Showing papers in "Fuel in 1971"

TL;DR: In this article, the water sorption isotherms of Victorian brown coals were used to study the effect of hydrogen bonding of the water to functional groups on the coal surface, and a mechanism for the hysteresis effect was proposed based on differences between the desorption and adsorption data.

TL;DR: The coal anion is formed by transfer of negative charges from the alkali metal to the aromatic clusters in coal with naphthalene acting as an electron transfer agent as discussed by the authors.

TL;DR: In this paper, water adsorbs on hydrophilic sites provided by oxygen functional groups on the coal surface and by mineral matter in a monolayer of anthracite and HVC coal.

TL;DR: In this article, the desorption of water from brown coal has been investigated at temperatures from 30 °C to 120 °C, and the amount of water which can be desorbed after prolonged evacuation to a constant weight increases with increasing temperature, and is accompanied by the evolution of carbon dioxide at temperatures above 60 °C.

TL;DR: A detailed structural analysis of Athabasca asphaltenes using proton magnetic resonance spectroscopy was performed in this article, showing that individual condensed aromatic sheets vary from a six-ring unit to, at least, a fourteen ring unit.

TL;DR: In this paper, it was shown that it is possible to estimate the differential heat of adsorption of these coals from an isotherm obtained at a single temperature, provided that the equilibrium points at different temperatures fall satisfactorily on a single straight line of the Dubinin-Polanyi equation.

TL;DR: In this paper, a low temperature ashing technique was applied to some thirty-three coal samples of varying rank, twelve of which are discussed in some detail in detail in this paper.

TL;DR: In this article, the authors measured the rates of heat release from different coals by a calorimeter during sorption of water vapour in isothermal conditions, and found that the rate of heat generation in a particular coal increases with the equilibrium humidity deficiency of the coal, i.e. with the difference of equilibrium humidity of air and coal.

TL;DR: In this article, the authors applied neutron activation analysis of coal samples to the problem of the mode of occurrence of chlorine in coal and determined that both sodium and chlorine were determined on the same 1-gram portion of each coal sampled.

TL;DR: Fluidizing feeders have been developed to provide stable flows of fine (−100 μ m) particles in the range 1-1000 g/h as discussed by the authors, where materials fed are coals, chars, cokes, alumina and silicon carbide.

TL;DR: In this paper, American coals and chars have been compared with commercially available active carbons for dye adsorption, showing that the amount of dye removed from solution by raw coals is made up of two parts, one due to interaction with some mineral constituents and the other due to adorption on the porous surface.

TL;DR: In this article, Lambert-Beer's law has been confirmed to be applicable for 3450cm − 1 absorption with different ranks of coals and a correlation between these two absorptions has been established.

TL;DR: In this paper, the results of a large number of grindability tests on coal, carbonaceous shales, and shales have been statistically analysed to determine the magnitude of errors in sample preparation, in loss of product material, and in the overall determination.

TL;DR: In this paper, a simplified mathematical rate expression based on this postulate is used to derive a relation between methane yield and hydrogen partial pressure that is applicable over all ranges of hydrogen pressure.

TL;DR: The water solubility of Athabasca asphaltenes has been shown to be increased by oxidizing the asphalte and then sulphomethylating or sulphonating the oxidized material as mentioned in this paper.

TL;DR: Reflectivities of vitrinites (Carbon 83·1, 88·6 and 93·3%) carbonized at 450, 600 and 750°C have been measured at a number of wavelengths between 403 and 709 run and refractive and absorptive indices derived for the samples using Beer's relationship as discussed by the authors.

TL;DR: In this article, the authors applied proton magnetic resonance spectroscopic analysis to Athabasca asphaltenes to demonstrate the overall effects of the oxidation processes on the aromatic sheets of the asphtenes and, in conjunction with other analytical techniques, indicate plausible routes by which degradation may occur.

TL;DR: In this article, the ratio of peripheral carbon atoms (Cp) to the total number of aromatic carbon atoms was determined from nuclear magnetic resonance/infra-red measurements and carbon-hydrogen analysis.

TL;DR: In this paper, the results were discussed in terms of σ -bonded halogen rather than formation of charge-transfer complexes, rather than forming of charge transfer complexes.

TL;DR: In this paper, a stepwise solvent extraction of an orthohydrous and a perhydrous coal in an autoclave at a maximum temperature of 300 °C gave yields of aliphatic and aromatic hydrocarbons approximating to those found in the corresponding low temperature tars from these coals.

TL;DR: In this article, the interactions of Athabasca asphaltenes and heavy oil with metal chlorides are described, and it is shown that inter-and intramolecular condensation by dehydrogenation and dealkylation accompany chlorination.

TL;DR: In this paper, material soluble in chloroform has been extracted from bright bituminous coals of two different ranks 1) following preheating to the temperatures of maximal plasticity; 2) after treatment with sodium in liquid ammonia; 3) by fractionating the pyridine extracts; 4) after preliminary acetylation with acetic anhydride in the presence of Pyridine.

TL;DR: The US Bureau of Mines developed an automated reflectance scanning microscope system, primarily for determination of volume proportions, size distribution, and mode of association of the physical (petrographic) components of coals as discussed by the authors.

TL;DR: In this paper, the proportion of germanium in Ge-C linkage was found to be highest in high volatile bitumous coal, lower in peat, and lowest in brown coals and lignites.

TL;DR: In this paper, the optimum content of the reactive macerals (vitrinite and exinite) in a coal or coal blend was found to be in excess of 70%.

TL;DR: In this paper, eight whole coals have been catalytically dehydrogenated and the results were compared with dehydrogenation of vitrinites from bituminous coals.

TL;DR: In this article, changes produced in the properties of a Durham bituminous coal by an igneous intrusion have been measured by the following techniques, i.e., crystallite size determinations from the line-broadening of x-ray diffractions and rate of volatile evolution.

TL;DR: Chloroform extraction for Yūbari coal both raw and preheated at 300, 350 and 400 °C was carried out at various temperatures as discussed by the authors, and the results showed that 50 cm 3 of chloroform per 1 g of sample is sufficient to extract almost completely, whatever the extraction temperature, the chlorodynamic solubility of each sample.