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981.
Teri L. Conner William A. Lonneman Robert L. Seila 《Journal of the Air & Waste Management Association (1995)》2013,63(5):383-394
Abstract Samples representative of transportation-related hydrocarbon emissions were collected as part of the 1990 Atlanta Ozone Precursor Monitoring Study. Motor vehicle emissions were sampled in canisters beside a roadway in a tunnel-like underpass during periods of heavy traffic. Airport and aircraft emissions were approximated by canister samples obtained at a major airport facility. Three octane grades of gasoline were purchased from six major vendors in Atlanta. Canister samples were prepared using these fuels to approximate the whole gasoline and gasoline vapor composition of the fuels in use during the study. All samples were analyzed by gas chromatography/flame ionization detection (GC/FID) for their hydrocarbon content. Detailed speciated hydrocarbon profiles were developed from this source sampling and analysis program for use in the Chemical Mass Balance (CMB) model. Profiles presented and discussed here represent the hydrocarbon composition of emissions from a roadway, composite headspace gasoline at two temperatures, composite whole gasoline, whole gasoline at three octane grades, and an airport. The roadway profile is compared with similar profiles in the literature, and recommendations are made regarding its use in the CMB model. The roadway and fuel profiles are discussed in the context of the MOBILE5 model outputs. The headspace gasoline vapor profile presented here is compared with a headspace gasoline vapor profile calculated from the whole gasoline profile by means of Raoult’s law. Agreement between the measured and calculated headspace profiles is excellent. The airport profile demonstrates the importance of high molecular weight volatile hydrocarbons in airport and aircraft emissions. 相似文献
982.
Cynthia L. Gage Gary T. Rochelle 《Journal of the Air & Waste Management Association (1995)》2013,63(7):926-935
Batch limestone dissolution experiments were carried out in a pH stat apparatus at 55°C with CO2 sparging and dissolved sulfite. Particle size distribution, utilization, sulfite in solution, limestone type, and the approach to calcite equilibrium were all found to contribute to the limestone reactivity. In the absence of sulfite, limestone dissolution was controlled solely by mass transfer. For a given stone under mass transfer control, film thickness was found to be independent of pH. The dissolution rate in the presence of sulfite was controlled by a combined surface kinetics/mass transfer regime. SEM micrographs supported this conclusion. A surface rate correlation was developed which accounted for observed inhibition by an inverse dependence on calcium sulfite concentration at the limestone surface. While the form of the rate expression was applicable to all stones, the surface rate constant was stone dependent. A computer code which accounted for mass transfer with surface kinetics was tested against experimental observations of four limestone types. Changes in pH and the concentrations of calcium, carbonate, sulfite, sulfate, and adipic acid were accurately modeled. 相似文献
983.
C. Jean Bustard Kenneth M. Cushing Ramsay L. Chang 《Journal of the Air & Waste Management Association (1995)》2013,63(9):1240-1249
Pulse-jet fabric filters (PJFFs) are widely used in U.S. industrial boiler applications and in utility and industrial boilers abroad. Their small size and reduced cost relative to more conventional reverse-gas baghouses makes the use of PJFFs appear to be an attractive particulate control option for utility boilers. This paper (Part 2 of a three-part series) summarizes the results of pilot PJFF studies sponsored by the Electric Power Research Institute at different utility sites in the United States. The purpose of these tests is to evaluate PJFF performance for U.S. fossil-fuel-fired applications. These data are also used to corroborate the results of a recent worldwide survey of PJFF user experience, as described in Part 1 of this series. Part 3 will provide a cost comparison of PJFFs to other particulate control options such as electrostatic precipitators and reverse-gas baghouses. 相似文献
984.
John A. Willemin Carl C. Nesbitt George R. Dewey John F. Sandell Lawrence L. Sutler 《Journal of the Air & Waste Management Association (1995)》2013,63(11):871-876
Abstract A completely mixed batch reactor leaching method utilizing flow injection analysis (the CMBR-FIA method) was developed to study the lead leaching characteristics of municipal waste combustor fly ash. Flow injection analysis (FIA) coupled with atomic absorption spectrophotometry enabled the determination of lead concentrations at one minute intervals. The pH and oxidation-reduction potential of the solution were continuously monitored to characterize the leaching conditions. Automatic titration was used to alter the solution pH to defined endpoints. The CMBR-FIA method offers the ability to immediately observe alterations to the leaching solution, and grants the freedom to study a number of parameters concurrently. The CMBR-FIA method is a rapid and reliable means to investigate leaching characteristics. This paper describes the method and demonstrates its use to monitor the leaching of lead from municipal solid waste combustor fly ash as a function of pH. Soluble lead concentrations are shown to increase quickly with decreasing pH. A maximum of 50% of the total lead concentration was available in solution at pH 2. This value gradually decreased with time to over 35% of the total. 相似文献
985.
Karen R. Anderson Edward L. Avol Scott A. Edwards Deborah A. Shamoo Ru-Chuan Peng William S. Linn 《Journal of the Air & Waste Management Association (1995)》2013,63(6):770-776
Respirable carbon or fly ash particles are suspected to increase the respiratory toxicity of coexisting acidic air pollutants, by concentrating acid on their surfaces and so delivering it efficiently to the lower respiratory tract. To investigate this issue, we exposed 15 healthy and 15 asthmatic volunteers in a controlled- environment chamber (21°C, 50 percent relative humidity) to four test atmospheres: (i) clean air; (ii) 0.5-μm H2SO4 aerosol at =100 μg/m3, generated from water solution; (iii) 0,5-μm carbon aerosol at =250 μg/m3, generated from highly pure carbon black with specific surface area comparable to ambient pollution particles; and (iv) carbon as in (iii) plus =100 μg/m3 of ultrafine H2SO4 aerosol generated from fuming sulfuric acid. Electron microscopy showed that nearly all acid in (iv) became attached to carbon particle surfaces, and that most particles remained in the sub-μm size range. Exposures were performed double-blind, 1 week apart. They lasted 1 hr each, with alternate 10-min periods of heavy exercise (ventilation =50 L/min) and rest. Subjects gargled citrus juice before exposure to suppress airway ammonia. Lung function and symptoms were measured pre-exposure, after initial exercise, and at endexposure. Bronchial reactivity to methacholine was measured after exposure. Statistical analyses tested for effects of H2SO4 or carbon, separate or interactive, on health measures. Group data showed no more than small equivocal effects of any exposure on any health measure. One individual's responses were consistent with a clinically significant excess airway constriction from H2SO4 plus carbon, and 2-3 others showed slight excess responses to the combined pollutants, but all these observations might have reflected chance variations. We conclude that coexisting carbon aerosol did not increase respiratory irritancy of H2SO4, in most healthy and asthmatic subjects exposed for 1 hr under simulated "worst-case" ambient conditions. 相似文献
986.
V. A. Cundy C. Lu C. A. Cook A. M. Sterling C. B. Leger A. L. Jakway 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1084-1094
Comparisons are made, for the first time, between the combustion characteristics of dichloromethane and xylene in an industrial rotary kiln incinerator. The comparisons are made under different operating conditions, including variable kiln rotation rate and operation both with and without turbulence air. Continuous gas composition and temperature measurements and batch gas composition measurements were obtained from two vertical locations hear the exit region of the rotary kiln. The measurements show that there is significant vertical stratification at the exit of the kiln. Addition of turbulence air enhanced combustion conditions throughout the kiln during xylene processing. During dichloromethane processing, however, the addition of turbulence air had minimal effect and only promoted greater bulk mixing; chlorinated compounds transported from the lower kiln during operation with turbulence air were not efficiently processed in the upper kiln. Evolution of test liquids from the bed was not constant but rather was characterized by intermittent peaks. The field-scale data of this work suggest that the evolution rate of the test liquid was increased as kiln rotation rate increased. Many of the differences between xylene and dichloromethane processing during these experiments are explained by a simple stoichiometric analysis. 相似文献
987.
Lauraine G. Chestnut Robin L. Dennis 《Journal of the Air & Waste Management Association (1995)》2013,63(3):395-402
The Acid Rain Provisions (Title IV) of the Clean Air Act Amendments of 1990 call for about a 10 million ton reduction in annual SO2 emissions in the United States. Although the provisions apply nationwide, most of the reduction will occur in the eastern half of the country, where use of high-sulfur coal for electricity generation is most common. One potentially large benefit of Title IV is the expected improvement in visibility conditions in the eastern United States due to the reductions in secondary sul-fate aerosols. This paper combines available economic estimates of willingness to pay for improvements in visibility with current estimates of the difference between expected visibility conditions in the eastern United States with and without Title I V, to estimate the expected visibility benefits of Title IV. The results suggest an annual value of $2.3 billion (in 1994 dollars) in the year 2010, as a result of visibility improvements due to Title IV in residential areas of the eastern United States. The results also suggest a possible additional annual value for eastern U.S. residents of as much as $1-2 billion for visibility improvements at national parks in the Southeast. 相似文献
988.
Norman L. Eatough Michele Eatough Delbert J. Eatough Jyothi M. Joseph Fern M. Caka 《Journal of the Air & Waste Management Association (1995)》2013,63(3):455-467
The precision and accuracy of the determination of particu-late sulfate and fluoride, and gas phase SO2 and HF are estimated from the results obtained from collocated replicate samples and from collocated comparison samples for high-and low-volume filter pack and annular diffusion denuder samplers. The results of replicate analysis of collocated samples and replicate analyses of a given sample for the determination of spherical aluminosilicate fly ash particles have also been compared. Each of these species is being used in the chemical mass balance source apportionment of sulfur oxides in the Grand Canyon region as part of Project MOHAVE, and the precision and accuracy analyses given in this paper provide input to that analysis. The precision of the various measurements reported here is ±1.8 nmol/m3 and ±2.5 nmol/m3 for the determination of SO2 and sulfate, respectively, with an annular denuder. The precision is ±0.5 nmol/m3 and ±2.0 nmol/m3 for the determination of the same species with a high-volume or low-volume filter pack. The precision for the determination of the sum of HF(g) and fine particulate fluoride is ±0.3 nmol/m3. The precision for the determination of aluminosilicate fly ash particles is ±100 particles/m3. At high concentrations of the various species, reproducibility of the various measurements is ±10% to ±14% of the measured concentration. The concentrations of sulfate determined using filter pack samplers are frequently higher than those determined using diffusion denuder sampling systems. The magnitude of the difference (e.g., 2-10 nmol sulfate/m3) is small, but important relative to the precision of the data and the concentrations of particulate sul-fate present (typically 5-20 nmol sulfate/m3). The concentrations of SO2(g) determined using a high-volume cascade impactor filter pack sampler are correspondingly lower than those obtained with diffusion denuder samplers. The concentrations of SOx (SO2(g) plus particulate sulfate) determined using the two samplers during Project MOHAVE at the Spirit Mountain, NV, and Hopi Point, AZ, sampling sites were in agreement. However, for samples collected at Painted Desert, AZ, and Meadview, AZ, the concentrations of SOx and SO2(g) determined with a high-volume cascade impactor filter pack sampler were frequently lower than those determined using a diffusion denuder sampling system. These two sites had very low ambient relative humidity, an average of 25%. Possible causes of observed differences in the SO2(g) and sulfate results obtained from different types of samplers are given. 相似文献
989.
L. Alonso N. Durana M. Navazo J.A. García J.L. Ilardia 《Journal of the Air & Waste Management Association (1995)》2013,63(8):916-924
ABSTRACT During a preliminary field campaign of volatile organic compound (VOC) measurements carried out in an urban area, two complementary analysis techniques were applied to establish the technical and scientific bases for a strategy to monitor and control VOCs and photochemical oxidants in the Autonomous Community of the Basque Country. Integrated sampling was conducted using Tenax sorbent tubes and laboratory analysis by gas chromatography, and grab sampling and in situ analysis also were conducted using a portable gas chromatograph. With the first technique, monocyclic aromatic hydrocarbons appeared as the compounds with the higher mean concentrations. The second technique allowed the systematic analysis of eight chlorinated and aromatic hydrocarbons. Results of comparing both techniques, as well as the additional information obtained with the second technique, are included. 相似文献
990.
Abstract Contaminated solid wastes exist in many industrial sites, gas plants, and oil refineries. One method of decontaminating the soil is to subject it to high temperatures in a rotary calciner in an anaerobic environment. Preliminary results from a computational model are presented in this paper for the flow and heat transfer from granular solid particles under treatment in a rotary kiln calciner. A fluidization model using kinetic theory of granular flow has been employed to solve the particle flow and heat transfer problem. While a two-dimensional model is used to predict the rotation induced flow of the solid particles, a pseudo three-dimensional model for heat transfer is developed where the axial bulk temperature gradient is obtained from a one-dimensional energy balance model. The model predictions indicate interesting features of the flow and temperature fields in the bed material. Future tasks include the development of a devolatilization model to study the decontamination of waste soil in the rotary calciner. 相似文献