Kinetics of thermal liquefaction of coal

Abichandani, Jeevan S.; Shah, Yatish T.; Cronauer, Donald C.; Ruberto, Raffaele G.

doi:10.1016/0016-2361(82)90125-9

Cited by 24 publications

(4 citation statements)

References 3 publications

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“…As seen from these plots, the model adequately represents the product distribution for all conditions examined in the present study. The previously discussed model (Abichandani et al, 1982) containing 15 parameters was also tested against the present data. This model gave a marginally better fit (average error = 3.2%) over the model presented above.…”

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confidence: 99%

Kinetics of short contact time coal liquefaction. Part I: Effect of operating variables

et al. 1984

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Kinetics of short contact time coal liquefaction. Part I: Effect of operating variables

et al. 1984

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“…It is noted that the above similarities in the depth of conversion of Belle Ayr subbituminous and Powhatan bituminous coals in this batch stirred-tank reactor are not consistent with those of liquefaction runs made using these coals in a flow unit (CSTR). Namely, Cronauer and Ruberto (1979) and Abichandani et al (1982) reported a greater extent of conversion of the higher rank coal to pyridine solubles using hydrogenated anthracene oil as the solvent in a CSTR unit. This difference of conversion levels may be due to a combination of reactor configuration, liquefaction solvent, and/or extraction solvent.…”

Section: Effect Of the Nature Of Coalmentioning

confidence: 99%

Kinetics of short contact time coal liquefaction. Part II: Effect of nature of coal and solvent

et al. 1984

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A bituminous coal (Powhatan No. 5 ) and a subbituminous coal (Belle Ayr) were liquefied in the presence of hydrogen donor solvents. Statistical analyses of the data showed that for contact times up to 10 min, the coal conversion, measured in terms of tetrahydrofuran solubles, was not significantly different for the two coals. However, the subbituminous coal gave more asphaltenes than the bituminous coal.The hydrogen-donating capacity of the solvent was varied by the addition of hydrogenated phenanthrene to SRC-I1 recycle solvent. The results indicated that there are two routes for the formation of oils from coal. One is by adduct formation giving asphaltenes and preasphaltenes, which in turn gives oils, and the other is direct oil formation from coal. The preferred route depends on the hydrogendonating capacity of the solvent, The kinetic model, proposed in Part I of this paper, is extended to account for the change in the donor capacity of the solvent. SCOPECoal liquefaction can be characterized as occurring in three stages, namely dissolution, hydrogen transfer, and hydrogenation. In each of these stages the nature of the solvent can affect the rate of reaction and the selectivity of the products. Solvent components which affect the behavior of coal liquefaction processes can be classified as hydrogen donors, hydrogen shuttlers, and components that aid in solubilization. Recent studies have shown that poor bydrogendonating solvents form adducts with coal to give insoluble products. This appears to occur to a lesser extent with good donor solvents. It is likely that for the case of good hydrogen donor solvents the formation of soluble products compensate for the adduct formation. Kinetic measurements at short contact times (up to 10 min) with solvents of varying hydrogen donor capacity have been made to provide a better understanding of the processes of liquefaction and adduct formation. CONCLUSIONS AND SIGNIFICANCEIn a stirred tank batch reactor, there appears to be no significant difference in the conversion of Powhatan No. 5 bituminous and Belle Ayr subbituminous coal to pentane and tetrahydrofuran (THF) solubles for contact times up to 10 min. More asphaltenes are recovered from the liquefaction of Belle Ayr coal than from that of Powhatan coal. Both the coals, when contacted with SRC-I1 recycle solvent, show an initial effective loss of solvent.The initial depletion of oils progressively decreases with an increase in the hydrogen-donating capacity of the solvent, indicating that the initial loss of solvent is independent of the nature of coal, but it is dependent on the hydrogen-donating capacity of the solvent. Oils can be formed either directly from coal or by an indirect route via asphaltenes and preasphaltenes through adduct formation. The latter results in an initial loss of solvent. The former route gains preference over the latter as the hydrogen-donating capacity of the solvent is increased. A single kinetic model entailing both direct and indirect routes is shown to adequately represent the data o...

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“…Weller et al (1950Weller et al ( , 1951 first proposed essentially linear reaction pathways: coal to asphaltene, followed by asphaltene to oil. Thereafter, this simplistic series thermal reaction model was extensively developed to various combinations of series and parallel reaction pathways (Liebenberg and Potgieter, 1973;Cronauer et al, 1978;Shalabi et al, 1979;Mohan and Silla, 1981;Abichandani et al, 1982Abichandani et al, , 1984. Kinetics of catalytic coal liquefaction was further investigated by many researchers (Ruether, 1977;Gollakota et al, 1985;Pradhan et al, 1992;Suzuki, 1994).…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Thermal and Catalytic Coal Liquefaction with Plastic-Derived Liquids as Solvent

Ding¹,

Liang²,

Anderson³

1997

Ind. Eng. Chem. Res.

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Results of a kinetic study of thermal and catalytic (Fe impregnated on coal) liquefaction of DECS-6 coal with plastic-derived liquids (PDL) as solvent have been obtained. The experimental work was conducted in 27-cm 3 horizontally shaken microreactors at temperatures of 360-400 °C with isothermal reaction times ranging from 0 to 180 min. The reaction pressure was about 2000 psig H 2 , and the solvent-to-coal weight ratio was 2:1. Experimental data were correlated by a kinetic model which assumed the reaction pathways: coal to preasphaltenes, coal to asphaltenes, coal to gas + oil, preasphaltenes to asphaltenes, preasphaltenes to gas + oil, and asphaltenes to gas + oil. It was shown that this reaction model fit experimental data reasonably well at the conditions used, and the six rate constants exhibited Arrhenius-type temperature dependence. Some reactions were also carried out at a higher temperature (420 °C) to validate the model at reaction conditions other than conditions used for obtaining the kinetic parameters. Direct coal liquefaction reactions were predominant for both thermal and catalytic DECS-6 coal liquefaction with PDL as solvent, although the catalyst promoted consecutive reactions to a larger extent.

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Kinetics of thermal liquefaction of coal

Cited by 24 publications

References 3 publications

Kinetics of short contact time coal liquefaction. Part I: Effect of operating variables

Kinetics of short contact time coal liquefaction. Part I: Effect of operating variables

Kinetics of short contact time coal liquefaction. Part II: Effect of nature of coal and solvent

Kinetics of Thermal and Catalytic Coal Liquefaction with Plastic-Derived Liquids as Solvent

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