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02407 Carbon nanotubes-supported Ru catalyst for the generation of COx-free hydrogen from ammonia
01 Solid fuels (derived solid fuels)
Economics, business, marketing, policy 05•02405 A correlation for calculating HHV from proximate analysis of solid fuels Parikh, J. et al. Fuel, 2005, 84, (5), 487-494. Higher heating value (HHV) and composition of biomass, coal and other solid fuels, are important properties which define the energy content and determine the clean and efficient use of these fuels. There exists a variety of correlations for predicting H H V from ultimate analysis of fuels. However, the ultimate analysis requires very expensive equipments and highly trained analysts. The proximate analysis on the other hand only requires standard laboratory equipments and can be run by any competent scientist or engineer. A few number of correlations of H H V with proximate analysis have appeared in the solid fuel literature in the past but were focused on one fuel or dependent on the country of origin. This work introduces a general correlation, based on proximate analysis of solid fuels, to calculate HHV, using 450 data points and validated further for additional 100 data points. The entire spectrum of solid carbonaceous materials like coals, lignite, all types of biomass material, and char to residue-derived fuels have been considered in derivation of present correlation which is given as below: H H V = 0.3536FC + 0.1559VM - 0.0078ASH (MJ/kg) (where FC 1.0-91.5% fixed carbon, VM 0.92-90.6% volatile matter and ash 0.12-77.7% ash content in wt% on a dry basis). The average absolute error of this correlation is 3.74% and bias error is 0.12% with respect to the measured value of HHV, which is much less than that of previous correlations of the similar kind. The major advantage of this correlation is its capability to compute H H V of any fuel simply from its proximate analysis and thereby provides a useful tool for modeling of combustion, gasification and pyrolysis processes. It can also be used in examining old/new data for probable errors when results lie much outside the predicted results.
05102406 The rise and fall of German hard coal subsidies Storchmann, K. Energy Policy, 2005, 33, (ll), 1469 1492. Beginning with the coal crisis of 1958, the survival of the German hard coal mining sector has been heavily dependent on subsidies for several decades. These subsidies are a complex system of almost 60 different measures often with conflicting objectives. Annual financial support for this subsidy system grew from £0.6 billion in 1958 to e7.5 billion in 1989 with the majority of the funding financed outside the public budget by a special fund based on the 'coal penny' (Kohlepfennig). In 1995, the abolishment of the 'coal penny', in connection with budget constraints, led to a significant subsidy decrease to ~3.5 billion. A recent agreement between the Federal government and the mining state of North-Rhine Westphalia in 2003, however, seems to have fixed German hard coal subsidies at the £2 billion level for the time after 2012.
Derived solid fuels 05•02407 Carbon nanotubes-supported Ru catalyst for the generation of COx-free hydrogen from ammonia Yin, S. F. et al. Catalysis Today, 2004, 93-95, 27-38. In comparison to Ru catalysts supported on activated carbon (AC), MgO, A1203, and TiOz under similar reaction conditions, Ru catalyst using carbon nanotubes as support (Ru/CNTs) was found to show high NH3 conversion for the generation of COx-free hydrogen from NH3. The modification of the catalyst with K O H leads to a significant irnprovement in activity, either in terms of NHs conversion or TOF. The Ru/CNTs catalyst prepared from acetone solvent is more active than that from water solvent, and the use of the former leads to an increase in Ru dispersion and a decrease in residual C1 concentration. The results of Hz-TPD and H R T E M characterization disclosed that the excellent catalytic activity of Ru/CNTs could be ascribed to the high dispersion of Ru particles, and to the high graphitization and high purity of the CNTs material. The residual C1 originated from the RuC13 precursor was found to be a strong inhibitor for the decomposition reaction. Once the residual C1 is in the form of KC1, it is difficult to remove. The results of N2-TPD studies imply that the desorption of N2 is the rate-determining step, and the modification with KOH leads to a decrease in N2 desorption temperature and in apparent activation energy of NH3 decomposition over Ru/CNTs.
05102408 Adsorption of Hg and NOx on coal by-products Rubel, A. et al. Fuel, 2005, 84, (7-8), 911-916. The adsorption of Hg and NO:( on gasifier and combustion byproducts was investigated. Carbon-rich fractions were produced by a density separation technique from a gasifier char (GC) and a pulverized
356
Fuel and Energy Abstracts
November 2005
coal combustion blended fly/bottom ash (CC) recovered from a pond. Both fractions were subjected to steam activation at 875°C. As-received and activated chars and two commercial carbons developed specifically for Hg and N O x adsorption were tested and compared for Hg and N O z adsorption capacities. The Hg adsorption capacity of GC was found as good as a specialty commercial carbon designed for Hg capture from flue gases. Steam activation or heating to 900°C destroyed GC's adsorption capability. GC adsorbed one-third of the N O x uptake of a commercial carbon used for N O x adsorption. Hg-laden GC captured even more N O x than the as-received GC. Possible explanations for the performance of GC will be discussed. The CC material was a poor performer for both Hg and N O x capture.
05/02409 Crystallisation of a multiparaffinic wax in normal tetradecane under high pressure Pauly, J. et al. Fuel, 2005, 84, (4), 453-459. The wax appearance temperature as well as the amount and composition of wax precipitation were determined as a function of pressure in a synthetic complex system tetracosane + (multiparaffinic commercial wax). Measurements were performed by using two different experimental techniques: (1) a high pressure microscopy apparatus for the solid-liquid phase boundary measurement, (2) a filtration apparatus coupled to a chromatographic analysis of the partially frozen mixtures for the determination of the solid phase behaviour. Experimental results were compared with the values calculated by a predictive model. The influence of pressure on wax formation is shown to be as important as the influence of temperature and the model used can provide an excellent description of the melting behaviour over a wide pressure range.
05/02410 Desulfurization of coke by recycling COG in coking process Guo, Z. et al. Fuel, 2005, 84, (7-8), 893 901. The technology of desulfurization of coke during coking is conceptually designed, in which the coking oven gas (COG) is blown into the eoking chamber of the coke oven during the coking stage. Analysis based on laboratory experiments and computer simulation shows the possibility to reduce sulfur of coke by 0.2% by recycling 20% of COG. The technology may be an economic way to produce low sulfur coke or to produce metallurgical coke using high sulfur coal.
05/02411 Preparation of high performance electrorheological fluids with coke-like particles from FCC slurry conversion Dong, P. et al. Fuel, 2005, 84, (6), 685 689. The electrorheological fluid (ERF) with coke-like particles from thermal conversion of fluid catalytic cracking (FCC) slurry was prepared and their ER performance was investigated. The results show that an ERF containing these solids is a high performance material with high shear stress, low current density and long-term stability. Shear stress higher than 2 kPa and current density less than 60 gA/em 2 was obtained in a 2 kV/mm DC field. The volume fraction of clear liquid released from the E R F was less than 5 vol% after several months of static test, indicating the E R F is stable and meets commercial application requirements. The influence of thermal conversion level and the orientation of condensed aromatics on E R F performance are discussed.
05/02412 Production of fuel briquettes from esparto partially pyrolyzed Debdoubi, A. et al. Energy Conversion and Management, 2005, 46, (11 12), 1877-1884. The aim of this study is to prepare a solid fuel from the most abundant biomass of Morocco that can be used by the local populafion, and in particular by the rural ones, instead of the wood of forest, which is less available and its exploitation is negative for the environment. Esparto is the most available biomass, with a production of 560,000 tons annually of dry matter approximately. However, briquettes of esparto have low calorific power and their mechanical properties are bad. To improve the quality of the briquettes and to have an economically competitive product at the same time, the esparto was partially pyrolysed at temperatures between 160°C and 400°C, and the pressure of densification has been examined. The combustion profile of the samples has been studied by applying the derivative thermogravimetry technique, and the mechanical properties of the briquettes were tested to evaluate the impact resistance and water resistance. This study showed that strong briquettes can be obtained with a higher calorific value when the esparto is partiafly pyrolysed, and a relatively elevated densification pressure is applied.
Economics, business, marketing, policy 05•02405 A correlation for calculating HHV from proximate analysis of solid fuels Parikh, J. et al. Fuel, 2005, 84, (5), 487-494. Higher heating value (HHV) and composition of biomass, coal and other solid fuels, are important properties which define the energy content and determine the clean and efficient use of these fuels. There exists a variety of correlations for predicting H H V from ultimate analysis of fuels. However, the ultimate analysis requires very expensive equipments and highly trained analysts. The proximate analysis on the other hand only requires standard laboratory equipments and can be run by any competent scientist or engineer. A few number of correlations of H H V with proximate analysis have appeared in the solid fuel literature in the past but were focused on one fuel or dependent on the country of origin. This work introduces a general correlation, based on proximate analysis of solid fuels, to calculate HHV, using 450 data points and validated further for additional 100 data points. The entire spectrum of solid carbonaceous materials like coals, lignite, all types of biomass material, and char to residue-derived fuels have been considered in derivation of present correlation which is given as below: H H V = 0.3536FC + 0.1559VM - 0.0078ASH (MJ/kg) (where FC 1.0-91.5% fixed carbon, VM 0.92-90.6% volatile matter and ash 0.12-77.7% ash content in wt% on a dry basis). The average absolute error of this correlation is 3.74% and bias error is 0.12% with respect to the measured value of HHV, which is much less than that of previous correlations of the similar kind. The major advantage of this correlation is its capability to compute H H V of any fuel simply from its proximate analysis and thereby provides a useful tool for modeling of combustion, gasification and pyrolysis processes. It can also be used in examining old/new data for probable errors when results lie much outside the predicted results.
05102406 The rise and fall of German hard coal subsidies Storchmann, K. Energy Policy, 2005, 33, (ll), 1469 1492. Beginning with the coal crisis of 1958, the survival of the German hard coal mining sector has been heavily dependent on subsidies for several decades. These subsidies are a complex system of almost 60 different measures often with conflicting objectives. Annual financial support for this subsidy system grew from £0.6 billion in 1958 to e7.5 billion in 1989 with the majority of the funding financed outside the public budget by a special fund based on the 'coal penny' (Kohlepfennig). In 1995, the abolishment of the 'coal penny', in connection with budget constraints, led to a significant subsidy decrease to ~3.5 billion. A recent agreement between the Federal government and the mining state of North-Rhine Westphalia in 2003, however, seems to have fixed German hard coal subsidies at the £2 billion level for the time after 2012.
Derived solid fuels 05•02407 Carbon nanotubes-supported Ru catalyst for the generation of COx-free hydrogen from ammonia Yin, S. F. et al. Catalysis Today, 2004, 93-95, 27-38. In comparison to Ru catalysts supported on activated carbon (AC), MgO, A1203, and TiOz under similar reaction conditions, Ru catalyst using carbon nanotubes as support (Ru/CNTs) was found to show high NH3 conversion for the generation of COx-free hydrogen from NH3. The modification of the catalyst with K O H leads to a significant irnprovement in activity, either in terms of NHs conversion or TOF. The Ru/CNTs catalyst prepared from acetone solvent is more active than that from water solvent, and the use of the former leads to an increase in Ru dispersion and a decrease in residual C1 concentration. The results of Hz-TPD and H R T E M characterization disclosed that the excellent catalytic activity of Ru/CNTs could be ascribed to the high dispersion of Ru particles, and to the high graphitization and high purity of the CNTs material. The residual C1 originated from the RuC13 precursor was found to be a strong inhibitor for the decomposition reaction. Once the residual C1 is in the form of KC1, it is difficult to remove. The results of N2-TPD studies imply that the desorption of N2 is the rate-determining step, and the modification with KOH leads to a decrease in N2 desorption temperature and in apparent activation energy of NH3 decomposition over Ru/CNTs.
05102408 Adsorption of Hg and NOx on coal by-products Rubel, A. et al. Fuel, 2005, 84, (7-8), 911-916. The adsorption of Hg and NO:( on gasifier and combustion byproducts was investigated. Carbon-rich fractions were produced by a density separation technique from a gasifier char (GC) and a pulverized
356
Fuel and Energy Abstracts
November 2005
coal combustion blended fly/bottom ash (CC) recovered from a pond. Both fractions were subjected to steam activation at 875°C. As-received and activated chars and two commercial carbons developed specifically for Hg and N O x adsorption were tested and compared for Hg and N O z adsorption capacities. The Hg adsorption capacity of GC was found as good as a specialty commercial carbon designed for Hg capture from flue gases. Steam activation or heating to 900°C destroyed GC's adsorption capability. GC adsorbed one-third of the N O x uptake of a commercial carbon used for N O x adsorption. Hg-laden GC captured even more N O x than the as-received GC. Possible explanations for the performance of GC will be discussed. The CC material was a poor performer for both Hg and N O x capture.
05/02409 Crystallisation of a multiparaffinic wax in normal tetradecane under high pressure Pauly, J. et al. Fuel, 2005, 84, (4), 453-459. The wax appearance temperature as well as the amount and composition of wax precipitation were determined as a function of pressure in a synthetic complex system tetracosane + (multiparaffinic commercial wax). Measurements were performed by using two different experimental techniques: (1) a high pressure microscopy apparatus for the solid-liquid phase boundary measurement, (2) a filtration apparatus coupled to a chromatographic analysis of the partially frozen mixtures for the determination of the solid phase behaviour. Experimental results were compared with the values calculated by a predictive model. The influence of pressure on wax formation is shown to be as important as the influence of temperature and the model used can provide an excellent description of the melting behaviour over a wide pressure range.
05/02410 Desulfurization of coke by recycling COG in coking process Guo, Z. et al. Fuel, 2005, 84, (7-8), 893 901. The technology of desulfurization of coke during coking is conceptually designed, in which the coking oven gas (COG) is blown into the eoking chamber of the coke oven during the coking stage. Analysis based on laboratory experiments and computer simulation shows the possibility to reduce sulfur of coke by 0.2% by recycling 20% of COG. The technology may be an economic way to produce low sulfur coke or to produce metallurgical coke using high sulfur coal.
05/02411 Preparation of high performance electrorheological fluids with coke-like particles from FCC slurry conversion Dong, P. et al. Fuel, 2005, 84, (6), 685 689. The electrorheological fluid (ERF) with coke-like particles from thermal conversion of fluid catalytic cracking (FCC) slurry was prepared and their ER performance was investigated. The results show that an ERF containing these solids is a high performance material with high shear stress, low current density and long-term stability. Shear stress higher than 2 kPa and current density less than 60 gA/em 2 was obtained in a 2 kV/mm DC field. The volume fraction of clear liquid released from the E R F was less than 5 vol% after several months of static test, indicating the E R F is stable and meets commercial application requirements. The influence of thermal conversion level and the orientation of condensed aromatics on E R F performance are discussed.
05/02412 Production of fuel briquettes from esparto partially pyrolyzed Debdoubi, A. et al. Energy Conversion and Management, 2005, 46, (11 12), 1877-1884. The aim of this study is to prepare a solid fuel from the most abundant biomass of Morocco that can be used by the local populafion, and in particular by the rural ones, instead of the wood of forest, which is less available and its exploitation is negative for the environment. Esparto is the most available biomass, with a production of 560,000 tons annually of dry matter approximately. However, briquettes of esparto have low calorific power and their mechanical properties are bad. To improve the quality of the briquettes and to have an economically competitive product at the same time, the esparto was partially pyrolysed at temperatures between 160°C and 400°C, and the pressure of densification has been examined. The combustion profile of the samples has been studied by applying the derivative thermogravimetry technique, and the mechanical properties of the briquettes were tested to evaluate the impact resistance and water resistance. This study showed that strong briquettes can be obtained with a higher calorific value when the esparto is partiafly pyrolysed, and a relatively elevated densification pressure is applied.