1987 Joint EPRI/EPA Symposium on Stationary Combustion NOX Control

From March 23rd to 26th, 1987, the city of New Orleans hosted 350 attendees, including representatives from 15 foreign countries, at the 1987 Joint Symposium on Stationary Combustion NO_x Control. Cosponsored by the Electric Power Research Institute (EPRI) and the U.S. Environmental Protection Agency (EPA), the symposium provided attendees the opportunity to hear 49 papers in nine sessions covering technological and regulatory developments on NO_x control in the United States and abroad since the May 1985 symposium in Boston. Session topics included general environmental issues, low-NO_x combustion equipment (i.e., low-NO_x burners, reburning, etc.), flue gas treatment, fundamental combustion research, and special issues for cyclone coal-fueled boilers, oil- and gas-fired boilers, and industrial combustion applications.

Advances to the state-of-the-art presented at this symposium include: improved and/or newly applied combustion modifications for pulverized coal-fired boilers; further analyses of reburning, the leading combustion modification option for cyclone-equipped boilers; initial experiences with catalytic flue gas treatment in Europe; studies of NO_x control retrofit options for oil- and gas-fired utility systems; and new technology developments for coal, oil, and gas fueled utility and industrial combustors.

This paper summarizes those presentations that discussed significant changes since May 1985 in areas of potential interest to EPRI and its utility members. Where appropriate, they include our perspectives on the applicability of these newly disclosed findings to utility systems.     

Summary of the 1991 EPA/A&WMA International Symposium: Measurement of Toxic and Related Air Pollutants

A joint conference cosponsored for the sixth year by the Atmospheric Research and Exposure Assessment Laboratory (AREAL) of the U.S. Environmental Protection Agency and the Air & Waste Management Association was held in Durham, North Carolina, May 6–10, 1991. The technical program consisted of 220 presentations, held in 25 technical sessions, on recent advances in ambient and source atmospheres. Covering a wide range of measurement topics and supported by 78 exhibitors of instrumentation and consulting services, the symposium was attended by almost a thousand professionals from the United States and other countries. This overview highlights a selection of the technical presentations, and includes a synopsis of the keynote address.     

Summary of the 1989 EPA/A&WMA International Symposium: Measurement of Toxic and Related Air Pollutants

A joint conference, for the fourth straight year cosponsored by the Air & Waste Management Association’s TP-6, TP-7, and ITF-2 technical committees, and the Atmospheric Research and Exposure Assessment Laboratory of the U. S. Environmental Protection Agency, was held at Raleigh, North Carolina, May 2-5, 1989. The technical program consisted of 145 presentations, held in 14 separate technical sessions, on recent advances in the measurement and monitoring of toxic and related pollutants found in ambient and source atmospheres. Covering a wide range of measurement topics and superbly supported by 57 exhibitors of instrumentation and consulting services, the symposium was enthusiastically received by more than 700 attendees from the United States and other countries. This overview contains a selection of the highlights from the technical presentations. A synopsis of the keynote address to the symposium is also included.     

A Summary of the APCA/EPA International Specialty Conference

Atmospheric change has emerged as a major global environmental issue of national and international concern in the 1990's. The dominance of the legislative and regulatory perception of atmospheric processes over their scientific understanding has left both regulators and atmospheric scientists ill-prepared to respond to emerging atmospheric-environmental issues. A view of clean air is presented whereby the legislative/regulatory and scientific perception of the physical and chemical processes of the atmosphere are linked to achieve the goal of a healthy atmosphere and sustainable environment.     

Stationary Combustion NOX Control A Summary of the 1989 Symposium

This paper summarizes information and results presented at the 1989 Symposium on Stationary Combustion NOX Control, held March 6-9, 1989 in San Francisco. Cosponsored by the Electric Power Research Institute (EPRI) and the U.S. Environmental Protection Agency, (EPA) the symposium was the fifth in a biennial series.     

A Summary of the A&WMA/EPA International Specialty Conference

“Visibility and Fine Particles“, the fourth in a series of international specialty conferences on atmospheric visibility, was sponsored by the Air and Waste Management Association and the U.S. Environmental Protection Agency. The purpose of this conference was to provide a forum to disseminate the results of recent advances in visibility and fine particles. The 110 papers presented at the conference covered six topics: policy and regulatory issues, visibility and fine particle measurements, human perception of visibility, meteorological factors affecting visibility, economic valuation of visibility, and visibility and fine particle modeling and source apportionment. Eighty-five of those papers are included in the conference Transactions and are summarized in this article.     

Accuracy Assessment of EPA Protocol Gases Purchased In 1991

ABSTRACT

Fixed-roof tanks are used extensively at manufacturing, waste management, and other facilities to store or process liquids containing volatile organic compounds. Federal and state air standards require the control of organic air emissions from many of these tanks. A common practice used for some fixed-roof tanks that are required to use controls is to vent the tank through an activated carbon canister. When organic vapors are adsorbed on activated carbon, heat is released. Under certain conditions, the temperature of the carbon bed can increase to a level at which the carbon or organic vapors spontaneously ignite, starting a fire in the carbon bed. Bed fires in carbon canisters are not uncommon and can present a significant safety hazard at facilities if proper safety measures are not implemented. This article discusses how carbon adsorber bed fires occur and presents general guidance on safety measures for carbon canisters installed on fixed-roof tanks to reduce the likelihood of a carbon bed fire and to minimize the impact in the event of a fire.     

SO2的生物监测与防治

SO2是我国大气的主要污染物之一，一般大气中的SO2多采用化学法监测，而生物对SO2的监测具有独到的作用，文中就SO2对人类的危害和生物监测及防治进行了初探。     

Status of the DOE/GEESI In-Duct Scrubbing Pilot Study

The recent promulgation of stack height regulations and possible changes in the National Ambient Air Quality Standards for sulfur dioxide and the associated dispersion model methodologies, could require older power plants to develop new compliance strategies and upgrade emission control systems. In such situations, an inexpensive, moderate removal efficiency flue gas desulfurization technology could maintain the cost effectiveness of these plants. Such a technology was selected by the Department of Energy for demonstration in its Acid Rain Precursor Control Technology Initiative. The process applies the rotary atomizer techniques developed for lime slurry dry flue gas desulfurization spray absorbers, and utilizes existing ductwork and particulate collectors. This induct scrubbing technology is anticipated to result in a dry desulfurization process of moderate removal efficiency. The critical elements for successful application are (i) adequate mixing for efficient reactant contact, (ii) sufficient residence time to produce a non-wetting product, and (iii) appropriate ductwork cross sectional areas to prevent deposition of reaction products before drying. The ductwork in many older power plants, previously modified to meet 1970 Clean Air Act requirements for particulate control, usually meets these criteria. A pilot study of the process is now in design-construct phase. Testing will start in 1987 and determine conditions under which the technology would be a cost effective approach to meeting emission reduction design criteria     

聚多巴胺/蒙脱土复合材料对SO2的吸附性能

采用原位插层聚合制备聚多巴胺改性蒙脱土复合材料并研究其SO2吸附性能。对复合材料进行元素分析、红外分析、热稳定性和X射线衍射表征,结果证实,聚多巴胺大分子链不仅在蒙脱土表面包覆改性,同时插层进入蒙脱土层间,增大蒙脱土层间距。讨论SO2起始质量分数、吸附剂用量和吸附温度对单位吸附容量的影响,结果表明,聚多巴胺改性蒙脱土的SO2吸附性能显著提高。在SO2起始质量分数为0.5、吸附剂用量为8 g、吸附温度为125℃时,聚多巴胺改性蒙脱土复合材料的单位吸附容量为1.225 g/g。     

Relationship of Particulate Control,SO2 Removal,and Waste Management

Results with the EPRI 2.5 MW(e) Integrated Environmental Control Pilot Plant (IECPP) indicate the interrelationship of particulate penetration, SO₂ scrubber operation, waste production, and waste properties. Tests compared a fabric filter/wet scrubber and ESP/wet scrubber, the latter operated to simulate 1979 New Source Performance Standards (NSPS), 1971 NSPS, and pre-NSPS ESP units. Tests were conducted with low-sulfur coal producing a flue gas concentration of400ppm; flue gas spiking could be used to increase SO₂ to 2000 ppm. Scrubber waste was dewatered in a thickener and vacuum belt filter (to 55 percent solids content), and mixed with fly ash. The pilot SO₂ scrubber—when preceded by an ESP and forced to operate in zero-discharge—captured less SO₂ than when preceded by a fabric filter. Also, scrubber operation with the ESP produced a greater quantity of waste with difficult handling characteristics, as compared to operation with the fabric filter. These difficulties occurred with particulate penetration above 0.10 lb/MBtu, which could reduce reagent utilization to 80percent. These results are attributable to inhibited limestone dissolution due to accumulation of an aluminum/fluoride compound. For both lowsulfur and simulated high-sulfur test conditions, allowing wastewater discharge to purge aluminum/fluoride content restored performance to design levels. Particulate control efficiency also affected solid waste physical properties. The fabric filter/wet scrubber produced the lowest solid waste permeability (10^?8 cm/s). ESP operation at 1979 NSPS and pre-1971 NSPS ESPs increased solid waste permeability to 10^?7 and 10^?6 cm/s, respectively. These results are meaningful for SO₂ scrubbers both for new plants and for retrofit to units with pre-NSPS ESPs, and could become significant with the increasing trend to restricted water discharge.     

A Study of Sulfur Dioxide in Photochemical Smog I. Effect of SO2 and Water Vapor Concentration in the 1-Butene/NOx/SO2 System

There is an appreciable chemical interaction between SO₂ and photochemical smog which depends on the concentration of SO₂ and water vapor. The rate of decay of SO₂ concentration is greatly increased in the presence of photochemical smog. With 0.75 ppm SO₂, a light-scattering aerosol is produced in dry systems and systems at 22 and 55% relative humidity (RH). Aerosol is not observed until after the NO₂ peak has been reached and the NO concentration has fallen to a very low value. The formation of aerosol corresponds in time to the region of most rapid decrease in the SO₂ profile. In systems at 65% RH or with smaller amounts of SO₂, no light scattering is observed, but the percentage of SO₂ disappearing is greater. In relatively dry systems the presence of SO₂ results in a general slowing down of the photochemical smog reactions. In systems containing water vapor concentrations comparable to those found in the atmosphere, the inhibiting influence of SO₂ on the smog reaction is less pronounced. However, the maximum concentration of oxidant produced by the photochemical smog reactions is significantly lower when SO₂ is present.     

CeO2-CuO/粉煤灰吸附SO2/NO性能分析

利用室温液相浸渍法将粉煤灰制备成CeO2-CuO/粉煤灰,提高了粉煤灰对SO2/NO的吸附效率。采用XRF、XRD、SEM等手段对其进行表征测试,结果表明,粉煤灰的晶相结构主要为石英和莫来石,且改性后表面变得更为粗糙,孔隙增多。利用吸附反应装置优化SO2/NO的反应条件,结果表明：在样品量为0.3 g、温度为50 ℃、SO2流速为8 mL·min-1、O2流速为4?mL·min-1时,CeO2-CuO/粉煤灰对SO2吸附效果最佳;在样品量为0.4?g、温度为70?℃、NO流速为6?mL·min-1、O2流速为4?mL·min-1时,对NO吸附效果最佳。共吸附会降低各自的吸附效率。利用原位FTIR分析表明：SO2在CeO2-CuO/粉煤灰表面主要生成硫酸盐和亚硫酸盐物种;NO则主要生成硝酸盐和亚硝酸盐物种。     

Transferable Discharge Permits for Control of SO2 Emissions from Illinois Power Plants

A large scale simulation model was employed in evaluating various policy alternatives for reducing SO₂ emissions from Illinois electric power plants for a broad range of nuclear power capacity addition scenarios. A dynamic simulation of a transferable discharge permit (TDP) program suggests a market oriented management system can assure an acceptable level of environmental quality while achieving typical cost savings of 40-60 percent over a program based on uniform decreases in existing emission standards. This cost advantage can be realized without any major decline in the demand for coal generally or indigenous coals in particular. Several options for initiating the TDP market are evaluated. The analysis concludes that initiating the market by government sales may not constitute a major financial burden on the electric utilities or their customers.     

Dry deposition of SO2

SO₂ concentration gradient measurements are reported, which have been carried out between May 1975 and September 1976 at the Kernforschungsanlage Jülich. Most of the measurements were made with differential optical absorption spectroscopy.Mirrors at various heights (30, 80, 120m) on the meterological tower were used to reflect the light beam back to the laboratory placed at the ground. In this way absorption paths of about 600m were obtained. In some cases, the optical data were compared with chemical measured concentration profiles (after West & Gaeke. 1976) showing an agreement within ±20%. From simultaneously measured temperature and wind profiles the transfer resistance of the turbulent boundary layer was calculated.Average values of the vertical SO₂-flux obtained from SO₂ concentration gradient and atmospheric transfer resistance varied from about 0.6 μg m⁻²s⁻¹ in winter and 0.1 to 0.4 μg m⁻²s⁻¹ in summer, corresponding to a lifetime for SO₂. if dry deposition is taken as the only sink mechanism, of half a day up to several days, respectively.     

Sensitivity of Native Desert Vegetation To SO2 and to SO2 and NO2 Combined

Interest in air pollution injury to native vegetation has been generated with the construction and planned construction of large coal-fired power plants near the coal reserves in the southwest desert areas of the United States. Since information on the effects of SO₂ on these native species was not available in the literature, fumigation studies were conducted with portable chambers placed over native species in the field with SO₂ and SO₂ + NO₂. Pollutant concentrations were measured and controlled with instruments located in a mobile laboratory. Each fumigation was of two hours duration and the concentration ranged from 0.5 to 11 ppm SO₂ and from 0.1 to 5 ppm NO₂. Concentrations of SO₂ above 2 ppm were required to cause injury to all but a few of the 87 species studied. Many of the native desert species proved to be highly resistant to injury from these gases.