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04093 Influence of thermal conductivity and aspect ratio on stable combustion inside a refractory tube
12 Refractories/ceramics
12
(properties, production,
applications)
97104089 Energy conservation tages of waste recycling
REFRACTORIES/ CERAMICS Properties, Production,
Applications
Application of refractories in chemical and petrochemical industries
97lO4083
Gue, Z. and Zhang, H. China’s Refract., 1997, 6, (1). 27-33. China’s chemical and petrochemical industries have developed significantly over the last decade. Fluid catalytic cracking, steam reforming furnace, carbon black reactor, oil gasifier and coal gasifier are common chemical reactors operated at high temperature. Several high technology refractory bricks and castables, mainly developed by LIRR, have been used in their serious working environments. The properties and service performance of these materials are reviewed.
Aspects of preliminary economic viability of the use of coal ashes in the preparation of glass-ceramics
97/04004
Marques, M and Fonseca, M. Ceramica, 1996, 42 (277), 669-672. (In Portugese) The glass-ceramic fabrication process involves high temperature and significant energy consumption. The characteristics of the coal ash from the south of Brazil and its relative energy consumption compared to the use of conventional raw material for the production of glass-ceramics were taken into account. Significant energy saving is possible with the use of coal ash. This is attributed to the residual energy content of the coal ash and also to the silicate network forming reactions that had already occurred in the ash.
Ceramic compositions containing shaped ceramic products, and their manufacture
97lO4085
and environmental
advan-
Monfort, E. and Enrigue, J. E. Ceram. Ind., 1996, I, (4/S), 14-20. (In Portuguese) Specific consumption of thermal energy has been reduced progressively and spectacularly over the past 15 yr in the sector of ceramic flooring and coatings. Maximum reduction has been approached, accompanied by reduced emissions of CO* and SO, Conversion from slow double-firing to single-firing and rapid-cycling, the increased use of less contaminating fuels, fundamentally natural gas, and optimization of energy use with recovery of hot gases have all helped minimize the direct environmental impact of thermal energy use. In the short- and medium-term, cogenerational energy systems will be more important. The level of waste recycling generated in the ceramic floor and coating sector is greater than 50% by weight. For wastewater treatment sludges, the wastes with greatest potential toxicity, recycling is realized almost exclusively as raw materials for ceramic biscuit.
Evaporation characteristics of fuel spray and low emissions in a lean premixed-prevaporization combustor for a 100 kW automotive ceramic gas turbine
97lQ4090
Ohkubo, Y. el al. Energy Cowers. Mgml, 1997, 38, (IO-l3), 1297-1309. In order to meet the Japanese emission standards for passenger cars without using an after-treatment system, a lean premixed-pre-vaporization combustor (PPL-1) for a 100 kW automotive ceramic gas turbine has been developed. The design of a fuel injector and a pre-vaporization-premixing tube (PP-tube) in the PPL-I combustor is a key subject for promotion of evaporation of fuel spray. The Sauter mean diameter and the nonevaporated mass fraction of fuel spray in the PP-tube were measured employing a phase Doppler particle analyser. The evaporation of the fuel spray in the PP-tube was promoted by higher swirl number, air velocity, air temperature and increased atomization of the fuel injector. It was, however, suppressed by higher air pressure and fuel properties such as distillation in high temperature. The characteristics of NO, CO and HC emissions were measured with a combustor test rig and influences of the evaporation characteristics of fuel spray are discussed. Results show that a mass fraction of non-evaporated fuel of less than 10% and lean fuel-air mixtures reduce the PPL-I combustor emissions of NO, and CO.
coal ashes,
Kajima, A. and Shimada, K. Jpn. Kokai Tokkyo Koho JP 09,100,153 [97,100,153] (Cl. C04B35/00), 15 Apr 1997, Appl. 95/254,898,2 Ott 1995,20 pp. (In Japanese) Coal ashes, Al phosphates, water, and agents for controlling hardening comprise these compostitions. The products are obtained by shaping-drying or drying-shaping, followed by sintering. The process comprises casting of slurries and heating at 250-600”. The process also involves drying the compositions to give pre-ceramic compositions, and hot pressing. The shaping may include injection moulding or extrusion moulding of the preceramic compositions. Also described is the mixing process of the raw material compositions. The resulting ceramic products show high strength and fire resistance.
Characterization of phonolite used in the formation of ceramic tiles
97lO4086
Mussolin, S. et al. Ceromica (Sao P&o), 1996, 42, (278), 876-879. Due to its excellent liquid phase characteristics at the temperature used in fast firing process, phonolite has been used as a fluxing agent in ceramic tile manufacture in Brazilian ceramic industries. The study aims to characterize the phonolite from a Brazilian mine. The characterization techniques used were scanning electronic microscopy with microanalysis by X-ray energy dispersive, X-ray diffraction, system thermal analysis and ICP chemical analysis.
Charcoal-containing ceramics for purification of air and water and their manufacture
97104087
Murata, S. et al. Jpn. Kokai Tokkyo Koho JP 09,118,559 [97,118,559] (Cl. C04B33/13), 6 May 1997, Appl. 95/303,444, 26 Ott 1995,4 pp. (In Japanese) Air- and water-permeable ceramics are mixed with charcoal. The ceramics are produced by kneading ceramic slurries with charcoal, forming into desired shapes, then firing after drying. The charcoal-containing ceramics are useful for air and water purification.
Electroceramics made of iron-nickel manganite spinels: synthesis and microstructural and electrical properties
97104091 An experimental study of heavy oil ultrafiltration using ceramic membranes Duong, A. ef al. Fuel, 1997, 76, (9). 821-828. Asymmetric, single-tube ceramic membranes were used for the ultrafiltration of Cold Lake heavy oil in a hatch ultrafiltration unit operated with partial recycle of retentate. This process is investigated in this paper. Both permeate flux and asphaltene content were monitored as a function of time on-stream during each experiment. Ultrafiltration resulted in rapid fouling of the membranes, which significantly reduced the permeate flux but increased the retention of asphaltenes. The decrease in asphaltene content of the permeate compared with the feed was correlated with decreases in permeate density, viscosity and Ni and V contents. The effect of membrane pore diameter and cross-flow velocity on permeate flux and asphaltene retention proved that membrane fouling occurred initially by a porerestriction mechanism. The formation of a gel layer was important near the end of the run.
High-thermal-conductivity aluminum nitride ceramics: the effect of thermodynamic, kinetic, and microstructural factors 97104092
Jackson, T. B. J.Am. Ceram. Sot., 1997, 80, (6). 1421-1435. Additives characterized by their high thermodynamic affinity toward alumina can be used to improve the thermal condition of aluminium nitride (AIN). Proof of this can be seen in the aluminium nitride-yttria (AIN-Y,03) system. A wide variety of lanthanide dopants are compared at equimolar lanthanide oxide:alumina ratios. Samaria (Sm30x) gave the highest- and lutetia (LuzO,) the lowest-thermal-condition AIN composites. The choice of the sintering aid and the dopant level is much more important than the microstructure that evolves during sintering. A contiguous AIN phase provides rapid heat conduction slightly as the annealing times increase in the range of l-1000 min at 1850°C. However, there results a substantial increase in thermal condition, because AIN grains are purified by dissolution-reprecipitation and bulk diffusion. Removal of grainboundary phases, with a concurrent increase in AIN contiguity, occurs at high annealing temperature or at long times and is a natural consequence of high dihedral angles (poor wetting) in liquid-phase-sintered AIN ceramics.
97104088
Battault, T. el al. .I. Mater. Synth. Process., 1996, 4, (6), 361-370. By calcination of the mixed corresponding metal oxalate, single-phase ironnickel manganite spinels were prepared. Through careful selection of the experimental conditions, it was possible to obtain powders having grains of an overall octahedral shape and a narrow size distribution suitable for highquality sintering. X-ray diffraction, thermogravimetric analysis, and Mossbauer spectroscopy of the iron-nickel manganite solid solutions obtained made it possible to determine the cation distribution over the tetrahedral (A) and octahedral (B) sites of the spine1 structure. Conductivity measurements performed on the electroceramics derived from the above phases were used to validate this cation distribution.
344
Fuel and Energy Abstracts
September 1997
Influence of thermal conductivity and aspect ratio on stable combustion inside a refractory tube
97104093
Kansuntisukmongkol, R. and Ozoe, H. Energy Cowers. Mgmt, 1997, 38, (lo-13), 1051-1059. A numerical investigation was carried out into the characteristics of combustion flame for premixed propane and air flowing inside an adiabatic refractory tube without a flameholder. The effect of thermal conductivity of a tube wall k, and a tube aspect ratio L = I/D on the flame front was studied for the stable combustion at multiple locations. Both upstream and downstream flame locations are shifted into the centre of the tube with decreasing thermal conductivity of the tube wall. The flame is extinguished
13
in the centre of the tube because of insufficient thermal results are presented and were found to be quite different conventional combustion.
feedback. The from those for
97/04094 Macroscopic modelling of the reaction bonding of aluminum oxide Gaus, S. P. J. Eur. Ceram. Sot., 1997, 17, (S), 971-975. The paper presents the reaction-bonded aluminium oxide (RBAO) process, a novel method to produce monolithic alumina-base ceramics. In order to gain some insight into the process, a macroscopic model, which considers the interaction of oxygen diffusion and reaction within a porous body, has been developed. The model facilitates prediction of the effects of parameters such as heat-treatment cycle, atmosphere, and scale to a first approximation, as well as important consideration for industrial applications. Thermogravimetric (TG) curves predicted by the model show reasonable agreement with experimental data and indicate that a combination of reaction and diffusion controls the process. Manufacture of ceramic from coal ash as filtering 97104095 materials Ogawa, K. Jpn. Kokai Tokkyo Koho JP 09,156,998 [97,156,998] (Cl. C04B35/00), 17 Jun 1997, Appl. 951334,057, 29 Nov 1995, 5 pp. (In Japanese) Ceramic products can be manufactured with coal ash microparticles having particle size l-10 ,rm, that have been shaped and sintered. In these products, coal ash particles are bound together giving a porous microstructure through the entire product. They are useful as filtering materials and adsorbents. Production of ceramic building materials in Russia 97104096 from anthracite tailings Siefke, C. Kernm. Z., 1997, 49, (5), 362-364, 366-367. (In German) Methods of producing thermal insulating ceramic bricks from anthracite tailings with a high C content, allowing the excess energy to be used for other purposes are reported. Silica bricks after fifteen years in service. Critical 97104097 study Zamboni, L. A. et al. lnterceram, 1997, 46, (3). 162-164, 166. Various refractory bricks were selected for examination after used 15 years of operation in coke oven batteries. The SiOz bricks at the fire side showed a mechanical and chemical resistant microstructure. The coke side showed fissures due to stress resulted from gas formation by air entrance and coal combustion, and thermal shock during operation. Its vitreous phase quality, quantity, and distribution made the coke side microstructure weak. 97104096 Sol-gel synthesis of lanthanum chromite powder. Bilger, S. et al. J. Eur. Ceram. Sot., 1997, 17, (8), 1027-1031. A ceramic material with conduction characteristics satisfactory for the interconnector of solid oxide fuel cells (SOFC) is alkali earth-doped LaCr03 For the synthesis of highly sinterable LaCr03 powders, spraydrying of adequate precursors like solutions based on alkoxides has been used. Lanthanum chromium hydroxide solution was prepared by hydrolysis and chromium hydroxide solution was prepared by hydrolysis of synthesised methoxide complexes. The chemical reactions during hydrolysis and peptization of the precursors are described. The crystal-phase formation during the heat treatment of spray-dried amorphous gel consisting of hydroxide and contaminant chloride ligands was characterized by thermal analysis methods (TG, DTG, DTA) and X-ray diffraction analysis. The progressive oxidation of Cr(II1) by thermal dehydroxylation transforms the powder into fine crystal La(II1) Cr(V) hydroxo-oxychloride at 450°C. A thermal treatment permits complete chlorine removal forming sinterable crystal LaCrOJ perovskite powder at temperatule above 720°C. The same sol-gel process can be applied to chlorine-free nitrate-containing alkoxide solutions. The properties of sinterable lanthanum chromite powders obtained from these sols are compared with powders made by direct spray-drying of lanthanum-chromium nitrate solutions. 97104099 Specific heat capacity of new porous carbon materials: Woodceramics Kano, M. et al. Thermochim. Acta, 1997, 292, (l-2), 175-177 ‘Woodceramics’ are new carbon porous materials developed by carbonizing wood or woody materials impregnated with thermosetting resin. The carbonization takes place in a vacuum furnace at high temperature. Woodceramics have superior characteristics from the point of view of engineering and ecological materials: they are hard and strong, have porous structure and low density, are made from natural resources, do not cause environmental pollution, and are cheap to manufacture. Differential scanning calorimetry was carried out to determine the heat capacity at high temperature. 97104100 Specific heat capacity of new porous carbon materials: Woodceramics Kane, M. et al. Thermochin. Acto, 1997, 292, (l-2), 175-177. Wood or woody materials impregnated with thermosetting resin are carbonized in a vacuum furnace at high temperature to produce ‘Woodceramics’. These have superior characteristics from an engineering and ecological point of view: they are hard and strong, have porous
Space heating
and cooling
structure and low density, are made from natural resources, do not cause environmental pollution, and are cheap to manufacture. Differential scanning calorimetry has been employed to determine their heat capacity at high temperature. 97lO4101 Spray repairing materials for refractory linings Mitsui, H. et al. Jpn. Kokai Tokkyo Koho JP 09,132,470 [97,132,470] (Cl. C04B35/66), 20 May 1997, Appl. 95/317,194, 10 Nov 1995, 5 pp. (In Japanese) Metallic Si 10-30, coke having particle diameter ilOO ,lrn 0.5-5.0 wt%, and balance fired refractory powder comprise the spray repairing materials. The materials are fed at hot state into an 02 stream to melt the refractory powder by the combustion heat of the metallic Si, to repair the refractory linings.
97104102 Study of the synthesis of ammonium dawsonite. Part II. Characterization Ceramica, 1996, 42, (278), 776-779. Sakamoto, R. G. The paper describes the preparation of ammonium aluminium hydroxy carbonate (AAHC) known as ammonium dawsonite by precipitation from ammonium aluminium sulfate (AA) and ammonium hydrogen carbonate (AHC). The precipitate was washed three times and its purity degree was determined after each washing. X-ray diffractometry, SEM, thermal analysis, as well as qualitative and quantitative chemical analyses of the impurities present were implemented to characterize the material after each step. The results showed that the obtained AAHC had high purity and its grain size was l-3 pm dimension.
Thermochemistry and kinetics [of ceramic materials] Flagan, R. C. Carbide, Nitride Boride Mater. Synth. Process., 1997, 275-306. Edited by Weimer, A. W., Chapman & Hall, London, UK. The thermochemical and kinetics of vapour-phase synthesis of ceramic materials are investigated.
97104103
13
SPACE HEATING COOLING
AND
97104104 Applicability of zeolite for CO* storage in a CaOCO* high temperature energy storage system Kyaw, K. et al. Energy Cowers. Mgmt, 1997, 38, (lO-13), 1025-1033. This paper reviews reversible thermal dissociation reactions for application in thermal energy storage at very high temperatures. Among them, dissociation of CaCOJ seems very promising as the material can dissociate at 1098 K under atmospheric condition and the reactants involved are free from toxicity. One of the dissociation products, CO2 gas, requires a storage system. Three CO2 storage systems are being considered and the thermal operating efficiencies, COP, of the respective CaO-CO2 energy storage systems are evaluated. The system with a zeolite adsorbent for CO2 storage can compete with the other systems when the adsorptivity of the adsorbent increases to higher values. The CO2 adsorption characteristics of zeolite 13X and super activated carbon under a temperature range 303-573 K are studied. Zeolite 13X adsorbent was found to be suitable as a CO2 storage medium in a CaO-CO2 high temperature thermal energy storage system.
97104105 The comfort zone and the oscillation of the driving temperature Morillbn, D. et al. Applied Energy, 1997, 57, (l), l-l I. For the purpose of calculating the heating and cooling loads of a single room, a Fourier-analysis based method is proposed. The method includes the effects of thermal inertia and climate. Two situations are studied: firstly when the driving outdoor-temperature fluctuates within the comfort zone and secondly when this temperature fluctuates out of the comfort zone. Some experimental measurements were performed at different locations in order test the validity of the method.
97104106 Design and testing of current leads made from AgAu sheathed 81-2223 superconducting wires Sasaoka, T. et al. Cryogenics, 1997, 37, (S), 409-415. The paper describes the manufacture of a pair of current leads consisting of spirally assembled Ag-Au sheathed Bi-2223 superconducting wires. The heat leak into liquid helium (LHe) was measured in a vapour cooler under a self-cooling condition. The heat cycle of the fabricated superconducting current lead had no influence on the characteristics of both superconducting and joint parts. The paper presents the findings from the tests.
Fuel and Energy Abstracts
September
1997
345
12
(properties, production,
applications)
97104089 Energy conservation tages of waste recycling
REFRACTORIES/ CERAMICS Properties, Production,
Applications
Application of refractories in chemical and petrochemical industries
97lO4083
Gue, Z. and Zhang, H. China’s Refract., 1997, 6, (1). 27-33. China’s chemical and petrochemical industries have developed significantly over the last decade. Fluid catalytic cracking, steam reforming furnace, carbon black reactor, oil gasifier and coal gasifier are common chemical reactors operated at high temperature. Several high technology refractory bricks and castables, mainly developed by LIRR, have been used in their serious working environments. The properties and service performance of these materials are reviewed.
Aspects of preliminary economic viability of the use of coal ashes in the preparation of glass-ceramics
97/04004
Marques, M and Fonseca, M. Ceramica, 1996, 42 (277), 669-672. (In Portugese) The glass-ceramic fabrication process involves high temperature and significant energy consumption. The characteristics of the coal ash from the south of Brazil and its relative energy consumption compared to the use of conventional raw material for the production of glass-ceramics were taken into account. Significant energy saving is possible with the use of coal ash. This is attributed to the residual energy content of the coal ash and also to the silicate network forming reactions that had already occurred in the ash.
Ceramic compositions containing shaped ceramic products, and their manufacture
97lO4085
and environmental
advan-
Monfort, E. and Enrigue, J. E. Ceram. Ind., 1996, I, (4/S), 14-20. (In Portuguese) Specific consumption of thermal energy has been reduced progressively and spectacularly over the past 15 yr in the sector of ceramic flooring and coatings. Maximum reduction has been approached, accompanied by reduced emissions of CO* and SO, Conversion from slow double-firing to single-firing and rapid-cycling, the increased use of less contaminating fuels, fundamentally natural gas, and optimization of energy use with recovery of hot gases have all helped minimize the direct environmental impact of thermal energy use. In the short- and medium-term, cogenerational energy systems will be more important. The level of waste recycling generated in the ceramic floor and coating sector is greater than 50% by weight. For wastewater treatment sludges, the wastes with greatest potential toxicity, recycling is realized almost exclusively as raw materials for ceramic biscuit.
Evaporation characteristics of fuel spray and low emissions in a lean premixed-prevaporization combustor for a 100 kW automotive ceramic gas turbine
97lQ4090
Ohkubo, Y. el al. Energy Cowers. Mgml, 1997, 38, (IO-l3), 1297-1309. In order to meet the Japanese emission standards for passenger cars without using an after-treatment system, a lean premixed-pre-vaporization combustor (PPL-1) for a 100 kW automotive ceramic gas turbine has been developed. The design of a fuel injector and a pre-vaporization-premixing tube (PP-tube) in the PPL-I combustor is a key subject for promotion of evaporation of fuel spray. The Sauter mean diameter and the nonevaporated mass fraction of fuel spray in the PP-tube were measured employing a phase Doppler particle analyser. The evaporation of the fuel spray in the PP-tube was promoted by higher swirl number, air velocity, air temperature and increased atomization of the fuel injector. It was, however, suppressed by higher air pressure and fuel properties such as distillation in high temperature. The characteristics of NO, CO and HC emissions were measured with a combustor test rig and influences of the evaporation characteristics of fuel spray are discussed. Results show that a mass fraction of non-evaporated fuel of less than 10% and lean fuel-air mixtures reduce the PPL-I combustor emissions of NO, and CO.
coal ashes,
Kajima, A. and Shimada, K. Jpn. Kokai Tokkyo Koho JP 09,100,153 [97,100,153] (Cl. C04B35/00), 15 Apr 1997, Appl. 95/254,898,2 Ott 1995,20 pp. (In Japanese) Coal ashes, Al phosphates, water, and agents for controlling hardening comprise these compostitions. The products are obtained by shaping-drying or drying-shaping, followed by sintering. The process comprises casting of slurries and heating at 250-600”. The process also involves drying the compositions to give pre-ceramic compositions, and hot pressing. The shaping may include injection moulding or extrusion moulding of the preceramic compositions. Also described is the mixing process of the raw material compositions. The resulting ceramic products show high strength and fire resistance.
Characterization of phonolite used in the formation of ceramic tiles
97lO4086
Mussolin, S. et al. Ceromica (Sao P&o), 1996, 42, (278), 876-879. Due to its excellent liquid phase characteristics at the temperature used in fast firing process, phonolite has been used as a fluxing agent in ceramic tile manufacture in Brazilian ceramic industries. The study aims to characterize the phonolite from a Brazilian mine. The characterization techniques used were scanning electronic microscopy with microanalysis by X-ray energy dispersive, X-ray diffraction, system thermal analysis and ICP chemical analysis.
Charcoal-containing ceramics for purification of air and water and their manufacture
97104087
Murata, S. et al. Jpn. Kokai Tokkyo Koho JP 09,118,559 [97,118,559] (Cl. C04B33/13), 6 May 1997, Appl. 95/303,444, 26 Ott 1995,4 pp. (In Japanese) Air- and water-permeable ceramics are mixed with charcoal. The ceramics are produced by kneading ceramic slurries with charcoal, forming into desired shapes, then firing after drying. The charcoal-containing ceramics are useful for air and water purification.
Electroceramics made of iron-nickel manganite spinels: synthesis and microstructural and electrical properties
97104091 An experimental study of heavy oil ultrafiltration using ceramic membranes Duong, A. ef al. Fuel, 1997, 76, (9). 821-828. Asymmetric, single-tube ceramic membranes were used for the ultrafiltration of Cold Lake heavy oil in a hatch ultrafiltration unit operated with partial recycle of retentate. This process is investigated in this paper. Both permeate flux and asphaltene content were monitored as a function of time on-stream during each experiment. Ultrafiltration resulted in rapid fouling of the membranes, which significantly reduced the permeate flux but increased the retention of asphaltenes. The decrease in asphaltene content of the permeate compared with the feed was correlated with decreases in permeate density, viscosity and Ni and V contents. The effect of membrane pore diameter and cross-flow velocity on permeate flux and asphaltene retention proved that membrane fouling occurred initially by a porerestriction mechanism. The formation of a gel layer was important near the end of the run.
High-thermal-conductivity aluminum nitride ceramics: the effect of thermodynamic, kinetic, and microstructural factors 97104092
Jackson, T. B. J.Am. Ceram. Sot., 1997, 80, (6). 1421-1435. Additives characterized by their high thermodynamic affinity toward alumina can be used to improve the thermal condition of aluminium nitride (AIN). Proof of this can be seen in the aluminium nitride-yttria (AIN-Y,03) system. A wide variety of lanthanide dopants are compared at equimolar lanthanide oxide:alumina ratios. Samaria (Sm30x) gave the highest- and lutetia (LuzO,) the lowest-thermal-condition AIN composites. The choice of the sintering aid and the dopant level is much more important than the microstructure that evolves during sintering. A contiguous AIN phase provides rapid heat conduction slightly as the annealing times increase in the range of l-1000 min at 1850°C. However, there results a substantial increase in thermal condition, because AIN grains are purified by dissolution-reprecipitation and bulk diffusion. Removal of grainboundary phases, with a concurrent increase in AIN contiguity, occurs at high annealing temperature or at long times and is a natural consequence of high dihedral angles (poor wetting) in liquid-phase-sintered AIN ceramics.
97104088
Battault, T. el al. .I. Mater. Synth. Process., 1996, 4, (6), 361-370. By calcination of the mixed corresponding metal oxalate, single-phase ironnickel manganite spinels were prepared. Through careful selection of the experimental conditions, it was possible to obtain powders having grains of an overall octahedral shape and a narrow size distribution suitable for highquality sintering. X-ray diffraction, thermogravimetric analysis, and Mossbauer spectroscopy of the iron-nickel manganite solid solutions obtained made it possible to determine the cation distribution over the tetrahedral (A) and octahedral (B) sites of the spine1 structure. Conductivity measurements performed on the electroceramics derived from the above phases were used to validate this cation distribution.
344
Fuel and Energy Abstracts
September 1997
Influence of thermal conductivity and aspect ratio on stable combustion inside a refractory tube
97104093
Kansuntisukmongkol, R. and Ozoe, H. Energy Cowers. Mgmt, 1997, 38, (lo-13), 1051-1059. A numerical investigation was carried out into the characteristics of combustion flame for premixed propane and air flowing inside an adiabatic refractory tube without a flameholder. The effect of thermal conductivity of a tube wall k, and a tube aspect ratio L = I/D on the flame front was studied for the stable combustion at multiple locations. Both upstream and downstream flame locations are shifted into the centre of the tube with decreasing thermal conductivity of the tube wall. The flame is extinguished
13
in the centre of the tube because of insufficient thermal results are presented and were found to be quite different conventional combustion.
feedback. The from those for
97/04094 Macroscopic modelling of the reaction bonding of aluminum oxide Gaus, S. P. J. Eur. Ceram. Sot., 1997, 17, (S), 971-975. The paper presents the reaction-bonded aluminium oxide (RBAO) process, a novel method to produce monolithic alumina-base ceramics. In order to gain some insight into the process, a macroscopic model, which considers the interaction of oxygen diffusion and reaction within a porous body, has been developed. The model facilitates prediction of the effects of parameters such as heat-treatment cycle, atmosphere, and scale to a first approximation, as well as important consideration for industrial applications. Thermogravimetric (TG) curves predicted by the model show reasonable agreement with experimental data and indicate that a combination of reaction and diffusion controls the process. Manufacture of ceramic from coal ash as filtering 97104095 materials Ogawa, K. Jpn. Kokai Tokkyo Koho JP 09,156,998 [97,156,998] (Cl. C04B35/00), 17 Jun 1997, Appl. 951334,057, 29 Nov 1995, 5 pp. (In Japanese) Ceramic products can be manufactured with coal ash microparticles having particle size l-10 ,rm, that have been shaped and sintered. In these products, coal ash particles are bound together giving a porous microstructure through the entire product. They are useful as filtering materials and adsorbents. Production of ceramic building materials in Russia 97104096 from anthracite tailings Siefke, C. Kernm. Z., 1997, 49, (5), 362-364, 366-367. (In German) Methods of producing thermal insulating ceramic bricks from anthracite tailings with a high C content, allowing the excess energy to be used for other purposes are reported. Silica bricks after fifteen years in service. Critical 97104097 study Zamboni, L. A. et al. lnterceram, 1997, 46, (3). 162-164, 166. Various refractory bricks were selected for examination after used 15 years of operation in coke oven batteries. The SiOz bricks at the fire side showed a mechanical and chemical resistant microstructure. The coke side showed fissures due to stress resulted from gas formation by air entrance and coal combustion, and thermal shock during operation. Its vitreous phase quality, quantity, and distribution made the coke side microstructure weak. 97104096 Sol-gel synthesis of lanthanum chromite powder. Bilger, S. et al. J. Eur. Ceram. Sot., 1997, 17, (8), 1027-1031. A ceramic material with conduction characteristics satisfactory for the interconnector of solid oxide fuel cells (SOFC) is alkali earth-doped LaCr03 For the synthesis of highly sinterable LaCr03 powders, spraydrying of adequate precursors like solutions based on alkoxides has been used. Lanthanum chromium hydroxide solution was prepared by hydrolysis and chromium hydroxide solution was prepared by hydrolysis of synthesised methoxide complexes. The chemical reactions during hydrolysis and peptization of the precursors are described. The crystal-phase formation during the heat treatment of spray-dried amorphous gel consisting of hydroxide and contaminant chloride ligands was characterized by thermal analysis methods (TG, DTG, DTA) and X-ray diffraction analysis. The progressive oxidation of Cr(II1) by thermal dehydroxylation transforms the powder into fine crystal La(II1) Cr(V) hydroxo-oxychloride at 450°C. A thermal treatment permits complete chlorine removal forming sinterable crystal LaCrOJ perovskite powder at temperatule above 720°C. The same sol-gel process can be applied to chlorine-free nitrate-containing alkoxide solutions. The properties of sinterable lanthanum chromite powders obtained from these sols are compared with powders made by direct spray-drying of lanthanum-chromium nitrate solutions. 97104099 Specific heat capacity of new porous carbon materials: Woodceramics Kano, M. et al. Thermochim. Acta, 1997, 292, (l-2), 175-177 ‘Woodceramics’ are new carbon porous materials developed by carbonizing wood or woody materials impregnated with thermosetting resin. The carbonization takes place in a vacuum furnace at high temperature. Woodceramics have superior characteristics from the point of view of engineering and ecological materials: they are hard and strong, have porous structure and low density, are made from natural resources, do not cause environmental pollution, and are cheap to manufacture. Differential scanning calorimetry was carried out to determine the heat capacity at high temperature. 97104100 Specific heat capacity of new porous carbon materials: Woodceramics Kane, M. et al. Thermochin. Acto, 1997, 292, (l-2), 175-177. Wood or woody materials impregnated with thermosetting resin are carbonized in a vacuum furnace at high temperature to produce ‘Woodceramics’. These have superior characteristics from an engineering and ecological point of view: they are hard and strong, have porous
Space heating
and cooling
structure and low density, are made from natural resources, do not cause environmental pollution, and are cheap to manufacture. Differential scanning calorimetry has been employed to determine their heat capacity at high temperature. 97lO4101 Spray repairing materials for refractory linings Mitsui, H. et al. Jpn. Kokai Tokkyo Koho JP 09,132,470 [97,132,470] (Cl. C04B35/66), 20 May 1997, Appl. 95/317,194, 10 Nov 1995, 5 pp. (In Japanese) Metallic Si 10-30, coke having particle diameter ilOO ,lrn 0.5-5.0 wt%, and balance fired refractory powder comprise the spray repairing materials. The materials are fed at hot state into an 02 stream to melt the refractory powder by the combustion heat of the metallic Si, to repair the refractory linings.
97104102 Study of the synthesis of ammonium dawsonite. Part II. Characterization Ceramica, 1996, 42, (278), 776-779. Sakamoto, R. G. The paper describes the preparation of ammonium aluminium hydroxy carbonate (AAHC) known as ammonium dawsonite by precipitation from ammonium aluminium sulfate (AA) and ammonium hydrogen carbonate (AHC). The precipitate was washed three times and its purity degree was determined after each washing. X-ray diffractometry, SEM, thermal analysis, as well as qualitative and quantitative chemical analyses of the impurities present were implemented to characterize the material after each step. The results showed that the obtained AAHC had high purity and its grain size was l-3 pm dimension.
Thermochemistry and kinetics [of ceramic materials] Flagan, R. C. Carbide, Nitride Boride Mater. Synth. Process., 1997, 275-306. Edited by Weimer, A. W., Chapman & Hall, London, UK. The thermochemical and kinetics of vapour-phase synthesis of ceramic materials are investigated.
97104103
13
SPACE HEATING COOLING
AND
97104104 Applicability of zeolite for CO* storage in a CaOCO* high temperature energy storage system Kyaw, K. et al. Energy Cowers. Mgmt, 1997, 38, (lO-13), 1025-1033. This paper reviews reversible thermal dissociation reactions for application in thermal energy storage at very high temperatures. Among them, dissociation of CaCOJ seems very promising as the material can dissociate at 1098 K under atmospheric condition and the reactants involved are free from toxicity. One of the dissociation products, CO2 gas, requires a storage system. Three CO2 storage systems are being considered and the thermal operating efficiencies, COP, of the respective CaO-CO2 energy storage systems are evaluated. The system with a zeolite adsorbent for CO2 storage can compete with the other systems when the adsorptivity of the adsorbent increases to higher values. The CO2 adsorption characteristics of zeolite 13X and super activated carbon under a temperature range 303-573 K are studied. Zeolite 13X adsorbent was found to be suitable as a CO2 storage medium in a CaO-CO2 high temperature thermal energy storage system.
97104105 The comfort zone and the oscillation of the driving temperature Morillbn, D. et al. Applied Energy, 1997, 57, (l), l-l I. For the purpose of calculating the heating and cooling loads of a single room, a Fourier-analysis based method is proposed. The method includes the effects of thermal inertia and climate. Two situations are studied: firstly when the driving outdoor-temperature fluctuates within the comfort zone and secondly when this temperature fluctuates out of the comfort zone. Some experimental measurements were performed at different locations in order test the validity of the method.
97104106 Design and testing of current leads made from AgAu sheathed 81-2223 superconducting wires Sasaoka, T. et al. Cryogenics, 1997, 37, (S), 409-415. The paper describes the manufacture of a pair of current leads consisting of spirally assembled Ag-Au sheathed Bi-2223 superconducting wires. The heat leak into liquid helium (LHe) was measured in a vapour cooler under a self-cooling condition. The heat cycle of the fabricated superconducting current lead had no influence on the characteristics of both superconducting and joint parts. The paper presents the findings from the tests.
Fuel and Energy Abstracts
September
1997
345