Fuel
To estimate the hydrogen mobility of coal and solvent quantitatively, reactions of tetralin, decalin and 1-methylnaphthalene with tritiated gaseous hydrogen in the absence and presence of Wandoan coal were performed under conditions generally used for coal liquefaction: 300-400°C, initial H 2 pressure 5.9 MPa. Tritium in the gas phase was transferred to coal and solvent mainly through hydrogen...
This paper reports the characterization of successive extract fractions collected during the liquefaction in tetralin of a UK low-rank bituminous coal (Linby), by the use of size exclusion chromatography and u.v. absorption and u.v. fluorescence spectroscopies in a closely related manner. Successive liquefaction product fractions shift progressively to greater molecular masses with increasing extent...
A new simulation method has been performed for an entrained-flow coal gasifier. A multivariable model for the gasifier has been set up on the basis of equilibrium, mass balance and energy balance by means of non-linear programming. The Shell coal gasifier was used as a typical model for an entrained-flow coal-oxygen gasifier, and the calculated gasification products are very close to the actual...
The thermal behaviour of selected polymorphic even-numbered and odd-numbered n-alkanes, namelyn -C 2 3 H 4 8 n-C 2 5 H 5 2 , n-C 2 8 H 5 8 ,n -C 3 0 H 6 2 , n-C 3 3 H 6 8 , n-C 3 4 H 7 0 andn -C 3 7 H 7 6 was studied using differential...
One recently considered concept of beneficiation of low rank coal is elimination of moisture by immersion of the coal in hot heavy oil. The problem of the subsequent drainage of oil from the coal particles is cited as a major difficulty of this process. In the present paper a theoretical analysis of drainage hydrodynamics has been carried out to indicate the practical possibility for application...
Mineral matter was removed from anthracite by heating in 0.1 MPa Cl 2 at 600-1400°C. The mineral matter undergoes carbothermic reduction, followed by chlorination of metals to volatile chlorides. Removal of mineral matter increases the porosity of the coal and enhances the accessibility of additional mineral matter to Cl 2 . Exposure to Cl 2 results in the fixation of chlorine...
Gasification characteristics are described for five coals of different rank which were gasified with air-steam or oxygen-steam mixtures in a 5 kg coal h - 1 continuous spouted bed reactor at pressures to 1440 kPa. Results show the suitability of the different coals for dry ash spouted-fluid bed gasification, the processing requirements for low and medium calorific value gas, and the approach...
Activity for the hydrodenitrogenation (HDN) of quinoline has been studied at an overall pressure of 7 MPa in the temperature range 623-698 K, on a series of doubly promoted ZnCo-Mo catalysts supported on fluorinated alumina (0.0-2.0 wt% F). For the F free catalysts the partial substitution of Co by Zn does not affect HDN activity. However, for the fluorinated catalyst series, the HDN activity was...
High temperature desulfurization of gases from coal gasification processes has important aspects for many industrial applications and electrical power generation plants. MnO, supported by γ-Al 2 O 3 (MnO/γ-Al 2 O 3 ), was used as a regenerable sorbent for high temperature removal of H 2 S from gases. The sorbent was prepared by wet impregnation and tested for...
Analysis by Fourier transform infrared (FT-i.r.) spectroscopy of coals and their extraction products, i.e. extracts and residues, gives an insight into the chemical structure of the initial material and changes due to the separation procedure. High quality spectra are obtained for solids by diffuse reflectance FT-i.r. spectroscopy. They also provide rather broad overlapping bands which have to be...
The solubility of four coal tar pitches in several organic solvents and the semiquantitative gas chromatographic analysis of the corresponding volatile fraction extracts are discussed. Close relationships between the extraction yield and the chromatographic material concentration of the several extracts studied are found. These correlations show that the increase in extraction ability from one solvent...
Two bituminous non-coking coals were selected to investigate the contribution of pressure and gas atmosphere (hydrogen and helium) on their textural and microtextural evolution during carbonization in a 100 g fixed bed semi batch unit. Microtextural analysis was carried out by transmission electron microscopy (TEM) with the help of 0 0 2 dark field images, whereas the texture was established by polarizing...
For engineering design considerations, it is essential to correlate adequately the results obtained from R&D with those from commercial plants, so that the effect of scaling-up can efficiently be taken into account in predicting NO x levels when designing large combustion equipment to be employed in different end-use applications. INETI has very recently started compiling both R&D...
Soot formation during the pyrolysis of argon-diluted mixtures of toluene and n-heptane and of toluene and iso-octane in a reflected-shock tube was studied. Soot induction times and rates of formation measured at 632.8 nm by laser beam attenuation showed an Arrhenius dependence on reflected-shock temperature. The maximum in bell-shaped distribution of soot yield and concentration as a function of...
Emissions of N 2 O from various coal fired appliances have been measured. The results show that conventional appliances generally emit low levels of N 2 O [< 30 mg m - 3 (STP)]. Fluidized beds usually emit considerably higher levels, due to the lower combustion temperatures prevailing in such plant. In order to study the mechanisms underlying N 2 O formation...
Thermal decomposition of pure cyclotrimethylene trinitramine (RDX) shows an endothermic peak at 205°C attributed to melting, followed by exothermic decomposition leading to a strong peak at 240°C, and a very strong thermogravimetric peak at 260°C with a mass loss of 95%. However, the mixture of RDX, nitrocellulose and carbon (FX 300) shows a melting peak at 202°C with reduced intensity, and a decomposition...
Fourier transform infrared (FT-i.r.) spectroscopy was used to calculate the research octane number (RON) of naphtha feed and reformate during the course of performance evaluation of reforming catalysts. Five absorption regions that correspond to aliphatic and aromatic bands within the mid-infrared region were utilized for developing the correlation for RON estimation. Statistical methods were used...
The use of particle size distribution for distinguishing asphalt colloidal types was compared with a more traditional rheological method. Six petroleum and natural asphalts representing the full range of types were examined. The results indicate that size distribution shows a good correlation with the colloidal type as determined by rheological means and may be a satisfactory basis for distinguishing...
Iron-loaded raw and demineralized birch chars were hydrogasified in a thermobalance to examine the influence of ash removal on their reactivities at 700 and 800°C. Demineralization was so effective in enhancing the reactivity in the low-temperature region that 4 wt% iron loading gave a conversion of 90 wt% at 700°C. The increased catalytic effect of iron in the absence of wood ash can be explained...