Coal hydroliquefaction using highly dispersed catalyst precursors

Recent Advances in Direct Coal Liquefaction

“…It was widely recognized that a highly dispersed catalyst can be superior to a supported catalyst, because the dispersed catalyst has an intimate contact with the surface of coal particles, which facilitates the activation and transfer of hydrogen to the coal-derived fragments and reactive sites. Accordingly, finer particles and a higher dispersion of the catalyst species would lead to a higher catalytic activity [57][58][59][60]. Liu et al [58] tested DCL with an in situ impregnated iron-sulfide catalyst, where the coal was mixed with Na 2 S solution, followed by the addition of FeCl 3 solution, washing, filtration and drying.…”

“…Ikenaga et al [57] reported that highly dispersed catalysts such as Mo(CO) 6 -S and Ru 3 (CO) 12 remarkably increased the oil yields. Song et al [62] found that a bimetallic catalyst generated from Mo 2 Co 2 S 4 (Cp) 2 (CO) 2 [Cp = cyclopentadiene] was substantially more active than the physical mixture of the two metal carbonyls, Mo(CO) 6 + Co 2 (CO) 8 , or the mixture plus sulfur.…”

Comparison of catalytic hydroliquefaction of Xiaolongtan lignite over FeS, FeS+S and SO42-/ZrO2

“…The THF-extractable portion was sequentially extracted with n-hexane and toluene to afford oil (n-hexane-extractable portion), asphaltene (n-hexane-inextractable but toluene-extractable portion) and preasphaltene (toluene-inextractable but THF-extractable portion) [24]. The above residue was extracted with acetone to remove THF adsorbed in the residue and dried in vacuum at 80 C for 24 h. The resulting asphaltene and preasphaltene were also dried under the same conditions.…”

Effects of Sodium Carbonate Additive on the Hydroliquefaction of a Sub-bituminous Coal with Fe-Based Catalyst under Mild Conditions

“…Except for reducing the severity of liquefaction conditions, the addition of active catalyst can enhance the oil yield and the economy of DCL technologies, especially the mild DCL technologies. ,− ,− Catalysts play an important role in accelerating the rates of the desirable reactions such as hydrogenation, hydrocracking, and heteroatom removal in coal liquefaction. To date, an Fe-based catalyst is regarded as the most practical for coal hydroliquefaction due to its relatively high activity, low cost, and environmentally benign property for disposal. ,− However, it is widely accepted that the catalytic activity is not high enough is the major problem of an Fe-based catalyst, especially under mild conditions . In the past few decades, a large number of investigations are focused on how to enhance the activity of an Fe-based catalyst in coal hydroliquefaction, and many methods are adopted to achieve this goal, such as reduce the particle size to nanometer scale and improve the dispersion of the Fe-based catalyst. ,,, …”

“…To date, an Fe-based catalyst is regarded as the most practical for coal hydroliquefaction due to its relatively high activity, low cost, and environmentally benign property for disposal. ,− However, it is widely accepted that the catalytic activity is not high enough is the major problem of an Fe-based catalyst, especially under mild conditions . In the past few decades, a large number of investigations are focused on how to enhance the activity of an Fe-based catalyst in coal hydroliquefaction, and many methods are adopted to achieve this goal, such as reduce the particle size to nanometer scale and improve the dispersion of the Fe-based catalyst. ,,, …”