Coal Hydroliquefaction Research Articles

Kinetic studies on the hydroliquefaction of coals using organometallic complexes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetic studies on the hydroliquefaction of coals using organometallic complexesToshimitsu Suzuki, Toshihiro Ando, and Yoshihisa WatanabeCite this: Energy Fuels 1987, 1, 3, 294–300Publication Date (Print):May 1, 1987Publication History Published online1 May 2002Published inissue 1 May 1987https://doi.org/10.1021/ef00003a013RIGHTS & PERMISSIONSArticle Views39Altmetric-Citations17LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (786 KB) Get e-Alerts Get e-Alerts

Mössbauer study of iron catalysis in Victorian brown coal liquefaction

Mössbauer spectroscopy was used to investigate the means by which iron promotes the hydroliquefaction of Victorian brown coal. Microparticulate ferric oxyhydroxide incorporated in the initial coal is reduced during hydrogenation through magnetite and troilite to α-iron, which transforms to cementite at 380 °C. It is proposed that a transient divalent iron species slows the initial thermal degradation of coal and that α-Fe is responsible for enhancing the ultimate liquefaction yield.

ＩＶｂ族有機金属化合物を触媒前駆体として用いる石炭の液化反応

The catalytic activities of group IVb organometallic compounds for the hydroliquefaction of Wandoan coal were compared.Among the group IVb organometallic compounds tetrabutyl-stannane exhibited the highest catalytic activity followed by tetrabutylgermane and tetraphenyllead. Organosilcon compounds, however, did not show any catalytic activity.Effect of hydrogen partial pressure and the amount of catalyst on the liquefaction yield were more pronouncedly observed for less active Ge and Pb based catalyst.From the change in the product distribution against reaction time, n-Bu 4 Ge based catalyst seems to promote direct paths from coal to preasphaltene, asphaltene, and oil fractions, rather than step wise process such as;Coal→Preasphaltene→AsphalteneGermanium oxide exhibited poor catalytic activity on the hydroliquefaction of the coal.Well dispersed state of metallic Ge or Pb derived from organometallic compounds could be responsible for the higher catalytic activities of organometallic based catalyst.

Catalytic Effects of MoCl3- and NiCl2-Containing Molten Salts for Hydroliquefaction of Morwell Brown and Taiheiyo Subbituminous Coals

Abstract The catalytic effects of MoCl3–LiCl–KCl and NiCl2–LiCl–KCl molten salts were studied for the hydroliquefaction of Morwell brown and Taiheiyo subbituminous coals at 400 °C for 1 h in a batch reactor with an initial hydrogen pressure of 9.8 MPa. The conversion to pyridine-soluble materials and the yield of hexane-soluble materials (HS) with the MoCl3 catalyst were 82 and 42% for Morwell coal, and 84 and 61% for Taiheiyo coal, respectively. The conversion and HS yield with the NiCl2 catalyst were 87 and 43% for Morwell coal, and 82 and 56% for Taiheiyo coal, respectively. The HS yield of the catalytic runs was about 2.6–3.2 times higher than that of noncatalytic runs. This finding established the effectiveness of the two new catalysts for the hydroliquefaction of brown and subbituminous coals. Detailed analyses of the reaction products have revealed that these catalysts promoted a depolymerization of the coals and strongly catalyzed the hydrocracking of polynuclear aromatic structures of heavy products into hydroaromatic and aromatic structures with smaller ring sizes. Most of these smaller hydroaromatic and aromatic structures did not undergo much further ring-opening reactions. This accounts for the high HS selectivity of the catalysts.

Specific catalysis of SnCl 2 melt for hydroliquefaction of subbituminous coal

Hydroliquefaction of two subbituminous coals (Taiheiyo and Wandoan) was studied in a batch autoclave system at 400°C for 3 h in the presence of KCl-containing melts, such as ZuCl 2KCl (3:2 mole ratio), SnCl 2KCl (3:2), ZnCl 2SnCl 2KCl (3:3:4), and corresponding KCl-free melts. Three KCl-containing melts showed a catalytic superiority to the corresponding KCl-free melts (this being in line with previous results of bituminous coal), except for the fact that SnCl 2 afforded higher hexane solubles (HS) yield and higher conversion with consumption of a lesser amount of H 2 compared with SnCl 2 KCl melt. Solubility tests of two benzene insolubles obtained from short-reaction-time liquefaction of Taiheiyo coal indicated that benzene insolubles (BI) with SnCl 2KCl melt are more intractable than those with SnCl 2: the former BI were difficult to convert to lighter fraction as reaction time was prolonged. ESCA spectra and X-ray diffraction measurements of the spent melt catalyst on BI showed the formation of substantial amounts of Sn powder with pure SnCl 2 melt, which could assist in the effective distribution of hydrogen to intermediates from coal organic materials in the early stages of coal liquefaction, this being a rationale for the enhanced reactivity of subbituminous coal with pure SnCl 2.

Effect of Pore-Size Distribution on the Catalytic Performance for Coal Liquefaction. II. Carbonaceous and Metallic Deposition on the Catalyst

Abstract The behavior of carbonaceous and metallic depositions on catalysts during hydroliquefaction of coal was investigated by using several kinds of catalyst supports with different pore-size distribution values in order to obtain the fundamental data for designing long-life catalysts. Higher concentration of carbonaceous deposition was observed on large-pore and bimodal catalysts than was observed on the comparative small pore and unimodal catalysts, respectively. However, the carbonaceous deposit was distributed more evenly inside large pores than it was inside small pores. The micropores of the bimodal catalysts were more effectively used than were those of the unimodal catalysts. Thus, the unimodal catalysts with small pores suffered more severe pore-mouth poisoning than the bimodal or the large-pore catalysts. The penetration behavior of the metallic components was found to be different for each metal. Discrete minerals such as clay could not penetrate into the catalyst pores and were deposited on the external surface of the catalyst particle. While, the metallic components coordinated with organic compounds such as phenolates or chelates deposited inside the macro- and mesopores. Easy access of the large asphaltenic molecules to the active sites resulted in high coal-liquefaction activity for the catalyst. This was accompanied by large amounts of both carbonaceous and metallic depositions. It is concluded that large-pore or bimodal pore structure is required for both high liquefaction activity and suppression of pore-mouth poisoning.

Coal hydroliquefaction using MoCl 3- and NiCl 2-containing salts as catalysts: difference in catalysis between solid and molten catalysts

Both MoCl 3- and NiCl 2-LiCl-NaCl-KCl quaternary solid salts and both MoCl 3- and NiCl 2-LiCl-KCl ternarly molten salts were examined as catalysts for hydroliquefaction of subbituminous Wandoan coal at 400 °C for 1 h in a batch reactor with an initial H 2 pressure of 9.8 M Pa. Conversions (to pyridine solubles) and yields of hexane solubles (HS) ranged from 80 to 92 wt% and from 55 to 65 wt%, respectively. The results suggested that both solid and molten catalysts are highly effective for hydrocracking of coal, with the latter being superior in terms of conversion and HS yield. H 2 consumption of the reaction suggested that the hydrogenating ability of the catalysts decreases in the following order: NiCl 2 (molten) > MoCl 3 (molten) > MoCl 3 (solid) > NiCl 2 (solid). Cracking ability of these catalysts decreases in the order: MoCl 3 (molten) > MoCl 3 (solid) > NiCl 2 (molten) > NiCl 2 (solid). It was tentatively concluded that the molten catalysts have higher hydrogenating and cracking abilities for coal hydroliquefaction than the corresponding solid ones.

Hydroliquefaction of Yallourn coal catalysed by organotin compounds

The hydroliquefaction of Yallourn coal was investigated in a batch micro autoclave, using halogen free organotin compounds as a catalyst precursor. The catalytic activities of tin compounds were compared as a function of reaction time, initial hydrogen pressure and catalyst concentration. All the organotin compounds studied showed moderate to good catalytic activity in the liquefaction of Yallourn coal. In the presence of 1 wt% of tetra- n-butyl tin ( n- Bu 4 Sn) as Sn, at 698 K under an initial hydrogen pressure of 5.0 MPa in a non-hydrogen donating solvent, 1-methyl-naphthalene, coal conversion was increased from 36.7% to 78.6% with catalyst. An amount of hydrogen transferred to coal from the gas phase also increased from 0.8 to 1.6 wt% of d.a.f. coal with the 1 wt% of n- Bu 4 Sn. An increase in the catalyst concentration of more than 2 wt% did not show any remarkable change in coal conversion or the amount of hydrogen absorbed. After the reaction time of 20 min, coal conversion, yield of asphaltene and yield of oil fraction levelled off. An increase in the initial hydrogen pressure substantially affected the catalytic activity of n- Bu 4 Sn. Catalytically active species derived from n- Bu 4 Sn seem to activate molecular hydrogen and may transfer hydrogen directly to coal fragment radicals to stabilize them.

Generalized kinetic model for the uncatalyzed hydroliquefaction of coal

A kinetic model, incorporating dehydrogenation of tetralin, for the liquefaction of coals has been developed and tested with data from a variety of low- and medium-rank coals. The model postulates that coal essentially consists of three lumps. Of these, one dissociates almost instantaneously, the second is characterized by slow internal hydrogen shuttling, and only the third lump requires external hydrogen. The reactivity of each lump does not vary between coals; however, different coals are found to contain different fractions of each lump. The rate of reaction of coal is about 3 orders of magnitude faster than the tetralin dehydrogenation reaction. This study clearly shows that it is not only the solvent's capacity to donate hydrogen but also the rate at which hydrogen is donated that is important in coal liquefaction.

Evolution of highly dispersed catalysts during hydroliquefaction of coal

Two iron oxides aerosols with low particle sizes ( < 80 nm) were used as catalyst precursors in hydroliquefaction of coal (Freyming, France). Their sulfidation was carried out in situ by addition of elemental sulfur. As shown by X-ray diffraction patterns and TEM/STEM-X-ray microanalysis (EDS), the resulting non-stoichiometric pyrrhotites were highly sensitive to sintering in the absence of coal. The phenomenon was strongly inhibited in the presence of coal probably due to textural promotor effects of the heavy organic residues deposited at the surface of the catalyst during the reaction.

Hydroliquefaction of coal in presence of iron catalysts

The catalytic effect of a red mud and of a ferric oxide aerosol were compared using the same high volatile bituminous coal and three different solvents: tetralin and two coal-derived heavy oils. Reactions were carried out in a tubing bomb system with two microreactors of 55 cm 3 ; cyclohexane soluble and insoluble products were separated by centrifugation. The addition of iron catalysts significantly increased the soluble fraction yield when heavy oils were used as solvents. The stronger catalytic effect observed for the ferric oxide aerosol appeared to be related to its particle size and its ability to disperse well in the reaction mixture.

Minerals, sediments and coals

A survey is presented of some of the recent uses of Mossbauer spectroscopy in studying chemical changes in mineral systems. The changes considered include those occurring naturally, such as weathering, leaching, soil formation, lake and river sedimentation and coal oxidation, and some induced by man, such as chemical leaching, precipitate ageing, coal hydroliquefaction and ash resulting from coal combustion.

Modelization of hydrogen transfer in coal hydroliquefaction. III. The reaction of benzylphenylether with 9,10-dihydrophenanthrene at 300°C

The title reaction is made quantitative by using glass tubes in home-made microreactors. Reaction products are analyzed by quantitative 1H NMR at 400 MHz and by qualitative GC/MS. 69 % of 9,10-dihydrophenanthrene are converted to phenanthrene after 90 min. By-products are characterized by four performance indices which are interpreted as an indication of the average predominance of doubly substituted (benzyl or/and phenoxy) phenanthrenic units.

Catalytic hydroliquefaction of coal : about the methodology in batch experiments

The results of catalytic hyroliquefaction under batch conditions depend on a large number of variables. The present results concern a few of these variables, in particular the influence of the catalyst concentration, of the mode of sulfidation or(and) of introduction of the catalyst in the coal/solvent mixture, and of the nature of the model compound solvent. Our results indicate that increasing the concentration of catalyst increases the conversion of coal into toluene soluble products and the hydrogen consumption but has a small effect on oil formation. An inhibition of the first fractions of a NiMo/A1203 catalyst added is shown. Strong effects of the sulfiding mode of an iron oxide catalyst, and of the temperature of introduction of the iron oxide into the autoclave are observed relative to the hydrogenation activity of the iron catalyst, when at the same time there is no influence on coal conversions. The replacement of tetralin by a non-donor solvent, 1-methyl naphthalene, suggests that the direct hydrogen transfer process from molecular hydrogen to coal fragment radicals on the catalyst surface may be important.

Mössbauer study of some aspects of coal hydroliquefaction process

Solid residues of hydroliquefaction of Freyming coal exhibit NGR spectra from which it is mainly stated that in a temperature range around 673 K the efficiency of Fe2O3 catalysts results from their ability to give highly deficient monosulfides of small particle size.

119Sn Mössbauer study of the promotion of Victorian brown coal hydroliquefaction by tin compounds

The chemistry of tin added in various forms as catalyst in the liquefaction of Victorian brown coal was determined by 119Sn Mössbauer analysis. After 60 min hydrogenation at 380 °C and 6 MPa initial hydrogen pressure, tin was principally distributed between β-Sn, SnS and SnO 2. No significant dependence of liquefaction yield on the initial tin compound was apparent. The results extend earlier work and support the previous conclusion that elemental tin is the important species for promoting hydroliquefaction in these systems.

HYDROLIQUEFACTION OF COAL AND HYDROGENATION OF PHENANTHRENE WITH IRON CATALYSTS ACTIVATED BY NEW METHOD

Abstract Iron catalysts obtained by the CO pretreatment of iron oxide and iron ore suspended in hydrocarbon solvents presented high catalytic activities for the hydroliquefaction of coal and hydrogenation of phenanthrene.

The use of various metal carbonyls as catalyst precursors for coal hydroliquefaction

The catalytic activity of metal carbonyl complexes of chromium, molybdenum, tungsten, manganese, iron, cobalt, and nickel in the liquefaction of coal (Illinois No. 6, Wandoan and Mi-ike) was investigated. The carbonyl compounds of molybdenum, tungsten, iron, cobalt, and nickel acted as highly active catalysts for the liquefaction of Illinois No. 6 coal, resulting in high coal conversion (>90%) and high oil yield (>32%), under hydrogen pressure of 50 kg cm −1 in a nonhydrogen-donating solvent at 425°C for 60 min. Among the catalysts surveyed, Mo(CO) 6 gave the highest oil yield (57.7%) and the largest amount of hydrogen transferred to coal (3.1 wt.% of d.a.f. coal). However, the molybdenum and tungsten carbonyls did not exhibit high catalytic activity for low sulfur Wandoan coal in the absence of added sulfur. On the other hand, cobalt and nickel carbonyls showed high catalytic activity irrespective of the amount of sulfur in the reaction system. Fe(CO) 5Mo(CO) 6 binary catalyst promoted hydroliquefaction of Wandoan coal, resulting in increases in oil yield and transfer of hydrogen to coal in the presence of sulfur.

Hydroliquefaction of subbituminous coal Effectiveness of pretreatment by organic reduction with Na or k

Hydroliquefaction of subbituminous Taiheiyo coal, without any pretreatment and after organic reduction, was carried out in the presence of tetralin using fine iron powder as catalyst. Two pretreatment procedures were used (A) reduction of coal with Na in liquid ammonia solution and (B) treatment with K in refluxing THF. Samples of treated coal with well-dispersed iron powder were prepared by co-reduction of coal coated with FeBr 2 using both procedures. Non-catalytic liquefaction of coal treated by A showed double the yield of hexane-solubles compared with that from liquefaction of the original coal while non-catalytic liquefaction of the coal treated by B roughly tripled the hexane-solubles yield and consumed the same amount of hydrogen. The presence of iron powder increased hexane-solubles by 5 wt% while increasing benzene-solubles by 13 wt% compared with non-catalytic liquefaction of treated coal by procedure B. The coals prepared by co-reduction (A and B) showed highest conversion (73 and 77%) along with highest yield of HS (38 and 43%). This significant effect on hydroliquefaction could be correlated with a slight increase of hydrogen atoms added to coal organic materials and the loosening of clusters of aromatic sheets.

Hydroliquefaction of coal with tin oxide catalyst

Liquefaction of coal was studied using 3 coals (2 Japanese, 1 Chinese) in the presence of various metal oxide catalysts under conditions of 7-15 MPa of hydrogen and 380-450 C. Tin oxide showed the highest activity on the hydroliquefaction of a Japanese bituminous coal. The conversion of coal reached 100%, and the yield of n-hexane-soluble oil fraction was about 80%. With the 3 coals, it was found that the conversion decreased as the amount of fixed carbon increased. The tin oxide catalyst was reduced to metallic tin, the particles of which were molten and mixed with coal ash. The recovered ash containing tin particles showed almost the same activity as fresh tin oxide catalyst.