- Email: [email protected]
05986 Oxidation and ablation of 3D carbon-carbon composite at up to 3000°C
04 Modiflcatlon of coal-tar pitch by air-blowing - I. 95lO5975 Variation of pitch comporltlon and properties Femandcz, J. J. et al., Carbon, 1995, 33, (3), 295-307. Pitch oxidation by air-blowing has been studied as a possible method to modify pitch properties for composite pre aration. Two commercial coaltar pitches, an impregnating pitch and a \*mder pitch, were air-blown at tern ratures between 250-3OO”C,for 18 and 14 h, respective1 , to produce pitc E” es of similar softening point rangink from 148 to 223OZ Parent and treated pitches were characterized by elemental analysis, FTIR, thermal analysis, solubility in toluene and quinoline, XPS, X-ray diffraction, and optical microscopy. Modlflsd coal ash for roll Improvement Q!i/O5977 Kato, H. et al., (Assigned to) Shinnippon Seiretsu KK; Kiragawa Ryokuka Kogyo KK; Nippon Darsushuki KK, JAP. Pat. JP.O7,26,261, Jan. 1995.
Decribes a coal ash powder which is treated first with an alkali solution and then with hot water and mixed with water to form a slurry, and the slurry is then spread on the surface of a acidic soil. The treated coal ash can be used as a zeolite substitute in a inclined area for soil modification without washing away the material. Multllayer coating for carbon-carbon composlter 95/05978 Morimoto, T. er al., Carbon, 1995, 33, (4), 351-357. Because of the excellent mechanical properties at elevated temperature, carbon-fibre refinforced carbon (carbon-carbon) corn osites have received much attention for high-temperature structural app lfcations. One serious drawback against actual use of carbon-carbon composites is their poor oxidation resistance in high-temperature oxidizing atmospheres. In mamy attempts to develop an effective oxidation-protection coating, silicon carbide coating has shown the best performance for short periods of up to 1900 K. For longer periods and higher temperature application!, a challenging coating system should be developed. There exist certain difficulties in establishing a new coating system, such as coefficients of thermal expansion mismatch between coating layer and carbon-carbon composites, and chemical stability of the interface, Describes a basic idea for a new multilayer coating system. Multlstage reduction of coals In the potar95lO5979 rlum/llauld ammonla svstem WachoAka, H. and Kozlo&ki, M. Fuel, Sep. 1995,74, (9), 1398-1403. Two Polish coals and an anthracite were subjected to four-stage reduction in potassium/liquid ammonia. After each staee, s6lubulity of the products in methylene chloride was studied. Extraction yield was found to increase with increasing number of stages. The highest yield of transformation to soluble oroducts was obtained for the orthocokinn coal. The ‘H n.m.r. investigitions provided that aromaticity of the extr&ts from flame coal is lower than that of the orthocoking coal extracts. The main substituents of the aromatic system of the average structural unit of the extracts from orthocoking coal are alkyl or naphthlene groups. In the case of flame coal their contribution is lower and can be related to a higher contribution of oxygen groups. Natural graphltlzatlon of anthracite: Experlmental 95/05980 conslderatlonr Bustin, R. M. el al., Carbon, 1995, 33, (S), 679-691. An anthracite coal was deformed in the steady state‘at various pressures, temperatures, and experimental configurations to assess the effects of stress, strain, and strain energy on graphitization. In simple shear tests, graphite first appears at temperature as low as 600°C and samples tested at 900°C are predominately graphitized, as evident from optical microscopy, XRD, and transmission electron microscopy. The graplute is lamellar, has punctual hkl reflections or Debye-Scherrer (hkl) rings (triperiodic order), and long stiff and stacked lattice fringes typical of well-crystallized graphite. New techniques for the productlon of chars and 95/05991 sorbents from coal Buchtele, J. Acta Mont, Ser. B, 1994, 4, 83-96. The paper discusses the techniques for production of chars and *orbents from coal. Both the caking and noncaking coals with a broad range of coalification (brown coals, bituminous coals, anthracites) are carbonized by new nontraditional techniques, i.e. by the so-called two-product process. Nltrlc acid oxldatlon of carbon fibers and the 95lO5902 effects of subsequent treatment In refluxlng aqueous NaOH Wu, 2. et al., Carbon, 1995, 33, (5), 597-605. Nitric acid oxidation effectively created acidic functional groups on PANbased high-strength carbon fibres. The acidic capacities of carbon fibres increased with oxidation time. Typically, 60 minutes of oxidation created 60 ueq acidic functional groups on each gram of carbon fibres. Nitric acid oxidation also caused tensile strength decreases and fibre weight losses. By treating fibres in refluxing aqueous NaOH after nitric acid oxidation, a weakly bound layer of partially oxidized graphitic fragments was removed and this caused higher weight losses. This treatment also removed a source of interference in later analvses. Also investieated were the effects of aaueous NaOH treatment after ‘oxidation on the kechanical properties (ten’sile strengh, Izod, IS, IFSS, and US) of fibres and their composites.
By-products related to fuels
95105993 Non-fuel uses of coals and ryntheolr of chemicals and matrrlalr Song, C. and Schobert, H. H. Prepr. Pap.-Am. Chem. Sot., Div. Fuel Chem., 1995? 40, (2), 249-259. The paper discusses energy supply and demand of fossil fuels, non-fuel
uses of fossil fuels, and synthesis of chemicals and polymers and production of carbon materials from coal. Emphasis is put on coal as the demonstrated coal reserves in the world are enough for consumption of over 220 years at the 1991 level, while the petroleum reserves are only about 40 times of the world’s consumption level in 1992. 95105984 Occurrence of 28.nor-lBalpha-oleanane In the hydrous p rolyzate of a llgnlte Armanios, r!. et al., Org. Geochem., 19G5, 23, (l), 21-27. The paper describes how 28-nor-lSalpha-oleanane was isolated from the hydrous pyrolyzate of a Western Australian lignite and characterized by smgle-crystal X-ray structure determination. 95/0s985 Outline of warhlna of flv ashes Sawachi, M. and Fukunaga, 1. PPk,-l99>,~26, (4), 17-23. (In Japanese) The paper discusses the treatment of waste incinerator fly ashes containing Cu, Cd, Pb, and Zn. 95105986 Oxldatlon and ablation of 3D carbon-carbon composlte at up to 3OOO’C Han, J. C. et al., Carbon, 1995, 33, (4), 473-478. The reactivity of fine-weave pierced 3D carbonzarbon composites in air at temperatures up to 3000°C was studied. The corrosion mo hology and microstructure of oxidized samples were investigated by XPx , SEM, and XRD techniques, and the non-equilibrium nature of the oxidation process was pointed out. A thermochemical ablation model of C-C composites controlled by gas phase diffusion and reaction kinetics was developed. The oxldatlon of an Asturlan bltumlnous coal In air 95lO5907 and Its Influence on rubseauent actlvatlon bu.steam Centeno, T. A. and Stoeckli, F. ’ Carbon, 1995, 33,-(S), 581-586. It is shown that the oxidation of an Asturian bituminous coal by air, at 150’ and 27O”C,has a considerable influence on the microporous structure of the carbon obtained by subsequent carbonization and steam activation to 50% burn-off. The direct activation of the coal leads to an open micropore system of 0.2 cm3/g, with an average pore size near 0.8 nm. On the other hand. much lamer svstems of microoores can be obtained in the final prod&, de enzing & the tempera&e of pretreatment in air. The oxidation at 270OEeventually leads to supermicropores and to a small system of narrow micropores near 0.3-0.5 nm. The oxldatlve stablllzatlon and carbonlzatlon of 8 95/05988 synthetic mesophase pitch. Part I: The oxldatlve rtablllzatlon orocess brbohlav, J. and Stevenson, W. T. Carbon, 1995, 33, p), 693-711. The transformation of mesophase pitch to an ordered carbon by hightemperature heat treatment in an inert atmosphere must be preceded by a suitable period of thermosetting or oxidative stabilization. The chemical process bf oxidative stabilizalion is not well characterized, although research has clearly indicated that the oxidation history of the mesophase has a profound impact on the mechanical qualities of the resultant carbon product. In this study, the authors oxidized samples of a commercially available, synthetic mesophase pitch to determine the effect of different time/temperature profiles of oxidation on the quantity and type of introduced functionality. 95105989 The oxldatlve stablllzatlon and carbonlzatlon of a rvnthetlc mesoohase oltch, Part II: The cerbonlzatlon process Dibohlav, J. and Stevensin, W..T. Carbon, 19&! 33, (5), 713-731. The carbonization behaviours of a series of synthetic naphthalene-derived mesophase pitch powders subjected to different time and temperature profiles of oxidative stabilization were studied by thermogravimetric analysis and thermal volatilization analysis/sub-ambient thermal volatilization analysis. 95lO5990 Phoepho ypeum-fly ash cementltlous blnder - Its hydratlon and strengta development Singh, M. and Garg, M. Cem. Concr. Res., 1995, 25, (4)? 752-758. The paper discusses the formulation of a cementitious bmder based on calcined phosphogypsum, fly ash, hydrated lime and portland cement. Strength properties and hydration of the cementitious binder studied at room temperature and at 50°C in over 90% relative humidity are presented. It was found that the compressive strength of the cementitious binder was remarkably enhanced at 50°C than at 27°C. 95/05991 Pitch coke as a filler for structural grsphltes Ostrovskii, V. S. et al., Khim. Tverd. Topl. (Moscow), 1995, (l), 56-61. (In Russian) Describes how pitch coke is used as an inexpensive and abundant substitute for the more expensive and scarce petroleum coke as a filler in structural graphite. Pitch coke approaches the properties of petroleum coke with respect to ash content, sul hur content, microstructure, density, strength, interaction with binder anB stabihty ‘. of properties.
Fuel and Energy Abstracts November 1995 425
Decribes a coal ash powder which is treated first with an alkali solution and then with hot water and mixed with water to form a slurry, and the slurry is then spread on the surface of a acidic soil. The treated coal ash can be used as a zeolite substitute in a inclined area for soil modification without washing away the material. Multllayer coating for carbon-carbon composlter 95/05978 Morimoto, T. er al., Carbon, 1995, 33, (4), 351-357. Because of the excellent mechanical properties at elevated temperature, carbon-fibre refinforced carbon (carbon-carbon) corn osites have received much attention for high-temperature structural app lfcations. One serious drawback against actual use of carbon-carbon composites is their poor oxidation resistance in high-temperature oxidizing atmospheres. In mamy attempts to develop an effective oxidation-protection coating, silicon carbide coating has shown the best performance for short periods of up to 1900 K. For longer periods and higher temperature application!, a challenging coating system should be developed. There exist certain difficulties in establishing a new coating system, such as coefficients of thermal expansion mismatch between coating layer and carbon-carbon composites, and chemical stability of the interface, Describes a basic idea for a new multilayer coating system. Multlstage reduction of coals In the potar95lO5979 rlum/llauld ammonla svstem WachoAka, H. and Kozlo&ki, M. Fuel, Sep. 1995,74, (9), 1398-1403. Two Polish coals and an anthracite were subjected to four-stage reduction in potassium/liquid ammonia. After each staee, s6lubulity of the products in methylene chloride was studied. Extraction yield was found to increase with increasing number of stages. The highest yield of transformation to soluble oroducts was obtained for the orthocokinn coal. The ‘H n.m.r. investigitions provided that aromaticity of the extr&ts from flame coal is lower than that of the orthocoking coal extracts. The main substituents of the aromatic system of the average structural unit of the extracts from orthocoking coal are alkyl or naphthlene groups. In the case of flame coal their contribution is lower and can be related to a higher contribution of oxygen groups. Natural graphltlzatlon of anthracite: Experlmental 95/05980 conslderatlonr Bustin, R. M. el al., Carbon, 1995, 33, (S), 679-691. An anthracite coal was deformed in the steady state‘at various pressures, temperatures, and experimental configurations to assess the effects of stress, strain, and strain energy on graphitization. In simple shear tests, graphite first appears at temperature as low as 600°C and samples tested at 900°C are predominately graphitized, as evident from optical microscopy, XRD, and transmission electron microscopy. The graplute is lamellar, has punctual hkl reflections or Debye-Scherrer (hkl) rings (triperiodic order), and long stiff and stacked lattice fringes typical of well-crystallized graphite. New techniques for the productlon of chars and 95/05991 sorbents from coal Buchtele, J. Acta Mont, Ser. B, 1994, 4, 83-96. The paper discusses the techniques for production of chars and *orbents from coal. Both the caking and noncaking coals with a broad range of coalification (brown coals, bituminous coals, anthracites) are carbonized by new nontraditional techniques, i.e. by the so-called two-product process. Nltrlc acid oxldatlon of carbon fibers and the 95lO5902 effects of subsequent treatment In refluxlng aqueous NaOH Wu, 2. et al., Carbon, 1995, 33, (5), 597-605. Nitric acid oxidation effectively created acidic functional groups on PANbased high-strength carbon fibres. The acidic capacities of carbon fibres increased with oxidation time. Typically, 60 minutes of oxidation created 60 ueq acidic functional groups on each gram of carbon fibres. Nitric acid oxidation also caused tensile strength decreases and fibre weight losses. By treating fibres in refluxing aqueous NaOH after nitric acid oxidation, a weakly bound layer of partially oxidized graphitic fragments was removed and this caused higher weight losses. This treatment also removed a source of interference in later analvses. Also investieated were the effects of aaueous NaOH treatment after ‘oxidation on the kechanical properties (ten’sile strengh, Izod, IS, IFSS, and US) of fibres and their composites.
By-products related to fuels
95105993 Non-fuel uses of coals and ryntheolr of chemicals and matrrlalr Song, C. and Schobert, H. H. Prepr. Pap.-Am. Chem. Sot., Div. Fuel Chem., 1995? 40, (2), 249-259. The paper discusses energy supply and demand of fossil fuels, non-fuel
uses of fossil fuels, and synthesis of chemicals and polymers and production of carbon materials from coal. Emphasis is put on coal as the demonstrated coal reserves in the world are enough for consumption of over 220 years at the 1991 level, while the petroleum reserves are only about 40 times of the world’s consumption level in 1992. 95105984 Occurrence of 28.nor-lBalpha-oleanane In the hydrous p rolyzate of a llgnlte Armanios, r!. et al., Org. Geochem., 19G5, 23, (l), 21-27. The paper describes how 28-nor-lSalpha-oleanane was isolated from the hydrous pyrolyzate of a Western Australian lignite and characterized by smgle-crystal X-ray structure determination. 95/0s985 Outline of warhlna of flv ashes Sawachi, M. and Fukunaga, 1. PPk,-l99>,~26, (4), 17-23. (In Japanese) The paper discusses the treatment of waste incinerator fly ashes containing Cu, Cd, Pb, and Zn. 95105986 Oxldatlon and ablation of 3D carbon-carbon composlte at up to 3OOO’C Han, J. C. et al., Carbon, 1995, 33, (4), 473-478. The reactivity of fine-weave pierced 3D carbonzarbon composites in air at temperatures up to 3000°C was studied. The corrosion mo hology and microstructure of oxidized samples were investigated by XPx , SEM, and XRD techniques, and the non-equilibrium nature of the oxidation process was pointed out. A thermochemical ablation model of C-C composites controlled by gas phase diffusion and reaction kinetics was developed. The oxldatlon of an Asturlan bltumlnous coal In air 95lO5907 and Its Influence on rubseauent actlvatlon bu.steam Centeno, T. A. and Stoeckli, F. ’ Carbon, 1995, 33,-(S), 581-586. It is shown that the oxidation of an Asturian bituminous coal by air, at 150’ and 27O”C,has a considerable influence on the microporous structure of the carbon obtained by subsequent carbonization and steam activation to 50% burn-off. The direct activation of the coal leads to an open micropore system of 0.2 cm3/g, with an average pore size near 0.8 nm. On the other hand. much lamer svstems of microoores can be obtained in the final prod&, de enzing & the tempera&e of pretreatment in air. The oxidation at 270OEeventually leads to supermicropores and to a small system of narrow micropores near 0.3-0.5 nm. The oxldatlve stablllzatlon and carbonlzatlon of 8 95/05988 synthetic mesophase pitch. Part I: The oxldatlve rtablllzatlon orocess brbohlav, J. and Stevenson, W. T. Carbon, 1995, 33, p), 693-711. The transformation of mesophase pitch to an ordered carbon by hightemperature heat treatment in an inert atmosphere must be preceded by a suitable period of thermosetting or oxidative stabilization. The chemical process bf oxidative stabilizalion is not well characterized, although research has clearly indicated that the oxidation history of the mesophase has a profound impact on the mechanical qualities of the resultant carbon product. In this study, the authors oxidized samples of a commercially available, synthetic mesophase pitch to determine the effect of different time/temperature profiles of oxidation on the quantity and type of introduced functionality. 95105989 The oxldatlve stablllzatlon and carbonlzatlon of a rvnthetlc mesoohase oltch, Part II: The cerbonlzatlon process Dibohlav, J. and Stevensin, W..T. Carbon, 19&! 33, (5), 713-731. The carbonization behaviours of a series of synthetic naphthalene-derived mesophase pitch powders subjected to different time and temperature profiles of oxidative stabilization were studied by thermogravimetric analysis and thermal volatilization analysis/sub-ambient thermal volatilization analysis. 95lO5990 Phoepho ypeum-fly ash cementltlous blnder - Its hydratlon and strengta development Singh, M. and Garg, M. Cem. Concr. Res., 1995, 25, (4)? 752-758. The paper discusses the formulation of a cementitious bmder based on calcined phosphogypsum, fly ash, hydrated lime and portland cement. Strength properties and hydration of the cementitious binder studied at room temperature and at 50°C in over 90% relative humidity are presented. It was found that the compressive strength of the cementitious binder was remarkably enhanced at 50°C than at 27°C. 95/05991 Pitch coke as a filler for structural grsphltes Ostrovskii, V. S. et al., Khim. Tverd. Topl. (Moscow), 1995, (l), 56-61. (In Russian) Describes how pitch coke is used as an inexpensive and abundant substitute for the more expensive and scarce petroleum coke as a filler in structural graphite. Pitch coke approaches the properties of petroleum coke with respect to ash content, sul hur content, microstructure, density, strength, interaction with binder anB stabihty ‘. of properties.
Fuel and Energy Abstracts November 1995 425