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02901 Changes in the structure of coals of different rank due to oxidation-effects on pyrolysis behavior
07
01
Solid fuels (sources, winning, properties)
SOLID Sources,
FUELS Winning,
Properties
99102898 Assessment of coal handleability Lahlouls, E. H. et al. World Congr. Part. Technol. 3, [computer optical disk], 1998, 3350-3362. This paper describes the design and use of a tester developed to enable rapid-assessment of the handling characteristics of a coal, which is of importance for the smooth operation of a coal handling plant. The Edinburgh Cohesion Tester is for use of uniaxial unconfined compression of bulk solids. It was designed to be easy to use, portable, robust and relatively cheap. The tester undergoes rigorous testing including checking for test repeatability and sensitivity to the test operator. Additionally, the effects of various factors such as consolidation pressure, moisture content and particle size have been investigated. The results indicate great potential for this cohesion tester. Calculation of the Frank-Kamenetskii critical 99102899 parameter for a cubic reactant shape from experimental results on bituminous coals Jones, J. C. Fuel, 1999, 78, (1) 89-91. Using results previously reported for the spontaneous heating of bituminous coals, the Frank-Kamenetskii parameter is calculated in respect of each for the cubic reactant assembly used in the original experimental work. Comparisons are made with the results of other attempts to obtain this quantity by means of ignition experiments. Carbonization of iron-treated Loy Yang coal 99102900 Ozaki, J.-i. et al. Fue/, 1999, 78, (4), 489-499. At selected temperatures in the range of 200-7OO”C, carbonization of untreated and iron-treated Loy Yang coal was carried out. The electrical conductivity was higher in all the iron-treated samples, except for the sample prepared at 7Oo”C, which was identical. Arrhenius plots of the conductivity of carbons treated above 500°C exhibited considerable nonlinearity but showed that the conductivity increase was caused by a change in the pre-exponential factor rather than in the activation energy. Mossbauer measurements revealed that the three, initially dispersed, paramagnetic iron species were transformed into magnetite and then principally, o- and y-iron between 400°C and 600°C. The electrical conductivity depended strongly on the concentration of carboxyl groups and suggested a model in which conduction between the r-electron reservoirs was via an electron hopping mechanism along hydrogen-bonded cross-links. The enhanced removal of the carboxyl groups by the presence of iron aids the destruction of these poorly conducting links during carbonization. 99102901 Changes in the structure of coals of different rank due to oxidation-effects on pyrolysis behavior de la Puente, G. er al. .I. Analysis Appl. Pyrolysis, 1998, 47, (l), 33-42. In this paper, relations between structural changes, due to coalification and oxidation and the changes in pyrolysis behaviour of coals are discussed. Five coals of different rank were used for the study. Information about changes in functional groups was obtained using Fourier transform infrared spectroscopy (FTIR). The pyrolysis behaviour of coals was evaluated by means of differential thermal analysis (DTA). The temperature of maximum volatile release was used as a parameter indicative of coal rank. The results obtained showed that oxidation leads to an increase in carbonyl and carboxyl functionalities at the expense of both aliphatic and aromatic hydrogen. The presence of these oxygenated groups in the structure of the coals gave rise to an increase in the percentage of volatile matter released in the low temperature range. The reactivity of aliphatic hydrogen plays a major role in pyrolysis behaviour in the intermediate temperature range. There may exist a relation between the relative proportion of volatile matter evolved at high temperatures and the proportion of aromatic hydrogen. A classification of coals that reflects rank and oxidation degree can be constructed on the basis of the relative amount of volatiles released during the various stages of pyrolysis. Characterisation of Spanish coal by means of 99102902 Mossbauer spectroscopy Ahmed, M. A. et al. Fuel, 1999, 78, (4), 453-457. Ranging from lignite to semi-anthracite, seven Spanish coals have been characterized by Mossbauer spectroscopy (MS) at room temperature (RT) and 80 K. The aromaticities as obtained from Fourier transform infrared spectroscopy (FTIR) varied from 0.44 to 0.96. From the analysis of the Mossbauer spectra the iron bearing minerals were found to be mainly pyrite and sulphates in all the samples. Jarosite was only found to be present in lignite, brown and sub-bituminous coal. However, iron carbonates, mainly as siderite were only detected in the bituminous and semi-anthracite that have higher aromaticities (0.71, 0.95 and 0.96).
310
Fuel and Energy Abstracts
September
1999
Characteristics of nitrogen-containing aromatic 99102903 compounds in coal tars during secondary pyrolysis Yu, L. E. et al. Fuel, 1999, 78, (3), 377-385. The classification of nitrogen-containing polycyclic aromatic compounds (NPAC) emitted from two types of coal throughout secondary pyrolysis was established according to their fused aromatic ring number. During the very early stages of secondary pyrolysis, neutral NPACs decrease due to direct conversion to soot, which is similar to that previously observed for neutral PAC. As secondary pyrolysis proceeds, neutralization of more polar compounds causes an increase in the non-polar NPAC and the two- and three-ring NPAC exhibit a greater persistence than their corresponding neutral PAC analogues. Unique trends in two-ring NPAC for both coal tars during the latter half of secondary pyrolysis, reported here for the first time, can be attributed to a reaction between acetylene and pyridine. Although soot formation is not significantly affected by the small quantity of NPAC present, the observed stability of NPAC under severe thermal conditions suggests that they may be present in emissions. Coal mine helps endangered wallaby survive 99102904 Anon QGMJ, 1999, 100, (1167), 52-53. This article reports on the role of BHP’s Gregory coal mine near Emerald, Queensland, in saving one of Australia’s most endangered species, the wallaby, from extinction. The mine is being used to establish a viable Bridled Nailtail wallaby population before its release into the wild. 99102905 Coal studies by small angle X-ray scattering Mitropoulos, A. C. et al. Microporous Mesoporous Mater., 1998, 24, (l-3), 29-39. Adsorption and small-angle X-ray scattering (SAXS) was used to characterize two highly volatile bituminous coal samples. The SAXS measurements were repeated on samples that had been brought to equilibrium at various relative pressures of carbon tetrachloride which has a similar electron density as the coals. The validity of this combined technique was ascertained by reconstructing the adsorption isotherms from the SAXS data. A theoretical approach connecting the two methods was considered and simple formulas were derived. The reconstruction of the adsorption isotherm is influenced by several parameters. Adsorption in conjunction with SAXS can provide information on the pore structure, the adsorption mechanism and the swelling of the solid matrix upon adsorption. Corn arison of coal composition and elemental 99102906 distribution in se Pected seams of the Sydney and Stellarton Basins, Nova Scotia, eastern Canada Mukhopadhyay, P. K. et al. Int. J. Coal Geol., 1998, 37, (l-2). 113-141. In order to derive their organic and inorganic components, selected high to medium volatile bituminous coal seams of Carboniferous age from the Sydney and Stellarton Basins, Nova Scotia, Eastern Canada were analysed. These studies evaluated: (a) the evolution of the ancestral mires (coal facies) that formed various seams; (b) the lateral and vertical distribution of various elements within coal facies (lithotypes); and (c) the mode of occurrence of various elements. 99102907 Conditions for formation and germanium content in the Lower Jurassic coal deposits in the western part of Northern Caucasus Kizil’shtein, L. Y. Izv. Vyssh. Uchebn. Zaved., Sev.-Kavk. Reg., Estesfv. Nauki, 1998, (2), 90-95. (In Russian) The paper discusses the palaeogeographical evolution of conditions of peat accumulation and genetic interpretation of occurrence of germanium and other elements in coals based on petrogenetic composition of coal-bearing strata. It was suggested that consideration of economics of field development should include coal seams, mining and geological conditions of extraction and use. 99102908 Effect of mixing coal on the indexes of coal quality Wang, X. et al. Huagong Kuangwu Yu Jiagong, 1998, 27, (5), 17-19. (In Chinese) Three typical types of coal were subjected to mixing coal tests. The determination and computation results of main quality mixing-ratio indexes of coal used for export, application example and the points for attention of mixing and sampling are introduced. Evaluation of efficient use of reserves of coking 99102909 coals Freidina, E. N. et al. Fiz. Tekh. Probl. Razrab. Polezn. Iskop., 1997, (5), 9099. (In Russian) Based on coal proximate composition (ash content), mining process characteristics and beneficiation yields, the actual (useable) reserves and production goals of coking coal deposits are calculated. 99102910 FTIR spectroscopy and reflectance of modern charcoals and fungal decayed woods: implications for studies of inertinite in coals Guo, Y. and Bustin, R. M. Int. 3. Coal Geol., 1998, 37, (l-2), 29-53. Using FTIR and standard petrol techniques, the chemical and physical characteristics of laboratory produced charcoals, natural charcoals, fungal decayed woods and inertinite from a variety of western Canadian coals have been investigated. These studies confirm and extend earlier work in
01
Solid fuels (sources, winning, properties)
SOLID Sources,
FUELS Winning,
Properties
99102898 Assessment of coal handleability Lahlouls, E. H. et al. World Congr. Part. Technol. 3, [computer optical disk], 1998, 3350-3362. This paper describes the design and use of a tester developed to enable rapid-assessment of the handling characteristics of a coal, which is of importance for the smooth operation of a coal handling plant. The Edinburgh Cohesion Tester is for use of uniaxial unconfined compression of bulk solids. It was designed to be easy to use, portable, robust and relatively cheap. The tester undergoes rigorous testing including checking for test repeatability and sensitivity to the test operator. Additionally, the effects of various factors such as consolidation pressure, moisture content and particle size have been investigated. The results indicate great potential for this cohesion tester. Calculation of the Frank-Kamenetskii critical 99102899 parameter for a cubic reactant shape from experimental results on bituminous coals Jones, J. C. Fuel, 1999, 78, (1) 89-91. Using results previously reported for the spontaneous heating of bituminous coals, the Frank-Kamenetskii parameter is calculated in respect of each for the cubic reactant assembly used in the original experimental work. Comparisons are made with the results of other attempts to obtain this quantity by means of ignition experiments. Carbonization of iron-treated Loy Yang coal 99102900 Ozaki, J.-i. et al. Fue/, 1999, 78, (4), 489-499. At selected temperatures in the range of 200-7OO”C, carbonization of untreated and iron-treated Loy Yang coal was carried out. The electrical conductivity was higher in all the iron-treated samples, except for the sample prepared at 7Oo”C, which was identical. Arrhenius plots of the conductivity of carbons treated above 500°C exhibited considerable nonlinearity but showed that the conductivity increase was caused by a change in the pre-exponential factor rather than in the activation energy. Mossbauer measurements revealed that the three, initially dispersed, paramagnetic iron species were transformed into magnetite and then principally, o- and y-iron between 400°C and 600°C. The electrical conductivity depended strongly on the concentration of carboxyl groups and suggested a model in which conduction between the r-electron reservoirs was via an electron hopping mechanism along hydrogen-bonded cross-links. The enhanced removal of the carboxyl groups by the presence of iron aids the destruction of these poorly conducting links during carbonization. 99102901 Changes in the structure of coals of different rank due to oxidation-effects on pyrolysis behavior de la Puente, G. er al. .I. Analysis Appl. Pyrolysis, 1998, 47, (l), 33-42. In this paper, relations between structural changes, due to coalification and oxidation and the changes in pyrolysis behaviour of coals are discussed. Five coals of different rank were used for the study. Information about changes in functional groups was obtained using Fourier transform infrared spectroscopy (FTIR). The pyrolysis behaviour of coals was evaluated by means of differential thermal analysis (DTA). The temperature of maximum volatile release was used as a parameter indicative of coal rank. The results obtained showed that oxidation leads to an increase in carbonyl and carboxyl functionalities at the expense of both aliphatic and aromatic hydrogen. The presence of these oxygenated groups in the structure of the coals gave rise to an increase in the percentage of volatile matter released in the low temperature range. The reactivity of aliphatic hydrogen plays a major role in pyrolysis behaviour in the intermediate temperature range. There may exist a relation between the relative proportion of volatile matter evolved at high temperatures and the proportion of aromatic hydrogen. A classification of coals that reflects rank and oxidation degree can be constructed on the basis of the relative amount of volatiles released during the various stages of pyrolysis. Characterisation of Spanish coal by means of 99102902 Mossbauer spectroscopy Ahmed, M. A. et al. Fuel, 1999, 78, (4), 453-457. Ranging from lignite to semi-anthracite, seven Spanish coals have been characterized by Mossbauer spectroscopy (MS) at room temperature (RT) and 80 K. The aromaticities as obtained from Fourier transform infrared spectroscopy (FTIR) varied from 0.44 to 0.96. From the analysis of the Mossbauer spectra the iron bearing minerals were found to be mainly pyrite and sulphates in all the samples. Jarosite was only found to be present in lignite, brown and sub-bituminous coal. However, iron carbonates, mainly as siderite were only detected in the bituminous and semi-anthracite that have higher aromaticities (0.71, 0.95 and 0.96).
310
Fuel and Energy Abstracts
September
1999
Characteristics of nitrogen-containing aromatic 99102903 compounds in coal tars during secondary pyrolysis Yu, L. E. et al. Fuel, 1999, 78, (3), 377-385. The classification of nitrogen-containing polycyclic aromatic compounds (NPAC) emitted from two types of coal throughout secondary pyrolysis was established according to their fused aromatic ring number. During the very early stages of secondary pyrolysis, neutral NPACs decrease due to direct conversion to soot, which is similar to that previously observed for neutral PAC. As secondary pyrolysis proceeds, neutralization of more polar compounds causes an increase in the non-polar NPAC and the two- and three-ring NPAC exhibit a greater persistence than their corresponding neutral PAC analogues. Unique trends in two-ring NPAC for both coal tars during the latter half of secondary pyrolysis, reported here for the first time, can be attributed to a reaction between acetylene and pyridine. Although soot formation is not significantly affected by the small quantity of NPAC present, the observed stability of NPAC under severe thermal conditions suggests that they may be present in emissions. Coal mine helps endangered wallaby survive 99102904 Anon QGMJ, 1999, 100, (1167), 52-53. This article reports on the role of BHP’s Gregory coal mine near Emerald, Queensland, in saving one of Australia’s most endangered species, the wallaby, from extinction. The mine is being used to establish a viable Bridled Nailtail wallaby population before its release into the wild. 99102905 Coal studies by small angle X-ray scattering Mitropoulos, A. C. et al. Microporous Mesoporous Mater., 1998, 24, (l-3), 29-39. Adsorption and small-angle X-ray scattering (SAXS) was used to characterize two highly volatile bituminous coal samples. The SAXS measurements were repeated on samples that had been brought to equilibrium at various relative pressures of carbon tetrachloride which has a similar electron density as the coals. The validity of this combined technique was ascertained by reconstructing the adsorption isotherms from the SAXS data. A theoretical approach connecting the two methods was considered and simple formulas were derived. The reconstruction of the adsorption isotherm is influenced by several parameters. Adsorption in conjunction with SAXS can provide information on the pore structure, the adsorption mechanism and the swelling of the solid matrix upon adsorption. Corn arison of coal composition and elemental 99102906 distribution in se Pected seams of the Sydney and Stellarton Basins, Nova Scotia, eastern Canada Mukhopadhyay, P. K. et al. Int. J. Coal Geol., 1998, 37, (l-2). 113-141. In order to derive their organic and inorganic components, selected high to medium volatile bituminous coal seams of Carboniferous age from the Sydney and Stellarton Basins, Nova Scotia, Eastern Canada were analysed. These studies evaluated: (a) the evolution of the ancestral mires (coal facies) that formed various seams; (b) the lateral and vertical distribution of various elements within coal facies (lithotypes); and (c) the mode of occurrence of various elements. 99102907 Conditions for formation and germanium content in the Lower Jurassic coal deposits in the western part of Northern Caucasus Kizil’shtein, L. Y. Izv. Vyssh. Uchebn. Zaved., Sev.-Kavk. Reg., Estesfv. Nauki, 1998, (2), 90-95. (In Russian) The paper discusses the palaeogeographical evolution of conditions of peat accumulation and genetic interpretation of occurrence of germanium and other elements in coals based on petrogenetic composition of coal-bearing strata. It was suggested that consideration of economics of field development should include coal seams, mining and geological conditions of extraction and use. 99102908 Effect of mixing coal on the indexes of coal quality Wang, X. et al. Huagong Kuangwu Yu Jiagong, 1998, 27, (5), 17-19. (In Chinese) Three typical types of coal were subjected to mixing coal tests. The determination and computation results of main quality mixing-ratio indexes of coal used for export, application example and the points for attention of mixing and sampling are introduced. Evaluation of efficient use of reserves of coking 99102909 coals Freidina, E. N. et al. Fiz. Tekh. Probl. Razrab. Polezn. Iskop., 1997, (5), 9099. (In Russian) Based on coal proximate composition (ash content), mining process characteristics and beneficiation yields, the actual (useable) reserves and production goals of coking coal deposits are calculated. 99102910 FTIR spectroscopy and reflectance of modern charcoals and fungal decayed woods: implications for studies of inertinite in coals Guo, Y. and Bustin, R. M. Int. 3. Coal Geol., 1998, 37, (l-2), 29-53. Using FTIR and standard petrol techniques, the chemical and physical characteristics of laboratory produced charcoals, natural charcoals, fungal decayed woods and inertinite from a variety of western Canadian coals have been investigated. These studies confirm and extend earlier work in