity. The process was sponsored by the U.S. Office of Coal Research 1964-1969 the work was carried out by EMC Corporation, Atlantic Richfield Company, and Blaw-Knox Company. Results from the pilot plant were encouraging but the project was abandoned because the benefits were judged insufficient to justify the complexity. 

Ufer A proces for refining the light oil produced in coal carbonization. The oil is washed with sulfuric acid and a controlled amount of water is then added to the mixture. The complex mixture of reaction products ( resins ) enters the oil phase the dilute sulfuric acid can be used directly for making ammonium sulfate. Invented in Germany in 1924 by A. Ufer operated in Germany and Canada in the 1920s and 1930s. 

The flame ionization detector (FID) can be used for the detection and quantitative estimation of components separated by the GC. Identification of major species can be achieved by a mass spectrometer which can not be used for quantitative analysis of complex mixtures such as coal liquids. 

Mass spectrometers used to be expensive and complex for routine use as a GC detector. The Ion Trap Detector (ITD, Finnigan) is a low priced mass spectrometer (MS) for capillary chromatography. Three analytical tools - SEC, GC, and ITD - are incorporated into a powerful analytical system for the analysis of complex mixtures such as coal liquids, petroleum crude and various refinery products. The instrumentation and the SEC-GC-MS analysis of a coal liquid are presented in this paper in order to demonstrate the technology. 

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