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To examine the influence of calcium on the mechanisms of brown coal pyrolysis and gasification, the morphology of chars from raw and calcium-exchanged Yallourn brown coal was analysed. The chars were obtained by slow pyrolysis in a thermo gravimetric analyser and rapid pyrolysis in fluidized bed reactors operating at atmospheric pressure and at 1.1 MPa. They were examined by optical microscopy to...
Scanning force microscopy (SFM), also referred to as atomic force microscopy (AFM), has been used for the surface characterization of untreated and pyrolysed rice husk samples. This technique, unlike scanning electron microscopy, provides both qualitative and quantitative measurements. The principles of SFM and sample preparation are discussed. Quantitative data in the form of surface roughness,...
The use of catalysts for upgrading volatile matter from hydropyrolysis of Millmerran coal was investigated. The activities of Mo, W, Co-Mo, Ni-Mo and Ni-W catalysts, all loaded on Al 2 O 3 , together with various zeolites were tested for the hydrocracking of coal volatile matter under high hydrogen pressure. The activities of the metal-loaded catalysts reached maxima at a moderate...
The thermal decomposition of cellulose in a reactive hydrogen atmosphere (1 and 5 vol.% hydrogen in argon) and in pure argon was studied under conditions of high temperature (700-2200°C), very short reaction time (0.3-3.0 ms), high heating rates and rapid quenching in a single-pulse shock tube. Compared with the yields obtained in pure argon, the methane yield increased by a factor or 2 in 5 vol...
Fushun and Maoming shale oils (FSO and MMO) boiling < 350°C were separated into subgroups by four chromatographic columns in series with deactivated adsorbent. The eluate fractions were analysed by g.c. and g.c.-m.s. 574 compounds were identified in MMO < 350°C, including 272 non-hydrocarbons, 221 aromatic compounds and 81 alkanes and alkenes. 974 compounds were identified in FSO < 350°C,...
Used tyres were thermally decomposed under vacuum in a process development unit. At 510°C and total pressure 2-20 kPa, the process yielded 50 wt% oil, 25 wt% carbon black, 9 wt% steel, 5 wt% fibres and 11 wt% gas. Distillation of the pyrolytic oil yielded 20 wt% light naphtha (i.b.p. 160°C), 6.8 wt% heavy naphtha (160-204°C), 30.7 wt% middle distillate (204-350°C) and 42.5 wt% of bottom residue...
In this study, the kerogen types of Goynuk, Beypazari oil shale from Turkey and Timahdit oil shale from Morocco were defined by infrared spectroscopy. Aliphatic, carboxyl/carbonyl and aromatic compounds were considered in order to classify the kerogen types. The IR-analysis result shows that the samples can be classified in kerogen evaluation path I for Goynuk, Timahdit oil shales and path II for...
The hydrogenation of 24 coals (LV bituminous to lignite) in the presence of Mo was studied. The hydrogenation temperatures were 300, 350 and 400°C, the hydrogen pressures 5 and 10 MPa, and the reaction time 30 min. At 300°C the Mo salts deposited on the coals do not decompose to the active MoS 2 state, so the hydrogenation process is not significantly different from that in the absence of...
The porous matrix combustor-heater is a combined combustion-heat-transfer device in which the heat exchange surfaces are embedded in a stationary bed of refractory material where gaseous fuel is burned. A basic experimental study was conducted on a 60 kW bench-scale porous matrix combustor-heater with two rows of water-cooled tube coils to evaluate its performance and explore the mechanism of combined...
In connection with the purification of fuel gas for gas turbines in the IGCC process to meet NO x standards and maintain the thermal efficiency of the process, tests were carried out with a 7.5 cm pressurized reactor to decompose ammonia at high temperature (700-900°C) and pressure (2 MPa) using Ni-based catalysts. The effects of temperature, pressure, ammonia concentration and gas residence...
Earthy brown coal was used as a carrier for catalysts (or adsorbents) prepared for flue gas desulfurization. As the active phase, the following metal ions were used: Ca 2+ , Mg 2+ , Zn 2+ , Cu 2+ , Fe 2+ , Fe 3+ , Co 2+ , Ni 2+ , V 4+ , Mo 6+ , Cr 3+ , Mn...
The rate of formation of elemental sulfur on the surface of lignite particles during leaching by acidic ferric chloride was found to depend on the concentration and acidity of the ferric chloride, the particle size of the sample, the temperature and the rate of stirring. Generally, S formation increased during the first 40-45 min of leaching and subsequently decreases. It was more significant with...
Asphaltenes obtained from an Arabian Mix vacuum residue were cracked under hydrogen in a batch autoclave at 410-460°C for 5-90 min. The products were fractionated into gas, naphtha, oil, asphaltenes and coke. The feed and several product fractions were characterized by elemental analysis, by average molecular mass and by 1 H n.m.r. The variation of product fraction yields and analyses with...
Published equations for the calculation of maximum reflectance from random reflectance data are, as shown by comparison with the authors' data, applicable only up to 1.8% R max . At higher coalification they result in too low values because of the non-linear increase in R max . Based on 210 measurements, linear regression equations are presented for the calculation...
The effects of pressure (2-16 bar), gas temperature (800-1100°C) and the partial pressures of carbon dioxide (0.01-4 bar) and oxygen (0.2-2 bar) on the formation of N 2 O, NO and NO 2 from coal-N were studied. Bituminous coal, 75-125 μm, was burned as a dilute pressurized suspension in an electrically heated pressurized entrained-flow reactor. Nitrogen oxides were analysed by an...
This paper described an experimental and modelling study of NO x formation and reduction in pressurized fluidized bed combustion (PFBC) of coal. The aim was to evaluate the Thermal DeNO x process with NH 3 injection and staged combustion in PFBC as measures for the reduction of NO x emissions, and to develop a mathematical model for the emission of NO x . ...
A packed tower is modelled transiently for fluid-solid reactions. Heat and mass transfer are considered, with allowance for structural changes. The Knudsen, molecular and bulk flow terms are accounted for in the packed tower and within the pellets of the packing. Homogeneous, heterogeneous and catalytic reactions are handled. Conduction, convection and radiation model of heat transfer are considered...
Vitrinite from Polish medium-rank coal (85.6 wt% C) heated in an inert atmosphere at 300-650°C was investigated by electron paramagnetic resonance in the X-band (9.3 GHz). The e.p.r. spectra of the vitrinite, recorded using different microwave powers, were approximated by superposition of a Gauss line and two Lorentz lines. The g factor, linewidth of the components and their fraction in the total...
A one-dimensional in situ combustion model was developed for oil and gas production calculations using a frontal-advance theory combined with mass and energy balance equations and simplified by boundary conditions, limitations and assumptions. The model is run for data from laboratory combustion tube experiments. Model runs for such experiments show that the results are in good agreement with the...
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