Showing papers in "Fuel in 1983"

TL;DR: In this paper, a demineralized lignite has been used in a fundamental study of the role of carbon active sites in coal char gasification, where the chars were prepared in N 2 under a wide variety of conditions of heating rate (10 K min −1 to 10 4 K s −1 ), temperature (975 − 1475 K) and residence time (0.3 s-1 h).

TL;DR: The catalytic effects of alkali metal salts in the gasification of carbonaceous materials by oxygen, steam and carbon dioxide are described in this article, and current theories of the mechanism of this type of catalysis are reviewed.

TL;DR: In this article, a new explanation for the endothermic reactions below 650 °C reported by previous workers is proposed as a consequence of the unexpectedly high specific heat predicted in this region using the above model.

TL;DR: In this paper, the nature of the organic and mineral reactions during the pyrolysis of Saline-zone Colorado oil shale containing large amounts of nahcolite and dawsonite has been determined.

TL;DR: In this paper, an oxygen functional group analysis was performed to determine the carboxylic acid, hydroxyl and ether group content of the coal before, during and after the reaction.

TL;DR: In this paper, a model of the chemical changes during thermal decomposition of coal is presented, which describes the kinetics of the release of the main volatile matter constituents, thereby permitting the changes in the mass and composition of the solid residue to be estimated by element balances.

TL;DR: In this article, the use of X-ray photoelectron spectroscopy to probe the chemistry of coal surfaces is reviewed and its application to the functional group composition of bulk coals is discussed.

TL;DR: In this article, Fourier transform infrared spectroscopy (FT-i.r) was used to investigate the low-temperature oxidation of coal and the results were correlated to changes in the thermoplastic properties of the coal measured by a Gieseler plastometer.

TL;DR: In this article, basic features of the reaction kinetics of potassium-catalysed coal gasification and how small-scale data were used for the conceptual design of large fluidized-bed gasifiers are discussed.

TL;DR: In this paper, the existence of surface salt complexes on alkali-catalysed carbon surfaces under gasification conditions (770-1000 K) has been demonstrated, and chemical characterization of these complexes coupled with kinetic measurements provide insight into their role in catalytic gasification.

TL;DR: In this paper, a study was made of the gasification behavior of coal chars doped with small amounts of alkali metal carbonates, and the kinetic data were consistent with catalytic mechanisms involving oxidation/reduction cycles on the char substrates.

TL;DR: In this article, a high-resolution Fourier transform infrared spectrometer was used to provide additional support for the assignment of the 1600 cm−1 band to an aromatic stretching mode.

TL;DR: The effect of traces of sulphur in the gas stream on catalysis of gasification or carbon-forming reactions by calcium, potassium, or sodium is not well understood at present as discussed by the authors.

TL;DR: In this article, a demineralized North Dakota lignite was loaded with 2.9 wt% Ca by ion exchange and X-ray diffraction analysis was carried out to obtain information on the state and dispersion of the Ca species on the various chars.

TL;DR: In this paper, the laser Raman microprobe (MOLE) was used to estimate the size of microcrystalline regions of high temperature cokes and the results were compared with conventional optical microscopy measurements whereby it was shown that the optical texture and Raman spectra of cokes are not closely related.

TL;DR: The use of ruthenium tetroxide for the catalytic oxidation of coal molecules under mild conditions has been examined in this paper, where the selectivity of the reagent for aromatic nuclei has been assessed by a study of the oxidation of selected benzene, naphthalene and phenanthrene derivatives.

TL;DR: In this paper, Saudi Arabian medium crude oil has been characterized by 1H and 13C n.m.n.r. spectroscopy and several structural parameters such as the percentage of aliphatic carbons, aromatic carbons and n-alkanes, naphthenes, branched alkanes and chain length of paraffinic chains were calculated.

TL;DR: In this paper, a reflection on the gasification-kinetics of alkali-doped coal was carried out and the catalytic activities of Li, Na, K, Cs were compared.

TL;DR: In this article, a review of mineral matter of German hard coal, its reactions with catalysts during gasification with steam to form new crystalline phases are dealt with by means of microscopy, XRD, XRF and microprobe analysis.

TL;DR: In this paper, the catalytic effect of K 2 CO 3, KHCO 3, KOH, K 2 SO 4 and KCl during steam gasification of coal and carbon chars has been evaluated by gravimetric measurements at 750 °C.

TL;DR: In this article, a model of heat transfer in a coke-oven charge is presented, which uses, as submodels, the descriptions of the physical properties and chemical changes in coal during its decomposition to coke as given previously.

TL;DR: In this paper, reaction rate data are presented of potassium carbonate-catalysed C02 gasification of an activated carbon, measured in a Packed Bed Balance Reactor over a C02 pressure range of 0.05-2.03 MPa at 1050 K.

TL;DR: In this article, the fine structure associated with phenols and ethers in coal pyrolysis liquids has been characterized and the contributions to the liquid pyrolysates of the phenolic functional groups already existing in coal have been separated from the contributions of these same same groups generated by ether cleavage during the pyroglysis.

TL;DR: Nickel catalyst exhibited an extremely high activity in the gasification of some low rank coals at a temperature as low as 750 K as discussed by the authors, and approximately 85% of Yallourn coal was converted within 30 min in steam at 773 K. But hydrogen sulphide was strongly adsorbed on the nickel catalyst and retarded this reaction.

TL;DR: Sorption data have been obtained for a range of vapours on a Kentucky No.12 coal and the results indicate that surface areas obtained in this way are influenced by vapour-induced swelling effects as discussed by the authors.

TL;DR: In this article, the cross polarization technique combined with magic-angle spinning has been applied to obtain 13C n.m. spectra of a sedimentologically homogeneous series of peat, lignite and bituminous coal derived from higher plants.

TL;DR: In this paper, an unreactive hvC bituminous coal has been hydrogenated in a batch-stirred reactor using pyrite, hydrogen sulphide, and Pyrite+hydrogen sulphide as catalysts.

TL;DR: Fischer assay shale oil from the Condor oil shale deposit at Proserpine, Queensland, was chemically separated into 20 fractions and analyzed by gas chromatography-mass spectrometry as discussed by the authors.

TL;DR: In this paper, gas chromatography and mass spectrometers were used for the detailed examination of nitrogen compounds in basic fractions from an anthracene oil and a low-temperature coal tar.

TL;DR: In this article, it was found that an inverse relationship exists between the level of precarbonization reflectance (PCR) of inertinite and the reflectance and bireflectance of its coke, and that the proportion of reactive inertinite is larger than allowed for in most petrography-based coke stability calculations.