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Measurement of soot and char in pulverized coal fly ash
04 By-products related to fuels series of experiments were conducted. In the first series, two model decanting wells were tested with geotextile lining; in the second series, a number of model earthen bunds were tested with and without geotextiles. The economics of providing geotextiles in earthen bunds was studied. Results indicated geotextile use is economical and effective in improving performance of decanting wells and earthen bunds of an ash pond.
Hot corrosion of nickel-base alloys in biomass derived fuel simulated atmosphere
00100226
Leyens, C. er al. Elevated Temp. Coat.: Sci. Technol. III, Proc. Symp., 1999, 79-90. Edited by Hampikian J.M., Dahotre N.B. There are many promising renewable energy sources and biomass fuel is one of them. However, impurities present in the fuel may cause corrosion problems with the materials used in the hot sections of gas turbines and only limited data are available at the present. As part of the advanced turbine systems program initiated by the U.S. Department of Energy, the present study provides primary data on the hot corrosion resistance of different nickel-base alloys against sodium sulfate-induced corrosion as a baseline and against salt components simulating biomass-derived fuel deposits. Single crystal nickel-superalloy Rene N5, a cast NiCrAlY alloy, a NiCoCrAlY alloy representing industrially used overlay components and a model P-NiAI+Hf alloy were tested in one hour thermal cycles at 950” with different salt coatings deposited onto the surfaces. Whereas the NiCoCrAlY alloy exhibited reasonable resistance against pure sodium sulfate deposits, the NiCrAlY alloy and Rene N5 were attacked severely. Although considered to be an ‘ideal’ alumina former in air and oxygen at higher temperature, @NiAl+Hf also suffered from rapid corrosion attack at 950” when coated with sodium sulfate. The higher level of potassium present in biomass fuels compared with conventional fuels was addressed by testing a NiCoCrAlY alloy coated with salts of different K!Na atomic ratios. Starting at zero Na, the corrosion rate increased considerably when sodium was added to potassium sulfate. In an intermediate region the corrosion rate was initially insensitive to the W Na ratio but accelerated when Na-rich compounds were deposited. In conclusion, sodium sulfate as opposed to potassium sulfate was found to be the key driver of the NiCoCrAlY alloy corrosion process.
Hydrogen-steel interaction: hydrogen embrittlement in pipes for power former plant effluents
char by liquid-suspension gravity separation was used with both laboratory-scale and power plant fly ash samples. For low-NO. staged, pilot-scale combustion of bituminous coal the soot in the furnace exit ash was estimated to be 0.2-0.6% of the fuel carbon, which was about 35% of the total unburned carbon.
00100230 Measuring control system for impulse corona desulfurization method for treatment of flue gas in coal burning electric plant Tang, B. ef al. Huagong Zidonghua Ji Yibiao, 1999, 26, (4). 55-57. (In Chinese) The measuring control system for impulse corona desulfurization method for treatment of flue gas in coal burning electricity plant was introduced. A description is also included of the anti-interference methods, the design of the measuring control system and the structural characteristics of the software.
00100231 Method for treating carbon fiber surface Yang, Y. er al. Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1,157,354 (Cl. D06Ml5/19), 20 Aug 1997, Appl. 96,102,154, 14 Feb 1996. 7. (In Chinese) This paper presents a method for the production of high tensile strength carbon fibres. The procedure involves an organic coating material in an organic solvent being applied to the surfaces of carbon fibres, the organic solvent is then removed through drying and the fibres undergo gas phase oxidation at 100-1000” for lo-600 seconds. The coating material is selected from phenolic resin, polyvinyl alcohol, coal pitch, mesophase asphalt, petroleum asphalt, aliphatic and aromatic hydrocarbons.
Prediction of fl -ash size distribution: a correlation between the c Kar transition radius and coal properties
00/00232
Seggiani, M. et al. Fuel, 2000, 79, (S), 999-1002. The random coalescence (RC) model, predicting the size distributions of the fly-ash produced from coal combustion, is applied to correlate the char transition radius with coal size and the size and volume fraction of the mineral inclusions for different types of coals.
00100227
Borruto, A. et al. Inr. J. Hydrogen Energy, 1999, 24, (7). 651-659. ASTM A335 Pll is the type of steel industrially employed for the transport of liquid hydrocarburics in the presence of hydrogen at high temperatures. Three different types of tests were performed: tests of premature fracture, tests of thermal analysis and IR analysis. The present work has deeply studied the mechanisms of interaction between hydrogen and steel, trying to integrate and motivate the industrial data, commonly used for plant planning and sizing (A.P.I. Diagrams), proving that the cause for the damaging of this material is primarily due to the inclusion with hydrogen and the harmful interaction of carbides.
00100229 Influence of thermal, hydrothermal, and acid-base treatments on structural stability and surface properties of macro-, meso-, and microporous carbons Akolekar, D. B. Bhargava, S. K. J. Colloid Interface Sci, 1999, 216, (2). 309-3 19. Effects of thermal treatment (at 723 K), hydrothermal treatment [lowpressure steam vapour (34 torr) at 723 and 923 K and Hz0 (at autogenous pressure) at 398 and 473 K], and acid-base treatment (at 473 K) on the structural stability and physical properties of porous carbon samples prepared from both natural and synthetic sources were investigated. BET was used to characterize these thermally, hydrocarbon, thermogravimetric and thermally, and, acid-base-treated infrared techniques. Studies of the treated carbon samples revealed that the pore structure, thermal stability, pore size distribution and surface area are strongly affected by the thermal, hydrothermal, and acid-base treatments. Fourier transform infrared spectroscopy studies show that the carbon structures are significantly influenced by the hydrothermal and acid-base treatments. The surface and pore structure modifications of the microporous carbon were also studied by controlled air decomposition and high temperature aliphatic and aromatic organic vapour deposition.
00100233
al. Meifan Zhuanhua, 1999, 22, (4), 79-83. (In Chinese) The relationship between the sulfurized pitch structure and its carbon yield, rheology property at high temperature, thermal stability, a method of preparing high carbon yield pitch and its impregnating properties were investigated. The pitch prepared from sulfurization was shown to have a high carbon yield (>65%) and good rheology property, plus, excellent thermal stability when its softening point is in the range of 170-200°C.
Preparation of fullerenes using carbon rods manufactured from Chinese hard coals
00100234
Qiu, J. S. ef al. Fuel, 2000, 79, (11), 1303-1308. This paper reports on a feasibility study for the production of fullerenes (CsO and C7a) using carbon rods manufactured from Chinese coal, which is one of the cheapest natural resources of carbon. A DC arc method is employed using coal-derived carbon rods as electrode materials. The carbon rods are prepared from seven typical Chinese hard coals including bituminous coals and anthracite. The results show that all Chinese coals tested can be used to produce significant quantities of fullerenes. Their yields are strongly affected by the methods of preparing carbon electrodes and the parameters of the arc process, which are directly related to the coal properties and characteristics. These test results indicate that the two-step carbonization method is significantly better than the one-step hot-pressing method with regard to the fullerene yields, as such the two-step method is recommended for fullerenes production from Chinese coals. It is found that the fullerene yield increases as the carbon content in coal increases and as ash content in coal decreases. This suggests that the mineral matter in coals could somehow inhibit the fullerenes production. An interesting linear relationship between the C,&7a ratios and the volatile matter content in Chinese coals is also noted. 00/00235
W/O0229
Measurement of soot and char in pulverized coal
fly ash Veranth, J. M. et al. Fuel, 2000, 79, (9), 1067-1075. The unburned carbon in the fly ash produced by low-NO, pulverized coal combustion has been shown by electron microscopy to be a mixture of porous coal char particles and aggregates of submicron particles, which are thought to be soot. The carbon is bimodally distributed with large soot aggregates mixed with the char in the particles larger than 10 pm and dispersed soot found with the submicron particles. A method for determining the mass of soot and
Preparation and property of high-carbon yield
pitch Lu, C. et
Preparation of stabilized fiber from Avgamasya
asphaltite El, A. et nl. Energy Fuels, 1999, 13, (5), 1030-1036. A description of the various procedures for preparing stabilized fibres from Avgamasya asphaltite products is presented. Three different methods of solvent extraction, vacuum distillation of fluidized bed pyrolysis tar and air blowing of the vacuum distilled products were used. The asphaltite pitches obtained by different methods are characterized by various techniques such as elemental analysis, thermogravimetric analysis (TGA and DTG). softening point (SF’), Fourier transform IR spectroscopy (FTIR), and solution H and C Fuel and Energy Abstracts
January 2001 23
Hot corrosion of nickel-base alloys in biomass derived fuel simulated atmosphere
00100226
Leyens, C. er al. Elevated Temp. Coat.: Sci. Technol. III, Proc. Symp., 1999, 79-90. Edited by Hampikian J.M., Dahotre N.B. There are many promising renewable energy sources and biomass fuel is one of them. However, impurities present in the fuel may cause corrosion problems with the materials used in the hot sections of gas turbines and only limited data are available at the present. As part of the advanced turbine systems program initiated by the U.S. Department of Energy, the present study provides primary data on the hot corrosion resistance of different nickel-base alloys against sodium sulfate-induced corrosion as a baseline and against salt components simulating biomass-derived fuel deposits. Single crystal nickel-superalloy Rene N5, a cast NiCrAlY alloy, a NiCoCrAlY alloy representing industrially used overlay components and a model P-NiAI+Hf alloy were tested in one hour thermal cycles at 950” with different salt coatings deposited onto the surfaces. Whereas the NiCoCrAlY alloy exhibited reasonable resistance against pure sodium sulfate deposits, the NiCrAlY alloy and Rene N5 were attacked severely. Although considered to be an ‘ideal’ alumina former in air and oxygen at higher temperature, @NiAl+Hf also suffered from rapid corrosion attack at 950” when coated with sodium sulfate. The higher level of potassium present in biomass fuels compared with conventional fuels was addressed by testing a NiCoCrAlY alloy coated with salts of different K!Na atomic ratios. Starting at zero Na, the corrosion rate increased considerably when sodium was added to potassium sulfate. In an intermediate region the corrosion rate was initially insensitive to the W Na ratio but accelerated when Na-rich compounds were deposited. In conclusion, sodium sulfate as opposed to potassium sulfate was found to be the key driver of the NiCoCrAlY alloy corrosion process.
Hydrogen-steel interaction: hydrogen embrittlement in pipes for power former plant effluents
char by liquid-suspension gravity separation was used with both laboratory-scale and power plant fly ash samples. For low-NO. staged, pilot-scale combustion of bituminous coal the soot in the furnace exit ash was estimated to be 0.2-0.6% of the fuel carbon, which was about 35% of the total unburned carbon.
00100230 Measuring control system for impulse corona desulfurization method for treatment of flue gas in coal burning electric plant Tang, B. ef al. Huagong Zidonghua Ji Yibiao, 1999, 26, (4). 55-57. (In Chinese) The measuring control system for impulse corona desulfurization method for treatment of flue gas in coal burning electricity plant was introduced. A description is also included of the anti-interference methods, the design of the measuring control system and the structural characteristics of the software.
00100231 Method for treating carbon fiber surface Yang, Y. er al. Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1,157,354 (Cl. D06Ml5/19), 20 Aug 1997, Appl. 96,102,154, 14 Feb 1996. 7. (In Chinese) This paper presents a method for the production of high tensile strength carbon fibres. The procedure involves an organic coating material in an organic solvent being applied to the surfaces of carbon fibres, the organic solvent is then removed through drying and the fibres undergo gas phase oxidation at 100-1000” for lo-600 seconds. The coating material is selected from phenolic resin, polyvinyl alcohol, coal pitch, mesophase asphalt, petroleum asphalt, aliphatic and aromatic hydrocarbons.
Prediction of fl -ash size distribution: a correlation between the c Kar transition radius and coal properties
00/00232
Seggiani, M. et al. Fuel, 2000, 79, (S), 999-1002. The random coalescence (RC) model, predicting the size distributions of the fly-ash produced from coal combustion, is applied to correlate the char transition radius with coal size and the size and volume fraction of the mineral inclusions for different types of coals.
00100227
Borruto, A. et al. Inr. J. Hydrogen Energy, 1999, 24, (7). 651-659. ASTM A335 Pll is the type of steel industrially employed for the transport of liquid hydrocarburics in the presence of hydrogen at high temperatures. Three different types of tests were performed: tests of premature fracture, tests of thermal analysis and IR analysis. The present work has deeply studied the mechanisms of interaction between hydrogen and steel, trying to integrate and motivate the industrial data, commonly used for plant planning and sizing (A.P.I. Diagrams), proving that the cause for the damaging of this material is primarily due to the inclusion with hydrogen and the harmful interaction of carbides.
00100229 Influence of thermal, hydrothermal, and acid-base treatments on structural stability and surface properties of macro-, meso-, and microporous carbons Akolekar, D. B. Bhargava, S. K. J. Colloid Interface Sci, 1999, 216, (2). 309-3 19. Effects of thermal treatment (at 723 K), hydrothermal treatment [lowpressure steam vapour (34 torr) at 723 and 923 K and Hz0 (at autogenous pressure) at 398 and 473 K], and acid-base treatment (at 473 K) on the structural stability and physical properties of porous carbon samples prepared from both natural and synthetic sources were investigated. BET was used to characterize these thermally, hydrocarbon, thermogravimetric and thermally, and, acid-base-treated infrared techniques. Studies of the treated carbon samples revealed that the pore structure, thermal stability, pore size distribution and surface area are strongly affected by the thermal, hydrothermal, and acid-base treatments. Fourier transform infrared spectroscopy studies show that the carbon structures are significantly influenced by the hydrothermal and acid-base treatments. The surface and pore structure modifications of the microporous carbon were also studied by controlled air decomposition and high temperature aliphatic and aromatic organic vapour deposition.
00100233
al. Meifan Zhuanhua, 1999, 22, (4), 79-83. (In Chinese) The relationship between the sulfurized pitch structure and its carbon yield, rheology property at high temperature, thermal stability, a method of preparing high carbon yield pitch and its impregnating properties were investigated. The pitch prepared from sulfurization was shown to have a high carbon yield (>65%) and good rheology property, plus, excellent thermal stability when its softening point is in the range of 170-200°C.
Preparation of fullerenes using carbon rods manufactured from Chinese hard coals
00100234
Qiu, J. S. ef al. Fuel, 2000, 79, (11), 1303-1308. This paper reports on a feasibility study for the production of fullerenes (CsO and C7a) using carbon rods manufactured from Chinese coal, which is one of the cheapest natural resources of carbon. A DC arc method is employed using coal-derived carbon rods as electrode materials. The carbon rods are prepared from seven typical Chinese hard coals including bituminous coals and anthracite. The results show that all Chinese coals tested can be used to produce significant quantities of fullerenes. Their yields are strongly affected by the methods of preparing carbon electrodes and the parameters of the arc process, which are directly related to the coal properties and characteristics. These test results indicate that the two-step carbonization method is significantly better than the one-step hot-pressing method with regard to the fullerene yields, as such the two-step method is recommended for fullerenes production from Chinese coals. It is found that the fullerene yield increases as the carbon content in coal increases and as ash content in coal decreases. This suggests that the mineral matter in coals could somehow inhibit the fullerenes production. An interesting linear relationship between the C,&7a ratios and the volatile matter content in Chinese coals is also noted. 00/00235
W/O0229
Measurement of soot and char in pulverized coal
fly ash Veranth, J. M. et al. Fuel, 2000, 79, (9), 1067-1075. The unburned carbon in the fly ash produced by low-NO, pulverized coal combustion has been shown by electron microscopy to be a mixture of porous coal char particles and aggregates of submicron particles, which are thought to be soot. The carbon is bimodally distributed with large soot aggregates mixed with the char in the particles larger than 10 pm and dispersed soot found with the submicron particles. A method for determining the mass of soot and
Preparation and property of high-carbon yield
pitch Lu, C. et
Preparation of stabilized fiber from Avgamasya
asphaltite El, A. et nl. Energy Fuels, 1999, 13, (5), 1030-1036. A description of the various procedures for preparing stabilized fibres from Avgamasya asphaltite products is presented. Three different methods of solvent extraction, vacuum distillation of fluidized bed pyrolysis tar and air blowing of the vacuum distilled products were used. The asphaltite pitches obtained by different methods are characterized by various techniques such as elemental analysis, thermogravimetric analysis (TGA and DTG). softening point (SF’), Fourier transform IR spectroscopy (FTIR), and solution H and C Fuel and Energy Abstracts
January 2001 23