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02490 Experiments on the pyrolysis of large beechwood particles in fixed beds
09 Combustion (burners, combustion systems) diffusion and its reaction with molten phosphate salts. Improving oxygen content mitigated the diffusion resistance in ash layer, and hence, more the sodium and zinc were vaporized.
04/02487 Combustion synthesis of perovskite-type catalysts for natural gas combustion Civera, A. et al. Catalysis Today, 2003, 83, (1~4), 199-211. Combustion synthesis has been applied to LaMnO3 production with a view to boosting its activity towards natural gas combustion by enhancing its specific surface area. With a highly exothermic and self-sustaining reaction, this oxide can be quickly prepared from an aqueous solution of metal nitrates (oxidizers) and urea (fuel). The favourable conditions for LaMnO3 formation were sought: only fuelrich mixtures are effective, but carbonaceous deposits are formed when too much urea is used. In the field of operating conditions in which the combustion synthesis reaction takes place, the specific surface areas were not dramatically higher than those obtained with traditional methods; moreover, even short thermal treatments have been found to rapidly deactivate the catalysts by rapid sintering. With a view to tackling these problems, NH4NO 3 was chosen as an additive for its low costs, highly exothermic decomposition and because it generates gaseous products only, without altering the proportion of the other elements in the catalysts. With ammonium nitrate, specific area was enhanced from 4 m2/g up to about 20 mZ/g. A short thermal treatment at 900°C partially deactivates also the NH4NO3-derived catalysts. It was found that NH4NO3-boosted mixtures produce materials whose activity, after a similar thermal treatment, behave practically as the perovskites obtained by the 'citrates' method. Combustion synthesis is though rather cheap - in terms of reactants employed - and quick, given that the process requires few minutes at low temperature without successive calcination. However, the main drawback of this method is that hazardous or polluting compounds are emitted during the synthesis (mainly NH3 or NO:c). The MgO introduction, which should act both as a structural promoter and as a sulphur poisoning limiting agent, has proved to be harmful: since MgO does not physically interpose between perovskite grains, it does not offer resistance to deactivation induced by high temperatures.
04/02488 Effects of hydrocarbon substitution on atmospheric hydrogen-air flame propagation Law, C. K. and Kwon, O. C. International Journal of Hydrogen Energy, 2004, 29, (8), 867-879. In order to evaluate the potential of partial hydrocarbon substitution to improve the safety of hydrogen use in general and the performance of internal combustion engines in particular, the outward propagation and development of surface cellular instability of spark-ignited spherical premixed flames of mixtures of hydrogen, hydrocarbon, and air were experimentally studied at NTP condition in a constant-pressure combustion chamber. With methane, ethylene, and propane being the substituents, the laminar burning velocities, the Markstein lengths, and the propensity of cell formation were experimentally determined, while the laminar burning velocities and the associated flame thicknesses were computed using recent kinetic mechanisms. Results show substantial reduction of laminar burning velocities with hydrocarbon substitution, and support the potential of propane as a suppressant of both diffusional-thermal and hydrodynamic cellular instabilities in hydrogen-air flames. Such a potential, however, was not found for methane and ethylene as substituents.
04/02489 furnace
Evolution of feed materials for the electric arc
Poveromo, J. J. ISSTech Conference Proceedings, 1st, Indianapolis, IN, United States, 27-30 April, 2003, 1877-1888. In this report the usage of scrap and alternative Fe units in electric arc furnace (EAF) steelmaking is described, as is the role played by the Quebec Cartier Mining (QCM) Company in supplying feed materials to the EAF sector. The future growth of the mini-mill concept will be enhanced, rather than limited, by the raw material options for the EAF. Scrap will continue to be the primary feed material. The supply of home and prompt industrial scrap will continually decrease due to technological changes in both the steel producing and steel consuming industries. The supply of obsolete scrap will increase simply due to the harvesting of scrap from steel products produced during an era of increasing North American and worldwide steel production in the past three decades. The ability to use lower grades of obsolete scrap will be extended by the options for alternative iron units (AIUs) available to the EAF steelmaker. Captive gas-based shaft furnace DRI plants will continue to be built in regions poor in scrap but rich in natural gas. In areas without tow-priced gas, some on-site coal-based hot metal plants could be expected to be built to feed larger scale (> t.5 MTPY) minimills making high-end products. Other EAF plants will have little problem securing AIUs (direct reduced iron (DRI)/hot-briquetted or pig iron) from merchant sources. QCM is participating in mini-mill growth by supplying Mt Wright concentrate to an on-site hot metal plant feeding an EAF plant. In the area of DR grade pellet production,
348
Fuel and Energy Abstracts September 2004
QCM has focused improvements in three areas: SiO2 reduction, elimination of roved pellet properties have contributed directly to improved D R shaft furnace and EAF steelmaking performance, which in turn has led to reduced DRI and liquid steel costs.
04•02490 Experiments on the pyrolysis of large beechwood particles in fixed beds Schr6der, E. Journal of Analytical and Applied Pyrolysis, 2004, 71, (2), 669-694. Fixed beds of beechwood particles 10 m m in size were pyrolysed under conventional pyrolysis conditions. For this purpose, the beds were heated to a maximum temperature of 525°C at rates 3-10 K/rain by a flow of hot nitrogen. The loss of mass of the beds in the decomposition process was recorded as a function of time in addition to the temperature field inside the beds, which was measured continuously. The yields of char, tar and gas were quantified, and the composition of the products was analysed with respect to their elemental composition and calorific values at various temperatures. The results are compared with the findings made in various studies of this topic. The results are an important tool for validating physical and chemical models of heating, drying, and pyrolysing fixed beds of biomass.
04/02491 Extension of No. 3 coke oven service life at JFEFukuyama works Maruoka, M. et al. ISSTech Conference Proceedings, 1st, Indianapolis, IN, United States, 2~30 April, 2003, 1197-1206. The efforts to extent the coke oven service life in a Japanese coke plant are presented. The present coke oven is described as well as the influence of the damages on the operation. The mechanisms of coke oven deterioration are outlined, and countermeasures and repair methods are given. The operational improvement achieved by repair and damage countermeasures are presented.
04/02492 Fixed-bed pyrolysis of rapeseed (Brassica napus L.) Onay, O. and Koqkar, O. M. Biomass andBioenergy, 2004, 26, (3), 289299. Fixed-bed slow and fast pyrolysis experiments have been conducted on a sample of rapeseed. The experiments were performed in two different pyrolysis reactors, namely a fixed-bed Heinze and a wellswept fixed-bed tubular retort to investigate the effects of heating rate, pyrolysis temperature, particle size, sweep gas velocity on the pyrolysis product yields and chemical compositions. The maximum oil yield of 51.7% was obtained in the Heinze reactor 550°C, with a particle size range of +0.6-1.8 m m (sweep gas 100 cm 3 min 1 N2) at a heating rate of 30°C min -1. In the well-swept fixed-bed reactor, the maximum oil yield of 68% was obtained at a heating rate of 300°C rain 1. Chromatographic and spectroscopic studies on the pyrolytic oil showed that the oil obtained from rapeseed could be use as a renewable fuels and chemical feedstock.
04102493 Formation and chemical speciation of arsenic-, chromium-, and nickel-bearing coal combustion PM2.5 Galbreath, K. C. and Zygarlicke, C. J. Fuel Processing Technology, 2004, 85, (6-7), 701-726. Mode of occurrence analyses indicate that As, Cr, and Ni in the Illinois No. 6 (Herrin) coal are generally associated with relatively large discrete mineral grains, whereas these elements are much more strongly associated with macerals and fine-grained minerals in Absaloka subbituminous (MeKay or Rosebud seam) coal. The coals were burned using conventional and low-NO~ conditions in an ~7-kW combustion system to evaluate the importance of elemental modes of occurrence and combustion conditions on As, Cr, and Ni volatility and speciation. Chemical analyses of size-classified (~0.4-7.7 ~m) Illinois No. 6 fly ash samples indicated that As, Cr, and Ni concentrations and relative enrichment/depletion (RED) factors generally increased with decreasing particle size which is consistent with an elemental vaporization-particle surface deposition process. Similar semivolatile partitioning systemafics were noted for Ni in Absaloka fly ashes. Consistent with nonvolatility, As and Cr in Absaloka fly ashes were characterized by relatively uniform particle-size distributions (PSDs) and R E D factors. Low-NOx combustion conditions promoted the elemental vaporization-particle surface deposition process, as evidenced by greater elemental concentrations on fine-particle surfaces. The As, Cr, and Ni speciation of PMz.5 samples were determined using X-ray absorption fine-structure spectroscopy (XAFS). Differences in Illinois No. 6 and Absaloka coal combustion conditions did not significantly affect As, Cr, or Ni speciation. As 5 +O4-containing phases occur in Illinois No. 6 and Absaloka PM2.5. Cr3+/Cr 6+ is much greater in Illinois No. 6 PM 25 relative to Absaloka PM2.5. The predominance of maceral-bound Cr 3+ and oxygen functional groups in Absaloka coal may have promoted Cr 6+ formation. Illinois No. 6 and Absaloka PM25 contain similar NiO-containing phases, possibly ferrite spinel.
04/02487 Combustion synthesis of perovskite-type catalysts for natural gas combustion Civera, A. et al. Catalysis Today, 2003, 83, (1~4), 199-211. Combustion synthesis has been applied to LaMnO3 production with a view to boosting its activity towards natural gas combustion by enhancing its specific surface area. With a highly exothermic and self-sustaining reaction, this oxide can be quickly prepared from an aqueous solution of metal nitrates (oxidizers) and urea (fuel). The favourable conditions for LaMnO3 formation were sought: only fuelrich mixtures are effective, but carbonaceous deposits are formed when too much urea is used. In the field of operating conditions in which the combustion synthesis reaction takes place, the specific surface areas were not dramatically higher than those obtained with traditional methods; moreover, even short thermal treatments have been found to rapidly deactivate the catalysts by rapid sintering. With a view to tackling these problems, NH4NO 3 was chosen as an additive for its low costs, highly exothermic decomposition and because it generates gaseous products only, without altering the proportion of the other elements in the catalysts. With ammonium nitrate, specific area was enhanced from 4 m2/g up to about 20 mZ/g. A short thermal treatment at 900°C partially deactivates also the NH4NO3-derived catalysts. It was found that NH4NO3-boosted mixtures produce materials whose activity, after a similar thermal treatment, behave practically as the perovskites obtained by the 'citrates' method. Combustion synthesis is though rather cheap - in terms of reactants employed - and quick, given that the process requires few minutes at low temperature without successive calcination. However, the main drawback of this method is that hazardous or polluting compounds are emitted during the synthesis (mainly NH3 or NO:c). The MgO introduction, which should act both as a structural promoter and as a sulphur poisoning limiting agent, has proved to be harmful: since MgO does not physically interpose between perovskite grains, it does not offer resistance to deactivation induced by high temperatures.
04/02488 Effects of hydrocarbon substitution on atmospheric hydrogen-air flame propagation Law, C. K. and Kwon, O. C. International Journal of Hydrogen Energy, 2004, 29, (8), 867-879. In order to evaluate the potential of partial hydrocarbon substitution to improve the safety of hydrogen use in general and the performance of internal combustion engines in particular, the outward propagation and development of surface cellular instability of spark-ignited spherical premixed flames of mixtures of hydrogen, hydrocarbon, and air were experimentally studied at NTP condition in a constant-pressure combustion chamber. With methane, ethylene, and propane being the substituents, the laminar burning velocities, the Markstein lengths, and the propensity of cell formation were experimentally determined, while the laminar burning velocities and the associated flame thicknesses were computed using recent kinetic mechanisms. Results show substantial reduction of laminar burning velocities with hydrocarbon substitution, and support the potential of propane as a suppressant of both diffusional-thermal and hydrodynamic cellular instabilities in hydrogen-air flames. Such a potential, however, was not found for methane and ethylene as substituents.
04/02489 furnace
Evolution of feed materials for the electric arc
Poveromo, J. J. ISSTech Conference Proceedings, 1st, Indianapolis, IN, United States, 27-30 April, 2003, 1877-1888. In this report the usage of scrap and alternative Fe units in electric arc furnace (EAF) steelmaking is described, as is the role played by the Quebec Cartier Mining (QCM) Company in supplying feed materials to the EAF sector. The future growth of the mini-mill concept will be enhanced, rather than limited, by the raw material options for the EAF. Scrap will continue to be the primary feed material. The supply of home and prompt industrial scrap will continually decrease due to technological changes in both the steel producing and steel consuming industries. The supply of obsolete scrap will increase simply due to the harvesting of scrap from steel products produced during an era of increasing North American and worldwide steel production in the past three decades. The ability to use lower grades of obsolete scrap will be extended by the options for alternative iron units (AIUs) available to the EAF steelmaker. Captive gas-based shaft furnace DRI plants will continue to be built in regions poor in scrap but rich in natural gas. In areas without tow-priced gas, some on-site coal-based hot metal plants could be expected to be built to feed larger scale (> t.5 MTPY) minimills making high-end products. Other EAF plants will have little problem securing AIUs (direct reduced iron (DRI)/hot-briquetted or pig iron) from merchant sources. QCM is participating in mini-mill growth by supplying Mt Wright concentrate to an on-site hot metal plant feeding an EAF plant. In the area of DR grade pellet production,
348
Fuel and Energy Abstracts September 2004
QCM has focused improvements in three areas: SiO2 reduction, elimination of roved pellet properties have contributed directly to improved D R shaft furnace and EAF steelmaking performance, which in turn has led to reduced DRI and liquid steel costs.
04•02490 Experiments on the pyrolysis of large beechwood particles in fixed beds Schr6der, E. Journal of Analytical and Applied Pyrolysis, 2004, 71, (2), 669-694. Fixed beds of beechwood particles 10 m m in size were pyrolysed under conventional pyrolysis conditions. For this purpose, the beds were heated to a maximum temperature of 525°C at rates 3-10 K/rain by a flow of hot nitrogen. The loss of mass of the beds in the decomposition process was recorded as a function of time in addition to the temperature field inside the beds, which was measured continuously. The yields of char, tar and gas were quantified, and the composition of the products was analysed with respect to their elemental composition and calorific values at various temperatures. The results are compared with the findings made in various studies of this topic. The results are an important tool for validating physical and chemical models of heating, drying, and pyrolysing fixed beds of biomass.
04/02491 Extension of No. 3 coke oven service life at JFEFukuyama works Maruoka, M. et al. ISSTech Conference Proceedings, 1st, Indianapolis, IN, United States, 2~30 April, 2003, 1197-1206. The efforts to extent the coke oven service life in a Japanese coke plant are presented. The present coke oven is described as well as the influence of the damages on the operation. The mechanisms of coke oven deterioration are outlined, and countermeasures and repair methods are given. The operational improvement achieved by repair and damage countermeasures are presented.
04/02492 Fixed-bed pyrolysis of rapeseed (Brassica napus L.) Onay, O. and Koqkar, O. M. Biomass andBioenergy, 2004, 26, (3), 289299. Fixed-bed slow and fast pyrolysis experiments have been conducted on a sample of rapeseed. The experiments were performed in two different pyrolysis reactors, namely a fixed-bed Heinze and a wellswept fixed-bed tubular retort to investigate the effects of heating rate, pyrolysis temperature, particle size, sweep gas velocity on the pyrolysis product yields and chemical compositions. The maximum oil yield of 51.7% was obtained in the Heinze reactor 550°C, with a particle size range of +0.6-1.8 m m (sweep gas 100 cm 3 min 1 N2) at a heating rate of 30°C min -1. In the well-swept fixed-bed reactor, the maximum oil yield of 68% was obtained at a heating rate of 300°C rain 1. Chromatographic and spectroscopic studies on the pyrolytic oil showed that the oil obtained from rapeseed could be use as a renewable fuels and chemical feedstock.
04102493 Formation and chemical speciation of arsenic-, chromium-, and nickel-bearing coal combustion PM2.5 Galbreath, K. C. and Zygarlicke, C. J. Fuel Processing Technology, 2004, 85, (6-7), 701-726. Mode of occurrence analyses indicate that As, Cr, and Ni in the Illinois No. 6 (Herrin) coal are generally associated with relatively large discrete mineral grains, whereas these elements are much more strongly associated with macerals and fine-grained minerals in Absaloka subbituminous (MeKay or Rosebud seam) coal. The coals were burned using conventional and low-NO~ conditions in an ~7-kW combustion system to evaluate the importance of elemental modes of occurrence and combustion conditions on As, Cr, and Ni volatility and speciation. Chemical analyses of size-classified (~0.4-7.7 ~m) Illinois No. 6 fly ash samples indicated that As, Cr, and Ni concentrations and relative enrichment/depletion (RED) factors generally increased with decreasing particle size which is consistent with an elemental vaporization-particle surface deposition process. Similar semivolatile partitioning systemafics were noted for Ni in Absaloka fly ashes. Consistent with nonvolatility, As and Cr in Absaloka fly ashes were characterized by relatively uniform particle-size distributions (PSDs) and R E D factors. Low-NOx combustion conditions promoted the elemental vaporization-particle surface deposition process, as evidenced by greater elemental concentrations on fine-particle surfaces. The As, Cr, and Ni speciation of PMz.5 samples were determined using X-ray absorption fine-structure spectroscopy (XAFS). Differences in Illinois No. 6 and Absaloka coal combustion conditions did not significantly affect As, Cr, or Ni speciation. As 5 +O4-containing phases occur in Illinois No. 6 and Absaloka PM2.5. Cr3+/Cr 6+ is much greater in Illinois No. 6 PM 25 relative to Absaloka PM2.5. The predominance of maceral-bound Cr 3+ and oxygen functional groups in Absaloka coal may have promoted Cr 6+ formation. Illinois No. 6 and Absaloka PM25 contain similar NiO-containing phases, possibly ferrite spinel.