[en] This paper reports the application of a full three-dimensional mathematical model to a fuel-oil fired power station boiler of the Portuguese Electricity Utility. Special emphasis is placed on the formation of nitric oxide. Models for thermal and fuel-NO formation are included and several variants of the models are employed. The predicted results are compared with measurements. Concentrations of O-2, CO₂ and CO are in good agreement with the data whereas the temperature, although in qualitative agreement, is underestimated along the profile crossing the flame region. It is shown that fuel NO is an important source of the total NO formed. Nevertheless, the NO mole fraction is underestimated. Several hypotheses were checked to identify the source of discrepancy and the most probable ones are the temperature underestimation in the flame region and the experimental uncertainties. (author)

[en] This report describes and summarizes the results of a field evaluation of the comanagement of utility low-volume wastes with high-volume coal combustion by-products at a 1,008-megawatt generating station in the midwestern US. The investigation at this plant, referred to as the SX site, consisted of six elements: identification of waste types and waste handling practices; sampling of individual and comanaged waste streams, geochemical characterization of wastes and porewaters in the comanagement units, site hydrogeologic characterization; groundwater sampling and analysis; and identification of land and groundwater uses in the vicinity of the site. The investigation centered on a 50-acre unlined primary ash pond constructed in 1967, a 46-acre lined secondary ash pond constructed in 1993, and surrounding areas. Historically, all coal combustion wastes were disposed of in the primary ash pond. Currently, bottom ash, economizer ash, boiler slag, drain sump wastes, and bottom ash tank overflow are conveyed to the primary ash pond. Fly ash, air heater wash water, coal area runoff, and demineralizer regenerant are conveyed to the secondary ash pond. The investigation concluded that there were no effects of comanagement observed because the low-volume wastes were either dilute in chemical composition or were volumetrically insignificant. Groundwater samples collected proximate to the unlined primary ash pond showed elevated levels of SO₄ and B due to high-volume by-products. No effects on groundwater quality from high-volume by-products, low-volume wastes, or comanaged wastes residing in the secondary ash pond were observed

[en] In this paper we have studied the visibility of exhaust smoke from the stack of a coal fired power plant. First, it was shown that using numerical simulations based on the Mie scattering theory, particles in exhaust smoke strongly contribute to the scattering phenomenon of light, and it was clarified that particles of 0.5 μm in size are very visible to human eyes when the visibility influences to the human sense of vision are taken into consideration. Subsequently, we measured exhaust smoke emitted from the stack of a coal-fired power plant and analyzed dust particles contained in the exhaust gas. The results showed that two different 0.5 μm in size particles of the fly ash component and the sulphur component are contained in the exhaust gas from the coal-fired boiler. Finally, it was shown that the use of the differences in color contrast parameter (ΔE) used on the color management filed can be most suitable to qualitative assessments of correlations between the smoke visibility and dust concentrations. These ΔE refer to the analyzed results on the dust concentrations, particle sizes and their properties, image data taken by video cameras throughout all the seasons and the simulation data, relative to exhaust smoke from the 1000 MW coal-fired boiler at Soma Power Plant in Japan, and these ΔE showed a good agreement with the empirically known values. The conclusions of this paper showed that the numerical simulations based on the Mie scattering theory and ΔE are useful methods to deal with the issue on visible smoke. 9 refs, 14 figs, 2 tabs

[en] The aim of the study on the title subject is to show that salmonides in a simulated cooling water outlet area of an electric power plant along the river Rhine do not experience long-term or permanent negative consequences of their presence in the heated water. Laboratory experiments were carried out with 'test trouts'. The water in which the trouts were kept was heated up from 9C to 16C in 30 minutes. The temperature of 16C was maintained for 3 hours. After the heating up skin samples were taken at different periods for 35 days. Histochemical and electron microscopic investigations were carried out. The short term increase of the water temperature clearly effected the ultrastructure of the fish. The changes in the epidermis did not recover within 35 days. It is suggested that a number of the found cellular reactions can be used as indicators for environmental stress. These reactions concern the production of lysosomes and the migration of macrophages in the epidermis. No serious effects as skin decomposition and an excess of mucous secretion were found

[en] Literature estimates for worldwide anthropogenic mercury (Hg) emissions range from 900 to 6200 t/yr. EPA recently estimated that US electric utilities emit about 93 t/yr. EPRI, DOE, and others have recently conducted field measurements to better quantify electric utility emissions of Hg and other trace substances. Hg emissions inventories based on these recent measurements indicate that total electric utility Hg emissions are about 40 t/yr - about half of these previous estimates. Furthermore, the results have indicated that Hg emissions are quite variable and are not consistently captured by conventional air pollution control technologies - electrostatic precipitators, fabric filters, and flue gas desulfurization systems. 12 refs., 5 figs., 4 tabs

[en] The Electric Power Research Institute (EPRI) and the United States Environmental Protection Agency (EPA) have carried out joint tests for validation of EPA (Draft) Method 29 ('multi-metals method') for measurement of mercury (Hg) and other selected metals in the stack gas of a coal-fired electric utility. The tests were performed according to the analyte spiking procedure of EPA Method 301 protocol for the field validation of stationary source emission measurements. Several other Hg measurement methods were also employed during the tests to provide a comparison to the Method 29 measurements; these include EPA Method 101A, the Hazardous Element Sampling Train (HEST), and two solid sorbent methods, one using activated charcoal and the other using iodated carbon traps in series with soda lime traps. Results indicate reasonably good agreement between the total Hg measurements by the different methods. 7 refs., 1 fig., 2 tabs

[en] In response to challenges from technologies such as IGCC and PFBC, the ABB LEBS Team has proposed removing the barriers to very large advances in environmental and thermal performance of pulverized coal plants. Pulverized coal will continue to be the source of more than half of our electric generation well into the next century and we must develop low-risk low-cost advances that will compete with the claimed performance of other technologies. This paper describes near-term PC technologies for new and retrofit applications which will accomplish this

[en] In coal-fired electricity generation, much can be achieved with current technologies. Modern designs offer levels of efficiency and economy in advance of older plant in many developing countries - the steady construction of such plant to meet new demand, and to replace plant at the end of its life, will greatly reduce emissions. Such technologies can be resourced by the human and financial means available to most countries. Newer technologies are under development, with the world's first commercial units now being commissioned. These technologies will undoubtedly undergo development and cost improvement over the next decade, leading to world-wide application. (author)

[en] Air-polluting emission rates and energy-efficiency ratings vary widely among power plants, depending on location, age and whether the power plant is repowered. Traditional regulations require installation of specified emission control equipment that varies among power plants. These regulations do not specify that utilities first dispatch the cleanest power plants as demand varies from peak to off-peak periods. This empirical analysis shows, for 2 years out of 20, that demand-side management (DSM) programs increase air pollution. One reason for this result is that regulations require installation of specific emission-control technology but do not provide the incentive to take actual emissions or their air quality impacts into account when operating the system. For certain types of air pollutants and in some regions, regulatory programs now include markets for tradable emission credits. Such programs may alter this incentive. (author)

[en] The challenge of the USA Agreement to reduce its emissions of greenhouse gases, especially carbon dioxide by 2010, is estimated to require 37% reduction over what it might have been. It is heavily dependent on international carbon permit tradings being implemented soon. New technologies are also very important, particularly energy efficiency, low carbon and renewable energy technologies. (UK)