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Atmospheric bubbling fluidised bed coal combustion (ABFBCC) of a bituminous coal and an anthracite with particle diameters in the range 500–4000μm was investigated in a pilot-plant facility, with and without limestone addition. The experiments were conducted at steady-state conditions using three excess air levels (10, 25 and 50%) and bed temperatures in the range 750–900°C. Combustion air was staged,...
Polished and dry-cut sections of samples of tuyere coke were studied by scanning electron microscopy to reveal the mechanism of appearance, distribution and effects of aluminosilicate spherules and irregular segregations of slag and spinel crystals formed in the coke matrix. It was found that the formation of spherules and slag is not destructive with respect to the host coke matrix. On the contrary,...
The aging properties of asphalts are evaluated using high pressure-gel permeation chromatography (HP-GPC) and Fourier Transform Infrared (FTIR) spectroscopy. The effect of a small amount (1wt%) of zinc dialkyldithiophosphate (ZDDP) on the chemical and physical properties, and molecular weight distribution of asphalts is studied. The asphalts are aged by means of the Thin Film Oven Test (TFOT) under...
Integration of coal gasification and CO 2 separation reactions in one reactor may produce a high concentration of hydrogen. To design a reactor for this new reaction system, it is necessary to know all reaction behaviors in the integrated reaction system. In our previous study, we performed a continuous reaction experiment of coal/CaO under high steam pressure and confirmed that H 2 ...
A study was carried out to determine the effect of pf particle size distribution on coal burnout propensity in a 1MW pulverised fuel burner. The specific aim of the work was to assess the improvement in combustion performance achievable by retrofitting commercially available high performance static or dynamic classifiers to existing plants. Two coals were used and were selected as representative of...
An investigation was undertaken to determine the kinetics of gasification of coal-chars (pulverized) derived from typical South African inertinite-rich (high-ash) coals involving char reactions with carbon dioxide and steam and the effects of carbon monoxide and hydrogen. The chars used were characterized with respect to structural, chemical, mineralogical and petrographic (maceral content) properties...
The oxidation of kerosene Jet-A1 and that of n-decane have been studied experimentally in a jet-stirred reactor at atmospheric pressure and constant residence time, over the high temperature range 900–1300K, and for variable equivalence ratio (0.5≤ϕ≤2). Concentration profiles of the reactants, stable intermediates, and final products have been obtained by probe sampling followed by on-line and off-line...
Thermogravimetry was applied to evaluate the heavy distillation residues of different Brazilian crude oils. The thermal characteristic of the samples could be studied by only one experiment. It was possible to evidence the linear correlations among the results obtained by the TG curves and by the patterned methodologies, therefore anticipating volatile and carbonaceous materials (coke) formed during...
Dehydrochlorinated poly(vinyl chloride) (PVC) and activated carbon were pyrolyzed with sodium hydroxide in a flow of steam and nitrogen at 3.0MPa and 560–660°C. In both cases, hydrogen and sodium carbonate were the main products, and methane, ethane, and carbon dioxide were minor products. The gasification rate increased with partial steam pressure, and the reaction order with respect to steam partial...
Moving bed combustion is commonly used for energy conversion of biomass. Conditions on the moving bed can be conveniently represented by a time dependent fixed bed. The present work experimentally investigates the combustion of four biomass materials having different fuel properties in a fixed bed under fuel-rich conditions. Temperature, gas composition and mass loss curves identified two distinct...
Mezino coal contains a high percentage of ash and both organic and inorganic sulfur. The ash and sulfur contents can be reduced using physical–chemical and chemical methods. ‘Froth flotation’ is a physical–chemical method that is capable of reducing inorganic sulfur and the ash content of coal. In this research, reducing the ash content of mezino coal by 83%, inorganic sulfur by 72% and its total...
The objective of this work is to obtain high calorific value/low ash content products from fine bituminous coals by aggloflotation with petroleum oils such as hexane, heptane, toluene and pentane. The two methods used were agglomeration and aggloflotation for cleaning fine bituminous coal. Oil agglomeration experiments first were carried out followed by aggloflotation at the optimum conditions obtained...
In order to obtain the densities of biodiesel fuels at temperatures up to 300°C, a capacitance type liquid level meter was designed to measure the increase in volume of 50ml of three commercial biodiesel fuels over the temperature range of 20–300°C. Densities were measured for methyl esters of canola and soy and ethyl esters of fish-oil. The frequency output from the meter was linear with temperature...
This paper deals with the modification of petroleum bitumen with four different types of waste polymers. EVA, EVA/LDPE blend, crumb tire rubber and ABS, all of them coming from recycling plants of waste plastic materials, were used as modifying agents of the bitumen employed in the pavement building. Optical microscopy, modulated calorimetry and a set of different rheological tests were developed...
The behaviour of some selected trace metals (Hg, Cd, As, Pb, Sb, Cr, Co, Cu, Mn, Ni and V) during co-combustion processes of bio-waste materials (sewage sludge, waste wood, refused derived fuel) and coal has been predicted by thermodynamic equilibrium calculations using the HSC-Chemistry 4.0 software. The influence of temperature, flue gas composition, trace element concentration and minor fly ash...
Specified mixtures of peat with bark and peat with straw were burned in a lab-scale entrained flow reactor that simulates conditions in the superheater region of a conventional biomass-fired boiler. The deposition rates were recorded on an air-cooled probe that was inserted into the reactor at the outlet. For both mixtures, the deposition behaviour followed a non-linear pattern, which suggests that...
The objective of this work is to understand the impact of biodiesel chemical structure, specifically fatty acid composition on particulate matter formation, particularly on the retention of hydrocarbons by soot due to the scrubbing effect and absorption processes.A typical diesel fuel supplied in petrol stations, two biofuels composed of methyl esters from the transesterification process of waste...
Hydrogenation of liptobiolitic coal from the Barzas Pit (Russia) in a petroleum residue as a solvent was investigated in the presence of an iron containing ore catalyst at 400–430°C and working pressure 7.1MPa. Near 94–97% of the coal organic mass was converted into gaseous and liquid products. The addition of the catalyst in amount of 5% to the coal mass increases the degree of the coal conversion...
Thermogravimetric-Fourier transform infrared (TG-FTIR) studies, using a ramp rate of 30°C/min, have been used to determine the total acidity and carboxylic acid contents for a range of lignites from the Latrobe Valley coal fields, Vic., Australia, some of which were also studied in water- and acid-washed form. The results are compared with values determined by barium ion-exchange. Total acidities...
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