Liddell Coal Research Articles

Gasification of bituminous coal with K-exchanged brown coal prepared from potassium chloride

A new method utilizing KCl as a catalyst precursor in the gasification of high rank coal was investigated. Potassium-loaded brown coal (Yallourn coal) prepared with KCl using an ion-exchange technique was physically mixed with a higher rank coal (Liddell coal). The mixture was gasified in steam (0.03 MPa) or carbon dioxide (0.1 MPa) with a thermobalance. The gasification temperature ranged from 873 to 973 K. Incorporation of potassium catalyst into Yallourn coal significantly enhanced the reactivity not only of Yallourn char but also of Liddell char. The effectiveness of the catalyst on the gasification of Liddell coal was dependent on coal particle size and the mixing ratio of K-exchanged Yallourn coal to Liddell coal. Electron probe microanalysis showed that potassium catalyst transferred from Yallourn char to Liddell char and spread out over the Liddell char surface in the gasification stage. The remarkable rate enhancement of high rank coal char by this technique was observed in both steam and carbon dioxide gasification.

Catalytic hydrocracking reactions of nascent coal volatiles in a two-stage reactor

The catalytic hydrocracking of nascent volatiles from rapid pyrolysis of Liddell coal was carried out over alumina-supported Co Mo , Ni Mo and Ni W catalysts. The effects of hydrocracking temperature, ratio of catalyst to volatiles, and type of catalyst on the pyrolysis results were investigated. Final product yield and distribution were influenced by all the above factors. Maximum CH 4 yield (23 wt%) was obtained when the volatiles were allowed to contact with an excess of Co Mo catalyst at 500 °C. Maximum BTX yield (2.6 wt%) was obtained at 500 °C with Ni W catalyst, whereas the BTX yield without catalyst was only 0.66 wt%.

The effects of temperature and residence time on the secondary reactions of volatiles from coal pyrolysis

The secondary reactions of volatiles from rapid pyrolysis of Liddell coal have been studied using a two-stage reactor. The effects of the cracking temperature and the residence time of volatiles on the final product yields were investigated in an inert atmosphere between 500–900°C and 0.2–14 s, respectively. The product yields of aliphatic and aromatic hydrocarbons, together with inorganic gases, were determined gas-chromatographically, and a detailed mass balance was established. The final product yields were strongly affected by the above two factors. The nature of the secondary reactions has been discussed using a reaction model based on the molecular structure of Liddell coal. Kinetic analyses were made on the formation and decomposition reactions of gaseous hydrocarbons.

Comparison of Radio Imaging Method (RIM) Electromagnetic Wave Tomography with In-Mine Geological Mapping in the Liddell, Bulli and Wongawilli Coal Seams

The radio imaging method (RIM) of coal seam mapping relies on the natural waveguide effect exhibited by coal seams to electromagnetic wave propagation. Whenever coal seams are disrupted by a natural geological discontinuity, the waveguide disruption causes a measurable change in the wave attenuation. Attenuation measurements can be analysed directly or, if sufficient data are available by tomography, to indicate the location of the anomaly and its likely severity. Such information is of vital importance in modern underground coal mining. In February, 1987 a series of trial surveys were conducted in three Australian mines by a survey team from Stolar Inc. of the USA. The results showed that the natural wave attenuation is 46 dB/100 m in the Liddell Seam, 36 dB/100 m in the Wongawilli Seam and 13 dB/100 m in the Bulli Seam. In the Bulli Seam propagation over distances in excess of 600 m is possible. The surveys were conducted over test sites where dykes and other geological features exist. Wave propagation was clearly disrupted by the dykes and it was possible to image their location by tomographic means. An application for RIM in Australian mines has been clearly indicated.

The composition of the bases in a supercritical gas extract

Average structure data for the basic fraction from a supercritical toluene extract of Liddell coal are reported based on 13C- and 1H-n.m.r. spectroscopy combined with elemental, functional group and molecular weight analyses. This data indicated an average aromatic ring size of two condensed rings with about a third of the possible aromatic sites substituted. The 13C-n.m.r. spectrum showed the presence of unsubstituted alkyl chains >C 8. A number of nitrogen heterocycles, ranging from one to five condensed rings, were identified by g.c.-m.s. and fluorescence and spectroscopy.

石炭中に捕そくされたラジカルのＥＳＲ

Spin probe technique has been applied to study pore structure and functional groups of coal through the interaction between a nitroxide radical and the coal surface. A hexane solution of 2, 2, 6, 6-tetramethyl-4-piperidinol-1-oxyl (TEMPOL) radical was added to Morewell (MO), Wandoan (WA), Liddell (LI) coals and MO's heat-treated at 200, 300, 400°C. The TEMPOL radical trapped in the coal gave an anisotropic triplet ESR signal at room temperature because of hindered rotation of the nitroxide molecule. However, the anisotropic pattern was averaged out at high temperatures as a result of the liberated motion. The extent of the interaction between the radical and the coal surface was evaluated from the temperature range at which the anisotropic spectrum was converted to isotropic one.The following results were obtained:(1) The molecular motion of the TEMPOL radical in WA was hindered up to higher temperatures. The result is considered to be associated with diffusion of the radical into small pores.(2) LI coal contains surface functional groups which own different interaction with the radical doped. Therefore, the spectral shift occurred at the wide temperature range.(3) The water molecules occluded in raw MO coal brought about the constrained motion to high temperatures, presumably because of hydrogen bonding. When the radical was doped to heat-treated MO coals the transition range from anisotropic to isotropic pattern was shifted to low temperature and also became wider. It suggests that the heterogeneous sites with various functionalities emerged owing to the heat-treatment of MO.

Fate of 13C-labelled alkyl groups on reductively alkylated Liddell coal during hydrogenation at 400°C

Medium volatile bituminous coal from Liddell, Australia, has been methylated and butylated using potassium in tetrahydrofuran (THF) and 13C-enriched reagents. The THF-insoluble material was examined by solid state 13C n.m.r. spectroscopy and found to have methyl or butyl groups incorporated into structures such as ethers, alkyl aromatics and, possibly, substituted hydroaromatics. The technique of dipolar dephasing was used to measure the relaxation time constants of the introduced alkyl groups in the coal structure which compared favourably with values for similar structures in model compounds. The alkylated coal was liquefied at 400°C and the products examined. It was shown that alkyl groups in ether structures were cleaved and reported as methane and butane in the gaseous products. Labelled alkyl groups were evident in the chloroform-soluble products and appeared to be in similar structures to those in the starting coal except for the loss of ether groups. Solid state n.m.r. examination of the residues, together with combustion analysis, showed that not all the introduced alkyl groups were lost during liquefaction at 400°C.

Simulation of chemical rate processes in short contact time coal liquefaction

Conversions and product distributions from the thermal dissolution of Liddell coal in the presence of tetralin have been simulated by a system of second-order rate equations. Satisfactory correlation with experimental data is obtained over the range of temperatures studied, i.e. 380–420 °C.

Short contact time dissolution of Liddell coal

The thermal dissolution of Liddell coal in tetralin at 400 °C proceeds rapidly. The addition of hydrogen to coal under moderate, uncatalysed conditions is significant and initially proceeds without the elimination of nitrogen, oxygen or sulphur. At extended reaction times, however, oxygen is eliminated via hydrogenolysis reactions. The simulation of product distributions from the thermal dissolution of Liddell coal at 400 °C, and short contact times, has been undertaken using a system of second-order pseudo-kinetic equations. Excellent agreement between the experimental data and the calculated conversions has been obtained.

Use of INEPT and GASPE n.m.r. pulse sequences: Assignment of position of incorporation of deuterium into tetralin during coal hydrogenation

GASPE and INEPT n.m.r. pulse sequences distinguish CH3, CH2D, CHD2, CD3, CH2, CHD, CH and CD groups in model compounds and in spent vehicle from the reaction of tetralin with deuterium and coal. In deutero-tetralin produced from deuteration in tetralin of Liddell coal at 425°C, deuterium is found in α and β aliphatic and aromatic positions. The INEPT and GASPE pulse sequences show that the mixture of tetralins consists of molecules which are mono-deuterated at the α and/or β aliphatic positions. No evidence was found for any molecules which are di-deuterated at either α or β positions. The results also show that deuterium is incorporated into naphthalene resulting from the dehydrogenation of tetralin.

Isothermal studies of the liquefaction of Liddell coal

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIsothermal studies of the liquefaction of Liddell coalNeil R. Foster, Michael A. Wilson, Ron G. Weiss, and Keith N. ClarkCite this: Ind. Eng. Chem. Prod. Res. Dev. 1983, 22, 3, 478–482Publication Date (Print):September 1, 1983Publication History Published online1 May 2002Published inissue 1 September 1983https://doi.org/10.1021/i300011a018RIGHTS & PERMISSIONSArticle Views30Altmetric-Citations9LEARN 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 (594 KB) Get e-Alerts

Structures of the distillates obtained from hydrogenation and pyrolysis of Liddell coal

The structures of the distillable fractions (oils, b.p. >200 °C and volatile fractions, b.p. <200 °C) of the products from hydrogenation and pyrolysis of an Australian bituminous coal (Liddell) were investigated by gas chromatography-mass spectrometry (g.c.-m.s.) and nuclear magnetic resonance spectroscopy (n.m.r.). The distillable oil generated from hydrogenation of Liddell coal at 400 °C, using nickel molybdenum ortin (II) chloride as catalyst and tetralin or recycle oil as vehicle, consisted of a wide range of compounds. Long straight-chain alkanes were important components together with alkyl-substituted benzenes and tetralins, phenols and polycyclic material. When yields were low, as in the case of catalytic experiments with nickel molybdenum catalysts and no vehicle, isoprenoids could be identified. When a substantial proportion of the coal was converted to oil, branched-chain alkanes were not important components of the product. The replacement of tetralin and nickel molybdenum catalyst with stannous chloride reduced the amounts of methyl tetralins in the product. When tetralin was replaced by recycle oil, alkanes were more important components of the liquid products. Although alkenes were absent in oils generated by hydrogenation, they were important components of oils generated by pyrolysis. The highly volatile fractions (b.p. <200 °C) produced during hydrogenation consisted of alkyl-substituted benzenes, decalins, methylindan and straight-chain alkanes. Straight-chain alkanes were more abundant in those volatile fractions generated by hydrogenation with recycle vehicle than with tetralin. The Brown-Ladner method of estimating the fraction of aromatic carbon in distillable oils was adequate for less volatile fractions but was inadequate for the highly volatile fractions because of the large amounts of α-CH 3 and β-CH 3 alkyl groups present.

Effect of temperature, catalyst and charge gas on the mean chemical structures of the products from hydrogenation of Liddell coal

Liddell coal (New South Wales, Australia) has been hydrogenated at 400, 425 and 450 °C with excess tetralin as vehicle and nitrogen or hydrogen as charge gas for 4 h at reaction temperature. In some experiments a nickel-molybdenum catalyst was used. The structures of the liquid and solid products were investigated by nuclear magnetic resonance spectroscopy, gel permeation chromatography and combustion analysis. Increasing the hydrogenation temperature from 400 to 450 °C decreases the yield of liquid products but increases conversion. At higher temperatures the liquid products are smaller in molecular size and molecular weight and contain a greater proportion of aromatic carbon and hydrogen; the solid residues also contain a greater proportion of aromatic carbon. The changes in variation of yield and structure with temperature are independent of the presence of catalyst under nitrogen and the nature of the charge gas. However, as the reaction system is capable of absorbing more hydrogen than can be supplied by the tetralin, the products from reactions with hydrogen as charge gas contain more hydrogen, some in hydroaromatic groups. Catalyst has little, if any, role in dissolution of the coal when a nitrogen atmosphere is used. When nitrogen is used as charge gas, reactions of coal-derived liquids with the catalyst do not alter the hydrogen, carbon or molecular size distributions in the products. The results show that the changes in composition of the liquid and solid products with increase in hydrogenation temperature are due to pyrolytic reactions and not to increased hydrogenation of aromatic rings.

Aromatic and aliphatic composition of the solid and liquid products from hydrogenation of Liddell coal

Aromatic and aliphatic composition of the solid and liquid products from hydrogenation of Liddell coal

Flash pyrolysis of Australian coals: Effects of pre-oxidation and of oxygen in the inlet gases on formation of agglomerated material

Addition of oxygen to nitrogen in the inlet gas during flash pyrolysis at 600 °C reduced the amount of char agglomerate formed from a relatively strongly caking Liddell seam coal and a weakly caking Millmerran seam coal. The reduction of agglomeration was significant over the entire ranges of variables used, viz, oxygen concentrations in the inlet gas of 2.62–10.5% (v/v) and oxygen to coal ratios of 0.02–0.12 (wt/wt). Pre-oxidation at 400 °C with solids residence times below 2 s, inlet concentrations of oxygen up to 10.5% and oxygen to coal ratios up to 0.10 (wt/wt) also effectively reduced agglomeration of Liddell coal. In terms of minimizing the oxygen requirement to obtain essentially nonagglomerating solids, the preferred method was found to be pre-oxidation followed by oxidative pyrolysis. The reduction of agglomeration by oxygen appears to be due to a combination of the extent of coal oxidation and the extents of polymerization and chemical condensation of the coal structure.

Flash pyrolysis of coals: behaviour of three coals in a 20 kg h −1 fluidized-bed pyrolyser

Flash pyrolysis of Loy Yang brown coal, and Liddell and Millmerran bituminous coals has been studied using a fluidized-bed reactor with a nominal throughput of 20 kg h −1. The apparatus and its performance are described. The yields of tar and hydrocarbon gases are reported for each coal in relation to pyrolysis temperature, as also are analytical data on the pyrolysis products. The peak tar yields for the dry, ash-free Loy Yang and Millmerran coals were respectively 23% wt/wt (at ≈ 580 °C) and 35% wt/wt (at $ ̃ 600 °C). The tar yield from Liddell coal was 31% wt/wt at ≈ 580 °C. Hydro-carbon gases were produced in notable quantities during flash pyrolysis; e.g. Millmerran coal at 810 °C gave 6% wt/wt (daf) methane, 0.9% wt/wt ethane, 6% wt/wt ethylene, and 2.5% wt/wt propylene. The atomic H C ratios and the absolute levels of hydrogen in product tars and chars decreased steadily with increasing pyrolysis temperature.

Flash pyrolysis of coals: comparison of results from 1 g h −1 and 20 kg h −1 reactors

The performances of 1 g h −1 and 20 kg h −1 flash pyrolysers are compared for three Australian coals: Loy Yang brown coal (Victoria), Liddell bituminous coal (New South Wales), and Millmerran sub-bituminous coal (Queensland). The two reactors gave comparable yields of tar, char and C 1–C 3 hydrocarbon gases over a range of operating conditions for each particular coal. The yield of total volatile matter from Millmerran coal was similar from both reactors, as were the compositions of chars from Loy Yang coal and tars from the Liddell and Millmerran coals. For Millmerran coal, the yields of tar, C 1–C 3 gases and volatiles from the large reactor below 650 °C, were slightly lower than for the small reactor, possibly owing to a shorter retention time of Millmerran coal particles in the large-scale reactor. At a temperature near 600 °C tar yields were independent of tar concentration in the effluent gas, over a range 0.0025–0.1 kg m −3 for Liddell coal, 0.005–0.26 kg m −3 for Millmerran coal and 0.0045–0.09 kg m −3 for Loy Yang coal. The tar yields from Millmerran and Liddell coals at 600 °C in the large reactor, correlate directly with the atomic H C ratio of the parent coal, in the same manner as that found for a wider range of bituminous coals in the small-scale reactor.

Effects of pre-extracting a Liddell coal on its agglomeration properties during flash pyrolysis

The effect is studied of solvent extraction of a strongly agglomerating Liddell coal upon its subsequent tendancies to agglomerate during flash pyrolysis. A sharply defined optimum combination of extraction time and temperature is found at which the pre-extracted coal is essentially nonagglomerating. The sharpness of the optimum restricts the design and operation of an extractive pretreatment step in a flash pyrolysis process. The acidity of aromatic solvents has little effect on agglomeration of the extracted coal.

Catalytic hydrogenation of liddell bituminous coal: Effects of process variables on coal dissolution in batch autoclaves

Batch autoclave experiments have shown that Liddell coal will dissolve in tetralin under mild conditions of temperature and pressure. In the presence of a catalyst and an initial (cold) hydrogen pressure of 2.7 MPa at least 80% dissolution is achieved for both untreated and demineralized coals after reaction for 4 h at 370°C. The extent of reaction depends strongly on temperature (up to ∼370°C) and reaction time (up to ∼ 4 h), thereafter increasing only slowly with increases in these parameters. Total reaction times of up to 12 h, and maximum temperatures up to 450°C were employed. Increasing the initial (cold) pressure from 3 to 18 MPa raises the amount of coal dissolved, after 4 h, from 81 to 92%.

Effects of in-situ mineral matter and a nickel — molybdenum catalyst on hydrogenation of Liddell coal

Hydrogenation experiments with batch autoclaves were performed on an Australian Permian bituminous coal (Liddell) using excess of tetralin (3 tetralin: 1 coal by weight) as vehicle. They show that the nickel-molybdenum catalyst, Cyanamid Aero HDS-3A, has only a mild effect on the conversion of Liddell coal and that this is also the case when the coal is passed through a magnetic separator and then extracted with hydrochloric and hydrofluoric acids before hydrogenation to remove minerals. Replacing the hydrogen consumed during reaction does not significantly affect the yield of conversion. Evidence is presented to show that major roles of the catalyst during conversion are to assist in dissolution of the coal by rehydrogenating the donor vehicle after dehydrogenation by the coal, and to convert the initial tetralin-soluble products of hydrogenation to oil. In the absence of catalyst, prior treatment of the coal by the separation and acid extraction procedures mentioned above, likewise has little effect on conversion.