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02034 Reactivity and structural change of coal char during steam gasification
02 Liquid fuels (sources, properties, recovery) tion temperature may serve to indicate the degree of dangerousness of a coal. The fissure pattern of the semicoke was found to be related to the coking pressure and semicoke contraction.
06102032 Physical characteristics of carbon materials derived from pyrolysed vascular plants Krzesinska, M. et al. Biomass and Bioenergy, 2006, 30, (2), 166-176. The purpose of this study was to develop new monolithic porous carbon materials from vascular plants using highly controlled pyrolysis. Perennial plants belonging to the grass family Poaceae such as bamboo (Bambusa vulgaris) and to the family Agavaceae such as yucca (Yucca .flaccidal characterized by a homogeneous profile and homogenous vessel distribution were selected for the study. They were heat-treated at temperatures 550 and 950°C in a nitrogen atmosphere to produce a crack-free monolithic porous carbon materials for which physical characteristics such as density, porosity, yield and dimensional changes were determined. The EPR spectroscopy, ultrasonic technique and optical microscopy were applied for further characterization. All samples studied demonstrated a reduction in apparent density and dimensions due to carbonization. It was found that similarly as in the case of hardwoods, the higher the carbonization temperature, the greater the dimensional shrinkage. The greatest changes were observed m "transverse' to plant fibres directions, i.e. for radial and tangential. It was found that the dimensional changes under heat-treatment exhibited transverse isotropy. Carbonized plants were characterized by elastic moduli almost independent of apparent density in contrast to elasticity of precursors. Elastic moduli of samples carbonized to 950°C were higher than those heat-treated to 550~C. Results showed that materials carbonized at higher temperature were stiffer and more ordered in structure. Microscopic observations showed that during heat-treatment of yucca and bamboo, their tissue structure remained unaltered. There was the increase in order of aromatic layers in the walls of fibres expressed by the increase of optical reflectance values through the carbonization process. It was found that heating plants to 950°C quenched paramagnetic centres in carbonized samples. This effect resulted from an increase of multi-ring aromatic units in the samples. The observed lack of saturation of the EPR spectra evidenced that during slow pyrolysis defects were not created. Carbonized woody stems of perennials studied were found as very porous, but stiff materials, which can be excellent precursors (as skeleton) for new ecomaterials, e.g. for wood-ceramics.
06/02035 The taphonomy of charcoal following a recent heathland fire and some implications for the interpretation of fossil charcoal deposits Scott, A. C. et al. Palaeogeograplzy. Palaeoclimatology, Palaeoecology, 2000, 164, (1-4), 1-31. In May 1995, fire burnt an area of heathland with stands of pine and birch trees in the Frensham Common Country Park near Tilford in Surrey, southeast England. Extensive areas were burnt by a rapidly spreading surface fire, and charcoal was produced from both the living plants and plant litter. Flames reached a height of no more than 2 m so that whilst much of the low growing vegetation was destroyed, the trees generally survived the burn. Samples were taken of unburnt living plants and unburnt litter as well as charcoal from heathland and adjacent woodland and small channels running through the locality. Much of the heathland charcoal was produced from living vegetation and included wood, leafy shoots, flowers and fruits of Callmla vulgaris (common heather) and rachises and pinnae of the fern Pteridium aquilinum (bracken). The surface peaty layer here was only charred to a depth of 1 or 2 mm. In contrast, the bulk of the charcoal from the Pimts svlvestris (scots pine) and Betula pendula (silver birch) trees was from litter, none of the lower branches of the trees having caught alight. Only a few fallen logs produced much wood charcoal. Fallen P. svh,estris female cones were typically only charred upon their upwardfacing surface. Strong winds across the heathland following the fire gathered the charred C. vulgaris small leafy shoots, flowers and fruits into ripple concentrates. Movement of the charcoal by water following rain storms was also tracked from the heathland onto bare crossing paths and into depressions and channels as well as into a small nearby lake. Water transport resulted in selective bias in favour of wood charcoal. None of the other charred organs reached the lake. Scanning electron microscopy shows that a wide range of plant taxa and organs may be anatomically preserved by charcoalification, and plants covered with fungal hyphae (possibly indicating decomposition) were also found charred. Studies of samples in polished blocks show that all plant organs have increased reflectance under oil. Mean random reflectance under oil of all samples was 1.53 (range 0.13-6.22), which indicates that if preserved in the fossil record, they would be classified as the coal maceral semifusinite. Comparisons with fossil deposits are made, and this study may contribute to our understanding of charcoalifled flower concentrates (e,g. the late Cretaceous of Sweden and the USA) and deposits rich in fern charcoal (e.g. of the early Cretaceous of southern England).
06•02033 Production and characterization of synthetic wood chars for use as surrogates for natural sorbents Brown, R. A. et ul. Organic Geochemistry, 2006, 37, (3), 321 333. Wood char is an important source of environmental black carbon that affects the fate of organic contaminants in soils and sediments and plays a role in carbon cycling. Currently, the research community has need for char standards for laboratory use that are representative of naturally occurring chars. This investigation presents a scientific approach to the production of synthetic chars that have properties of a natural char produced by forest fire. The natural char examined for this purpose was that of a pitch pine obtained from the New Jersey pine barrens; however, the developed characterization approach is more generally applicable toward understanding and producing surrogate synthetic materials for any natural wood char. Small blocks of pitch pine wood were pyrolysed using ramp rates between 30 and 1000°C/h and with maximum temperatures between 450 and 1000:C. The chars were then characterized using helium-based solid density, electrical resistivity, H/C ratio, PAH analysis and surface area measurements. A comparison of these key parameters among the synthetic and natural chars clearly demonstrated that the natural char had experienced maximum temperatures of 500-600°C. Additional studies based on reheating suggest that the char had experienced very rapid heating rates (greater than 200°C/h) during its formation.
06/02034 Reactivity and structural change of coal char during steam gasification Sekine, Y. et al. Fuel, 2006, 85, (2), 122 126. This study is intended to clarify the relationship among the reactivity of coal char with steam, structural change in residual carbon, and ash behaviour. Steam gasification of various coal chars and demineralized chars was carried out in a fixed-bed reactor. After gasification, the reacted char was analysed using laser raman spectroscope (LRS), and scanning electron microscope, energy dispersive X-ray spectroscope (SEM/EDX) mapping. Results of SEM images and EDX-mappings revealed that novel parallel analysis of cross correlation between EDXmapping and LRS-mapping was found to be very effective for the comprehensive evaluation of ash behaviour and carbonaceous structure. As the gasification reaction proceeds, the reactivity of the char was varied; existence of Si and A1 seemed to suffocate the char reactivity.
02
LIQUID FUELS Sources, properties, recovery
06•02036 Application of production geochemistry for new exploration of the Cicuco-Boquete-Violo area: Colombia Rangel, A. et al. Ciencia Tecnologia y Future, 2004, 2, (5), 69-82. This study involves the oil geochemical evaluation of 28 wells in the Cicuco-Boquete area with the purpose to establish reservoir continuity, to infer pathways of hydrocarbon migration and opportunities for new explorations in the area. As for reservoir connectivity, the Momposina and Boquilla fields are not connected among themselves or to the Cicuco-Boquete fields and the Cicuco-Boquete oils seem constitute various subgroups, indicating stratigraphic and/or structural discontinuities inside their reservoirs. The Cidnaga de Ore Formation is the main source rock in the area and their extracts show correlation with crude oils from the Cicueo-Boquete fields. As for the pathway of migration related to the Ci~naga de Ore formation, the generation zone can be divided in at least three areas, related to the two main faulting tendencies. These are four different migration routes related to the accumulations of: (1) Cicuco-Boquete; (2) Momposina-1; (3) Ayombe-1 and Guepaj6-1; and, (4) Apure-1 and Apure-2X. Regarding new exploration opportunities, it is suggested that structures located along the migration route be evaluated, especially those structures along the migration pathway.
06102037 Application of the Box-Wilson experimental design method for the spherical oil agglomeration of coal Cebeci, Y. and S6nmez, I. Fuel, 2006, 85, (3), 289-297. In this study, the Box-Wilson statistical experimental design method was employed to evaluate the effects of important variables such as bridging liquid (oil) concentration, salt (CaC12.2H20) concentration and stirring speed on the agglomeration of bituminous coal. Response function coefficients were determined by the regression analysis of
Fuel and Energy Abstracts
September 2006
315
06102032 Physical characteristics of carbon materials derived from pyrolysed vascular plants Krzesinska, M. et al. Biomass and Bioenergy, 2006, 30, (2), 166-176. The purpose of this study was to develop new monolithic porous carbon materials from vascular plants using highly controlled pyrolysis. Perennial plants belonging to the grass family Poaceae such as bamboo (Bambusa vulgaris) and to the family Agavaceae such as yucca (Yucca .flaccidal characterized by a homogeneous profile and homogenous vessel distribution were selected for the study. They were heat-treated at temperatures 550 and 950°C in a nitrogen atmosphere to produce a crack-free monolithic porous carbon materials for which physical characteristics such as density, porosity, yield and dimensional changes were determined. The EPR spectroscopy, ultrasonic technique and optical microscopy were applied for further characterization. All samples studied demonstrated a reduction in apparent density and dimensions due to carbonization. It was found that similarly as in the case of hardwoods, the higher the carbonization temperature, the greater the dimensional shrinkage. The greatest changes were observed m "transverse' to plant fibres directions, i.e. for radial and tangential. It was found that the dimensional changes under heat-treatment exhibited transverse isotropy. Carbonized plants were characterized by elastic moduli almost independent of apparent density in contrast to elasticity of precursors. Elastic moduli of samples carbonized to 950°C were higher than those heat-treated to 550~C. Results showed that materials carbonized at higher temperature were stiffer and more ordered in structure. Microscopic observations showed that during heat-treatment of yucca and bamboo, their tissue structure remained unaltered. There was the increase in order of aromatic layers in the walls of fibres expressed by the increase of optical reflectance values through the carbonization process. It was found that heating plants to 950°C quenched paramagnetic centres in carbonized samples. This effect resulted from an increase of multi-ring aromatic units in the samples. The observed lack of saturation of the EPR spectra evidenced that during slow pyrolysis defects were not created. Carbonized woody stems of perennials studied were found as very porous, but stiff materials, which can be excellent precursors (as skeleton) for new ecomaterials, e.g. for wood-ceramics.
06/02035 The taphonomy of charcoal following a recent heathland fire and some implications for the interpretation of fossil charcoal deposits Scott, A. C. et al. Palaeogeograplzy. Palaeoclimatology, Palaeoecology, 2000, 164, (1-4), 1-31. In May 1995, fire burnt an area of heathland with stands of pine and birch trees in the Frensham Common Country Park near Tilford in Surrey, southeast England. Extensive areas were burnt by a rapidly spreading surface fire, and charcoal was produced from both the living plants and plant litter. Flames reached a height of no more than 2 m so that whilst much of the low growing vegetation was destroyed, the trees generally survived the burn. Samples were taken of unburnt living plants and unburnt litter as well as charcoal from heathland and adjacent woodland and small channels running through the locality. Much of the heathland charcoal was produced from living vegetation and included wood, leafy shoots, flowers and fruits of Callmla vulgaris (common heather) and rachises and pinnae of the fern Pteridium aquilinum (bracken). The surface peaty layer here was only charred to a depth of 1 or 2 mm. In contrast, the bulk of the charcoal from the Pimts svlvestris (scots pine) and Betula pendula (silver birch) trees was from litter, none of the lower branches of the trees having caught alight. Only a few fallen logs produced much wood charcoal. Fallen P. svh,estris female cones were typically only charred upon their upwardfacing surface. Strong winds across the heathland following the fire gathered the charred C. vulgaris small leafy shoots, flowers and fruits into ripple concentrates. Movement of the charcoal by water following rain storms was also tracked from the heathland onto bare crossing paths and into depressions and channels as well as into a small nearby lake. Water transport resulted in selective bias in favour of wood charcoal. None of the other charred organs reached the lake. Scanning electron microscopy shows that a wide range of plant taxa and organs may be anatomically preserved by charcoalification, and plants covered with fungal hyphae (possibly indicating decomposition) were also found charred. Studies of samples in polished blocks show that all plant organs have increased reflectance under oil. Mean random reflectance under oil of all samples was 1.53 (range 0.13-6.22), which indicates that if preserved in the fossil record, they would be classified as the coal maceral semifusinite. Comparisons with fossil deposits are made, and this study may contribute to our understanding of charcoalifled flower concentrates (e,g. the late Cretaceous of Sweden and the USA) and deposits rich in fern charcoal (e.g. of the early Cretaceous of southern England).
06•02033 Production and characterization of synthetic wood chars for use as surrogates for natural sorbents Brown, R. A. et ul. Organic Geochemistry, 2006, 37, (3), 321 333. Wood char is an important source of environmental black carbon that affects the fate of organic contaminants in soils and sediments and plays a role in carbon cycling. Currently, the research community has need for char standards for laboratory use that are representative of naturally occurring chars. This investigation presents a scientific approach to the production of synthetic chars that have properties of a natural char produced by forest fire. The natural char examined for this purpose was that of a pitch pine obtained from the New Jersey pine barrens; however, the developed characterization approach is more generally applicable toward understanding and producing surrogate synthetic materials for any natural wood char. Small blocks of pitch pine wood were pyrolysed using ramp rates between 30 and 1000°C/h and with maximum temperatures between 450 and 1000:C. The chars were then characterized using helium-based solid density, electrical resistivity, H/C ratio, PAH analysis and surface area measurements. A comparison of these key parameters among the synthetic and natural chars clearly demonstrated that the natural char had experienced maximum temperatures of 500-600°C. Additional studies based on reheating suggest that the char had experienced very rapid heating rates (greater than 200°C/h) during its formation.
06/02034 Reactivity and structural change of coal char during steam gasification Sekine, Y. et al. Fuel, 2006, 85, (2), 122 126. This study is intended to clarify the relationship among the reactivity of coal char with steam, structural change in residual carbon, and ash behaviour. Steam gasification of various coal chars and demineralized chars was carried out in a fixed-bed reactor. After gasification, the reacted char was analysed using laser raman spectroscope (LRS), and scanning electron microscope, energy dispersive X-ray spectroscope (SEM/EDX) mapping. Results of SEM images and EDX-mappings revealed that novel parallel analysis of cross correlation between EDXmapping and LRS-mapping was found to be very effective for the comprehensive evaluation of ash behaviour and carbonaceous structure. As the gasification reaction proceeds, the reactivity of the char was varied; existence of Si and A1 seemed to suffocate the char reactivity.
02
LIQUID FUELS Sources, properties, recovery
06•02036 Application of production geochemistry for new exploration of the Cicuco-Boquete-Violo area: Colombia Rangel, A. et al. Ciencia Tecnologia y Future, 2004, 2, (5), 69-82. This study involves the oil geochemical evaluation of 28 wells in the Cicuco-Boquete area with the purpose to establish reservoir continuity, to infer pathways of hydrocarbon migration and opportunities for new explorations in the area. As for reservoir connectivity, the Momposina and Boquilla fields are not connected among themselves or to the Cicuco-Boquete fields and the Cicuco-Boquete oils seem constitute various subgroups, indicating stratigraphic and/or structural discontinuities inside their reservoirs. The Cidnaga de Ore Formation is the main source rock in the area and their extracts show correlation with crude oils from the Cicueo-Boquete fields. As for the pathway of migration related to the Ci~naga de Ore formation, the generation zone can be divided in at least three areas, related to the two main faulting tendencies. These are four different migration routes related to the accumulations of: (1) Cicuco-Boquete; (2) Momposina-1; (3) Ayombe-1 and Guepaj6-1; and, (4) Apure-1 and Apure-2X. Regarding new exploration opportunities, it is suggested that structures located along the migration route be evaluated, especially those structures along the migration pathway.
06102037 Application of the Box-Wilson experimental design method for the spherical oil agglomeration of coal Cebeci, Y. and S6nmez, I. Fuel, 2006, 85, (3), 289-297. In this study, the Box-Wilson statistical experimental design method was employed to evaluate the effects of important variables such as bridging liquid (oil) concentration, salt (CaC12.2H20) concentration and stirring speed on the agglomeration of bituminous coal. Response function coefficients were determined by the regression analysis of
Fuel and Energy Abstracts
September 2006
315