Liquefaction Of Subbituminous Coal Research Articles

Radical Reactions and Two-Step Kinetics of Sub-Bituminous Coal Liquefaction in Various Solvents

To understand the role of hydrogen donation from solvents to the coal-generated free-radical fragments (coal radicals) in direct coal liquefaction (DCL), a coal with 72.4 wt % carbon was reacted at...

The Isolation of Condensed Arenes from Shenmu-Fugu Coal Liquefaction Residue

Shenmu-Fugu subbituminous coal liquefaction residue was exhaustively extracted with petroleum ether (PE) to afford PE-extractable fraction (PEEF), which was then eluted with petroleum ether through a silica gel-filled column. The PEEF and eluates were analyzed with a gas chromatographer/mass spectrometer and a Fourier transform infrared spectrometer. As a result, a number of 4- to 7-ring condensed arenes (CAS) were detected in the PEEF series of 4- to 6-ring CAs along with long-chain alkanes were isolated from the PEEF by column chromatography.

Additive effect of cobalt-exchanged coal on the liquefaction of subbituminous coal

In comparison with the liquefaction (420 °C, with tetralin and elemental sulfur) of the proton-exchanged Adaro subbituminous coal with complex (metallocene or metal carbonyl) of cobalt, nickel or iron, the coal liquefaction was enhanced significantly on the liquefaction of cation (Co2+, Ni2+ or Fe2+) exchanged Adaro coal. However, for several kinds of subbituminous coal, metal cations hardly exchange due to the small content of carboxyl group in coal. Therefore, the simultaneous liquefaction of subbituminous coal and cobalt-exchanged coal were carried out in this study. Further, the simultaneous liquefaction of lower rank and subbituminous coals with Co2(CO)8 was carried out to compare the catalytic effect of cobalt derived from either the exchanged coal or Co2(CO)8. The catalytic effect of cobalt in the exchanged Morwell brown coal was appeared as the decrease of residue yield on the liquefaction with Yilan subbituminous coal. On the other hand, there was little enhancement on the simultaneous liquefaction of cobalt-exchanged Adaro and Yilan subbituminous coals. Accordingly, it is clarified that the hydroliquefaction of subbituminous coal, which was exchanged cation hardly, was enhanced by the addition of cobalt-exchanged brown coal.

Simulation of initial stage reactions in the direct coal liquefaction of sub-bituminous coals

Simulation of initial stage reactions in the direct coal liquefaction of sub-bituminous coals

Simulation of initial stage reactions in the direct coal liquefaction of sub-bituminous coals

In order to develop a reaction simulator for purposes of direct coal liquefaction, a kinetic model for the initial stage of the reaction was developed for sub-bituminous Wandoan and Tanitoharum coals. The kinetic parameters in the model were determined by fitting the model to experimental data obtained by autoclave tests. Based on the model, a simulator for a preheater was proposed. The yields of liquefaction products predicted by the simulator were verified from data obtained at the outlet of the preheater in a process support unit with a capacity of 1 t of coal per day.

97/01508 Development of an all-slurry liquefaction test for screening dispersed catalysts

Exceptionally high distillate yields have previously been achieved in the direct liquefaction of subbituminous coal using dispersed catalysts. As part of a program sponsored by the U.S. Department of Energy, selected dispersed catalysts are being evaluated in continuous bench-scale runs. In consequence, a laboratory test has been developed to screen candidate dispersed catalysts and determine the optimum range of operating conditions to maximize coal conversion and distillate yield. The objectives of the test are to simulate operation in an all-slurry mode with coal conversion and product selectivity at least as good as that achieved in 2-stage operation at the Wilsonville Advanced Coal Liquefaction Facility. Tests are conducted in microautoclaves using pilot plant derived solvents and a Wyodak coal in the ratio of 1.85/1. An Fe-Mo catalyst contained in a Wilsonville process solvent has been used as a reference. The influence of residence time at 440{degrees}C on 524{degrees}C+ resid conversion has been determined and evaluations of various Mo formulations will be discussed.

Technoeconomic assessment of advanced concepts for direct liquefaction of subbituminous coals

Technoeconomic assessment of advanced concepts for direct liquefaction of subbituminous coals

Technoeconomic assessment of dewaxing and hydrotreating recycle distillate solvent in subbituminous coal liquefaction

Technoeconomic assessment of dewaxing and hydrotreating recycle distillate solvent in subbituminous coal liquefaction

Application of petroleum processing technology to the upgrading of coal syncrude

The feasibility of producing distillate fuels (gasoline, diesel and aviation fuels) from coal syncrude was determined. A syncrude from direct liquefaction of subbituminous coal was first deasphalted by ultrasonic disaggregation in n-hexane, to reduce the heteroatom content. The oil was then catalytically hydrogenated in a continuous hydroprocessing unit at 450°C and 10 MPa hydrogen pressure. The hydroprocessed oil was fractionated by vacuum distillation and the cuts obtained were characterized. The high aromaticity of the hydroprocessed oil necessitated a second hydrotreatment under conditions suitable for hydrogenation of aromatic structures. Deasphalting removed 39% of the N, 43% of the S and 47% of the O. The first hydrotreatment removed 99% of the S, 87% of the N and 37% of the O, and increased the H C ratio. The second hydrotreatment provided an important reduction in aromaticity, necessary to achieve certain fuel quality specifications.

The effects of solvent quality on the liquefaction of two different types of coal

Thermal and catalytic liquefaction runs were performed at 400 and 430 °C for 30 min in hydrogen with different hydroaromatic:aromatic, hydroaromatic:naphthenic or naphthenic:aromatic solvent blend ratios for Australian bituminous and Indonesian subbituminous coals. The results indicate that the subbituminous coal needs more efficient external hydrogen transfer to maintain high conversion than does the bituminous coal, implying that both hydrogen transfer from donor solvent and catalytic transfer from molecular hydrogen are important in improving subbituminous coal liquefaction yields. In bituminous coal liquefaction, it appears that the form of hydrogen, whether molecular or donatable from hydroaromatic solvent, is not critical as long as the internal hydrogen is present in sufficient amount and in a form usable by the coal and a minimum hydroaromaticity of the solvent system (tetralin:naphthalene ratio 1:3) is maintained. A temperature increase from 400 to 430 °C significantly affects the bituminous coal liquefaction yield, but little improvement is observed for the subbituminous coal. To optimize liquefaction, the solvent quality, temperature and catalyst must be properly chosen, depending on coal rank.

Liquefaction of iron-loaded subbituminous coal in the presence of a sulphur source

Dispersion of disposable iron as a catalyst precursor was investigated to improve the catalytic activity in the liquefaction of a subbituminous coal. Treatment in FeSO 4 solution under vacuum conditions resulted in the incorporation of 0.25 and 0.33 wt% iron into the coal samples. Despite the low level of loading, the liquefaction of iron-loaded coal showed a significant increase in total conversion and oil yield in the presence of a sulphur source. Also the hydrogen consumption decreased with use of an iron-loaded catalyst. These facts suggest that the impregnation of iron is a beneficial method of enhancing the catalytic activity and reducing the amount required for the liquefaction process.

Behaviour of tetrahydroquinoline in temperature-staged liquefaction of subbituminous coal

Tetrahydroquinoline (THQ) is well known as a solvent and hydrogen donor in coal liquefaction. The separate roles of dissolution and hydrogen donation have been demonstrated by comparing the liquefaction behaviour of Deitz (Montana, USA) subbituminous coal in naphthalene — THQ mixtures as the solvent with two impregnated hydrogenation catalysts, sulphided ammonium molybdate and a novel catalyst in which THQ is incorporated. The addition of THQ to the solvent results in increased conversion and increased oil to asphaltene (O:A) ratios relative to otherwise similar experiments without THQ. The addition of THQ which is ‘locked’ into the catalyst provides no increase in total conversion, but gives a significant improvement in the O:A ratio. The increased conversion and O:A ratio with free THQ in the solvent is a result of the THQ attacking the macromolecular structure of the coal and solvating small fragments. THQ locked in the catalyst cannot participate in the attack and dissolution of the coal structure and thus provides no increase in conversion, but functions very effectively as a hydrogen donor on the catalyst surface, resulting in an improved O:A ratio. This work suggests that in liquefaction using impregnated catalysts, but in the absence of good hydrogen donor solvents (as, for example, in dry liquefaction), liquids formed by the breakdown of the coal structure must migrate to the catalyst particles, where they are then hydrogenated, effecting the conversion of asphaltenes to oils.

Investigation of effect of solvent quality on Indonesian subbituminous coal liquefaction under short contact time conditions

The role of the solvent upon Indonesian subbituminous coal during short contact time liquefaction in microreactors is examined by using various solvents such as non-polar hydroaromatics, non-polar aromatics, polar hydroaromatics and polar aromatics. The importance of solvents on the ability to convert coal to pyridine soluble (coal conversion) and pentane soluble (oil yield) products is evaluated. The hydrogen donor capability of the solvent is found to be the most important controlling factor. In the absence of hydroaromatics, such phenolic compounds as 1-naphthol can improve coal conversion, but a highly negative yield of oil is observed.

57Fe NGR studies on three-stage hydroliquefaction of coals

Iron Mossbauer spectroscopy has been performed on liquefaction residues of two different French coals. In a three-stage liquefaction of high volatile bituminous coal (Freyming), without an added catalyst, the coal pyrite is not entirely converted into pyrrhotites, whereas in the presence of an added catalyst, coal pyrite is totally transformed into more dispersed pyrrhotites than those from the sample without an added catalyst; furthermore, the whole added catalyst precursor is reduced into pyrrhotites. In the case of liquefaction of subbituminous coal (Gardanne), full conversion of coal pyrite into pyrrhotites (even without an added catalyst) occurs. In addition, in the presence of the added catalyst, besides pyrrhotites, FeS is evidenced. When molybdenum-iron oxide is added as a catalyst precursor, no mixed Fe−Mo phase is detected.

水素化溶媒を用いる石炭のソリボルシス ＩＩ 水素化アントラセン油溶媒

Solvolysis liquefaction of subbituminous coal by short contact time at high temperature has been carried out using hydrogenated anthracene oil (H-A0) as a model solvent concerning the property and liquefaction ability of the solvent in the development of the solvolysis liquefaction phase II process.The anthracene oil (AO) hydrogenated by sulfided Ni-Mo/Al2O3 catalyst was an excellent solvent for coal liquefaction in comparison with AO done by non-sulfided catalyst and original AO, and yielded the benzene- and quinoline-soluble fractions of coal in about 70% and 90%, respectively, by solvolysis liquefaction at 450°C for 10 min. Strongly hydrogenated AO was superior to weakly hydrogenated AO for the benzene-solublization of coal, but the quinoline-solublization of coal did not depend upon the degree of hydrogenation of AO. The hydroaromatics contained in H-AO were presumed to be hydrogen-donor species to coal; for they were converted to the corresponding aromatics in the analyses of the solvolysis liquefaction products.The solvolysis liquefaction with various distillate fractions of H-AO suggested that the liquefaction abilities of hydroaromatics increased in the order of di-, tri-, and tetracyclic hydroaromatics; it showed that the higher-boiling fraction of H-AO with higher aromaticity was effective for the quinoline-solublization of coal.

水素化溶媒を用いる石炭のソルボリシス ＩＩＩ 水素化多環芳香族炭化水素溶媒

Solvolysis liquefaction of subbituminous coal by short contact time at high temperature has been investigated using polycyclic hydroaromatic hydrocarbons, the main components of hydrogenated anthracene oil (H-AO), as solvents to determine the effective components of H-AU for liquefaction.Hydroaromatics were better solvents for liquefaction than the corresponding aromatics and yielded benzene-and quinoline-soluble fractions of coal in up to about 80% and 95%, respectively by solvolysis at 450°C for 10 min. Liquefaction reached sufficient levels with di- or tetrahydroaromatics. Overhydrogenation of solvent was not effective for liquefaction and is believed to be a waste of hydrogen.The hydroaromatics with naphthenic ring structure were hydrogen-donor species to coal; they were converted to the corresponding aromatics in the analyses of the solvolysis products. The liquefaction abilities of hydroaromatics increased in theorder of di-, tri-, and tetracyclic hydroaromatics. Tetrahydrofluoranthene and hydropyrenes were better solvents for liquefaction than any other hydroaromatics examined.

Short contact-time liquefaction of subbituminous coal: Directions for improving coal conversion

This study was undertaken to find ways to solubilize subbituminous coal in high yield at short contact times. Short contact-time hydroliquefaction runs were carried out in a continuous unit using Belle Ayr subbituminous coal with a solvent rich in hydrogen-donor molecules derived from the Lummus ITSL process, and also with solvents lower in donor concentration derived from the SRC processes. Catalysis by pyrite, molybdenum and supported cobalt-molybdenum was also studied. It was found that pyrite and other hydrogenation catalysts enhanced solubilization and also increased production of distillate oil. Solvent quality seemed to have no effect on the solubilization of Belle Ayr coal. The availability of H 2S also appeared to have no effect. Provided that pyrite was present, reaction could be carried out at severities high enough to give insoluble organic matter yields equivalent to those obtained with bituminous coals (5–10 wt% daf coal). At equivalent levels of solubilization, however, hydrocarbon gas and distillate yields were invariably higher for the subbituminous coal. Implications for two-stage processing of Belle Ayr coal are discussed.

Contribution of vitrinite macerals to the liquefaction of subbituminous coals

Four Alberta subbituminous coals were selected to investigate the contribution of vitrinite macerals to liquefaction. There are indications of a rectilinear correlation between conversion yields of different density fractions of coal and their vitrinite content, but it is too early to discern any conversion factor by which any maceral group may be used to predict the liquefaction behaviour of a subbituminous coal. Contrary to common belief, not all the vitrinite fraction of the feed coal is reactive. There seems to be a definite positive correlation between the percent vitrinite reacted and the liquefaction conversion yield. Much more research work is needed to further understand the contribution of vitrinite macerals to liquefaction of a subbituminous coal.

Liquefaction of subbituminous coals with a basic nitrogenous model process solvent

Liquefaction reactions in a tubing-bomb reactor have been carried out as a function of coal, coal sampling source, reaction time, atmosphere, temperature, coal pre-treatment, SRC post-treatment and process solvent. Pyridine as well as toluene conversions ranging from 70 to > 90 wt% involving both eastern bituminous and western subbituminous coals are obtained. 1,2,3,4-Tetrahydroquinoline (THQ) has been extensively used as a process solvent under optimized liquefaction conditions of 2:1 solvent: coal, 7.5 MPa H 2, 691 K and 30 min reaction time. Comparisons of THQ with other model process solvents such as methylnaphthalene and tetralin are described. Liquefaction product yield for conversion of subbituminous coal is markedly decreased when surface water is removed from the coal by drying in vacuo at room temperature prior to liquefaction. The effect of mixing THQ with Wilsonville hydrogenated process solvent in the liquefaction of Wyodak and Indiana V coals is described.

Liquefaction of subbituminous coals under apparently non-hydrogenative conditions

Reactivities of several coals of different ranks have been examined in degrading extractions with aromatic solvents under apparently non-hydrogenative reaction conditions. Pyrene and A240 pitch liquefied the fusible coals in high yields and the slightly-fusible coals in moderate yields, indicating the importance of fusibility in such liquefaction processes. A240-LS pitch is a powerful solvent for slightly-fusible coals. Considerable amounts of pyridine- or THF-soluble fractions were produced especially with A240-LS pitch. A240 pitch is a better solvent than pyrene for some slightly-fusible coals. However, the extent of depolymerization of liquefied coal, pyridine- or THF-solubility, was definitely inferior. Yields of such fractions are higher for lower-rank coals. The mechanism of coal liquefaction under apparently non-hydrogenative conditions is discussed with emphasis on the stabilization of thermal fragments derived from the coal.