Advances in the study of hydrogen transfer to model compounds for coal liquefaction

Wei, Xian‐Yong; Ogata, Eisuke; Zong, Zhi‐Min; Zhou, Shi-Lu; Qin, Zhihong; Liu, Jianzhou; Shen, Kai; Li, Hongqi

doi:10.1016/s0378-3820(99)00114-9

Cited by 54 publications

(27 citation statements)

References 20 publications

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“…Unlike Neavel [127], McMillen [130] offered that the direct transfer of hydrogen atoms from solvent derived radicals to substituted positions in aromatic rings is substantial as preliminary steps in depolymerization of coal structures. Wei et al [131] believe molecular hydrogen enhances the thermolysis, hydrogenation and hydrocracking of coal model compounds, as oppose to hydrogen donating solvents which inhibit these reactions. Although investigators opinions regarding liquefaction process may vary, there is a consensus that free radicals released during cleavage of the coal molecule needs to be stabilized by some hydrogen donor shuttle to suppress cross-linking reactions.…”

Section: Hydrogen and Free Radicals Interactionmentioning

confidence: 99%

A Review of Thermal Co-Conversion of Coal and Biomass/Waste

2014

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Abstract:Biomass is relatively cleaner than coal and is the only renewable carbon resource that can be directly converted into fuel. Biomass can significantly contribute to the world's energy needs if harnessed sustainably. However, there are also problems associated with the thermal conversion of biomass. This paper investigates and discusses issues associated with the thermal conversion of coal and biomass as a blend. Most notable topics reviewed are slagging and fouling caused by the relatively reactive alkali and alkaline earth compounds (K 2 O, Na 2 O and CaO) found in biomass ash. The alkali and alkaline earth metals (AAEM) present and dispersed in biomass fuels induce catalytic activity during co-conversion with coal. The catalytic activity is most noticeable when blended with high rank coals. The synergy during co-conversion is still controversial although it has been theorized that biomass acts like a hydrogen donor in liquefaction. Published literature also shows that coal and biomass exhibit different mechanisms, depending on the operating conditions, for the formation of nitrogen (N) and sulfur species. Utilization aspects of fly ash from blending coal and biomass are discussed. Recommendations are made on pretreatment options to increase the energy density of biomass fuels through pelletization, torrefaction and flash pyrolysis to reduce transportation costs.

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Section: Hydrogen and Free Radicals Interactionmentioning

confidence: 99%

A Review of Thermal Co-Conversion of Coal and Biomass/Waste

2014

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“…As a viable option of production of transportation fuels, direct liquefaction of coal is a promising approach for clean and effective utilization of coal in China (Wang et al, 2009;Wei et al, 2000). Moreover, it will play an important role in maintaining the worldwide energy safety (Ren et al, 2009b).…”

Section: Introductionmentioning

confidence: 99%

Modeling transport phenomena and reactions in a pilot slurry airlift loop reactor for direct coal liquefaction

Huang

Zhang

Yang

2015

Chemical Engineering Science

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“…That is why investigations into the kinetics and mechanism governing the catalytic hydrogenation of benzene insolubles and asphaltenes, and specifically studies on the role of the catalyst in the process [2][3][4][5][6][7], greatly facilitate the optimization of the parameters for the conversion of coal extracts into syncrude oils.…”

Section: Introductionmentioning

confidence: 99%

“…To carry out the task of nonlinear programming defined in this way, use was made of the optimizing procedures implemented in Mathematica (Minimize), Global Optimalization 7.0 (GlobalSearch) and Matlab (ktrlink). In order to achieve the best solution of the problem for the systems chosen, optimization was performed using the relations between theoretical and effective values of the rate constants of conversion (conditional optimization):The k ef values were calculated from an additionally performed numerical estimation of these parameters via fitting of the kinetic equations represented by Scheme 1 to the experimental results; Matlab -ktrlink, tab(2 ).…”

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confidence: 99%