- Email: [email protected]
Influences of coal type on the performance of a pressurised fluidised bed combustion power plant
12 Refractories/ceramics (properties, production, applications) temperatures: 40, 49.5, and 60°C. Results of the model predictions show very good agreement with a large number of experimental data obtained in drying wheat. The agreement of model prediction and experimental data indicates that the model is fully predictable for drying of other materials in the fluidized bed with no restriction in the range of operational conditions such as the air temperature and the relative humidity. The model can be applied to the other type of processes such as spouted bed and fixed-bed drying with slight modification. It is found that the drying of grain materials is usually controlled by internal mass transfer parameters. The inlet air temperature has an important effect on the magnitude of drying rate while the gas velocity and bed hold-up do not show significant contribution to the drying rate. The initial moisture content of the bed materials can have an important effect on the drying rate depending on the physical properties of bed materials.
Thermal design of contraflow exchangers incorporting entropy
00/00536
Smith, E. M. ImechE Cons. Trans., 1999, 33-38. Two-stream plate-fin contraflow exchangers have been previously optimized for minimum frontal area and minimum volume. Working with the information provided, which includes, mass flow rates, exchanger duty, allowable pressure losses and inlet temperatures, the search involved altering the local geometry of the compact surface until the optimum design was achieved. This paper takes the design process further, exploring how pressure losses and temperature profiles might also be selected for an acceptable rate of entropy production using fixed surface geometries.
Type performance of Fischer-Tropsch liquids in modified off-highway diesel engine test cycle
12
REFRACTORIES/ CERAMICS Properties, production,
applications
00100540 In-situ carbon content adjustment in polymerderived WC/N ceramics by reactive heat treatment. Calculations of the pyrolysis product composition Galusek, D. er al. Silic. Ind., 1999, 64, (l-2), 3-7. A simplified mechanistic approach has been developed to estimate the range of compositional changes during the reactive heat treatment of different preceramic organosilicon precursors resulting in their conversion to amorphous Si/C/N ceramics. The calculation uses the composition of cross-linked polysilazane as a starting value and combines the conversion degrees of them. reactions with the highest thermodynamical probability which take part during the precursor thermal decomposition This approach allows to estimate a stoichiometry of the Si/C/N ceramics, provided the reactions yield thermodynamically stable, equilibrium products. Calculated data are consistent with experimental values and indicate that the stoichiometry of the product is detected by the structure and chemical composition of the polymer, rather than the conditions applied during pyrolysis. However, in certain limits given by the chemistry of the polymer, the stoichiometry of the product can be affected by a proper adjustment of the experimental conditions.
00/00537
Suppes, G. J. et al. Sec. Automat. Eng.. [Spec. Publ.] SP, 1999, SP1461, 41-53. Fischer-Tropsch (FT) conversion of gasification products to liquid hydrocarbon fuel, generally involves FT synthesis followed by mild refining of the FT synthetic oil into diesel, kerosene, and naphtha. These FT products are derived typically by mixing condensable gaseous reactor effluent (=Cs-Cza) with hydrocracked liquid reactor effluent (=Czo+). This mixture of FI liquids (FTL), then undergoes hydrotreatment and distillation to yield the desired products. This paper evaluates compression-ignition engine performance during preliminary tests of the condensable gaseous reactor effluent (&s-C& portion of the (FTL) from a Syntroleurn Corporation plant. Engine operability, fuel economy, maximum torque and emissions were evaluated for both FIL and mixtures of FTL with gasoline, di-ethyl ether, hexanes and ethanol. It was the nitric oxide and particulate emissions that the emphasis was placed upon. However, hydrocarbon, carbon dioxide, and oxygen concentrations were also analysed. Engine tests were performed with neat FIL, as well as with FTL formulations containing (1) 25% gasoline; (2) 25% hexanes; (3) 20%, 25%, and 33% of a equal volume mixtures of ethanol and di-Et ether and (4) 20% and 25% ethanol. Comparisons were made of these performances with US 1D and US 2D diesels. A three-mode test sequence was performed consistent with heavy duty diesel engine applications and each of the fuels met or exceeded goals on reduced emissions and operability of the unmodified engine. With several of these formulations, significant emission performance advantages were observed.
00/00538 Use of pulverized coal fuel in Ukrainian blast furnaces; Part 1 Piskanovsky, S. T. er a/. Mefall. Gornorudn. Prom-~., 1998, 2, 8-l 1. (In Russian) In the ironmaking industry of the Ukrain, the possibility of using pulverized non-coking coals to partially replace coke has been suggested. Its impact on the technological parameters of blast furnace operation are discussed in this paper.
00100539 Influences of coal type on the performance of a pressurised fluidised bed combustion power plant Huang, Y. et al. Fuel, 2000, 79, (13), 1595-1601. The performance of a combined cycle pressurized fluidized bed combustion (PFBC) plant has been calculated, using the ECLIPSE process simulator, for a wide range of coal properties. The overall efficiency varies between 40.8 and 43.4% on a higher heating value basis according to the changing coal properties. A mathematical equation has been developed, using the least-squares algorithm, which can be used to predict the efficiency of a PFBC plant for a given coal. The prediction indicates that the parameters, such as ash content, moisture content, sulfur content and calorific value of the coals, affect the overall efficiency. However, the ash content is found to be the most significant factor influencing plant performance. 56
Fuel and Energy Abstracts
January 2001
An investigation into the crystallization of Dicer glass-ceramic
00100541
Wood, D. J. et al. J. Mater. Sci. Lett., 1999, 18, (13), 1001-1002. The aim of the present investigation is to study the crystallization of DicorTM glass-ceramic, with a particular emphasis on the role of fluorine and silicon tetrafluoride loss on the crystallization mechanism. The results obtained have implications for the use of DicorTM, since one of the advantages cited for this material is that its hardness is similar to human enamel, but the cerammed surface has been shown to be much harder and much more abrasive toward enamel than the bulk material. The formation of an enstatite phase at the surface of the glass-ceramic is clearly undesirable and has implications for the wear of opposing teeth and for the determination of fracture toughness using indentation methods.
Aqueous sol-gel method for the synthesis of nano-sized ceramic powders
00100542
Pramanik, P. Ghosh, N. N. Ceram. Trans., 1999, 94, 195-203. The aqueous sol-gel method was used to synthesize a series of nanosized multicomponent ceramic powders. Metal formates and precipitated silica were used as precursor compounds instead of metal alkoxides and water was used as reaction medium instead of the commonly used solvent alcohol. Precipitated silica and aqueous solutions of metal formates were mixed together in order to prepare the gels. The gels prepared using this method were calcined at different temperatures and characterized by X-ray powder diffraction, IR spectroscopy, DTA, TEM and TG. This aqueous sol-gel method is shown to provide homogeneous and nanosized ceramic powders at effectively low temperatures and offers the potential of technically simpler and cost effective route than other reported sol-gel methods.
Ceramic surfacing method for repair of coke oven refractories
00100543
Balanov, V. G. and Krupoder, L. V. Koks Khim., 1999, 5, 16-17. (In Russian) If a ceramic surfacing method is used to replace the damaged coating of the coke ovens with a similar refractory material, the surface life of coke ovens can be increased. Also outlined are the economic advantages of ceramic as compared to gunite.
Characterization of ceramic glass in hydroxyapatite containing glass coated titanium composites 00100544
Yang, X. et aLProcess. Fabr. Adv. Mater. VI, Proc. Symp., 6th, 1998, 2, 1693-1701. Edited by Khor K.A., Srivatsan T.S., Moore J.J. Hydroxyapatite (HA)-glass (G) ceramics were prepared using HA with different degrees of crystallinity and characteristics. For two hours, the HA was synthesized chemically and fired at various temperatures (2001200”). The properties of these HA-G ceramics as well as the reaction of glass with HA, were investigated by differential scanning calorimetry, X-ray diffraction and Fourier transform infrared spectroscopy. HA slightly reacted with glass and formed a small amount of boron containing apatite. The pull-out strength study of the HA-G-Ti
Thermal design of contraflow exchangers incorporting entropy
00/00536
Smith, E. M. ImechE Cons. Trans., 1999, 33-38. Two-stream plate-fin contraflow exchangers have been previously optimized for minimum frontal area and minimum volume. Working with the information provided, which includes, mass flow rates, exchanger duty, allowable pressure losses and inlet temperatures, the search involved altering the local geometry of the compact surface until the optimum design was achieved. This paper takes the design process further, exploring how pressure losses and temperature profiles might also be selected for an acceptable rate of entropy production using fixed surface geometries.
Type performance of Fischer-Tropsch liquids in modified off-highway diesel engine test cycle
12
REFRACTORIES/ CERAMICS Properties, production,
applications
00100540 In-situ carbon content adjustment in polymerderived WC/N ceramics by reactive heat treatment. Calculations of the pyrolysis product composition Galusek, D. er al. Silic. Ind., 1999, 64, (l-2), 3-7. A simplified mechanistic approach has been developed to estimate the range of compositional changes during the reactive heat treatment of different preceramic organosilicon precursors resulting in their conversion to amorphous Si/C/N ceramics. The calculation uses the composition of cross-linked polysilazane as a starting value and combines the conversion degrees of them. reactions with the highest thermodynamical probability which take part during the precursor thermal decomposition This approach allows to estimate a stoichiometry of the Si/C/N ceramics, provided the reactions yield thermodynamically stable, equilibrium products. Calculated data are consistent with experimental values and indicate that the stoichiometry of the product is detected by the structure and chemical composition of the polymer, rather than the conditions applied during pyrolysis. However, in certain limits given by the chemistry of the polymer, the stoichiometry of the product can be affected by a proper adjustment of the experimental conditions.
00/00537
Suppes, G. J. et al. Sec. Automat. Eng.. [Spec. Publ.] SP, 1999, SP1461, 41-53. Fischer-Tropsch (FT) conversion of gasification products to liquid hydrocarbon fuel, generally involves FT synthesis followed by mild refining of the FT synthetic oil into diesel, kerosene, and naphtha. These FT products are derived typically by mixing condensable gaseous reactor effluent (=Cs-Cza) with hydrocracked liquid reactor effluent (=Czo+). This mixture of FI liquids (FTL), then undergoes hydrotreatment and distillation to yield the desired products. This paper evaluates compression-ignition engine performance during preliminary tests of the condensable gaseous reactor effluent (&s-C& portion of the (FTL) from a Syntroleurn Corporation plant. Engine operability, fuel economy, maximum torque and emissions were evaluated for both FIL and mixtures of FTL with gasoline, di-ethyl ether, hexanes and ethanol. It was the nitric oxide and particulate emissions that the emphasis was placed upon. However, hydrocarbon, carbon dioxide, and oxygen concentrations were also analysed. Engine tests were performed with neat FIL, as well as with FTL formulations containing (1) 25% gasoline; (2) 25% hexanes; (3) 20%, 25%, and 33% of a equal volume mixtures of ethanol and di-Et ether and (4) 20% and 25% ethanol. Comparisons were made of these performances with US 1D and US 2D diesels. A three-mode test sequence was performed consistent with heavy duty diesel engine applications and each of the fuels met or exceeded goals on reduced emissions and operability of the unmodified engine. With several of these formulations, significant emission performance advantages were observed.
00/00538 Use of pulverized coal fuel in Ukrainian blast furnaces; Part 1 Piskanovsky, S. T. er a/. Mefall. Gornorudn. Prom-~., 1998, 2, 8-l 1. (In Russian) In the ironmaking industry of the Ukrain, the possibility of using pulverized non-coking coals to partially replace coke has been suggested. Its impact on the technological parameters of blast furnace operation are discussed in this paper.
00100539 Influences of coal type on the performance of a pressurised fluidised bed combustion power plant Huang, Y. et al. Fuel, 2000, 79, (13), 1595-1601. The performance of a combined cycle pressurized fluidized bed combustion (PFBC) plant has been calculated, using the ECLIPSE process simulator, for a wide range of coal properties. The overall efficiency varies between 40.8 and 43.4% on a higher heating value basis according to the changing coal properties. A mathematical equation has been developed, using the least-squares algorithm, which can be used to predict the efficiency of a PFBC plant for a given coal. The prediction indicates that the parameters, such as ash content, moisture content, sulfur content and calorific value of the coals, affect the overall efficiency. However, the ash content is found to be the most significant factor influencing plant performance. 56
Fuel and Energy Abstracts
January 2001
An investigation into the crystallization of Dicer glass-ceramic
00100541
Wood, D. J. et al. J. Mater. Sci. Lett., 1999, 18, (13), 1001-1002. The aim of the present investigation is to study the crystallization of DicorTM glass-ceramic, with a particular emphasis on the role of fluorine and silicon tetrafluoride loss on the crystallization mechanism. The results obtained have implications for the use of DicorTM, since one of the advantages cited for this material is that its hardness is similar to human enamel, but the cerammed surface has been shown to be much harder and much more abrasive toward enamel than the bulk material. The formation of an enstatite phase at the surface of the glass-ceramic is clearly undesirable and has implications for the wear of opposing teeth and for the determination of fracture toughness using indentation methods.
Aqueous sol-gel method for the synthesis of nano-sized ceramic powders
00100542
Pramanik, P. Ghosh, N. N. Ceram. Trans., 1999, 94, 195-203. The aqueous sol-gel method was used to synthesize a series of nanosized multicomponent ceramic powders. Metal formates and precipitated silica were used as precursor compounds instead of metal alkoxides and water was used as reaction medium instead of the commonly used solvent alcohol. Precipitated silica and aqueous solutions of metal formates were mixed together in order to prepare the gels. The gels prepared using this method were calcined at different temperatures and characterized by X-ray powder diffraction, IR spectroscopy, DTA, TEM and TG. This aqueous sol-gel method is shown to provide homogeneous and nanosized ceramic powders at effectively low temperatures and offers the potential of technically simpler and cost effective route than other reported sol-gel methods.
Ceramic surfacing method for repair of coke oven refractories
00100543
Balanov, V. G. and Krupoder, L. V. Koks Khim., 1999, 5, 16-17. (In Russian) If a ceramic surfacing method is used to replace the damaged coating of the coke ovens with a similar refractory material, the surface life of coke ovens can be increased. Also outlined are the economic advantages of ceramic as compared to gunite.
Characterization of ceramic glass in hydroxyapatite containing glass coated titanium composites 00100544
Yang, X. et aLProcess. Fabr. Adv. Mater. VI, Proc. Symp., 6th, 1998, 2, 1693-1701. Edited by Khor K.A., Srivatsan T.S., Moore J.J. Hydroxyapatite (HA)-glass (G) ceramics were prepared using HA with different degrees of crystallinity and characteristics. For two hours, the HA was synthesized chemically and fired at various temperatures (2001200”). The properties of these HA-G ceramics as well as the reaction of glass with HA, were investigated by differential scanning calorimetry, X-ray diffraction and Fourier transform infrared spectroscopy. HA slightly reacted with glass and formed a small amount of boron containing apatite. The pull-out strength study of the HA-G-Ti