Behaviors of tetralin and 9,10-dihydroanthracene as hydrogen donor solvents in the hydrogenolysis of coal-related model compounds

Li, Li; Hou, Yucui; Wu, Weize; Liang, Shisheng; Ren, Shuhang

doi:10.1016/j.fuproc.2019.04.005

Cited by 14 publications

(3 citation statements)

References 42 publications

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“…In this regard, a transfer of four atoms of hydrogen may be achieved by complete dehydrogenation of a tetralin molecule (Figure a), while the complete dehydrogenation of the saturated form of the monomer in SHTA renders 26 atoms of hydrogen (Figure b). In line with the function of hydrogen donor disclosed in the present study, various authors have consistently observed lowering of the amount of coke in thermal cracking of hydrocarbons when using hydrogen donors, − which is a consequence of the decrease of free-radical concentration yielding a slowdown of polymerization reactions that produce coke.…”

Section: Resultssupporting

confidence: 88%

Batch Reactor Study for Partial Upgrading of a Heavy Oil with a Novel Solid Hydrogen Transfer Agent

et al. 2020

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A novel solid hydrogen transfer agent (SHTA) based on an organic polymer containing fused-aromatic-ring units, supported in an inorganic matrix, was prepared and tested as a hydrogen donor in the upgrading of a heavy crude oil and its 274 and 343 °C+ residua. The SHTA performance is compared with that obtained using a conventional liquid hydrogen donor (tetralin). Three sets of experiments were carried out in a batch reactor: (1) hydrovisbreaking (HVB), (2) HVB with added tetralin, and (3) HVB with added SHTA. The results showed that the use of tetralin or SHTA in the HVB reaction enhances upgrading of heavy oils compared with the experiments without a hydrogen donor (HVB alone). Moreover, lower coke formation and a higher yield of liquid products were observed. The results obtained when using the novel SHTA are equivalent to those obtained when using tetralin as a hydrogen donor in the upgrading of a heavy crude oil and its 274 and 343 °C+ residua.

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Section: Resultssupporting

confidence: 88%

Batch Reactor Study for Partial Upgrading of a Heavy Oil with a Novel Solid Hydrogen Transfer Agent

et al. 2020

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“…The saturation of the aromatic rings enhances ring opening and hydrocracking in which the C-C bond cleavage is promoted by the catalyst support [25,29]. Table 2 shows the composition of the gas stream for the hydrogenation of naphthalene and the dehydrogenation of tetralin at 300 • C using the NiMo/Al 2 O 3 catalyst.…”

Section: Gaseous Productsmentioning

confidence: 99%

Hydrogenation and Dehydrogenation of Tetralin and Naphthalene to Explore Heavy Oil Upgrading Using NiMo/Al2O3 and CoMo/Al2O3 Catalysts Heated with Steel Balls via Induction

et al. 2020

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This paper reports the hydrogenation and dehydrogenation of tetralin and naphthalene as model reactions that mimic polyaromatic compounds found in heavy oil. The focus is to explore complex heavy oil upgrading using NiMo/Al2O3 and CoMo/Al2O3 catalysts heated inductively with 3 mm steel balls. The application is to augment and create uniform temperature in the vicinity of the CAtalytic upgrading PRocess In-situ (CAPRI) combined with the Toe-to-Heel Air Injection (THAI) process. The effect of temperature in the range of 210–380 °C and flowrate of 1–3 mL/min were studied at catalyst/steel balls 70% (v/v), pressure 18 bar, and gas flowrate 200 mL/min (H2 or N2). The fixed bed kinetics data were described with a first-order rate equation and an assumed plug flow model. It was found that Ni metal showed higher hydrogenation/dehydrogenation functionality than Co. As the reaction temperature increased from 210 to 300 °C, naphthalene hydrogenation increased, while further temperature increases to 380 °C caused a decrease. The apparent activation energy achieved for naphthalene hydrogenation was 16.3 kJ/mol. The rate of naphthalene hydrogenation was faster than tetralin with the rate constant in the ratio of 1:2.5 (tetralin/naphthalene). It was demonstrated that an inductively heated mixed catalytic bed had a smaller temperature gradient between the catalyst and the surrounding fluid than the conventional heated one. This favored endothermic tetralin dehydrogenation rather than exothermic naphthalene hydrogenation. It was also found that tetralin dehydrogenation produced six times more coke and caused more catalyst pore plugging than naphthalene hydrogenation. Hence, hydrogen addition enhanced the desorption of products from the catalyst surface and reduced coke formation.

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“…Utilization of many different types of additives in coke making and their influence on the modification of thermoplastic properties of coal have been subject to a wide array of experimental investigations. − ,− However, there is a noticeable scarcity of novel theoretical investigations which aim to provide a molecular-level understanding of the influence of organic additives on the development of coal fluidity. To the best of our knowledge, only recently, Hou et al have tried to shed light on the molecular mechanism of coal liquefaction employing density functional theory (DFT) calculations.…”

Section: Introductionmentioning

confidence: 99%

Deciphering the Differential Influence of Organic Additives on Coal Fluidity Development: A First-Principles Investigation

et al. 2021

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Formation of high-quality coke is essentially controlled by the development of the extended stability of the coal fluid phase during industrial carbonization processes. Stabilization of coal free radicals through hydrogenation leads to this development of coal fluidity. The donatable hydrogens are usually supplied by the donor hydrogen species formed through the thermal decomposition of a coal macromolecular network. In view of the limited reserve of the donor hydrogen species within a coal system, organic additives with characteristic hydrogen-donating ability are conventionally added to the system to maintain the desirable coal fluidity. However, the choice of compounds requires a clear understanding of their chemistry and associated reaction features. In this context, factors controlling hydrogen-donating properties of some organic donor hydrogen compounds are investigated herein within the framework of density functional theory. A mechanistic interpretation of the reaction of the compounds with the coal radical is offered. In addition to structural modification, the influence of the functional group, namely, the phenolic hydroxyl group, on the hydrogen-donating efficiency of the systems is validated through our calculations. The key role of molecular orbitals in facilitating the release of hydrogens from them is also elucidated. Thus, the work features an advanced understanding of a fundamental industrial process combining a detailed electronic description of the systems. The efficiency of a new compound to act as a superior hydrogen donor candidate is identified. The insights obtained are believed to help derive a rational understanding of the systems and structure−property relationships, which, in turn, can inspire future studies to engineer desired compounds with improved properties. The relevance of our findings to practical carbonization processes is also illustrated in the present work.

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Behaviors of tetralin and 9,10-dihydroanthracene as hydrogen donor solvents in the hydrogenolysis of coal-related model compounds

Cited by 14 publications

References 42 publications

Batch Reactor Study for Partial Upgrading of a Heavy Oil with a Novel Solid Hydrogen Transfer Agent

Batch Reactor Study for Partial Upgrading of a Heavy Oil with a Novel Solid Hydrogen Transfer Agent

Hydrogenation and Dehydrogenation of Tetralin and Naphthalene to Explore Heavy Oil Upgrading Using NiMo/Al2O3 and CoMo/Al2O3 Catalysts Heated with Steel Balls via Induction

Deciphering the Differential Influence of Organic Additives on Coal Fluidity Development: A First-Principles Investigation

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