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01213 Facilities requirements for 100% fly ash sales
04
By-products
99101213
related to fuels
Facilities requirements for 100% fly ash sales
Lister, R. A. EC (Am. Sot. Mech. Eng.), 1997, 5, (1). 153-157. A part of the fly ash produced is sold by many coal fired power plants. This paper addresses the unique materials handling requirements of such plants as they achieve higher sales levels and approach a sell out condition. Some of the issues include quality control, supply/demand mismatch and plant traffic. These advanced technological approaches are discussed, selective collection, mass storage and blending.
Fly ash and tire chips for highway embankments 99101214 Basheer, M. et al. Mater. New Millennium, Proc. Mater. Eng. Conf., 4rh, 1996, 1, 593-602. Edited by Chong, K. P., American Society of Civil Engineers, New York. Recycled materials such as fly ash and tyre chips are increasingly being used in highway embankments. Limited laboratory tests were performed, with and without clayey sand, on tyre chips and on Class-C and Class-F fly ash. The behaviour of mixtures of fly ash and tyre chips was also studied. Two leaching tests were used to measure the leachability of contaminants from the recycled materials. The addition of fly ash (non-plastic material) to the clayey sand did not affect its index properties. Fly ash-tyre chip mixtures had good shear strength properties. The maximum dry density of soil was changed by 10% by the addition of up to 30% of fly ash. Tyre chips and fly ash were found to be non-hazardous materials with very low concentrations of metals and organics in the leachate. 99101215
Fly ash beneficiation by ammonia removal
Fisher, B. C. and Blackstock, T. EC (Am. Sot. Mech. Eng.), 1997, 5, (l), 169-173. For the use of coal combustion by-products (CCB), opportunities are discussed, including the impact of government regulation on the use of CCB. The topics that are covered include: production and use of CCB; regulatory history; effect of environmental controls on fly ash use; impact on utilization; and the solution: the ASH PRO liberation process.
Formation of NO, NOz and NaO from Gardanne lignite and its char under pressurized conditions. [Erratum for 1997,11, 792-8001
99101216
Mallet, C. et al. Energy Fuels, 1998, 12, (4), 832. By modifying the cyclone geometry, which lowered furnace temperature and feed rate, nitrogen oxide emissions from a 250-MW, lignite fired, circulating fluidized-bed boiler were decreased from 300 to 200-250 mg/m3.
composition of fly ash binder after curing and long-term exposure in moist air, water and open air conditions were studied. It was determined that the main variable in the strength and durability of cured systems is ettringite. The positive effect of calcium silicate hydrates CSH, which are formed by interaction of high-calcium oil shale fly ash and low-calcium coal fly ash components, on the carbonation and dehydration resistance of fly ash binder in open air is pronounced. It was concluded that, as a binder for building products, high-calcium oil shale fly ash with high CaOlrcc and SO1 content can be used. 99101221 Improvement of waste concretes and coal ash Kubo, H. and Kawaji, T. Jpn. Kokai Tokkyo Koho JP 10 216,675 [98 216,675] (Cl. B09B3/00), 18 Aug 1998, Appl. 97125,290, 7 Feb 1997, 4 pp. (In Japanese) A mixture of 75-85 wt% waste concrete and 15-25 wt% roughly ground hardened materials, which contain 85-95 wt% coal ash and 5-15 wt% Portland cement is produced. The process is useful for the recycling of waste concrete and coal ash as paving materials and soil reclamation.
99101222 Influence of flue-gas desulfurization systems on coal combustion byproduct quality at Kentucky power stations burning high-sulfur coal Hower, J. C. et al. Waste Manage., 1997, 17, (8). 523-533. Burning similar blends of high-sulfur western Kentucky and southern Indiana coal, two Kentucky power plants provide a unique opportunity to examine the variations in coal combustion by-products as a result of differences in the method of wet flue-gas desulfurization (FGD). One plant employed carbide lime-based scrubbing for two units and a dual-alkali process for the third unit, while the second plant employed a Mississippian limestone from Kentucky for all four units. This study provides an example of optical and SEM petrographical techniques, supplemented by chemical analyses, applied to the study of, at least from the geological perspective, non-traditional materials. The FGD by-products displayed some potential, as yet unrealized for utilization.
99101223 Investigation of wastes from Abakanskaya thermal power plant for their potential use in cementless concretes Pavlenko,
S. I. and Malyshkin, V. I. fzu. Vyssh. Uchebn. Zaved., Swoit., (In Russian) This paper describes an investigation into the suitability of ash and granulated slag from coal combustion in the Abakanskaya power plant for production of cement-free concrete. Ash was milled to attain a surface area of 400 ml/g. Then IO-15 wt% micro-silica was added to bond free CaO thereby eliminating non-uniformity of a volume change. A two-step thermal treatment was applied. Granulated slag was also milled, a fraction of 55 mm diameter was used and no natural fillers were added. 1998, (2), 47-50.
Granulometrlc characterization of secondary raw materials in the building and construction material industry
99101217
Stark, U. and Mueller, A. Freiberg. Forschungsh. A, 1998, A841, (Partikeltechnologie), 26-40. (In German) An investigation into the granulometric properties of highly disperse coal ashes, silica dust and concrete milling powders was conducted using scanning electron microscope and laser deflection analysis. The grain size distribution of coal ashes was determined. Their chemical analysis showed that the SiOZ- and AlzO+ontent was decreasing whilst the proportion of magnetite increased in the coarse grained fractions. All six different silica dusts had grain sizes $1 /lrn. An increased compaction strength was shown by mixtures of fresh concrete with up to 20% concrete milling powders with grain sizes 14 mm.
Heat treatment of maceral groups obtained from 99101218 Turkish bituminous coals Vayisoglu, E. S. and Erbatur, N. G. Turk. J. Chem., 1998, 22, (2), 97-101. The maceral fractions and dilatation properties of parent coals were examined. In all the coal samples, the vitrinite maceral was the main petrographical constituent. Reflectance of the vitrinite and inertinite macerals increased after carbonization, while the liptinite maceral disappeared and caused large pores in the vitrinite macerals. All of the coals developed anisotropic coke.
High temperature desulfurization using an iron 99101219 oxide desulfurizer - kinetics of reduction and sulfldatlon Li, Y. et al. Ranliao Huaxue Xuebao, 1998, 26, (2), 130-134. (In Chinese) Using the thermogravimetric method, kinetics of HzS removal from coal gases by a desulfurizer made of red mud was investigated. The experimental results show that the rates of reduction and sulfidation were controlled initially by surface reaction rate and then shifted to grain diffusion controlled stage. The kinetic behaviour of reduction and sulfidation could be modelled by the equivalent grain model. The activation energies of surface reaction and diffusion were determined.
Hydratlon and strength development 99101220 based on high-calcium oil shale fly ash
of binder
Freidin, C. Gem. Concr. Res., 1998, 28, (6), 829-839. In this paper the properties of high-calcium oil shale fly ash and lowcalcium coal fly ash, which are produced in Israeli power stations, were investigated. High-calcium oil shale fly ash was found to contain a great amount of CaOr,,, and SOS in the form of lime and anhydrite. Mixtures of high-calcium oil shale fly ash and low-calcium coal fly ash, termed fly ash binder, were shown to cure and have improved strength. An examination was made on the influence of the composition and curing conditions on the compressive strength of fly ash binders. The microstructure and the
124
Fuel and Energy Abstracts
March 1999
99101224 Large molecules, radicals, ions and small soot particles in fuel-rich hydrocarbon flames part I: positive ions of polycyclic aromatic hydrocarbons (PAH) in low-pressure premixed flames of acetylene and oxygen Weilmilnster, P. et al. Cornbust. Flame, 1999, 116, (l/2), 62-83. Using molecular beam sampling with a reflectron time-of-flight mass spectrometer, large positive ions with masses up to lo4 have been studied in low-pressure, fuel-rich, premised, flat acetylene/oxygen flames. Absolute number densities of individual ions were determined through measuring the total ionic number density. This paper focuses on PAH+ and the transition to small charged soot particles. It is shown that the occurrence of large charged PAHs and the variation of their concentrations are representative of their neutral counterparts. High-resolution mass spectrometry reveals the variation in the hydrogen content of PAHC with the same number of carbon atoms. PAH+ ions occur with an even number of carbon atoms, both ionized and protonated. Also reported are carbon/hydrogen diagrams of all molecular formulae with even- and odd-numbered PAH up to 70 carbon atoms and also carbon/hydrogen ratios of the larger PAH ions, with up to 320 C atoms. From the relationships between molecular formulae and possible structures and also the profiles of individual ions, a growth mechanism of PAH+, which is very probably also valid for uncharged PAHs, is presented and discussed. The hydrogen content and therefore also the carbon structure of the PAH ions play an important role in their growth. The development of the carbon/hydrogen ratio of very large PAH ions is compared to that of small soot particles.
99101225
Manufacture of artificial aggregate using fly ash
Hayakawa, I. el al. Jpn. Kokai Tokkyo Koho JP 10 194,804 [98 194,804] (Cl. C04B18/08), 28 Jul 1998, Appl. 97/4,593, 14 Jan 1997, 7 pp. (In Japanese) The artificial aggregate is fabricated by a process of grinding the raw materials, comprised of fly ash, binder and sand, to an average particle size of ,<.lS /Lrn, mixing with water, moulding and firing at lOOO-1300°C. An artlftcial aggregate containing 50-80 wt% SiO2 and 15-35 wt% CaO is produced, with l-10 wt% coke and 3-12 wt% hematite added to the raw materials. Bentonite is used as the binder and l-10 wt% is added. The artificial aggregate has pellets of 5-15 mm.
By-products
99101213
related to fuels
Facilities requirements for 100% fly ash sales
Lister, R. A. EC (Am. Sot. Mech. Eng.), 1997, 5, (1). 153-157. A part of the fly ash produced is sold by many coal fired power plants. This paper addresses the unique materials handling requirements of such plants as they achieve higher sales levels and approach a sell out condition. Some of the issues include quality control, supply/demand mismatch and plant traffic. These advanced technological approaches are discussed, selective collection, mass storage and blending.
Fly ash and tire chips for highway embankments 99101214 Basheer, M. et al. Mater. New Millennium, Proc. Mater. Eng. Conf., 4rh, 1996, 1, 593-602. Edited by Chong, K. P., American Society of Civil Engineers, New York. Recycled materials such as fly ash and tyre chips are increasingly being used in highway embankments. Limited laboratory tests were performed, with and without clayey sand, on tyre chips and on Class-C and Class-F fly ash. The behaviour of mixtures of fly ash and tyre chips was also studied. Two leaching tests were used to measure the leachability of contaminants from the recycled materials. The addition of fly ash (non-plastic material) to the clayey sand did not affect its index properties. Fly ash-tyre chip mixtures had good shear strength properties. The maximum dry density of soil was changed by 10% by the addition of up to 30% of fly ash. Tyre chips and fly ash were found to be non-hazardous materials with very low concentrations of metals and organics in the leachate. 99101215
Fly ash beneficiation by ammonia removal
Fisher, B. C. and Blackstock, T. EC (Am. Sot. Mech. Eng.), 1997, 5, (l), 169-173. For the use of coal combustion by-products (CCB), opportunities are discussed, including the impact of government regulation on the use of CCB. The topics that are covered include: production and use of CCB; regulatory history; effect of environmental controls on fly ash use; impact on utilization; and the solution: the ASH PRO liberation process.
Formation of NO, NOz and NaO from Gardanne lignite and its char under pressurized conditions. [Erratum for 1997,11, 792-8001
99101216
Mallet, C. et al. Energy Fuels, 1998, 12, (4), 832. By modifying the cyclone geometry, which lowered furnace temperature and feed rate, nitrogen oxide emissions from a 250-MW, lignite fired, circulating fluidized-bed boiler were decreased from 300 to 200-250 mg/m3.
composition of fly ash binder after curing and long-term exposure in moist air, water and open air conditions were studied. It was determined that the main variable in the strength and durability of cured systems is ettringite. The positive effect of calcium silicate hydrates CSH, which are formed by interaction of high-calcium oil shale fly ash and low-calcium coal fly ash components, on the carbonation and dehydration resistance of fly ash binder in open air is pronounced. It was concluded that, as a binder for building products, high-calcium oil shale fly ash with high CaOlrcc and SO1 content can be used. 99101221 Improvement of waste concretes and coal ash Kubo, H. and Kawaji, T. Jpn. Kokai Tokkyo Koho JP 10 216,675 [98 216,675] (Cl. B09B3/00), 18 Aug 1998, Appl. 97125,290, 7 Feb 1997, 4 pp. (In Japanese) A mixture of 75-85 wt% waste concrete and 15-25 wt% roughly ground hardened materials, which contain 85-95 wt% coal ash and 5-15 wt% Portland cement is produced. The process is useful for the recycling of waste concrete and coal ash as paving materials and soil reclamation.
99101222 Influence of flue-gas desulfurization systems on coal combustion byproduct quality at Kentucky power stations burning high-sulfur coal Hower, J. C. et al. Waste Manage., 1997, 17, (8). 523-533. Burning similar blends of high-sulfur western Kentucky and southern Indiana coal, two Kentucky power plants provide a unique opportunity to examine the variations in coal combustion by-products as a result of differences in the method of wet flue-gas desulfurization (FGD). One plant employed carbide lime-based scrubbing for two units and a dual-alkali process for the third unit, while the second plant employed a Mississippian limestone from Kentucky for all four units. This study provides an example of optical and SEM petrographical techniques, supplemented by chemical analyses, applied to the study of, at least from the geological perspective, non-traditional materials. The FGD by-products displayed some potential, as yet unrealized for utilization.
99101223 Investigation of wastes from Abakanskaya thermal power plant for their potential use in cementless concretes Pavlenko,
S. I. and Malyshkin, V. I. fzu. Vyssh. Uchebn. Zaved., Swoit., (In Russian) This paper describes an investigation into the suitability of ash and granulated slag from coal combustion in the Abakanskaya power plant for production of cement-free concrete. Ash was milled to attain a surface area of 400 ml/g. Then IO-15 wt% micro-silica was added to bond free CaO thereby eliminating non-uniformity of a volume change. A two-step thermal treatment was applied. Granulated slag was also milled, a fraction of 55 mm diameter was used and no natural fillers were added. 1998, (2), 47-50.
Granulometrlc characterization of secondary raw materials in the building and construction material industry
99101217
Stark, U. and Mueller, A. Freiberg. Forschungsh. A, 1998, A841, (Partikeltechnologie), 26-40. (In German) An investigation into the granulometric properties of highly disperse coal ashes, silica dust and concrete milling powders was conducted using scanning electron microscope and laser deflection analysis. The grain size distribution of coal ashes was determined. Their chemical analysis showed that the SiOZ- and AlzO+ontent was decreasing whilst the proportion of magnetite increased in the coarse grained fractions. All six different silica dusts had grain sizes $1 /lrn. An increased compaction strength was shown by mixtures of fresh concrete with up to 20% concrete milling powders with grain sizes 14 mm.
Heat treatment of maceral groups obtained from 99101218 Turkish bituminous coals Vayisoglu, E. S. and Erbatur, N. G. Turk. J. Chem., 1998, 22, (2), 97-101. The maceral fractions and dilatation properties of parent coals were examined. In all the coal samples, the vitrinite maceral was the main petrographical constituent. Reflectance of the vitrinite and inertinite macerals increased after carbonization, while the liptinite maceral disappeared and caused large pores in the vitrinite macerals. All of the coals developed anisotropic coke.
High temperature desulfurization using an iron 99101219 oxide desulfurizer - kinetics of reduction and sulfldatlon Li, Y. et al. Ranliao Huaxue Xuebao, 1998, 26, (2), 130-134. (In Chinese) Using the thermogravimetric method, kinetics of HzS removal from coal gases by a desulfurizer made of red mud was investigated. The experimental results show that the rates of reduction and sulfidation were controlled initially by surface reaction rate and then shifted to grain diffusion controlled stage. The kinetic behaviour of reduction and sulfidation could be modelled by the equivalent grain model. The activation energies of surface reaction and diffusion were determined.
Hydratlon and strength development 99101220 based on high-calcium oil shale fly ash
of binder
Freidin, C. Gem. Concr. Res., 1998, 28, (6), 829-839. In this paper the properties of high-calcium oil shale fly ash and lowcalcium coal fly ash, which are produced in Israeli power stations, were investigated. High-calcium oil shale fly ash was found to contain a great amount of CaOr,,, and SOS in the form of lime and anhydrite. Mixtures of high-calcium oil shale fly ash and low-calcium coal fly ash, termed fly ash binder, were shown to cure and have improved strength. An examination was made on the influence of the composition and curing conditions on the compressive strength of fly ash binders. The microstructure and the
124
Fuel and Energy Abstracts
March 1999
99101224 Large molecules, radicals, ions and small soot particles in fuel-rich hydrocarbon flames part I: positive ions of polycyclic aromatic hydrocarbons (PAH) in low-pressure premixed flames of acetylene and oxygen Weilmilnster, P. et al. Cornbust. Flame, 1999, 116, (l/2), 62-83. Using molecular beam sampling with a reflectron time-of-flight mass spectrometer, large positive ions with masses up to lo4 have been studied in low-pressure, fuel-rich, premised, flat acetylene/oxygen flames. Absolute number densities of individual ions were determined through measuring the total ionic number density. This paper focuses on PAH+ and the transition to small charged soot particles. It is shown that the occurrence of large charged PAHs and the variation of their concentrations are representative of their neutral counterparts. High-resolution mass spectrometry reveals the variation in the hydrogen content of PAHC with the same number of carbon atoms. PAH+ ions occur with an even number of carbon atoms, both ionized and protonated. Also reported are carbon/hydrogen diagrams of all molecular formulae with even- and odd-numbered PAH up to 70 carbon atoms and also carbon/hydrogen ratios of the larger PAH ions, with up to 320 C atoms. From the relationships between molecular formulae and possible structures and also the profiles of individual ions, a growth mechanism of PAH+, which is very probably also valid for uncharged PAHs, is presented and discussed. The hydrogen content and therefore also the carbon structure of the PAH ions play an important role in their growth. The development of the carbon/hydrogen ratio of very large PAH ions is compared to that of small soot particles.
99101225
Manufacture of artificial aggregate using fly ash
Hayakawa, I. el al. Jpn. Kokai Tokkyo Koho JP 10 194,804 [98 194,804] (Cl. C04B18/08), 28 Jul 1998, Appl. 97/4,593, 14 Jan 1997, 7 pp. (In Japanese) The artificial aggregate is fabricated by a process of grinding the raw materials, comprised of fly ash, binder and sand, to an average particle size of ,<.lS /Lrn, mixing with water, moulding and firing at lOOO-1300°C. An artlftcial aggregate containing 50-80 wt% SiO2 and 15-35 wt% CaO is produced, with l-10 wt% coke and 3-12 wt% hematite added to the raw materials. Bentonite is used as the binder and l-10 wt% is added. The artificial aggregate has pellets of 5-15 mm.