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01205 Chemical and rheological characterization of air-blown coal-tar pitches
04 By-products related to fuels study the potential effects of alkali-aggregate reactions. The mortar bars for the autoclave expansion test were made in accordance with ASTM C 227. Sources in Kansas provided the aggregates for these expansion tests. Bench mark results were taken from standard sand. The fly ash was obtained from Kansas City Power and Light Plant burning sub-bituminous coal from Wyoming. The tests were performed using varying blends of ash content, aggregate-cementitious material ratios and water-cementitious material ratios in the bars. A large number of bars were tested to obtain statistically meaningful results. Strength tests were also carried out using 50 cm cubes of these blends.
Behavior of iron-bearing minerals in the early 99101202 stages of pulverized coal conversion processes Vuthaluru, H. B. et al. Fuel Process. Technol., 1998, 56, (l-2), 21-31. Studied were early stage transformations and deposition of iron-bearing coal minerals, in particular pyrite (Fe&). An atmospheric laboratory-scale facility was used to simulate the near burner environment in two different coal conversion processes: (i) low-NO pulverized coal combustion and (ii) entrained-flow gasification. Particle sampling showed that for both environments the pyrite transforms quickly to pyrrhotite (FeS). In the deposition experiments, this liquid pyrrhotite was impacted on substrate surfaces. The chemical composition and the morphology of the deposits formed under the two conditions showed clear differences. It appeared that the final product for low-NO, combustion conditions was FezOs, whereas for entrained-flow gasification conditions, iron was the final product. The deposits collected under both simulated gaseous environments did not contain sulfur. A descriptive model for pyrite transformations under both conditions is proposed, based on these experimental findings.
99io1203 Catalyst/wax separation device for slurry FischerTropsch reactor Benham. C. B. er al. PCT Int. Aool. WO 98 27.181 (Cl. ClOG2/00). ,I 25 Jun ’ 1998, US Appl. 33,375, 16 Dee 1996, 29 pp. In a Fisher-Tropsch reactor catalyst particles are separated from the wax by feeding a portion of the reactor slurry to a dynamic settler which does not require any pump. As the slurry flows down a pipe in the centre of the settler, the slurry flows into the surrounding annular region at the bottom of the settler. The heavier catalyst particles settle down and are removed as the slurry at the bottom of the settler is recycled back to the reactor. The wax rises up in the annular section and the clarified wax is removed by a wax outlet pipe. By purging the catalyst with an inert gas for a period of time and by treating the catalyst with naphtha, the Fischer-Tropsch catalyst can be regenerated.
99101204 Cement manufacture from waste products from flue gas desulfurizatlon Babu, M. et al. U.S. US 5, 766,339, (Cl. 106-745; C04B7/36), 16 Jun 1998, Appl. 852,798, 7 May 1997, 6 pp. Providing moist flue gas desulfurization waste containing 80-95 wt% CaSOs.0.5HzO and balance CaS0.+.0.5HzO is what the process comprises, adding a source of aluminium, iron, carbon and a siliceous material to the waste, agglomerating the moist mixture while drying the mixture with hot air to provide an agglomerated kiln feedstock containing 56 wt% water, calcining the feedstock in a rotary kiln to produce cement clinkers and pulverizing the clinkers to produce the cement. The calcination of the agglomerated kiln feedstock produces cement clinkers and SOz, the clinkers are removed from the kiln and pulverized to produce cement and the SOz is discharged from the kiln. uassed to an indirect heat exchaneer to heat air and the-heated air is used for removing water from the moist mixture during agglomeration. Containing 80-95 wt% CaSOa.O.SHzO and balance CaS04.0.5HzO the process comprises providing a moist flue gas desulfurization process waste product using a magnesium-enhanced lime slurry for reaction with SOz and adding fly ash containing aluminium and iron and carbon and sand to the waste to form a moist mixture.
99101205 Chemical and rheological characterization of airblown coal-tar pitches Menendez, R. er al. Carbon, 1998, 36, (7-8), 973-979. Isotropic pitches were produced from the air-blowing of a commercial impregnating coal-tar pitch at 275°C for 10, 18, 25 and 30 h. The pitches showed softening points ranging from 140 to 210°C. The parent and treated pitches were characterized by elemental analysis, Fourier transform IR, solubility in toluene and N-methylpyrrolidone, iodine adsorption and reflected light optical microscopy. The viscoelasticity of the pitches also was investigated using transient shear and controlled strain oscillatory rheometry. The chemical characterization of the pitches suggested that, as air-blowing proceeded, larger molecules formed through dehydrogenative polymerization (aromatization/condensation) and crosslinking of the pitch molecules. This is consistent with the rheological characterization of the pitches. The results obtained from transient shear and oscillatory rheometry showed that the parent impregnating pitch exhibited a viscous behaviour. In contrast, the air-blown pitches, which contained large aromatic molecules, showed viscoelastic properties.
99101205 Chemical process for coal desulfurization. I. Coal desulfurlzation in alkaline media
Balaz, P. Uhli-Rudy-Geol. Pruzkum, 1998, 5, (4), 127-129. Coal desulfurization by using alkaline media is reviewed. The emphasis is placed on the Ames and MCL (Molten Caustic Leaching; Gravimelt) processes.
Composite material from fly ash and post-consuLi, Y. et al. Resources, Conservation and Recycling, 1998, 24, (2), 87-93. From a coal-fired power plant, fly ash was combined with post-consumer polyethylene terephthalate (PET) from a municipal solid waste (MSW) landfill to produce a moulded composite material. Fly ash content varied from 0 to 50% by weight. The properties of compressive strength, water absorption and density of the products were tested. It was concluded that fly ash reduces the thermal decomposition of PET, expedites the melting and mixing of PET, reduces the shrinkage of the material during the moulding process and improves the properties of the final product. The addition of flv ash increased the comoressive streneth bv 31-53%. The micro-structure and bonding mechanism were inveitigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Water absorption was negligible for all the specimens.
99/01209
Comprehensive utilization of chromium-dregs
Fang, R. and Jin, C. Kuongchan Zonghe Liyong, 1997, (5), 40-44. (In Chinese) This paper presents a method for removing the toxicity of chromium-dregs by calcining the mixture of fly ash or coal gangue, limestone and chromiumdregs. The mechanism for removal and the factors which affect the removal are discussed. Additionally, the stability of the process was tested. A new type of belite cement is produced.
99101209
Constraints in the utilization of flyash
Nath, S. fndian J. Environ. Prot., 1997, 17, (2). 103-106. Existing in India are approximately 70 thermal power plants, who alone produce about 110 million tons of coal ash per year. It is anticipated that with the increasing number of thermal power projects coming up, the annual ash production in the country will rise to about 150 million ton per year by the year 2000. This will require about 30,000 ha of land for ash disposal purposes. The present disposal methods of coal ash are not only expensive but also have a disastrous effect on the environment. A lot has been talked about the utilization of fly ash, a major constituent of coal ash, but in the field of actual utilization, efforts seem to be lacking.
99lOl210 Effect of h dration conditions properties of fly ashCa( d H)2 sorbents
on the physical
Karatepe, N. ef ai. Energy sour&, 1998, 20, (6). 505-511. For the production of reactive sulfur dioxide sorbents fly ash samples taken from three different coal-fired Dower nlants in Turkev were used as reaeent material. For this purpose, fly ash-Ci(OH)z mixture; with different weight ratios were hydrated under different conditions. The effects of the hydration conditions such as temperature, time and fly ash/Ca(OH)z weight ratio on the physical properties of activated sorbents were investigated. By use of two-level factorial design matrix a statistical design technique was applied to interpret experimental results. It was found that increasing the temperature and hydration time caused an increase in the total surface area of the sorbents. However, in mixtures that have different fly ash/Ca(OH)? weight ratios, surface area values were generally not changed significantly for obtained sorbents.
99101211 The effect of potassium on the fusibility of coal ashes with hiah silica and alumina levels
Gupta, S. K. et zl. Fuel, 1998, 77, (ll), 1195-1201. Ashes with high SiOz and Al203 levels have poor repeatability and reproducibility -of fusibility temperatures. Such ashes are ‘studied in this paper using thermo-mechanical analysis (TMA) to indicate the shrinkage of samples progressively heated at the same rate as the test for standard ash fusibility temperatures (AFT). The results confirm that the extent and rate of change of shrinkage of the samples with low KzO levels (c 1 wt%) is low in regions of the deformation temperature (DT), resulting in poor accuracy of its determination. It was found that DT is mainly related to substantial melting of minerals containing KzO (i.e. illite) in these ashes. The effect of KzO interms on the extent of slag generation necessary for shrinkage were illustrated using scanning electron microscope (SEM) analysis of quenched ash samples and thermodynamic calculations. The TMA test is shown to provide a more sensitive alternative procedure for characterizing the ash fusibility.
99101212 Experlment on treatment of wastewater from sealing of coal gas by adsorption with coke and blast furnace slag
Liu, Y. Huanjing Baohu, 1997, (lo), 17-18. (In Chinese) This paper presents the process flow, equipment and technical parameter of coke/blast furnace slag adsorption process for treating coal gas - sealing water in a coal gas producer. The removal rate was 100% for sulfide, 95% for cyanide, 98% for phenol, 45% for COD, 71% for N and 90% for SS.
Fuel and Energy Abstmcts
March 1999
123
Behavior of iron-bearing minerals in the early 99101202 stages of pulverized coal conversion processes Vuthaluru, H. B. et al. Fuel Process. Technol., 1998, 56, (l-2), 21-31. Studied were early stage transformations and deposition of iron-bearing coal minerals, in particular pyrite (Fe&). An atmospheric laboratory-scale facility was used to simulate the near burner environment in two different coal conversion processes: (i) low-NO pulverized coal combustion and (ii) entrained-flow gasification. Particle sampling showed that for both environments the pyrite transforms quickly to pyrrhotite (FeS). In the deposition experiments, this liquid pyrrhotite was impacted on substrate surfaces. The chemical composition and the morphology of the deposits formed under the two conditions showed clear differences. It appeared that the final product for low-NO, combustion conditions was FezOs, whereas for entrained-flow gasification conditions, iron was the final product. The deposits collected under both simulated gaseous environments did not contain sulfur. A descriptive model for pyrite transformations under both conditions is proposed, based on these experimental findings.
99io1203 Catalyst/wax separation device for slurry FischerTropsch reactor Benham. C. B. er al. PCT Int. Aool. WO 98 27.181 (Cl. ClOG2/00). ,I 25 Jun ’ 1998, US Appl. 33,375, 16 Dee 1996, 29 pp. In a Fisher-Tropsch reactor catalyst particles are separated from the wax by feeding a portion of the reactor slurry to a dynamic settler which does not require any pump. As the slurry flows down a pipe in the centre of the settler, the slurry flows into the surrounding annular region at the bottom of the settler. The heavier catalyst particles settle down and are removed as the slurry at the bottom of the settler is recycled back to the reactor. The wax rises up in the annular section and the clarified wax is removed by a wax outlet pipe. By purging the catalyst with an inert gas for a period of time and by treating the catalyst with naphtha, the Fischer-Tropsch catalyst can be regenerated.
99101204 Cement manufacture from waste products from flue gas desulfurizatlon Babu, M. et al. U.S. US 5, 766,339, (Cl. 106-745; C04B7/36), 16 Jun 1998, Appl. 852,798, 7 May 1997, 6 pp. Providing moist flue gas desulfurization waste containing 80-95 wt% CaSOs.0.5HzO and balance CaS0.+.0.5HzO is what the process comprises, adding a source of aluminium, iron, carbon and a siliceous material to the waste, agglomerating the moist mixture while drying the mixture with hot air to provide an agglomerated kiln feedstock containing 56 wt% water, calcining the feedstock in a rotary kiln to produce cement clinkers and pulverizing the clinkers to produce the cement. The calcination of the agglomerated kiln feedstock produces cement clinkers and SOz, the clinkers are removed from the kiln and pulverized to produce cement and the SOz is discharged from the kiln. uassed to an indirect heat exchaneer to heat air and the-heated air is used for removing water from the moist mixture during agglomeration. Containing 80-95 wt% CaSOa.O.SHzO and balance CaS04.0.5HzO the process comprises providing a moist flue gas desulfurization process waste product using a magnesium-enhanced lime slurry for reaction with SOz and adding fly ash containing aluminium and iron and carbon and sand to the waste to form a moist mixture.
99101205 Chemical and rheological characterization of airblown coal-tar pitches Menendez, R. er al. Carbon, 1998, 36, (7-8), 973-979. Isotropic pitches were produced from the air-blowing of a commercial impregnating coal-tar pitch at 275°C for 10, 18, 25 and 30 h. The pitches showed softening points ranging from 140 to 210°C. The parent and treated pitches were characterized by elemental analysis, Fourier transform IR, solubility in toluene and N-methylpyrrolidone, iodine adsorption and reflected light optical microscopy. The viscoelasticity of the pitches also was investigated using transient shear and controlled strain oscillatory rheometry. The chemical characterization of the pitches suggested that, as air-blowing proceeded, larger molecules formed through dehydrogenative polymerization (aromatization/condensation) and crosslinking of the pitch molecules. This is consistent with the rheological characterization of the pitches. The results obtained from transient shear and oscillatory rheometry showed that the parent impregnating pitch exhibited a viscous behaviour. In contrast, the air-blown pitches, which contained large aromatic molecules, showed viscoelastic properties.
99101205 Chemical process for coal desulfurization. I. Coal desulfurlzation in alkaline media
Balaz, P. Uhli-Rudy-Geol. Pruzkum, 1998, 5, (4), 127-129. Coal desulfurization by using alkaline media is reviewed. The emphasis is placed on the Ames and MCL (Molten Caustic Leaching; Gravimelt) processes.
Composite material from fly ash and post-consuLi, Y. et al. Resources, Conservation and Recycling, 1998, 24, (2), 87-93. From a coal-fired power plant, fly ash was combined with post-consumer polyethylene terephthalate (PET) from a municipal solid waste (MSW) landfill to produce a moulded composite material. Fly ash content varied from 0 to 50% by weight. The properties of compressive strength, water absorption and density of the products were tested. It was concluded that fly ash reduces the thermal decomposition of PET, expedites the melting and mixing of PET, reduces the shrinkage of the material during the moulding process and improves the properties of the final product. The addition of flv ash increased the comoressive streneth bv 31-53%. The micro-structure and bonding mechanism were inveitigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Water absorption was negligible for all the specimens.
99/01209
Comprehensive utilization of chromium-dregs
Fang, R. and Jin, C. Kuongchan Zonghe Liyong, 1997, (5), 40-44. (In Chinese) This paper presents a method for removing the toxicity of chromium-dregs by calcining the mixture of fly ash or coal gangue, limestone and chromiumdregs. The mechanism for removal and the factors which affect the removal are discussed. Additionally, the stability of the process was tested. A new type of belite cement is produced.
99101209
Constraints in the utilization of flyash
Nath, S. fndian J. Environ. Prot., 1997, 17, (2). 103-106. Existing in India are approximately 70 thermal power plants, who alone produce about 110 million tons of coal ash per year. It is anticipated that with the increasing number of thermal power projects coming up, the annual ash production in the country will rise to about 150 million ton per year by the year 2000. This will require about 30,000 ha of land for ash disposal purposes. The present disposal methods of coal ash are not only expensive but also have a disastrous effect on the environment. A lot has been talked about the utilization of fly ash, a major constituent of coal ash, but in the field of actual utilization, efforts seem to be lacking.
99lOl210 Effect of h dration conditions properties of fly ashCa( d H)2 sorbents
on the physical
Karatepe, N. ef ai. Energy sour&, 1998, 20, (6). 505-511. For the production of reactive sulfur dioxide sorbents fly ash samples taken from three different coal-fired Dower nlants in Turkev were used as reaeent material. For this purpose, fly ash-Ci(OH)z mixture; with different weight ratios were hydrated under different conditions. The effects of the hydration conditions such as temperature, time and fly ash/Ca(OH)z weight ratio on the physical properties of activated sorbents were investigated. By use of two-level factorial design matrix a statistical design technique was applied to interpret experimental results. It was found that increasing the temperature and hydration time caused an increase in the total surface area of the sorbents. However, in mixtures that have different fly ash/Ca(OH)? weight ratios, surface area values were generally not changed significantly for obtained sorbents.
99101211 The effect of potassium on the fusibility of coal ashes with hiah silica and alumina levels
Gupta, S. K. et zl. Fuel, 1998, 77, (ll), 1195-1201. Ashes with high SiOz and Al203 levels have poor repeatability and reproducibility -of fusibility temperatures. Such ashes are ‘studied in this paper using thermo-mechanical analysis (TMA) to indicate the shrinkage of samples progressively heated at the same rate as the test for standard ash fusibility temperatures (AFT). The results confirm that the extent and rate of change of shrinkage of the samples with low KzO levels (c 1 wt%) is low in regions of the deformation temperature (DT), resulting in poor accuracy of its determination. It was found that DT is mainly related to substantial melting of minerals containing KzO (i.e. illite) in these ashes. The effect of KzO interms on the extent of slag generation necessary for shrinkage were illustrated using scanning electron microscope (SEM) analysis of quenched ash samples and thermodynamic calculations. The TMA test is shown to provide a more sensitive alternative procedure for characterizing the ash fusibility.
99101212 Experlment on treatment of wastewater from sealing of coal gas by adsorption with coke and blast furnace slag
Liu, Y. Huanjing Baohu, 1997, (lo), 17-18. (In Chinese) This paper presents the process flow, equipment and technical parameter of coke/blast furnace slag adsorption process for treating coal gas - sealing water in a coal gas producer. The removal rate was 100% for sulfide, 95% for cyanide, 98% for phenol, 45% for COD, 71% for N and 90% for SS.
Fuel and Energy Abstmcts
March 1999
123