Grantee Research Project Results
Final Report: Formation of Toxic By-Products in the Incineration of Hazardous Materials
EPA Grant Number: R825412Title: Formation of Toxic By-Products in the Incineration of Hazardous Materials
Investigators: Senkan, Selim M.
Institution: University of California - Los Angeles
EPA Project Officer: Hahn, Intaek
Project Period: November 1, 1996 through October 31, 1999
Project Amount: $389,553
RFA: Exploratory Research - Water Engineering (1996) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Safer Chemicals
Objective:
The objectives of this project were to investigate experimentally and theoretically the formation of toxic by-products in the incineration of hazardous materials, including halogenated hydrocarbons. The experimental program emphasized the use of one-dimensional premixed flames of methane, ethane, and other hydrocarbon fuels doped with hazardous additives. To a lesser extent, opposed jet diffusion flames also were explored. Flame chemistry has been determined using heated microprobe sampling coupled to online gas chromatography/mass spectrometry (GC/MS). In addition, resonance enhanced multiphoton ionization (REMPI) time of flight mass spectrometry (TOF/MS) has been used, to a limited extent, for the ultrasensitive detection of trace species. The objectives of the theoretical program have been to develop fundamentally based detailed reaction mechanisms describing the formation and destruction of toxic by-products in flames and in post flame gases, in collaboration with scientists of the Sandia National Laboratories and Lawrence Livermore National Laboratory. The rates and mechanisms of reactions taking place homogeneously in the gas phase and on surfaces also were investigated using computational quantum chemistry. These studies should ultimately provide a better basis for the operation, design, and control of practical incineration systems. The emphasis of the research programs has been on the determination of the trace chemistries of hydrocarbon flames. This was necessary because hazardous materials almost always are treated in the flames of hydrocarbon fuels to ensure their safe and reliable destruction. Therefore, to better understand how hazardous materials are destroyed in incinerators, the flame chemistries of hydrocarbon fuels, especially with regard to the formation of trace toxic combustion by-products such as polycyclic aromatic hydrocarbons (PAH), dioxins, furans, and soot must be established first. This also is necessary to better assess the risks hazardous waste incinerators pose relative to other combustion systems burning hydrocarbon fuels.Summary/Accomplishments (Outputs/Outcomes):
A number of significant results have been obtained in the program on several fronts. First, we generated the most comprehensive chemical structure data of the premixed and, on a more limited basis, diffusion flames of hydrocarbons, as well as hydrocarbons containing halogens, as a result of new experimental advances made in our laboratories. Specifically, we developed methods to rapidly determine the major, minor, and trace species concentration profiles in flames, together with soot and temperature profiles in a single experiment. With these developments, we now can generate unambiguous quantitative data for 50-80 species in each system covering a mole fraction range of 0.35-5.0 ? 10-7.Second, we developed an experimental facility to measure the soot volume fractions, particle number densities, and mean diameters using laser light extinction, scattering, and the Mie-Lorentz theory. We subsequently used this facility to establish the effects of equivalence ratio on soot properties in premixed and diffusion flames. Third, we currently are developing a versatile laser photoionization (LP) TOF/MS system for the ultrasensitive and real time detection of trace combustion by-products. Earlier experiments demonstrated the feasibility of real time detection of naphthalene at about 50 ppt, under REMPI conditions, representing nearly a factor of 1000 improvement over conventional GC/MS.
These advances are significant because, until our work, different features of flames were determined by different groups in different laboratories, which rendered the results difficult to compare to one another and use for flame simulations. As a result of these developments, we also made the surprising discovery that under certain conditions the levels of all the aromatics and PAH could be significantly lower in more sooting flames. This is a significant result that contradicts the generally held belief that increased soot formation must be associated with higher PAH levels. Our findings have significant implications to PAH, dioxin, and furan formation in incinerators, and raise important issues regarding the risks associated with the operation of combustion devices, in general, and incinerators, in particular.
Finally, we continued our productive collaborations with the scientists of the Sandia National Laboratories and Lawrence Livermore National Laboratory for the development of detailed chemical kinetic mechanisms describing the formation, destruction, and emission of toxic combustion by-products in premixed and diffusion flames. Our efforts to combine detailed experimentation and kinetic modeling already have met with success as evidenced by the publication of a number of landmark papers. The ultimate goal of this modeling activity was to provide guidance for the design and operation of cleaner combustion devices that result in the emission of the lowest possible levels of air toxics and, therefore, pose the least possible risk to the public health.
Journal Articles on this Report : 14 Displayed | Download in RIS Format
| Other project views: | All 15 publications | 14 publications in selected types | All 14 journal articles |
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Castaldi MJ, Senkan SM. Real-time, ultrasensitive monitoring of air toxics by laser photoionization time-of-flight mass spectrometry. Journal of the Air & Waste Management Association 1998;48(1):77-81. |
R825412 (Final) |
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Chan KYG, Inal F, Senkan S. Suppression of coke formation in the steam cracking of alkanes: ethane and propane. Industrial & Engineering Chemistry Research 1998;37(3):901-907. |
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Eastman JL, Coughenour MB, Pielke Sr. RA. The regional effects of CO2 and landscape change using a coupled plant and meteorological model. Global Change Biology 2001;7(7):797-815. |
R825412 (Final) R824993 (1999) R824993 (Final) R826730 (2000) |
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Gittins CM, Castaldi MJ, Senkan SM, Rohlfing EA. Real-time quantitative analysis of combustion-generated polycyclic aromatic hydrocarbons by resonance-enhanced multiphoton ionization time-of-flight mass spectrometry. Analytical Chemistry 1997;69(3):286-293. |
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Huang J, Senkan SM. Polycyclic aromatic hydrocarbon and soot formation in premixed flames of CH3Cl/CH4 and CH4. Symposium (International) on Combustion 1996;26(2):2335-2341. |
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Huang J, Onal I, Senkan SM. Formation of trace byproducts in the premixed flames of CH3Cl/C2H4. Environmental Science & Technology 1997;31(5):1372-1381. |
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Marinov NM, Pitz WJ, Westbrook CK, Castaldi MJ, Senkan SM. Modeling of aromatic and polycyclic aromatic hydrocarbon formation in premixed methane and ethane flames. Combustion Science and Technology 1996;116-117(1-6):211-287. |
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Marinov NM, Pitz WJ, Westbrook CK, Vincitore AM, Castaldi MJ, Senkan SM, Melius CF. Aromatic and polycyclic aromatic hydrocarbon formation in a laminar premixed n-butane flame. Combustion and Flame 1998;114(1-2):192-213. |
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Marinov NM, Pitz WJ, Westbrook CK, Lutz AE, Vincitore AM, Senkan SM. Chemical kinetic modeling of a methane opposed-flow diffusion flame and comparison to experiments. Symposium (International) on Combustion 1998;27(1):605-613. |
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Melton TR, Vincitore AM, Senkan SM. The effects of equivalence ratio on the formation of polycyclic aromatic hydrocarbons and soot in premixed methane flames. Symposium (International) on Combustion 1998;27(2):1631-1637. |
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Olten N, Senkan S. Formation of polycyclic aromatic hydrocarbons in an atmospheric pressure ethylene diffusion flame. Combustion and Flame 1999;118(3):500-507. |
R825412 (Final) R826730 (2000) |
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Senkan SM, Deskin SC. A continuous-purge pulsed valve suitable for high-temperature applications. Review of Scientific Instruments 1997;68(11):4286-4287. |
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Vincitore AM, Senkan SM. Experimental studies of the micro-structures of opposed flow diffusion flames: methane. Combustion Science and Technology 1997;130(1-6):233-246. |
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Vincitore AM, Senkan SM. Polycyclic aromatic hydrocarbon formation in opposed flow diffusion flames of ethane. Combustion and Flame 1998;114(1-2):259-266. |
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Supplemental Keywords:
ultrasensitive detection, real-time monitoring, resonance enhanced multiphoton ionization, REMPI, sooting flames, polycyclic aromatic hydrocarbons, PAHs, air pollution, engineering, modeling., RFA, Scientific Discipline, Toxics, Water, Waste, Ecology, Environmental Chemistry, Chemistry, CFCs, Engineering, Chemistry, & Physics, Incineration/Combustion, hydrocarbon, mass spectrometry, organometallic compounds, gas chromatography, hazardous materials, quantum chemistry, environmental contaminants, combustion, halons, incineration, organomettalic compounds, ionization, flame chemistry, toxic by-productsProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.