Pyrolysis of coal

Pyrolysis gasoline Pyrolysis-gc Pyrolysis of coal Pyrolysis processes Pyrolysis yields... 

F. B. Carlson, L. H. Yardumian, and M. T. Atwood, "The TOSCO AT, Process for Low Temperature Pyrolysis of Coal," paper presented at... 

Acetylene traditionally has been made from coal (coke) via the calcium carbide process. However, laboratory and bench-scale experiments have demonstrated the technical feasibiUty of producing the acetylene by the direct pyrolysis of coal. Researchers in Great Britain (24,28), India (25), and Japan (27) reported appreciable yields of acetylene from the pyrolysis of coal in a hydrogen-enhanced argon plasma. In subsequent work (29), it was shown that the yields could be dramatically increased through the use of a pure hydrogen plasma. 

Step 4 of the thermal treatment process (see Fig. 2) involves desorption, pyrolysis, and char formation. Much Hterature exists on the pyrolysis of coal (qv) and on different pyrolysis models for coal. These models are useful starting points for describing pyrolysis in kilns. For example, the devolatilization of coal is frequently modeled as competing chemical reactions (24). Another approach for modeling devolatilization uses a set of independent, first-order parallel reactions represented by a Gaussian distribution of activation energies (25). 

Sources of Raw Materials. Coal tar results from the pyrolysis of coal (qv) and is obtained chiefly as a by-product in the manufacture of coke for the steel industry (see Coal, carbonization). Products recovered from the fractional distillation of coal tar have been the traditional organic raw material for the dye industry. Among the most important are ben2ene (qv), toluene (qv), xylene naphthalene (qv), anthracene, acenaphthene, pyrene, pyridine (qv), carba2ole, phenol (qv), and cresol (see also Alkylphenols Anthraquinone Xylenes and ethylbenzenes). 

Background Converting coal to combustible gas has been practiced commercially since the early nineteenth century. The first gas-producing companies were chartered in 1812 in England and in 1816 in the United States to produce gas for illumination oy the heating or pyrolysis of coal. This method of producing gas is still in use the gas is a by-product of the carbonization of coal to manufacture coke for metallurgical purposes. 

There are challenges and opportunities in developing a process for in-situ pyrolysis of coal in which the char is the principal fuel. 

Innovatory boronated carbons (manufactured in the Institute of Chemistry and Technology of Petroleum and Coal, Wroclaw University of Technology, Poland) were obtained by co-pyrolysis of coal-tar pitch with a pyridine-borane complex. In the first stage of pyrolysis (520°C) the so-called semi-coke is obtained. Further carbonization at 2500°C leads to obtaining boron-doped carbonaceous material (sample labeled 25B2). 

Boron-containing carbons synthesized by co-pyrolysis of coal-tar pitch with pyridine-borane complex (series 25Bn) have already been considered as hosts for lithium insertion [4], Unlike the commercial graphites described above, the boron-doped carbon 25B2 (WUT) as received was not suitable for direct use in the cylindrical cell due to very large and hard particles. This feature makes the coating process very difficult. 

When pyrolysis of coal is carried out in the mass spectrometer in high vacuum of its ion source compartment, volatilization of broken fragments is likely to occur, unless they are of large molecular size. However, a large molecular size of a fragment would also reduce its rotational ability. 

Acetylene can be produced by pyrolysis of coal and by fuel-rich combustion of alkanes, a process that also produces soot or carbon black, the major ingredient in automobile tires. Acetylene can also be made with nearly stoichiometric efiiciency by decomposing calcium carbide, CaC, which is produced by pyrolyzing limestone and coke,... 

Dr. Friedel. No. Products of the pyrolysis of coal under high temperature carbonization conditions surely must arise from degradation. The quantitative prediction of C7 alkane isomers from coal may possibly indicate a relationship in compositions of coal and petroleum. The hydrocarbons from each perhaps should be similar since both are supposedly derived from organic plants ... 

Results show that though some methane is formed, the quantities are relatively small (about 5% or even less of the total methane obtainable by low temperature pyrolysis of coal) even though a considerable excess of hydrogen was used in the experiments. 

The volume of hydrogen reacting with coke is about 10 times that obtainable in situ during pyrolysis of coal at and up to 600 C. 

H. R. Linden High temperature pyrolysis of coal with high energy sources seems to follow readily predictable paths similar to hydrocarbon pyrolysis. The effects of pressure, gas atmosphere, reaction time, and the volatile matter" content of the coal bear the same relationship to yields of methane, ethane, ethylene, acetylene, and hydrogen as for simple hydrocarbons. Effective reaction temperature, although not directly measurable, could be estimated by means of a suitable chemical thermometer, such as the C-. H-. -C. H4-H. system which approaches equilibrium very rapidly. As Dr. Given also noted, equating the volatile matter" to the reactive portion of the coal is an oversimplification but adequate for empirical purposes the C H ratio of the coal would probably be more suitable. 

High-temperature tar heavy distillate from the pyrolysis of coal at a temperature of about 800°C (1470°F). 

Extracted coals from eastern Oklahoma were analyzed using pyrolysis-gas chromatography and a flame photometric detector (FPD) to characterize the organosulfur compounds produced by pyrolysis of coals. All coals from the Croweburg seam with calorific values below 13,000 BTU (Table I) were shown to produce similar distributions of organosulfur compounds. The ratio of dibenzothiophenes to thiophenes produced by pyrolysis was shown to be proportional to the calorific value of the coal. 

Machnikowski, J., Grzyb, B., Weber, J.V., Frackowiak, E., Rouzaud, J.N., and Beguin, F. Structural and electrochemical characterization of nitrogen enriched carbons produced by the co-pyrolysis of coal-tar pitch with polyacrylonitrile. Electrochim. Acta 49, 2004 423-432. 

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