Eddings, EG
2000
Fast Cook-Off Tests of an HMX-based Propellant in Pool Fires
Eddings, E.G.; Sarofim, A.F.; Ciro, W. and Beckstead, M.W.
19th JANNAF Propulsion Systems Hazards Meeting, CPIA No. 690, Vol I, 2000, pp. 317.
Contact: Beckstead
1999
Char Nitrogen Conversion: Implications to Emissions from Coal-Fired Utility Boilers
Molina, A.; Sarofim, A.F.; Eddings, E.G. and Pershing, D.W.
Progress in Energy and Combustion Science, to be submitted, November 1999.
The contribution of the nitrogen present in the char on the production of nitrogen oxides during char combustion was analyzed. A literature review summarized the current understanding of the mechanisms that account for the formation of NO and N2O from the nitrogen present in the char. The review focused on 1) The functionalities in which nitrogen is present in the coal and how they evolve during coal devolatilization; 2) The mechanism of nitrogen release from the char to the homogeneous phase and its further oxidation to NO; and 3) The reduction of NO on the surface of the char. The critical analysis of these three issues allowed to identify uncertainties and well-founded conclusions observed in the literature for this system.
The existent models for the production of nitrogen oxides from char-N were also reviewed. A critic analysis of the assumptions made in these models and how they affect the final predictions is presented. Finally, a simplified version of these models was used to perform a parametric analysis of the incidence of the rate of NO reduction on the char surface, the rate of carbon oxidation, and the instant during the char oxidation when the nitrogen is released; on the total conversion of char-N to NO. The results underscore the importance of the reaction of NO reduction on the char surface on the final conversion of char-N to NO.
1994
Determination of Metal Behavior During the Incineration of a Contaminated Montmorillonite Clay
Eddings, E.G.; Lighty, J.S. and Kozinski, J.
Environmental Science and Technology, 28:1791, 1994. Funded by ACERC (different contract) and National Science Foundation/Presidential Young Investigators.
The goal of this study was to develop an understanding of metals behavior during thermal treatment. Clay samples, contaminated with metals to obtain a surrogate waste, were analyzed prior to and following thermal treatment using nitric acid and/or hydrogen fluoride digestion, followed by inductively coupled plasma emission spectrophotometry analysis. Techniques were used to examine particle surface and metal distribution within cross sections. Lead, cadmium, and chromium results are discussed. With hydrogen fluoride-digested samples, the results indicated that vaporization increased slightly with increasing temperature for cadmium and lead. Chromium did not show increased vaporization. At higher temperatures, the nitric acid digestions did not completely remove the metals. Scanning electron microscope pictures showed that, at higher temperatures, the particle structure became compact and glassy; the electron microprobe results indicated that lead and cadmium were located in regions with high silicon, suggesting reactions with the silicon. Chromium distribution remained uniform, suggesting that chromium was immobilized due to structural changes not reactions.
1992
Behavior of Metal Contaminants during the Incineration of Solid Wastes
Eddings, E.G.
Behavior of Metal Contaminants during the Incineration of Solid Wastes, Ph.D./U of U, June 1992. Advisor: Lighty
Fundamental Studies of Metal Behavior During Solids Incineration
Eddings, E.G. and Lighty, J.S.
Combustion Science and Technology, 85:375-390, 1992. Funded by National Science Foundation, Gas Research Institute and ACERC.
An experimental apparatus was constructed which allows investigation of the vaporization behavior of metal contaminants during incineration of their host substrate. Comparisons were made between equilibrium predictions and experimental observations for a number of different metals in chlorinated, inert, and reducing environments between 150ºC and 650ºC.
The equilibrium predictions for Pb vaporization were found to show the greatest deviation from experimental observations. Comparisons showed that a knowledge of elements associated with the initial metal species, as well as omission of PbCl4 from the calculations, can be important for the equilibrium predictions. Experimental results showed that the formation of volatile PbCl4 predicted by equilibrium was not kinetically favorable under the conditions studied. Subsequent vaporization studies involving PbCl2 deposited on a silica substrate demonstrated an influence of initial concentration on the amount of Pb vaporization observed. The extent of vaporization appeared to be independent of a moderate increase in temperature and an increase in the time allowed for vaporization.
Evolution of Metal Contaminants from Incinerated Solids
Eddings, E.G. and Lighty, J.S.
Air Toxic Reduction and Combustion Modeling, 15:69-78, 1992. (Also presented at the ASME International Joint Power Generation Conference, Atlanta, GA, 1992). Funded by National Science Foundation-Presidential Young Investigators, Gas Research Institute and ACERC.
The vaporization behavior of metal contaminants was studied in both a bench-scale and pilot-scale reactor. The results of bench-scale experiments indicated that the behavior of metal contaminants at low concentrations on solid substrates can be very different from the pure component behavior of the metal contaminant.
Pilot-scale studies focused on characterizing the behavior of metal contaminants at low concentrations in a batch rotary kiln environment. Solid samples of the contaminated clay bed material were removed from the kiln at various intervals providing data for the concentration of chromium, cadmium, copper, barium, lead, zinc, and strontium in the clay material over time. The resulting evolution plots indicated that after an initial drop in concentration, a temperature dependent, pseudo-equilibrium concentration was maintained in the batch rotary kiln simulator. Further processing for time up to 2 hours did not result in additional vaporization. In addition, different initial metal contamination solutions were used in the pilot-scale experiment including nitrate, chloride, and sulfate solutions of the contaminant metals and the results indicated essentially the same vaporization behavior for most all of the metals regardless of the initial spiking solution.
1991
Behavior of Metals During Incineration of Solids
Eddings, E.G. and Lighty, J.S.
Western States Section/The Combustion Institute, Los Angeles, CA, October 1991. Funded by National Science Foundation.
Metal vaporization experiments were carried out in a bench-scale, Differential-Bed Reactor to identify possible inconsistencies between experimental behavior and predictions based on equilibrium considerations. It was found that, under the conditions investigated, the equilibrium model accurately reflected the behavior of Cr, Ni, and Zn, but there was disagreement between the model and the experimental behavior of Pb and Cu. Pb predictions were improved by including information about elements associated with the particular species of Pb present on the waste and by omitting volatile PbCl4 from the calculations.
Detailed experiments of Pb behavior exhibited a strong binding effect of the solid substrate at low concentrations of PbCl2 preventing volatile behavior at temperatures expected to promote vaporization. A surface effect was also noted with experiments involving Cu; however, the effect was to actually enhance the vaporization of CuSO4 at low concentrations in the solid substrate relative to its behavior at high concentrations. The combined effects resulted in overprediction of Pb volatility and underprediction of Cu volatility by the equilibrium model.
1990
Rate Limiting Processes in the Rotary-Kiln Incineration of Contaminated Solids
Lighty, J.S.; Eddings, E.G.; Lindgren, E.R.; Deng, X.-X.; Pershing, D.W.; Winter, R.M. and McClennen, W.H.
Combustion Science and Technology, 1990 (In press). Funded by ACERC, Gas Research Institute and Remediation Technology.
A study of transport processes during the desorption of organic and metallic contaminants from solids is being conducted using several fundamental experiments. This paper presents results from three experimental systems, a Particle-Characterization Reactor, Bed-Characterization Reactor, and Metals Reactor.
The organic experiments attempt to identify the controlling transports processes within a particle of soil and through a bed of particles, as well as quantify the necessary parameters to model these processes. Gas and solid-phase speciation data for field samples, soils contaminated with a variety of organics (boiling points from 220ºC to 495ºC), are discussed. The data suggest that local temperature and gas/solid contacting are important in the desorption process. As expected, lighter components desorb faster than the heavier hydrocarbons. Moisture content was also important in the desorption of contaminant.
The metals reactor has been used to determine the fate of metals, specifically the partitioning between the gas and solid, for a metal species on an inert solid matrix. Data from a parametric characterization study of partitioning of lead, in the form of lead oxide on an inert matrix, in different gas environments are presented. The results indicate that lead is most volatile in a dilute hydrogen chloride/nitrogen environment.
1989
A Fundamental Study of the Rate of Thermal Desorption of Contaminants from Soil Beds
Lighty, J.S.; Eddings, E.G.; Deng, X.-X.; VanOs, L.M. and Pershing, D.W.
82nd Annual Air and Waste Management Association Annual Meeting, Anaheim, California, 1989. Funded by the Gas Research Institute, Dave Linz, Project Manager, ACERC (National Science Foundation and Associates and Affiliates), the State of Utah, and US Department of Energy.
Thermal treatment is a proven, permanent destruction technology for most organic wastes and is presently available commercially. Rotary kiln incineration is one of the most common systems for thermal remediation of solids; however, new thermal technologies are being sought. The EPA Superfund Innovative Technology Evaluation (SITE) Program, which focuses on the use of innovative technologies for permanent remediation purposes, has identified seven thermal technologies that have been or will be demonstrated this has identified seven thermal technologies that have been or will be demonstrated this year. These technologies include infrared thermal destruction, circulating fluidized bed combustion, and in situ steam/air stripping. In each of these technologies important transport phenomena, specifically mass and heat transfer, must be understood to enable performance prediction, through modeling, for these technologies as full-scale processes.
The program at the University of Utah attempts to identify the fundamental transport rates in the decontamination of solids using thermal treatment. Once these phenomena are understood, the thermal treatment system can then be optimized. The experimental approach involves three fundamental rate reactors and two reactors designed specifically to address incineration in a rotary kiln environment. The fundamental experiments attempt to address incineration in a rotary kiln environment. The fundamental experiments attempt to identify the controlling processes at a particle level in a Particle-Characterization Reactor (PCR) and the resistances within a bed of solid in two Bed-Characterization Reactors (BCR). The fundamental insights gained from these reactors can be applied to any thermal treatment system, since the systems differ only in the mechanisms of heat transfer and mass treatment system, since the systems differ only in the mechanisms of heat transfer and mass transfer. For example, in infrared thermal destruction the transport limitations within the bed and radiation from the top of the bed are important processes that need to be understood. In a circulating fluidized bed combustor, an understanding of gas/solid contacting and convection needs to be gained. In situ steam/air stripping requires knowledge of the interactions between the water, contaminant, and soil matrix.
Two other experimental systems focus specifically on the unique features of rotary-kiln incineration technology. An ambient temperature mixing reactor and a rotary kiln simulator are used to evaluate mixing and combustion characteristics typical of a large-scale rotary kiln.
The paper focuses on results obtained in the Bed-Characterization Reactors. Mass transfer and heat transfer resistances have been found to be extremely important. The effects of packing density, moisture, and particle size on these resistances will be discussed.
Monitoring the Evolution of Organic Compounds from the Thermal Treatment of Contaminated Soil Samples Using Short Column GC/MS
McClennen, W.H.; Arnold, N.S.; Lighty, J.S.; Eddings, E.G.; Lindgren, E.R.; Roberts, K.A. and Meuzelaar, H.L.C.
Preprints of Papers Presented at the 198th ACS National Meeting, 34 (3), Miami Beach, Florida, 1989. Funded by the Gas Research Institute, Dave Linz, Project Manager, ACERC (National Science Foundation and Associates and Affiliates), the State of Utah, and US Department of Energy.
Incineration is an effective technology for the remediation of organic chemical contaminated wastes. For solid wastes, such as contaminated soils, processes involving separate stages of a primary desorber and secondary afterburner are particularly useful. The desorption stage is currently being modeled using a particle-characterization reactor (PCR, 0-500 g capacity), a bed-characterization reactor (BCR, 0.5-5 kg), and a rotary kiln simulator (2-15 kg) to study fundamental processes such as mass transfer, heat transfer, and volatilization of contaminants. This paper describes the analytical methods and preliminary results from monitoring the evolution of organic compounds in these and smaller reactors.
The samples are soil contaminated with a broad range of polynuclear aromatic (PNA) hydrocarbons such as those derived from coal tars. The analytical methods primarily involve mass spectrometry (MS) with a variety of sample introduction techniques. The on-going analyses include solvent and thermal extractions of soil before and after various thermal treatments as well as on-line monitoring of vapors during desorption.
Eddings, EG
2000
Fast Cook-Off Tests of an HMX-based Propellant in Pool Fires
Eddings, E.G.; Sarofim, A.F.; Ciro, W. and Beckstead, M.W.
19th JANNAF Propulsion Systems Hazards Meeting, CPIA No. 690, Vol I, 2000, pp. 317.
Contact: Beckstead
1999
Char Nitrogen Conversion: Implications to Emissions from Coal-Fired Utility Boilers
Molina, A.; Sarofim, A.F.; Eddings, E.G. and Pershing, D.W.
Progress in Energy and Combustion Science, to be submitted, November 1999.
The contribution of the nitrogen present in the char on the production of nitrogen oxides during char combustion was analyzed. A literature review summarized the current understanding of the mechanisms that account for the formation of NO and N2O from the nitrogen present in the char. The review focused on 1) The functionalities in which nitrogen is present in the coal and how they evolve during coal devolatilization; 2) The mechanism of nitrogen release from the char to the homogeneous phase and its further oxidation to NO; and 3) The reduction of NO on the surface of the char. The critical analysis of these three issues allowed to identify uncertainties and well-founded conclusions observed in the literature for this system.
The existent models for the production of nitrogen oxides from char-N were also reviewed. A critic analysis of the assumptions made in these models and how they affect the final predictions is presented. Finally, a simplified version of these models was used to perform a parametric analysis of the incidence of the rate of NO reduction on the char surface, the rate of carbon oxidation, and the instant during the char oxidation when the nitrogen is released; on the total conversion of char-N to NO. The results underscore the importance of the reaction of NO reduction on the char surface on the final conversion of char-N to NO.
1994
Determination of Metal Behavior During the Incineration of a Contaminated Montmorillonite Clay
Eddings, E.G.; Lighty, J.S. and Kozinski, J.
Environmental Science and Technology, 28:1791, 1994. Funded by ACERC (different contract) and National Science Foundation/Presidential Young Investigators.
The goal of this study was to develop an understanding of metals behavior during thermal treatment. Clay samples, contaminated with metals to obtain a surrogate waste, were analyzed prior to and following thermal treatment using nitric acid and/or hydrogen fluoride digestion, followed by inductively coupled plasma emission spectrophotometry analysis. Techniques were used to examine particle surface and metal distribution within cross sections. Lead, cadmium, and chromium results are discussed. With hydrogen fluoride-digested samples, the results indicated that vaporization increased slightly with increasing temperature for cadmium and lead. Chromium did not show increased vaporization. At higher temperatures, the nitric acid digestions did not completely remove the metals. Scanning electron microscope pictures showed that, at higher temperatures, the particle structure became compact and glassy; the electron microprobe results indicated that lead and cadmium were located in regions with high silicon, suggesting reactions with the silicon. Chromium distribution remained uniform, suggesting that chromium was immobilized due to structural changes not reactions.
1992
Behavior of Metal Contaminants during the Incineration of Solid Wastes
Eddings, E.G.
Behavior of Metal Contaminants during the Incineration of Solid Wastes, Ph.D./U of U, June 1992. Advisor: Lighty
Fundamental Studies of Metal Behavior During Solids Incineration
Eddings, E.G. and Lighty, J.S.
Combustion Science and Technology, 85:375-390, 1992. Funded by National Science Foundation, Gas Research Institute and ACERC.
An experimental apparatus was constructed which allows investigation of the vaporization behavior of metal contaminants during incineration of their host substrate. Comparisons were made between equilibrium predictions and experimental observations for a number of different metals in chlorinated, inert, and reducing environments between 150ºC and 650ºC.
The equilibrium predictions for Pb vaporization were found to show the greatest deviation from experimental observations. Comparisons showed that a knowledge of elements associated with the initial metal species, as well as omission of PbCl4 from the calculations, can be important for the equilibrium predictions. Experimental results showed that the formation of volatile PbCl4 predicted by equilibrium was not kinetically favorable under the conditions studied. Subsequent vaporization studies involving PbCl2 deposited on a silica substrate demonstrated an influence of initial concentration on the amount of Pb vaporization observed. The extent of vaporization appeared to be independent of a moderate increase in temperature and an increase in the time allowed for vaporization.
Evolution of Metal Contaminants from Incinerated Solids
Eddings, E.G. and Lighty, J.S.
Air Toxic Reduction and Combustion Modeling, 15:69-78, 1992. (Also presented at the ASME International Joint Power Generation Conference, Atlanta, GA, 1992). Funded by National Science Foundation-Presidential Young Investigators, Gas Research Institute and ACERC.
The vaporization behavior of metal contaminants was studied in both a bench-scale and pilot-scale reactor. The results of bench-scale experiments indicated that the behavior of metal contaminants at low concentrations on solid substrates can be very different from the pure component behavior of the metal contaminant.
Pilot-scale studies focused on characterizing the behavior of metal contaminants at low concentrations in a batch rotary kiln environment. Solid samples of the contaminated clay bed material were removed from the kiln at various intervals providing data for the concentration of chromium, cadmium, copper, barium, lead, zinc, and strontium in the clay material over time. The resulting evolution plots indicated that after an initial drop in concentration, a temperature dependent, pseudo-equilibrium concentration was maintained in the batch rotary kiln simulator. Further processing for time up to 2 hours did not result in additional vaporization. In addition, different initial metal contamination solutions were used in the pilot-scale experiment including nitrate, chloride, and sulfate solutions of the contaminant metals and the results indicated essentially the same vaporization behavior for most all of the metals regardless of the initial spiking solution.
1991
Behavior of Metals During Incineration of Solids
Eddings, E.G. and Lighty, J.S.
Western States Section/The Combustion Institute, Los Angeles, CA, October 1991. Funded by National Science Foundation.
Metal vaporization experiments were carried out in a bench-scale, Differential-Bed Reactor to identify possible inconsistencies between experimental behavior and predictions based on equilibrium considerations. It was found that, under the conditions investigated, the equilibrium model accurately reflected the behavior of Cr, Ni, and Zn, but there was disagreement between the model and the experimental behavior of Pb and Cu. Pb predictions were improved by including information about elements associated with the particular species of Pb present on the waste and by omitting volatile PbCl4 from the calculations.
Detailed experiments of Pb behavior exhibited a strong binding effect of the solid substrate at low concentrations of PbCl2 preventing volatile behavior at temperatures expected to promote vaporization. A surface effect was also noted with experiments involving Cu; however, the effect was to actually enhance the vaporization of CuSO4 at low concentrations in the solid substrate relative to its behavior at high concentrations. The combined effects resulted in overprediction of Pb volatility and underprediction of Cu volatility by the equilibrium model.
1990
Rate Limiting Processes in the Rotary-Kiln Incineration of Contaminated Solids
Lighty, J.S.; Eddings, E.G.; Lindgren, E.R.; Deng, X.-X.; Pershing, D.W.; Winter, R.M. and McClennen, W.H.
Combustion Science and Technology, 1990 (In press). Funded by ACERC, Gas Research Institute and Remediation Technology.
A study of transport processes during the desorption of organic and metallic contaminants from solids is being conducted using several fundamental experiments. This paper presents results from three experimental systems, a Particle-Characterization Reactor, Bed-Characterization Reactor, and Metals Reactor.
The organic experiments attempt to identify the controlling transports processes within a particle of soil and through a bed of particles, as well as quantify the necessary parameters to model these processes. Gas and solid-phase speciation data for field samples, soils contaminated with a variety of organics (boiling points from 220ºC to 495ºC), are discussed. The data suggest that local temperature and gas/solid contacting are important in the desorption process. As expected, lighter components desorb faster than the heavier hydrocarbons. Moisture content was also important in the desorption of contaminant.
The metals reactor has been used to determine the fate of metals, specifically the partitioning between the gas and solid, for a metal species on an inert solid matrix. Data from a parametric characterization study of partitioning of lead, in the form of lead oxide on an inert matrix, in different gas environments are presented. The results indicate that lead is most volatile in a dilute hydrogen chloride/nitrogen environment.
1989
A Fundamental Study of the Rate of Thermal Desorption of Contaminants from Soil Beds
Lighty, J.S.; Eddings, E.G.; Deng, X.-X.; VanOs, L.M. and Pershing, D.W.
82nd Annual Air and Waste Management Association Annual Meeting, Anaheim, California, 1989. Funded by the Gas Research Institute, Dave Linz, Project Manager, ACERC (National Science Foundation and Associates and Affiliates), the State of Utah, and US Department of Energy.
Thermal treatment is a proven, permanent destruction technology for most organic wastes and is presently available commercially. Rotary kiln incineration is one of the most common systems for thermal remediation of solids; however, new thermal technologies are being sought. The EPA Superfund Innovative Technology Evaluation (SITE) Program, which focuses on the use of innovative technologies for permanent remediation purposes, has identified seven thermal technologies that have been or will be demonstrated this has identified seven thermal technologies that have been or will be demonstrated this year. These technologies include infrared thermal destruction, circulating fluidized bed combustion, and in situ steam/air stripping. In each of these technologies important transport phenomena, specifically mass and heat transfer, must be understood to enable performance prediction, through modeling, for these technologies as full-scale processes.
The program at the University of Utah attempts to identify the fundamental transport rates in the decontamination of solids using thermal treatment. Once these phenomena are understood, the thermal treatment system can then be optimized. The experimental approach involves three fundamental rate reactors and two reactors designed specifically to address incineration in a rotary kiln environment. The fundamental experiments attempt to address incineration in a rotary kiln environment. The fundamental experiments attempt to identify the controlling processes at a particle level in a Particle-Characterization Reactor (PCR) and the resistances within a bed of solid in two Bed-Characterization Reactors (BCR). The fundamental insights gained from these reactors can be applied to any thermal treatment system, since the systems differ only in the mechanisms of heat transfer and mass treatment system, since the systems differ only in the mechanisms of heat transfer and mass transfer. For example, in infrared thermal destruction the transport limitations within the bed and radiation from the top of the bed are important processes that need to be understood. In a circulating fluidized bed combustor, an understanding of gas/solid contacting and convection needs to be gained. In situ steam/air stripping requires knowledge of the interactions between the water, contaminant, and soil matrix.
Two other experimental systems focus specifically on the unique features of rotary-kiln incineration technology. An ambient temperature mixing reactor and a rotary kiln simulator are used to evaluate mixing and combustion characteristics typical of a large-scale rotary kiln.
The paper focuses on results obtained in the Bed-Characterization Reactors. Mass transfer and heat transfer resistances have been found to be extremely important. The effects of packing density, moisture, and particle size on these resistances will be discussed.
Monitoring the Evolution of Organic Compounds from the Thermal Treatment of Contaminated Soil Samples Using Short Column GC/MS
McClennen, W.H.; Arnold, N.S.; Lighty, J.S.; Eddings, E.G.; Lindgren, E.R.; Roberts, K.A. and Meuzelaar, H.L.C.
Preprints of Papers Presented at the 198th ACS National Meeting, 34 (3), Miami Beach, Florida, 1989. Funded by the Gas Research Institute, Dave Linz, Project Manager, ACERC (National Science Foundation and Associates and Affiliates), the State of Utah, and US Department of Energy.
Incineration is an effective technology for the remediation of organic chemical contaminated wastes. For solid wastes, such as contaminated soils, processes involving separate stages of a primary desorber and secondary afterburner are particularly useful. The desorption stage is currently being modeled using a particle-characterization reactor (PCR, 0-500 g capacity), a bed-characterization reactor (BCR, 0.5-5 kg), and a rotary kiln simulator (2-15 kg) to study fundamental processes such as mass transfer, heat transfer, and volatilization of contaminants. This paper describes the analytical methods and preliminary results from monitoring the evolution of organic compounds in these and smaller reactors.
The samples are soil contaminated with a broad range of polynuclear aromatic (PNA) hydrocarbons such as those derived from coal tars. The analytical methods primarily involve mass spectrometry (MS) with a variety of sample introduction techniques. The on-going analyses include solvent and thermal extractions of soil before and after various thermal treatments as well as on-line monitoring of vapors during desorption.