Showing papers in "Fuel in 1984"

TL;DR: In this paper, a detailed chemical analysis of coal and products from various liquefaction schemes is presented to show the steps in the conversion process, and the nature of the products.

TL;DR: Aromaticities determined by 13 C n.m.r. as discussed by the authors for five shale oil samples (Green River formation) prepared under widely different pyrolysis conditions.

TL;DR: In this article, the authors make recommendations for the separation of asphaltenes from heavy feedstocks which ensure minimal entrapment of "resin" (i.e., precipitant soluble) material.

TL;DR: In this article, a method was developed for describing the reactivity or combustibility of solid fuels, such as lignite, bituminous coals and petroleum coke, in terms of a weighted mean apparent activation energy, derived from simultaneous TG DTG readings on a 20 mg sample heated at a constant rate in a flowing air atmosphere.

TL;DR: In this paper, it was shown that the pyrolysis reactions of hard coal may be interpreted in terms of parallel first-order reactions relating to the coal functional groups which can be considered as predecessors of the coal products, and the activation energies measured are of the same order of magnitude as the bonding energies of bridge CC bonds between the aromatic ring-systems in coal molecule.

TL;DR: In this paper, it was shown that the catalytic activity of carbons increases parallel to the incorporation of a nitrogen species which is pyridine-like, i.e. incorporated in the aromatic layers.

TL;DR: The literature on the potassium catalysed gasification of carbon in CO2 is critically reviewed with respect to the mechanism and the experimental "facts" relevant to the mechanistic considerations as mentioned in this paper.

TL;DR: The volumetric swelling procedure developed by Liotta was applied to a pair of coals using 10 solvents and the results were compared with the results of gravimetric swelling experiments as mentioned in this paper.

TL;DR: In this article, a comparative study of the dry thermolysis of tetrahydrothiophene has been carried out and a mechanism for this reaction is proposed and investigations into the aqueous decomposition of butanal have been conducted to support this mechanism.

TL;DR: In this paper, a systematic study of the catalytic activity of carbonates on CO 2 gasification of activated carbon revealed the following order: Li Na K Rb Cs, whereas the other alkali metals show a slight increase.

TL;DR: In this article, the activation of activated carbon is improved by impregnating the activated carbon with promoters such as iron and iodine, and the regeneration of spent carbon is carried out using hot gas desorption methods at temperatures around 450 °C.

TL;DR: In this paper, an experimental study of coal cuttings has been carried out with both a unipore diffusion model and a bi-disperse pore structure diffusion model to determine the time range of each model's validity.

TL;DR: In this paper, an experimental apparatus was developed to inject coal into an autoclave containing preheated supercritical water, which appeared to act as both solvent and reactant in the conversion of coal to gases and liquids.

TL;DR: Arrhenius kinetic parameters have been determined for the CO 2 gasification of chars (heat treatment at 1000 °C) prepared from well-characterized samples of a hardwood, a softwood and a Montana lignite as mentioned in this paper.

TL;DR: In this paper, a number of procedures have been investigated for the calibration of a size-exclusion chromatography column in the determination of molecular mass (MM) distributions of coal derivatives.

TL;DR: In this article, various methodologies used to determine the aliphatic and aromatic CH contents of coal are discussed and the problems associated with equation i.m.n.r. band intensities to elemental hydrogen are examined in some depth.

TL;DR: In this paper, the molecular weight distributions of tars produced during flash pyrolysis of coal have been determined by a combination of gel permeation chromatography and vapour phase osmometry.

TL;DR: In this paper, coal particles with diameters of 3-11 mm were injected into a small, hot bed of sand fluidized by nitrogen and their evolution was followed by sampling the exit gas stream and subsequent analysis by gas chromatography, concluding that heat transfer is the main process controlling the volatilization time in fluidized bed combustors.

TL;DR: In this paper, a method for the laboratory measurement of transient diffusivity parameters for methane in coal has been developed, which uses a pulse of methane gas which is introduced into a helium stream flowing through a long tube containing the coal sample.

TL;DR: In this paper, a Montana lignite was pretreated in either HCI-HF or ammonium acetate, and the pretreated lignites were then loaded with varying amounts of Ca and Mg, separately or jointly, by ion exchange.

TL;DR: In this paper, electron spin resonance spectroscopy has been used to study the changes in free-radical nature and content of brown coals as a result of vacuum drying the coal at various temperatures, and exposing the dried coal to either air at room temperature or oxygen at 105 °C.

TL;DR: In this paper, the influence of pH has been examined in the hydrolysis of both thiophene and tetrahydrothiophene considered to be reasonable models for organosulphur molecular types in heavy oils.

TL;DR: In this article, a non-isothermal coal devolatilization model was proposed for non-combusting fluidized coal in a noncombusting bed and the temperature profiles were computed from the analytical solution of the one-dimensional spherical coordinate unsteady heat transport equation with a convective boundary condition.

TL;DR: In this paper, a set of coal extracts have been characterized by FT-i.m. spectroscopy and proton n.r. bands were used to test the absorption coefficients of the coal extracts.

TL;DR: In this article, the thermal decomposition of pyrite crystals in coal from the Prince Colliery, Cape Breton, Nova Scotia, has been studied to determine both the temperature of decomposition and the distribution of the sulphur liberated into the coal matrix.

TL;DR: In this article, a detailed investigation of the thermal characteristics of six Kentucky bituminous coals undergoing pyrolysis in an inert atmosphere at three different heating rates was made by differential scanning calorimetry.

TL;DR: A suite of density-differentiated macerals from several coals was analysed by Fourier transform infrared spectroscopy to obtain information on the nature and magnitude of the variations exhibited by the various maceral fractions as mentioned in this paper.

TL;DR: In this paper, an improved method for nonaqueous ion exchange separation of liquid fossil fuels into acid, base and neutral fractions has been presented, and results of its application to different types of fuels and model compound mixtures are included.

TL;DR: In this paper, the chemistry of the steam-stimulated recovery of heavy oils, the hydrolysis and subsequent desulphurization of tetrahydrothiophene and thiophene by aqueous solutions of vanadyl and nickel salts was investigated.

TL;DR: Co-Mo, Fe and Mo catalysts were prepared on alumina and carbon supports and the reactivity of sulphide catalysts for thiophene hydrodesulphurization and the propensity for coke deposition of nonsulphided catalysts during propylene cracking and anthracene carbonization were measured as mentioned in this paper.