Showing papers in "Fuel in 1991"

TL;DR: In this article, the chemical and thermal responses of six dried coals on exposure to a flow of oxygen or air were studied using isothermal differential thermal analysis (DTA) and temperature-programmed in situ diffuse reflectance infrared Fourier Transform spectroscopy (DRIFTS).

TL;DR: In this article, the precursors used in this study were of vegetable and polymeric origin and one activation series based on natural coal was also included, which was used to assess quantitatively the evolution of active carbon properties.

TL;DR: In this article, one-and two-stage fermentation processes were developed for production of butanol and ethanol from coal-derived synthesis gas using Butyribacterium methylotrophicum.

TL;DR: In this paper, the role of microporous surface area in CO 2 gasification of chars from a sub-bituminous coal was investigated and it was shown that the reaction primarily takes place outside the micropore network on the surfaces of larger pores.

TL;DR: In this article, the heating value of agricultural residues such as wheat straw, wood fellings, vine shoots and cotton plant stalks in addition to forest residues (e.g. those from holm oaks and eucalyptuses) was determined and compared with that of fossil fuels.

TL;DR: In this paper, the asphaltenes from a waxy crude were isolated using several different n-paraffinic solvents at various temperatures, and the average molecular weight of the polygonal asphalte was found to increase with increase in carbon number and with temperature.

TL;DR: In this paper, coal swelled most extensively with large blow holes observed on the particle surfaces when pyrolysed at 0.8 MPa, an indication that volatiles transport occurred by bubble movement.

TL;DR: In this article, the formation of NO x precursors during the rapid pyrolysis of three Australian coals has been studied by the determination of HCN using long path length Fourier transform infrared spectrometry and of nitrogen-containing species in the tars using gas chromatography with a nitrogen-specific detector.

TL;DR: In this paper, a simple equilibrium model for gas composition and yield from coal gasifiers is proposed, which combines mass and energy balances with equilibrium relationships to calculate major and minor species in the produced gas.

TL;DR: In this article, the performance of both dispersed gas phase and dispersed liquid phase systems under both mass transfer controlled and non-mass transfer controlled conditions was examined. But the performance was limited to a few minutes for these gaseous substrate fermentations.

TL;DR: In coal pyrolysis O-containing structures such as ether bridges and phenolic groups play an important role as mentioned in this paper, and their reactions were studied by non-isothermal pyroplysis of a high volatile bituminous coal and some model polymers with gas Chromatographic detection of the gaseous pyrolys products.

TL;DR: The use of dilute aqueous NaOH solution under mild conditions at atmospheric pressure followed by acid leaching results in a 75 wt% demineralization of the coal as discussed by the authors.

TL;DR: In this article, the atmospheric pressure pyrolysis of sugar-cane bagasse and silver birch was determined in a wire-mesh reactor as a function of temperature (300-900 °C) and heating rate (1-1000 K s−1), over a range of holding times between 0 and 100 s.

TL;DR: In this paper, the effect of water vapour on the yield and composition of the products obtained by low temperature thermal destruction of solid fuels at atmospheric pressure, before and after complete extraction with ethanol-benzene, is investigated.

TL;DR: The macroporosity of carbons and activated carbons produced from wood and coal precursors has been investigated by mercury intrusion porosimetry and microscopic examination as discussed by the authors, which is believed to derive largely from the residual cellular structures of botanical origin that are present and identifiable in carbons from woods and coal of all ranks.

TL;DR: In this paper, the authors used selective chemical degradation with ruthenium tetroxide (RuO4) for the characterization of two kerogen isolates (Messel and Kimmeridge Clay), two kerogen-rich shales (Green River and Maoming) and a coal, (Loy Yang) was undertaken using a mild, oxidative technique.

TL;DR: In this paper, new formulae have been developed for estimating the calorific values of Turkish lignites from their proximate analyses data and all the correlations were obtained using least squares regression analysis.

TL;DR: In this article, an examination of the reported experiments used to measure the minimum gas temperature at ignition for pulverized coal particles reveals that increasing volatile matter and oxygen concentration has been found to decrease this temperature whereas the effect of particle size appears to depend on the experimental technique.

TL;DR: This article showed that pre-swelling of bituminous and lower-rank coals with a suitable solvent, followed by removal of the swelling agent, significantly enhances conversion and product quality during subsequent liquefaction.

TL;DR: In this paper, a comparison of the TPD pattern of H2S evolution for high-rank coal with those of chars made from lower-rank coals at 400 and 750 °C shows that they are remarkably similar and suggests that the thermal reactions induced in sulphur species in laboratory pyrolysis experiments could be related to those that occur as a result of thermal reactions during coal metamorphism.

TL;DR: In this paper, 13C and 1H nuclear magnetic resonance (n.m.r.) spectroscopy techniques were used to investigate the relationship between the chemical structure of coal and the char particles and condensed tar vapours produced from coals of various ranks at rapid heating conditions.

TL;DR: In this article, a reaction scheme consisting of three independent parallel reactions was used to describe the primary reactions of fir wood pyrolysis in a fluidized bed reactor, in the temperature range 400-500 °C.

TL;DR: In this article, the effect of process parameters on the formation of nitrogen compounds and tars was studied in a laboratory scale fluidized bed air gasifier under atmospheric pressure, using peat as fuel.

TL;DR: In this paper, a Fischer-Tropsch synthesis reaction was conducted in a supercritical fluid medium using a fixed bed reactor, and the supercritical phase reaction produced more higher carbon compounds (> C 25 ) than reactions in either liquid or gas phase.

TL;DR: In this paper, a general, second-order, effective conductivity formula for binary mixtures, valid for small differences between the conductivities of dispersed and continuous phases, was derived.

TL;DR: In this paper, the Fourier transform infrared (FT-i.r) was applied to evaluate the heterogeneity and to characterize the individual petrographic components of coal macerals and alteration phenomena.

TL;DR: A detailed analysis of coke oven emissions is reported in this paper, where measurements were made on samples collected at various workplace locations on the oven top and a new type of sampling system was used and is described.

TL;DR: Vitrinite reflectances are reported for coals and argillaceous sediments from nine borehole successions in the eastern and central Midland Valley of Scotland as mentioned in this paper.

TL;DR: In this article, the influence of functional groups in coal on cross-linking reactions during pyrolysis was investigated, and the early stages of CO2 and H2O evolution are directly related to the cross-link observed at low temperatures (<400 °C, which inhibits tar production.

TL;DR: Fourier transform infrared spectra were reported for an activated carbon, two pitches and two coals as a function of carbonization temperature (773-1073 K) and temperature (573-773 K) of subsequent oxidation treatment as mentioned in this paper.