Showing papers in "Fuel in 1977"

TL;DR: In this paper, a method of characterizing coal liquids in terms of fractions of different chemical functionality is described, based on Chromatographic fractionation of both benzene-soluble and pyridine-solerant components by sequential elution with specific solvents on silica gel columns.

TL;DR: In this paper, the pore-size distribution and effective surface area of micropores S micro were determined by means of relations derived from Dubinin's two-parameter equation.

TL;DR: In this paper, it is shown that cross-polarization spectra obtained with dipolar decoupling display chemical shift anisotropy which interferes with attempts to distinguish the resonances of aromatic and aliphatic carbons.

TL;DR: Pilot-scale pulverized-coal combustion experiments with two western Canadian coals have shown that the combustion efficiencies of the coals were inversely related to the inert contents.

TL;DR: In this paper, a detailed analysis has been carried out on the deasphaltened Athabasca bitumen using two different series of Chromatographic separations followed by computerized GC/MS studies of the separated fractions.

TL;DR: In this paper, the occurrence of humic compounds characterizes the immature stage; they rapidly disappear with natural evolution, hence the humic content would be an interesting marker of evolution during the immature stages, thus they are a valuable source of information about the original organic matter and deposit media.

TL;DR: In this paper, the oxygen distribution in the Athabasca asphaltene has been investigated and it was shown that 75% of the oxygen is present in the form of hydroxyl groups.

TL;DR: In this paper, surface area measurements of chars and activation energies for the hydrogasification reaction suggest that during the induction period the reaction is diffusion-controlled whereas in the constant-rate region it is chemically controlled.

TL;DR: In this article, a detailed study on molecular weights of products from reductive alkylation of high-rank vitrinite is reported, which is consistent with results from mild hydrogenolysis and air oxidation of bituminous coals.

TL;DR: The catalytic effect of boron on the graphitization behavior of three diverse industrial carbons has been studied in this paper, where it was found that the rate of graphitisation increases with increasing borons concentration in the ranges of catalyst employed.

TL;DR: In this article, two brown coals, xylitic and earthy, carbonized at 1173 K were activated with water vapour, carbon dioxide and oxygen, each producing a different distribution of porosity.

TL;DR: In this paper, the carbon-13 nuclear magnetic resonance spectroscopy was applied to coal-derived liquids in order to obtain additional information regarding molecular structure and composition, and it was shown that a significant amount of material is present in the form of normal paraffinic material both as free paraffins and alkyl substituents on aromatic and hydroaromatic materials.

TL;DR: In this paper, carbon deposition from the cracking of methane into the pores of a lignite char occurs at a significant rate at temperatures between 815 and 855 °C. Carbon deposition has a large and lasting adverse effect on the subsequent reactivity of the char to air.

TL;DR: In this article, the interaction of lignite, brown and black coal with molecular oxygen was studied by simultaneous TG and DTA, and the results showed that the interaction occurs by concurrent reactions the rate of which is controlled by the composition of the gas phase enclosed in the layer.

TL;DR: Athabasca oil sand on degassing in vacuo releases gases volatile at −78 °C which are composed of neopentane, methane, acetaldehyde, propane and propylene at elevated temperature, 70-210 °C, additional quantities of these materials are produced by thermolysis along with other C2C5 hydrocarbons, CO2, CO, H2S, COS, CS2 and SO2 as discussed by the authors.

TL;DR: The electrical conductivity of coal at either 1 kHz or d.c. was measured at 24 °C on samples recovered from pyrolysis experiments aimed at modelling conditions during in situ gasification of coal as discussed by the authors.

TL;DR: In this paper, an experimental method for determining the rate of burning of a carbon sphere within a fluidized bed of sand is described, and experiments have been carried out at three different bed temperatures.

TL;DR: Mossbauer measurements were carried out in several coal samples from various seams in West Virginia and the presence of iron pyrite and iron (II) sulphate was observed in all the samples studied as mentioned in this paper.

TL;DR: In this article, a new technique, Computer-Assisted Molecular Structure Construction (CAMSC), was developed for the structural elucidation of coal-derived compounds, which utilizes elemental analysis, n.m.r. spectra and molecular weight data to determine the allowable combinations of functional groups constituting the structure.

TL;DR: In this paper, the contribution of coal molecules to liquefaction products, donor solvents of discrete structure and narrow molecular-weight range have been satisfactorily employed for these studies.

TL;DR: In this article, X-ray photoelectron spectroscopy (XPS) was used to study coal-associated pyrites, oxidized for various time intervals at low temperatures with humid air or oxygen.

TL;DR: In this article, coal of different rank were treated with naphthalene anion in tetrahydrofuran and it was found that large amounts of unreactive oxygen bonds, possibly of the ether type, were cleaved.

TL;DR: In this paper, the authors reported that a part of the total heat released during hydrogenation of coals appears to be due to the exothermic reaction between H 2 and surface carbon-oxygen complexes removed during the reaction.

TL;DR: In this article, the carbonization of four kinds of solvent-refined-coal (SRC) pitches was investigated in order to determine the properties required for the formation of needle coke.

TL;DR: In this paper, the authors show that with sufficiently long residence times, changes that are more fundamental than "molecular stripping" must take place, probably involving condensation reactions that introduce increased coplanarity into the vitrinite molecules, and the implication of these data to thermal metamorphism of coals and to the normal coalification process is briefly discussed.

TL;DR: In this paper, an analytical model is formulated to describe the physical and chemical processes occurring in an entrained-bed pulverized coal gasifier, and the solutions to the formulations are presented in the form of local properties as functions of particle residence time and inlet conditions.

TL;DR: In this paper, a pulverized fuel ash (PFA) sample from the combustion of sub-bituminous Waikato coals has been analysed and three major mineral suites found in the coal were identified: hydrated iron carbonates and oxides, quartz and aluminosilicates, and calcium minerals, and a low density fraction was separated and found to be similar in composition to cenospheres found in British and American PFA.

TL;DR: In this article, a model for combustion of coal in fluidized beds with sulphur emission control by limestone or dolomite was developed for the coal combustion and solid flow analysis is based on multiple gas bubbles of varying sizes which rise through the particulate emulsion phase.

TL;DR: In this paper, the pyrolysis kinetics for single cylinders and spheres of 22 gal/ton (91.8l/t) oil shale are investigated and two mathematical models are developed in order to represent the pyrotechnic process.