Liquefaction of coal

Liquefaction. Liquefaction of coal to oil was first accompHshed in 1914. Hydrogen was placed with a paste of coal, heavy oil, and a small amount of iron oxide catalyst at 450° and 20 MPa (200 atm) in stirred autoclaves. This process was developed by the I. G. Earbenindustrie AG to give commercial quaUty gasoline as the principal product. Twelve hydrogenation plants were operated during World War II to make Hquid fuels (see CoAL... 

Owen, J., Liquefaction of coal. In Coal and Modern Coal Processing- An Introduction, ed. G. J. Pitt and G. R. Millward. Academic Press, New York, 1979, pp. 163 181. 

Liquefaction of coal involves the extraction of carbon by solvents at high pressures and at temperatures up to about 500 C, followed by separation of the extract, which is then hydrogenated in the presence of a catalyst to yield hydrocarbon oils. The corrosion conditions are not regarded as severe. 

The purpose of the collection of papers in this volume is to review what can be said about the susceptibility to liquefaction of coals from different parts of the world. We and later authors will present data relative to coals of the areas with which we are familiar. However, with the Editor s approval, we are going to devote the first part of this paper to making some general remarks about coal geology and geochemistry, in the hope that this will provide a useful background to what comes later. 

Clarke, L. Storch, H.H., "Hydrogenation and Liquefaction of Coal, Part 2 - Effect of Petrographic Composition and Rank of Coal", Technical Paper 642, US Bureau of Mines, 1942. 

The liquefaction of coals was studied in a 500 ml magnetically-stirred stainless steel antoclave. Two different reaction conditions were used in this study, hut the experimental procedures were almost the same in both conditions. 

At the Coal Research Establishment of the National Coal Board, methods for the liquefaction of coals to produce transport fuels, feedstocks for the chemical industry and high purity carbons suitable for electrode manufacture are being developed. 

Kinetics of Direct Liquefaction of Coal in the Presence of Molybdenum—Iron Catalyst... 

Many studies on direct liquefaction of coal have been carried out since the 1910 s, and the effects of kinds of coal, pasting oil and catalyst, moisture, ash, temperature, hydrogen pressure, stirring and heating-up rate of paste on coal conversion, asphaltene and oil yields have been also investigated by many workers. However, few kinetic studies on their effects to reaction rate have been reported. 

Liquefaction of coals in alkylated and hydrogenated pyrenes. Table 2 shows liquefaction activity of alkylated and hydrogenated pyrenes at 370°C, respectively. Although hexylpyrene showed just the same liquefaction ability as pyrene, propylation and ethylation certainly improved the liquefaction activity of pyrene with these coals of three different ranks. It is of value to note that ethylpyrene showed LY of 80% with West-Kentucky coal, which was significantly higher than with other coals. 

Atmospheric liquefaction of coals of three ranks were studied at temperature range of 37CW470°C, using decacyclene, pyrene, alkylated pyrene and hydrogenated pyrene as the liquefying solvent. Coal of high... 

The Effect of Mineral Matters on the Decomposition Ethers. Recently, the effect of mineral matters of coal on the coal liquefaction has received much attention. It was shown that small amounts of FeS or pyrite are responsible for the hydro-genative liquefaction of coal. Therefore, it is interesting to elucidate the effect of mineral matters of coal on the decomposition rate and products of aromatic ethers, and so three diaryl ethers were thermally treated in the presence of coal ash obtained by low temperature combustion of Illinois No.6 coal at about 200°C with ozone containing oxygen. 

Diaryl ether must be one of the important structures responsible for the liquefaction of coal among various oxygen-containing organic structures of coal. 

The dialin donor solvents were also used directly in coal liquefaction studies. Inasmuch as details of coal structure are unknown, the present theory can only be tested in a qualitative way, as follows. First, if the liquefaction of coal occurs under kinetic control with hydrogen-transfer from the donor solvent involved in the rate-determining step, then we should expect the dialin donors to be more effective than the control solvent T.et-ralin (and also Dfecalin). This is suggested by the theory because the dialins possess higher energy HOMOs than Tetralin and... 

The range of reactions which have been examined is wide (248) and includes hydrogenations (256), ammonia synthesis (257), polymerizations (257), and oxidations (258). Little activity has occurred in this area during the past few years. Recent reports of the effects of sonication on heterogeneous catalysis include the liquefaction of coal by hydrogenation with Cu/Zn (259), the hydrogenation of olefins by formic acid with Pd on carbon (260), and the hydrosilation of 1-alkenes by Pt on carbon (261). 

Fan (1989) provided a detailed historical development of three-phase fluidization systems in reactor applications. Only a brief review of the significant accomplishments and the economic factors affecting the development of three-phase reactors will be provided here. Table 1 provides the important contributions in the application of three-phase fluidization systems for the past several decades. The direct liquefaction of coal to produce liquid fuels was the first commercial reactor application of three-phase fluidization systems, with development having occurred from the mid-1920 s throughout the 1940 s. A large effort was put forth at this time in Europe for the production of liquid fuels from coal as a direct... 

In the reactor of Figure 8.3, a stable fluidized bed is maintained by recirculation of the mixed fluid through the bed and a draft tube. An external pump sometimes is used instead of the built-in impeller shown. Such units were developed for the liquefaction of coal and are called ebullating beds.. 

Gulf Oil Corporation, Information Brochure, "Solvent Refined Coal-II Turning Coal into Clean Energy," pp 4-5 Assessment of Technology for the Liquefaction of Coal, The National Research Council, Washington, 1977, pp 47-50. 

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