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00543 Effects of volatile-char interactions on the reactivity of chars from NaCl-loaded Loy Yang brown coal
01 Sofid fuels (derived solid fuels) 06/00539 Defining geographic coal markets using price data and shipments data W{trell, L. Energy Policy, 2005, 33, (17), 2216 2230. Given the i m p o r t a n c e of coal in world energy supply an analysis of the relevant geographic m a r k e t is essential for consumers, producers, as well as for competition policy. The purpose of this p a p e r is to define the relevant economic m a r k e t for steam and coking coal, and to test the hypothesis of single world markets for these coal products. Methodologically the paper relies on two different tests for defining markets, using both shipments data and price data. The results from both methods point in the same direction. In the case of coking coal the results indicate that the m a r k e t is essentially global in scope, and also that the m a r k e t has b e c o m e more integrated over time. The results for steam coal show that the m a r k e t is more regional in scope, and there exist no clear tendencies of increased integration over time. One policy implication of the finding that the s t e a m coal m a r k e t is more regional in scope, and thus that the m a r k e t b o u n d a r y is smaller than if the m a r k e t would have been international, is that a merger and acquisition in this m a r k e t likely would have been of a more concern for antitrust authorities than the same activity on the coking coal market.
06/00540 Energyplexes for the 21st century: coal gasification for co-producing hydrogen, electricity and liquid fuels Y a m a s h i t a , K. and Barreto, L. Energy, 2005, 30, (13), 2453 2473. This paper illustrates the role that integrated energy systems, also known as 'energyplexes', could play in supplying energy d e m a n d s in the long term. These systems could enable a multi-fuel, multi-product strategy with both economic and e n v i r o n m e n t a l benefits. They could increase the adaptability and robustness of energy-services companies in the marketplace, providing t h e m with flexibility in m e e t i n g d e m a n d s in different m a r k e t segments while achieving lower p r o d u c t i o n costs and, reducing the risks of reliance on a single feedstock. In addition, with the possibility of achieving high conversion efficiencies and low polluting emissions and facilitating carbon capture, they could deliver high-quality energy services in a cost-effective way while meeting stringent e n v i r o n m e n t a l requirements. Their potential is highlighted here using the case of coal-fired, synthesis-gas-based gasification systems that allow co-producing hydrogen, electricity and liquid fuels, i.e. Fischer Tropsch liquids and methanol, and could be a key building block in a clean-coal technology strategy. Co-production, also known as poly-generation, strategies may contribute to improve the economics of the system and exploit p o t e n t i a l synergies between the constituent processes. However, the technical feasibility and economic viability of poly-generation schemes have to be examined carefully on a case-bycase basis.
06/00541 The impact of carbon sequestration on the production cost of electricity and hydrogen from coal and natural-gas technologies in Europe in the medium term Tzimas, E. and Peteves, S. D. Energy, 2005, 30, (14), 2672 2689. C a r b o n sequestration is a distinct technological option with a potential for controlling carbon emissions; it c o m p l e m e n t s other measures, such as i m p r o v e m e n t s in energy efficiency and utilization of renewable energy sources. The d e p l o y m e n t of carbon sequestration technologies in electricity generation and hydrogen production will increase the production costs of these energy carriers. Our economic assessment has shown that the introduction of carbon sequestration technologies in E u r o p e in 2020, will result in an increase in the production cost of electricity by coal and natural gas technologies of 30 55% d e p e n d i n g on the electricity-generation technology used; gas turbines will remain the most competitive option for generating electricity; and integrated gasification combined cycle technology will b e c o m e competitive. W h e n carbon sequestration is coupled with natural-gas steam reforming or coal gasification for hydrogen production, the production cost of hydrogen will increase by 14 16%. F u r t h e r m o r e , natural-gas steam reforming with carbon sequestration is far more economically competitive than coal gasification.
and composition of charcoal in the feed stockpile of bauxite ore by solubility, laser R a m a n spectroscopy, Fourier transform infrared ( F T I R ) spectroscopy, nuclear magnetic resonance ( N M R ) spectroscopy, and pyrolysis gas c h r o m a t o g r a p h y mass spectrometry (pyGC/MS). The charcoal was treated under simulated Bayer process conditions of 245:C in 5 M sodium hydroxide. The alkaline digestion test showed that a large fraction of the charcoal was insoluble (approximately 90%). Surprisingly, the spectroscopic characterization revealed not only typical polycyclic aromatic networks expected for charcoals (aromaticity .fo = 0.64), but also showed an aliphatic character and that the sample contained alkvl chains ranging from nCl0 to nC23 carbon chain lengths. The role of'this material in bauxite refineries is discussed.
06/00543 Effects of volatile-char interactions on the reactivity of chars from NaCl-loaded Loy Yang brown coal Wu, H. et al. Fuel, 2005, 84, (10), 1221 1228. In a fluidized-bed gasifier, char particles are in constant contact with the volatiles and the products from the gasification and t h e r m a l cracking of volatiles. The highly reactive nature of volatiles as well as the vulnerable structure of char from brown coal means that there are strong interactions between volatiles and char. The purpose of this study is to investigate the effects of volatile char interactions on the reactivities of chars from a Victorian brown coal. NaCl-loaded and acid-washed Loy Y a n g brown coal samples were pyrolysed in a novel fluidized-bed/fixed-bed reactor at 900:C that has been specially designed to investigate the volatile char interactions. Char reactivity in air was m e a s u r e d in a t h e r m o g r a v i m e t r i c analyser (TGA) under conditions minimizing mass transfer limitations. The oxidation of char with air in the T G A showed a p p a r e n t kinetic c o m p e n s a t i o n effects between the a p p a r e n t activation energies and pre-exponential factors. The presence of the a p p a r e n t kinetic c o m p e n s a t i o n effect is a reflection of the h e t e r o g e n e o u s structure of char having sites of a wide range of energy levels. The results have clearly shown that volatile char interactions can lead to drastic decreases in char reactivity due to the volatilization of Na and the changes in char structure. The reactivities of chars from the pyrolysis of the catalystfree H-form Loy Y a n g brown coal provided unequivocal evidence for the changes in char structure after volatile char interactions. For chars from the NaCl-loaded Loy Y a n g brown coal, it appears that the condensation of ring structures in char as a result of volatile char interactions could have also led to changes in the dispersion of Na catalyst.
06•00544 Field emission from the film of the finely dispersed arc discharge black core material Hahn, J. et al. Carbon, 2005, 43, (5), 937 943. The authors have studied, for the first time, the field emission from the film, p r e p a r e d by a spray method, of the finely dispersed black core material, including multi-walled carbon nanotubes (MWNTs), fabricated by arc discharge. The black core m a t e r i a l was dispersed by using an ultrasonic processor and found that the dispersed ones were much finer than those observed when treated with a ball mill and n o r m a l ultra-sonic bath. By SEM, H R T E M and R a m a n analyses, the M W N T s were almost not d e f o r m e d and d a m a g e d d u r i n g ultra-sonication. The field emission current density m e a s u r e d from the film of the dispersed black core material was about 15 m A / c m 2 at an applied field of 8 V/~tm, which was about 23 times higher than that found by a ball mill. A current density of 1 m A / c m 2, which is required basically for flat p a n e l display, has been obtained at 5.3 V/~tm. The lifetime test of the dispersed black core material showed that the current density was almost u n c h a n g e d while the field was applied. Therefore, it is concluded that a black core material fabricated by arc discharge could be used to flat p a n e l displays as field emitters by dispersing with an ultrasonic processor, w i t h o u t further t r e a t m e n t like extraction or purification.
06/00545 Magnetic separation of Fe catalyst from singlewalled carbon nanotubes in an aqueous surfactant solution
Derived solid fuels 06/00542 bauxite
Characterisation of insoluble charcoal in Weipa
Marshall, C. P. et al. Carbon, 2005, 43, (6), 1279 1285. The role of charcoal-like c o m p o n e n t s (also referred to as char) in soil organic matter reactivity has b e c o m e increasingly evident. Recently we have d e m o n s t r a t e d the role of such m a t e r i a l in bauxite. Sodium hydroxide is used at elevated t e m p e r a t u r e s to separate a l u m i n i u m hydroxide from ferric oxide in bauxite in the Bayer process and charcoal like m a t e r i a l may interfere with the precipitation of a l u m i n i u m hydroxide. In this p a p e r we study the solubility, structure
Wiltshire, J. G. et al. Carbon, 2005, 43, (6), 1151 1155. W e report an efficient technique to separate ferromagnetic catalyst particles from an aqueous surfactant solution of single-walled carbon nanotubes (SWNTs) by the use of a 1.3 T p e r m a n e n t magnet. Highresolution transmission electron microscopy ( H R T E M ) d e m o n s t r a t e s that SWNTs are coated with a surfactant layer that stabilizes the aqueous dispersions of SWNTs. The residual quantities of Fe catalyst (approximately 3%) can be effectively removed from a colloid solution of SWNTs in a magnetic field while absorbance spectra of the initial and purified solutions show that the nanotube d i a m e t e r distribution remains unchanged.
06/00546 Modification of carbon nanostructures by high energy ball-milling under argon and hydrogen atmosphere Francke, M. et al. Carbon, 2005, 43, (6), 1204 1212.
Fuel and Energy Abstracts
March 2006
85
06/00540 Energyplexes for the 21st century: coal gasification for co-producing hydrogen, electricity and liquid fuels Y a m a s h i t a , K. and Barreto, L. Energy, 2005, 30, (13), 2453 2473. This paper illustrates the role that integrated energy systems, also known as 'energyplexes', could play in supplying energy d e m a n d s in the long term. These systems could enable a multi-fuel, multi-product strategy with both economic and e n v i r o n m e n t a l benefits. They could increase the adaptability and robustness of energy-services companies in the marketplace, providing t h e m with flexibility in m e e t i n g d e m a n d s in different m a r k e t segments while achieving lower p r o d u c t i o n costs and, reducing the risks of reliance on a single feedstock. In addition, with the possibility of achieving high conversion efficiencies and low polluting emissions and facilitating carbon capture, they could deliver high-quality energy services in a cost-effective way while meeting stringent e n v i r o n m e n t a l requirements. Their potential is highlighted here using the case of coal-fired, synthesis-gas-based gasification systems that allow co-producing hydrogen, electricity and liquid fuels, i.e. Fischer Tropsch liquids and methanol, and could be a key building block in a clean-coal technology strategy. Co-production, also known as poly-generation, strategies may contribute to improve the economics of the system and exploit p o t e n t i a l synergies between the constituent processes. However, the technical feasibility and economic viability of poly-generation schemes have to be examined carefully on a case-bycase basis.
06/00541 The impact of carbon sequestration on the production cost of electricity and hydrogen from coal and natural-gas technologies in Europe in the medium term Tzimas, E. and Peteves, S. D. Energy, 2005, 30, (14), 2672 2689. C a r b o n sequestration is a distinct technological option with a potential for controlling carbon emissions; it c o m p l e m e n t s other measures, such as i m p r o v e m e n t s in energy efficiency and utilization of renewable energy sources. The d e p l o y m e n t of carbon sequestration technologies in electricity generation and hydrogen production will increase the production costs of these energy carriers. Our economic assessment has shown that the introduction of carbon sequestration technologies in E u r o p e in 2020, will result in an increase in the production cost of electricity by coal and natural gas technologies of 30 55% d e p e n d i n g on the electricity-generation technology used; gas turbines will remain the most competitive option for generating electricity; and integrated gasification combined cycle technology will b e c o m e competitive. W h e n carbon sequestration is coupled with natural-gas steam reforming or coal gasification for hydrogen production, the production cost of hydrogen will increase by 14 16%. F u r t h e r m o r e , natural-gas steam reforming with carbon sequestration is far more economically competitive than coal gasification.
and composition of charcoal in the feed stockpile of bauxite ore by solubility, laser R a m a n spectroscopy, Fourier transform infrared ( F T I R ) spectroscopy, nuclear magnetic resonance ( N M R ) spectroscopy, and pyrolysis gas c h r o m a t o g r a p h y mass spectrometry (pyGC/MS). The charcoal was treated under simulated Bayer process conditions of 245:C in 5 M sodium hydroxide. The alkaline digestion test showed that a large fraction of the charcoal was insoluble (approximately 90%). Surprisingly, the spectroscopic characterization revealed not only typical polycyclic aromatic networks expected for charcoals (aromaticity .fo = 0.64), but also showed an aliphatic character and that the sample contained alkvl chains ranging from nCl0 to nC23 carbon chain lengths. The role of'this material in bauxite refineries is discussed.
06/00543 Effects of volatile-char interactions on the reactivity of chars from NaCl-loaded Loy Yang brown coal Wu, H. et al. Fuel, 2005, 84, (10), 1221 1228. In a fluidized-bed gasifier, char particles are in constant contact with the volatiles and the products from the gasification and t h e r m a l cracking of volatiles. The highly reactive nature of volatiles as well as the vulnerable structure of char from brown coal means that there are strong interactions between volatiles and char. The purpose of this study is to investigate the effects of volatile char interactions on the reactivities of chars from a Victorian brown coal. NaCl-loaded and acid-washed Loy Y a n g brown coal samples were pyrolysed in a novel fluidized-bed/fixed-bed reactor at 900:C that has been specially designed to investigate the volatile char interactions. Char reactivity in air was m e a s u r e d in a t h e r m o g r a v i m e t r i c analyser (TGA) under conditions minimizing mass transfer limitations. The oxidation of char with air in the T G A showed a p p a r e n t kinetic c o m p e n s a t i o n effects between the a p p a r e n t activation energies and pre-exponential factors. The presence of the a p p a r e n t kinetic c o m p e n s a t i o n effect is a reflection of the h e t e r o g e n e o u s structure of char having sites of a wide range of energy levels. The results have clearly shown that volatile char interactions can lead to drastic decreases in char reactivity due to the volatilization of Na and the changes in char structure. The reactivities of chars from the pyrolysis of the catalystfree H-form Loy Y a n g brown coal provided unequivocal evidence for the changes in char structure after volatile char interactions. For chars from the NaCl-loaded Loy Y a n g brown coal, it appears that the condensation of ring structures in char as a result of volatile char interactions could have also led to changes in the dispersion of Na catalyst.
06•00544 Field emission from the film of the finely dispersed arc discharge black core material Hahn, J. et al. Carbon, 2005, 43, (5), 937 943. The authors have studied, for the first time, the field emission from the film, p r e p a r e d by a spray method, of the finely dispersed black core material, including multi-walled carbon nanotubes (MWNTs), fabricated by arc discharge. The black core m a t e r i a l was dispersed by using an ultrasonic processor and found that the dispersed ones were much finer than those observed when treated with a ball mill and n o r m a l ultra-sonic bath. By SEM, H R T E M and R a m a n analyses, the M W N T s were almost not d e f o r m e d and d a m a g e d d u r i n g ultra-sonication. The field emission current density m e a s u r e d from the film of the dispersed black core material was about 15 m A / c m 2 at an applied field of 8 V/~tm, which was about 23 times higher than that found by a ball mill. A current density of 1 m A / c m 2, which is required basically for flat p a n e l display, has been obtained at 5.3 V/~tm. The lifetime test of the dispersed black core material showed that the current density was almost u n c h a n g e d while the field was applied. Therefore, it is concluded that a black core material fabricated by arc discharge could be used to flat p a n e l displays as field emitters by dispersing with an ultrasonic processor, w i t h o u t further t r e a t m e n t like extraction or purification.
06/00545 Magnetic separation of Fe catalyst from singlewalled carbon nanotubes in an aqueous surfactant solution
Derived solid fuels 06/00542 bauxite
Characterisation of insoluble charcoal in Weipa
Marshall, C. P. et al. Carbon, 2005, 43, (6), 1279 1285. The role of charcoal-like c o m p o n e n t s (also referred to as char) in soil organic matter reactivity has b e c o m e increasingly evident. Recently we have d e m o n s t r a t e d the role of such m a t e r i a l in bauxite. Sodium hydroxide is used at elevated t e m p e r a t u r e s to separate a l u m i n i u m hydroxide from ferric oxide in bauxite in the Bayer process and charcoal like m a t e r i a l may interfere with the precipitation of a l u m i n i u m hydroxide. In this p a p e r we study the solubility, structure
Wiltshire, J. G. et al. Carbon, 2005, 43, (6), 1151 1155. W e report an efficient technique to separate ferromagnetic catalyst particles from an aqueous surfactant solution of single-walled carbon nanotubes (SWNTs) by the use of a 1.3 T p e r m a n e n t magnet. Highresolution transmission electron microscopy ( H R T E M ) d e m o n s t r a t e s that SWNTs are coated with a surfactant layer that stabilizes the aqueous dispersions of SWNTs. The residual quantities of Fe catalyst (approximately 3%) can be effectively removed from a colloid solution of SWNTs in a magnetic field while absorbance spectra of the initial and purified solutions show that the nanotube d i a m e t e r distribution remains unchanged.
06/00546 Modification of carbon nanostructures by high energy ball-milling under argon and hydrogen atmosphere Francke, M. et al. Carbon, 2005, 43, (6), 1204 1212.
Fuel and Energy Abstracts
March 2006
85