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

Abstract

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.

Ultra-large-scale Synthesis of Fe3O4 Nanoparticles and Their Application for Direct Coal Liquefaction

“…Catalytic cracking of coal to obtain clean liquid fuels by using a catalyst has been the subject of research recently in order to solve the problem of petroleum shortage. − Various catalysts have been used for the direct coal liquefaction (DCL) process, such as Fe, Mo, Co, and Ni. − Among them, despite relatively low activity, iron-based catalysts have received extensive research interest because of their low cost and environmentally friendly behaviors. − An ideal small-sized iron-based catalyst is highly desirable for its high catalytic activity associated with a large surface area . Sharma et al , have reported that the 3–20 nm sized ferric sulfide showed a high selectivity to oil formation.…”

Interaction between Hydrogen-Donor and Nondonor Solvents in Direct Liquefaction of Bulianta Coal

“…Studies on model coal structures have provided evidence that H 2 can directly participate in free-radical reactions under liquefaction conditions and promote some hydrocracking reactions during DCL . Meanwhile, the beneficial effects of H 2 on DCL have also been verified by experimental results for coal. − When 1-methylnaphthalene was added to tetralin as the solvent, the gas yield was higher than that in pure tetralin, and the content of CH 4 in the gaseous product was higher than for the other non-hydrogen-donor/tetralin mixtures as the solvent. This indicates that the hydrogenolysis of 1-methylnaphthalene into CH 4 and naphthalene occurs during DCL.…”

Role of Iron-Based Catalyst and Hydrogen Transfer in Direct Coal Liquefaction

“…Compared with that in a N 2 atmosphere, the oil yield increases from 6.2% to 25.1%, and the gas yield reduces from 13.1% to 4.8% for the runs in a H 2 atmosphere without catalysts. From these results, it can be deduced that part of the H 2 joining in the liquefaction reaction is not affected by the catalyst, which is the so-called thermal liquefaction. , Thermal liquefaction is not the major reaction approach in DCL but cannot be ignored. The experimental results also show that the effects of the catalyst and H 2 are most obvious in the runs with the strongest hydrogen donation solvent, tetralin.…”