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The high temperature reaction of SO 2 with CaO was investigated in three reactors: a thermogravimetric reactor (TGA), a volumetric reactor (VR) and an entrained flow reactor (EFR). Several natural limestones with super fine particles were used as sorbents. It was found that the reaction could be well characterized by a two-stage process. The initial stage was very fast and lasted about...
This paper reviews the costs and technologies involved in an integrated system for the production of electricity from biomass in general and wood in particular. It first examines the economics of gasification, showing that the potential for this form of renewable energy lies in either processing low-cost wastes or relying on some sort of fiscal incentive, even at relatively large scales of operation...
Asphaltene association in crude oil in the native condition was studied using electron-nuclear double resonance (ENDOR) spectroscopy. Most of the asphaltene molecules are associated with each other in the range from room temperature up to 90°C. The core of the associate is a stack of condensed aromatic sheets of characteristic radius 10 . The effect of dilution by various low-molecular-weight...
A method is presented for the determination of V, Ni, Fe, Mg and Na in highly stable crude oil-water emulsions, of which Orimulsion , a new fuel product from the Venezuelan oil industry, is a typical example. The method is based on a dry ashing procedure for sample preparation which includes a dehydration process in the presence of ethyl alcohol, and determination of elements by flame atomic absorption...
A procedure for the extraction, separation and characterization of coal bitumen is described. A Carboniferous coal was subjected to exhaustive (single-step) extraction with dimethylacetamide (DMAA) at ambient temperature. The treatment solubilized 24 wt% of the organic matter. The bitumen was fractionated further and some fractions were separated into normal and branched/cyclic components. By...
The objective of this work was to study the effect of coal air oxidation on char gasification reactivity. Three bituminous coals with different rank, from a low volatile bituminous coal to a high volatile C bituminous coal, were used. Isothermal runs were carried out in air, using particle sizes ranging between 48 and 855 μm. The experimental results showed that char reactivity increases with degree...
Experiments with both model compounds (substituted phenols) and with 11 coals (nine British and two American) have established that microwave heating will greatly accelerate silylation reactions of the phenolic -OH groups, e.g. for Creswell coal complete silylation of -OH groups occurs in 35 min in the microwave oven, whereas 24 h is required using a bench reflux technique. Microwave reaction times...
Air blowing of paving grade asphalt has been carried out to produce industrial grade asphalt. Chemical changes during air blowing of asphalt, in the presence of transition metal salts, have been evaluated by adsorption-desorption chromatography. The elemental composition and structural parameters based on ultraviolet (u.v.) and nuclear magnetic resonance (n.m.r.) spectra indicate that straight chain...
Olefinic concentrates were separated from two naphthas, one from fluid catalytic cracking (FCC) and one thermal crackate, using column chromatography. The composition and structure of the olefins were determined by a combination of analytical techniques. FCC naphthas contain relatively higher levels of conjugated dienes. The monoolefins are highly branched. The thermal crackates have higher levels...
Microbial desulfurization of Polish flame coal, characterized by high total concentration of sulfur and a high concentration of pyrite sulfur, was studied. The optimum conditions of the process were established. When using Thiobacillus ferrooxidans bacteria, the best results were obtained with desulfurization carried out on coal samples making 2.4 wt% of the extraction mixture at the initial concentration...
The effect of composition of n-alkanes on the cloud and pour point of their solution in different solvent systems was investigated and a method of identifying the key components responsible for the adverse flow behaviour exhibited by petroleum fluids at low temperature was developed. It was observed that in a given solvent matrix the influence of the composition of the n-alkanes predominates over...
The process of oxidative pyrolysis of Kansk-Achinsk lignite was studied in a pilot installation with capacity 60 kg h - 1 . Powdered lignite with a particle size <0.5 mm was pyrolysed in an air-fluidized bed of open-hearth furnace slag particles. In the initial stage of lignite thermal treatment (0.3 s), intensive formation of mesopores is observed. An extended micropore system is...
Scrap tyres were pyrolysed in two bench-scale reactors: a static batch slow pyrolysis reactor and a fluidized bed reactor. The pyrolysis oils were analysed for their content of sulfur-polycyclic aromatic hydrocarbons (PASH), using a series of liquid column chromatography fractionations with oxidation and reduction to produce a PASH-enriched sample. The PASH were identified and quantified using coupled...
La Mure anthracite was studied by electrical and e.s.r. measurements. The results show a difference of one order of magnitude between the conduction measurements on powdered samples and those on the massive form, although a certain similarity in the development of the conductivity is observed for both e.s.r. measurements confirm to a certain extent the results obtained by dielectric loss measurements.
This paper describes the effect of scanning patterns and number of images in each scan on the accuracy of automated image analysis techniques used for maceral analysis. The results are compared with the accuracy of manual point counting. Current theoretical standards are discussed together with actual results obtained from within the laboratory. Ways of increasing the accuracy of automated maceral...
Olefinic naphthas derived from fluid catalytic cracking (FCC) or thermal cracking units are increasingly being used in high-octane motor gasoline with growing concern for resulting fuel quality. Hindered phenols and substituted arylamines are the two classes of antioxidants generally used for improving the stability of gasoline. The olefin types in cracked naphthas depend strongly on the process...
Diffuse-reflectance spectra (0.3-2.6 μm) of oil sands and mineral separates display a number of absorption bands which can be assigned to the spectrally significant minerals present in the samples. Minerals with strongly featured spectra such as kaolinite, illite and siderite can be identified even when they are minor constituents. Absorption bands in the 1.4 and 1.9 μm regions are most useful for...
Mineral matter of coals of different origin was analysed by several techniques (XRD, AAS and SEM-EDX) and mineral transformations during coal hydrogenation under different experimental conditions were studied. SEM-EDX provides more detailed information on the nature and distribution of these materials and their inorganic-organic relations, mainly revealed as the association of distinct cations (Ca,...
A residue from deasphalting of liquids obtained by direct liquefaction of a Spanish subbituminous coal was processed by thermal treatment. This residue is rich in asphaltenes which do not undergo cracking easily and are coke precursors in thermal cracking. The kinetics of the cracking and coke formation reactions were studied and the viscosity, coke content, boiling point distribution, elemental...