- Email: [email protected]
02291 Combustibility evaluation apparatus of coal
16
Fuel science and technology (fundamental
science, analysis, instrumentation)
99102289 Coal conversion. Materials for gasifier hot gas path components in advanced combined cycle power plants British Coal Corporation Comm. Eur. Communities, [Rep.] EUR, 1998, (EUR 17928), l-103. The development of a thorough knowledge of the materials requirements for critical components within the gasifier hot gas path of coal-fired combined cycle power plants was the aim of this project. Failure modes appropriate to the critical components were determined and studies carried out to provide the data required to introduce these issues into an existing life prediction model. Particular topics to be addressed included dew-point and down-time corrosion as well as the spallation of corrosion products from parts downstream of a fuel gas filter in hot clean-up systems of an advanced gasification plant. The components required in the hot gas paths of coal gasification systems were reviewed in order to determine their desired operations conditions and life. The operating conditions for each component were examined in terms of gas temperatures, component temperatures and stresses, gaseous environments, the likelihood of deposit formation and thermal cycling effects. Eight different classes of materials degradation were identified from this review. The performances of candidate materials for use in gasifier hot gas paths were determined in a series of laboratory tests and pilot plant exposures. These materials exposure studies were carried out in five test facilities at CTDD: three laboratory corrosion test rigs and two of the gasifier pilot plants. The laboratory tests investigated specific aspects of materials degradation, for example the spalling properties of the oxide/sulfide scales formed in coal gasifier gases and down-time corrosion under realistic ‘partial’ gasifier deposits, performance of welds and stressed materials, etc. Tests of fast thermal cycling behaviour in simulated gasifier gases were carried out in a novel corrosion facility developed specifically for this project. Two modes of spallation, known as buckling and wedging have been identified by SEM examination of materials samples which had been exposed in laboratory test rigs. The gasifier pilot plant hot gas path exposures provided materials performance data from real plant conditions, in which the materials degradation mechanisms could occur simultaneously or sequentially as the plant operations (and so hot gas path environments) varied. Of the candidate alloys tested, 316 stainless steel was the poorest performing alloy in the gaseous corrosion tests; the ranking of the other alloys varied between tests. In all the gaseous corrosion tests, relatively low rates of corrosion were observed, even after 4000 h of exposure. In the down-time corrosion tests, MA956 was the worst performing alloy, in agreement with plant observations. The performances of materials in well-controlled environments have greatly increased the data available on materials degradation in steady state gasifier operation. Together with more limited data available to CTDD from other sources, these data have been used to produce a new, greatly improved framework model for gaseous corrosion in gasifier gases and evaluated parameters for use in these models. Combination gas disengaging down comer-rejuve99102290 nation tube for in-situ slurry catalyst rejuvenation of spent hydrocarbon-synthesis catalysts Chang, M. et al. US 5,811,468 (Cl. 518-700; CO7C27/00), 22 Sep 1998, Appl. 851,865, 6 May 1997, 9 pp. The rejuvenation of a reversibly deactivated, particulate catalyst in a hydrocarbon synthesis slurry consists of circulating the slurry from a slurry body through: (1) a gas disengaging zone to remove gas bubbles from the slurry and increase its density; (2) a down comer which feeds the gasreduced, dense slurry into the bottom of a rejuvenating tube and applies a positive hydrostatic pressure to the tube; (3) a catalyst rejuvenation zone in which a catalyst rejuvenating gas, which also acts as a lift gas, contacts the catalyst in the slurry to form a rejuvenated catalyst slurry; and (4) back into the slurry body. The efficiency of rejuvenation can be improved by removing the gas bubbles prior to the rejuvenation and the down comer reduces the amount of rejuvenation gas required to maintain slurry circulation through the tube. The paper presents a process flow diagram. 99102291 Combustibility evaluation apparatus of coal Miyake, T. et al. Jpn. Kokai Tokkyo Koho JP 10 142,220 [98 142,220] (Cl. GOlN33/22), 29 May 1998, Appl. 961301,719, 13 Nov 1996, 5 pp. (In Japanese) In this paper an apparatus for the rapid and low-cost evaluation of the combustibility of coal, useful for circulating fluidized-bed boiler fuel is presented. It includes a quartz combustion tube having a quartz filter at the lower part of tube centre, a quartz fluidizing material above the filter, a fuel introduction tube inserted on top of the combustion tube, a gas inlet at the bottom and a gas outlet on top of the combustion tube, a heating furnace for heating the quartz combustion tube, a gas supply source for supplying the gas with a fixed oxygen concentration at a constant flow rate and a fuel supply hopper for feeding the fuel to the introduction tube. 99102292 Conversion of brown coal-fired power plants of the Upper Austrian Power Station Company to bituminous coal flring Guttenbrunner, M. et al. VGB Krafrwerkstech., 1998, 78, (6), 81-86. (In German) A description is given of the conversion measures in two power stations in which special arrangements and burner designs were required. The characteristic data of the brown coal and bituminous coal are presented. It was found that the reduction in fuel costs through the utilization of bituminous coal available at world market prices was advantageous.
234
Fuel and Energy Abstracts
May 1999
99102293 Cost-based decision making framework for CFC conversion strategy Said, S. A. M. ef al. Energy Convers. Manage., 1999, 40, (3). 273-279. A framework is detailed for cost-based decision making for a CFC conversion strategy. In order to perform a cost analysis, the elements required are outlined by a flow chart, which leads to decision making. Hard ‘What If?’ questions can now be answered using this flow chart, A case study using data pertaining to a 500 ton CFCll chiller is presented using the suggested framework.
99192294 Current status of EPA-sponsored inhouse research of PCDDIPCDF formation and control Bruce, K. R. and Raghunathan, K. Proc., Annu. Meet. Air Waste Manage. Assoc., 1996, 89, ~~9806, 1-15. Over the past six years, the Air Pollution Prevention and Control Division of the US Environmental Protection Agency’s National Risk Management Research Laboratory has conducted in-house research investigating fundamental mechanisms behind PCDDiPCDF formation to prevent or control emissions. Researchers have made important findings, using benchand pilot-scale test units, leading to a better understanding of how PCDD/ PCDF are formed in incinerators. Bench-scale tests have demonstrated the role of copper in the catalysing formation and the role of Cl? has been established. Tests have shown that the addition of sulfur compounds to the combustion process can decrease formation. Pilot-scale tests with injection of field-sampled municipal waste combustor (MWC) ash have shown formation and indicated that burn quality has a major impact. Tests with MWC ash have confirmed the inhibition of formation by sulfur for natural gas and coal combustion. Tests with coal alone showed little formation, PCDD/PCDF formation increased to significant levels on the addition of HCl. HCI concentration, quench rate and burn quality affected formation. Gas phase formation, inflight versus fixed bed formation and de nova versus precursor-based formation mechanisms are being investigated in ongoing tests. Tests are planned to verify sulfur inhibition by cofiring refuse-derived fuel with coal.
99192295 Current status of gasification melting for processing wastes Osada, M. Kogyo Kanetsu, 1998, 35, (3). 15-25. (In Japanese) 99102296 Development and field testing of a continuous realtime, speciating mercury analyser Sjostrom, S. et al. Proc., Annu. Meet. Air Waste Manage. Assoc., 1997, 90, WA72A06, 1-14. Wet chemical and solid sorbent measurement methods are available that can provide reasonable time-average measurements for the mercury concentration in utility flue gas from coal-fired boilers. However, a method that responds in real-time to mercury perturbations in the flue gas stream, can differentiate between elemental mercury and mercury compounds and is not affected by varying levels of sulfur dioxide would be a useful alternative to manual methods. ADA Technologies has been developing such a continuous mercury analyser for the past few years. The analyser is based on absorption of UV light emitted by a mercury lamp. The system consists of two sample cells each with sensitive photodetectors, a mercury species converter and a calibration system. Elemental mercury is detected in the first sample cell. Sample gas exiting the first cell is passed through a ‘converter’ to change speciated mercury compounds to elemental mercury that is then measured in a second cell (total mercury). New developments in the calibration technique, sampling system, measurement and signal processing have resulted in a system capable of measuring mercury concentrations on a slipstream from a coal-fired power plant in real time (0.1 to 0.8 ppb mercury). The system is configured to automatically calibrate on a regular basis. It has been found that it is also possible to measure the sulfur dioxide concentration because sulfur dioxide absorbs UV light at the wavelength of the mercury lamp emission. Descriptions of these recent developments and resulting field test data are presented.
99102297 Development of a tensile test method for highdensity coal under carbonization Suzuki, A. et al. Tefsu to Hagane, 1998, 84, (5), 321-326. (In Japanese) The development of a new tensile test method under carbonization for high-density coal that would be used in the coke making process next century took place in order to estimate the appearance mechanism of coke strength. This method can clarify the appearance mechanism of coke strength under carbonization. The result came through that the tensile strength and Young’s modulus become large in proportion to the final temperature. In the case of large heating rate, the tensile strength and Young’s modulus were large. From the microscope observation, coal particles agglomerated to each other around the softening temperature and the strength increased with an increase of heating rate. Factors were also estimated relating to the appearance mechanism of the strength using a coal pyrolytic model. The large strength is caused by the progress of coke graphitization and an increase of internal tar contributing to sticking on each particle.
Fuel science and technology (fundamental
science, analysis, instrumentation)
99102289 Coal conversion. Materials for gasifier hot gas path components in advanced combined cycle power plants British Coal Corporation Comm. Eur. Communities, [Rep.] EUR, 1998, (EUR 17928), l-103. The development of a thorough knowledge of the materials requirements for critical components within the gasifier hot gas path of coal-fired combined cycle power plants was the aim of this project. Failure modes appropriate to the critical components were determined and studies carried out to provide the data required to introduce these issues into an existing life prediction model. Particular topics to be addressed included dew-point and down-time corrosion as well as the spallation of corrosion products from parts downstream of a fuel gas filter in hot clean-up systems of an advanced gasification plant. The components required in the hot gas paths of coal gasification systems were reviewed in order to determine their desired operations conditions and life. The operating conditions for each component were examined in terms of gas temperatures, component temperatures and stresses, gaseous environments, the likelihood of deposit formation and thermal cycling effects. Eight different classes of materials degradation were identified from this review. The performances of candidate materials for use in gasifier hot gas paths were determined in a series of laboratory tests and pilot plant exposures. These materials exposure studies were carried out in five test facilities at CTDD: three laboratory corrosion test rigs and two of the gasifier pilot plants. The laboratory tests investigated specific aspects of materials degradation, for example the spalling properties of the oxide/sulfide scales formed in coal gasifier gases and down-time corrosion under realistic ‘partial’ gasifier deposits, performance of welds and stressed materials, etc. Tests of fast thermal cycling behaviour in simulated gasifier gases were carried out in a novel corrosion facility developed specifically for this project. Two modes of spallation, known as buckling and wedging have been identified by SEM examination of materials samples which had been exposed in laboratory test rigs. The gasifier pilot plant hot gas path exposures provided materials performance data from real plant conditions, in which the materials degradation mechanisms could occur simultaneously or sequentially as the plant operations (and so hot gas path environments) varied. Of the candidate alloys tested, 316 stainless steel was the poorest performing alloy in the gaseous corrosion tests; the ranking of the other alloys varied between tests. In all the gaseous corrosion tests, relatively low rates of corrosion were observed, even after 4000 h of exposure. In the down-time corrosion tests, MA956 was the worst performing alloy, in agreement with plant observations. The performances of materials in well-controlled environments have greatly increased the data available on materials degradation in steady state gasifier operation. Together with more limited data available to CTDD from other sources, these data have been used to produce a new, greatly improved framework model for gaseous corrosion in gasifier gases and evaluated parameters for use in these models. Combination gas disengaging down comer-rejuve99102290 nation tube for in-situ slurry catalyst rejuvenation of spent hydrocarbon-synthesis catalysts Chang, M. et al. US 5,811,468 (Cl. 518-700; CO7C27/00), 22 Sep 1998, Appl. 851,865, 6 May 1997, 9 pp. The rejuvenation of a reversibly deactivated, particulate catalyst in a hydrocarbon synthesis slurry consists of circulating the slurry from a slurry body through: (1) a gas disengaging zone to remove gas bubbles from the slurry and increase its density; (2) a down comer which feeds the gasreduced, dense slurry into the bottom of a rejuvenating tube and applies a positive hydrostatic pressure to the tube; (3) a catalyst rejuvenation zone in which a catalyst rejuvenating gas, which also acts as a lift gas, contacts the catalyst in the slurry to form a rejuvenated catalyst slurry; and (4) back into the slurry body. The efficiency of rejuvenation can be improved by removing the gas bubbles prior to the rejuvenation and the down comer reduces the amount of rejuvenation gas required to maintain slurry circulation through the tube. The paper presents a process flow diagram. 99102291 Combustibility evaluation apparatus of coal Miyake, T. et al. Jpn. Kokai Tokkyo Koho JP 10 142,220 [98 142,220] (Cl. GOlN33/22), 29 May 1998, Appl. 961301,719, 13 Nov 1996, 5 pp. (In Japanese) In this paper an apparatus for the rapid and low-cost evaluation of the combustibility of coal, useful for circulating fluidized-bed boiler fuel is presented. It includes a quartz combustion tube having a quartz filter at the lower part of tube centre, a quartz fluidizing material above the filter, a fuel introduction tube inserted on top of the combustion tube, a gas inlet at the bottom and a gas outlet on top of the combustion tube, a heating furnace for heating the quartz combustion tube, a gas supply source for supplying the gas with a fixed oxygen concentration at a constant flow rate and a fuel supply hopper for feeding the fuel to the introduction tube. 99102292 Conversion of brown coal-fired power plants of the Upper Austrian Power Station Company to bituminous coal flring Guttenbrunner, M. et al. VGB Krafrwerkstech., 1998, 78, (6), 81-86. (In German) A description is given of the conversion measures in two power stations in which special arrangements and burner designs were required. The characteristic data of the brown coal and bituminous coal are presented. It was found that the reduction in fuel costs through the utilization of bituminous coal available at world market prices was advantageous.
234
Fuel and Energy Abstracts
May 1999
99102293 Cost-based decision making framework for CFC conversion strategy Said, S. A. M. ef al. Energy Convers. Manage., 1999, 40, (3). 273-279. A framework is detailed for cost-based decision making for a CFC conversion strategy. In order to perform a cost analysis, the elements required are outlined by a flow chart, which leads to decision making. Hard ‘What If?’ questions can now be answered using this flow chart, A case study using data pertaining to a 500 ton CFCll chiller is presented using the suggested framework.
99192294 Current status of EPA-sponsored inhouse research of PCDDIPCDF formation and control Bruce, K. R. and Raghunathan, K. Proc., Annu. Meet. Air Waste Manage. Assoc., 1996, 89, ~~9806, 1-15. Over the past six years, the Air Pollution Prevention and Control Division of the US Environmental Protection Agency’s National Risk Management Research Laboratory has conducted in-house research investigating fundamental mechanisms behind PCDDiPCDF formation to prevent or control emissions. Researchers have made important findings, using benchand pilot-scale test units, leading to a better understanding of how PCDD/ PCDF are formed in incinerators. Bench-scale tests have demonstrated the role of copper in the catalysing formation and the role of Cl? has been established. Tests have shown that the addition of sulfur compounds to the combustion process can decrease formation. Pilot-scale tests with injection of field-sampled municipal waste combustor (MWC) ash have shown formation and indicated that burn quality has a major impact. Tests with MWC ash have confirmed the inhibition of formation by sulfur for natural gas and coal combustion. Tests with coal alone showed little formation, PCDD/PCDF formation increased to significant levels on the addition of HCl. HCI concentration, quench rate and burn quality affected formation. Gas phase formation, inflight versus fixed bed formation and de nova versus precursor-based formation mechanisms are being investigated in ongoing tests. Tests are planned to verify sulfur inhibition by cofiring refuse-derived fuel with coal.
99192295 Current status of gasification melting for processing wastes Osada, M. Kogyo Kanetsu, 1998, 35, (3). 15-25. (In Japanese) 99102296 Development and field testing of a continuous realtime, speciating mercury analyser Sjostrom, S. et al. Proc., Annu. Meet. Air Waste Manage. Assoc., 1997, 90, WA72A06, 1-14. Wet chemical and solid sorbent measurement methods are available that can provide reasonable time-average measurements for the mercury concentration in utility flue gas from coal-fired boilers. However, a method that responds in real-time to mercury perturbations in the flue gas stream, can differentiate between elemental mercury and mercury compounds and is not affected by varying levels of sulfur dioxide would be a useful alternative to manual methods. ADA Technologies has been developing such a continuous mercury analyser for the past few years. The analyser is based on absorption of UV light emitted by a mercury lamp. The system consists of two sample cells each with sensitive photodetectors, a mercury species converter and a calibration system. Elemental mercury is detected in the first sample cell. Sample gas exiting the first cell is passed through a ‘converter’ to change speciated mercury compounds to elemental mercury that is then measured in a second cell (total mercury). New developments in the calibration technique, sampling system, measurement and signal processing have resulted in a system capable of measuring mercury concentrations on a slipstream from a coal-fired power plant in real time (0.1 to 0.8 ppb mercury). The system is configured to automatically calibrate on a regular basis. It has been found that it is also possible to measure the sulfur dioxide concentration because sulfur dioxide absorbs UV light at the wavelength of the mercury lamp emission. Descriptions of these recent developments and resulting field test data are presented.
99102297 Development of a tensile test method for highdensity coal under carbonization Suzuki, A. et al. Tefsu to Hagane, 1998, 84, (5), 321-326. (In Japanese) The development of a new tensile test method under carbonization for high-density coal that would be used in the coke making process next century took place in order to estimate the appearance mechanism of coke strength. This method can clarify the appearance mechanism of coke strength under carbonization. The result came through that the tensile strength and Young’s modulus become large in proportion to the final temperature. In the case of large heating rate, the tensile strength and Young’s modulus were large. From the microscope observation, coal particles agglomerated to each other around the softening temperature and the strength increased with an increase of heating rate. Factors were also estimated relating to the appearance mechanism of the strength using a coal pyrolytic model. The large strength is caused by the progress of coke graphitization and an increase of internal tar contributing to sticking on each particle.