Showing papers in "Fuel in 1990"

TL;DR: In this article, the authors investigated the relationship between the coal matrix shrinkage and the gas flow path in coalbeds and found that the coal volume shrinks by ≈ 0.4% when the gas pressure falls from 6.9 MPa to atmospheric pressure.

TL;DR: In this article, pyrolysis temperatures up to 720 °C and at heating rates between 5 and 80 °C min−1 were used to determine the composition and properties of the derived gases and oils.

TL;DR: X-ray photoelectron spectroscopy (XPS) was applied to the problem of speciating and quantifying organically bound forms of sulphur in nonvolatile and solid hydrocarbons as mentioned in this paper.

TL;DR: In this article, a char morphology system based on the physical and optical characteristics known to influence the burning of pulverized coal is outlined, and the proportions of different pyrolysis char types produced by any coal are shown to depend on coal rank, petrographic composition, maceral fusibility, and possibly ash content and composition.

TL;DR: A pyrolysis-gas chromatographic (py-g.c.) method for estimation of the S org C ratio in kerogens and other forms of sedimentary macromolecular organic matter is described in this paper.

TL;DR: An alternative use for coal ash was investigated, based on the metakaolin type material present in the ash as discussed by the authors, which was treated with sodium hydroxide at different concentrations and various times and temperatures of crystallization.

TL;DR: In this paper, it was shown that the catalytic effect of K was reduced by reaction with silica to form silicate during pyrolysis, and this was confirmed by addition of a high K, low Si sample (potato pulp) and by observation of reduced gasification rate in the derived char.

TL;DR: In this paper, the authors compared the abilities of various materials to catalyse the decomposition of tar constituents in fuel gas, and found that the most important effect of the catalyst appeared to be the catalysis of the reactions between the intermediate thermal degradation products, such as light hydrocarbons and deposited carbon, and water vapour.

TL;DR: In this paper, the results obtained show that CO 2 chemisorption is much more suitable than XRD, whereas the excess calcium has low dispersion, its mean particle size increases considerably, and does not have additional catalytic activity.

TL;DR: In this paper, a sulphur K edge X-ray absorption spectroscopic method has been developed for direct determination and quantification of the sulphidic and thiophenic forms of organically bound sulphur in nonvolatile petroleum and coal samples.

TL;DR: In this article, Torbanites of various origins (natural and laboratory-heated samples) were examined by quantitative Fourier transform infrared spectroscopy (FT-IR) using difference spectra, obtained by low temperature ash (LTA) subtraction, or from deconvoluted regions of such spectra.

TL;DR: In this article, the biomarker assemblage in the aliphatic fraction of the Tertiary brown coal from Zhoujing mine has been documented in detail, which consists of resin-derived diterpenoid and sesquiter-penoid hydrocarbons, long chain n-alkanes from vascular plant epicuticular waxes, and to a lesser extent terrigenous triterpenes.

TL;DR: In this paper, a micro-reaction system employed a Curie point pyrolyser to rapidly heat microgram n-hexadecane samples to high temperature, and a rapid direct quench system was used to stop the reactions and transfer the products to the analyser.

TL;DR: Results are presented from a new model which combines the geometry, chemistry and mass transport assumptions of the FG-DVC model with the mathematics of a modified percolation theory.

TL;DR: In this article, pyrolysis tar and char yields were measured at atmospheric pressure between 400-800 °C in three reactors with significantly different design characteristics: a fluidized bed; a wire-mesh reactor; and a hot-rod fixed bed reactor.

TL;DR: In this paper, the cation exchange properties of three Victorian brown coals were investigated and a simple model was proposed to explain the pH dependence of coal ion exchange properties, and the YNE coal exhibited a CEC double that of the other coals for all cations except sodium.

TL;DR: In this article, an upper bound on the number average molecular weight of a molecular mixture was derived in terms of quantities measured in mass spectrometry, which is useful for samples that do not completely sublime, such as the less soluble subfractions of vacuum residue.

TL;DR: In this article, the technology, kinetics, chemistry and reactor modelling of hydrocracking have been reviewed and a general overview of the recent advances in this process has been provided.

TL;DR: In this paper, coal chars containing calcium have been prepared from carboxymethyl cellulose in the calcium form and from pure cellulose containing sorbed calcium acetate, at several heat treatment temperatures (HTTs) in the range 400-900°C.

TL;DR: In this paper, X-ray absorption near edge structure (XANES) spectroscopy and Xray photoelectron spectroscopic (XPS) were used to study the chemistry of organically bound sulphur species in coal during mild coal oxidation.

TL;DR: In this article, the authors applied non-linear deconvolution and curve-fitting to the photoacoustic FT-i.r. spectra of the vitrinite, resinite and fusinite macerals separated from a subbituminous western Canadian coal.

TL;DR: In this paper, high-temperature coal-tar pitch was fractionated by preparative size exclusion chromatography on Sephadex LH-20 in pyridine at 60 °C and the fractions obtained were characterized by elemental analysis, molecular weight determination (vapour pressure osmometry), i.r. spectroscopy, and TGA.

TL;DR: In this article, the average molecular parameters and hypothetical structural models for these asphaltenes were proposed using n.m.r. measurements, calculated molecular weight of unit sheets and elemental analysis.

TL;DR: In this article, the authors investigated the relation of operating pressure with coal pyrolysis, coal caking, coal clinkering and coal char reactivity in coal gasification.

TL;DR: In this paper, the pyrolysis kinetics of oil shales from Yugoslavia, Northern Korea and the USSR were investigated under non-isothermal conditions using thermogravimetric analysis (TGA) and differential scanning calorimetry (d.s.c.).

TL;DR: In this paper, the authors investigated the catalytic decomposition of polyethylene (PE) in the presence of a catalytic catalyst and found that the decomposition occurred by the following process: polymer → thermally decomposed oligomer → catalytically decomposed low molecular weight components (gasification precursor, liquid fraction) → gas.

TL;DR: In this paper, the exudatinite, a secondary maceral, has been found as four different types in a Chinese Tertiary brown coal and their spectral fluorescence and the biomarker distribution provided definitive evidence for the generation, maturation and migration of immature hydrocarbons in the brown coal.

TL;DR: In this paper, the compressive strength of coal fly ashes and their activity in the sintering process measured by means of viscosity and surface tension were investigated. But the results showed that the strength of sintered pellets produced from crystallized Beulah lignite ash is weaker than those produced from the amorphous form of the ash.

TL;DR: In this paper, red mud was used as a coal liquefaction catalyst in the hydroliquefaction of rye straw, and different amounts of gaseous and liquid products were formed.