Coal-fueled Power Research Articles

Power Plant Wind Design Problems and Practices

The wind influences the design, construction, and operation of a coal-fueled power plant in many respects. This presentation explores several design, fabrication, erection, and serviceability problems and practices. Specifically considered are shortcomings of standards with regard to wall panel and fastener design, concerns about fatigue failures at low stress levels and analytical needs for wind-sensitive structures such as steel stacks and transmission poles, requirements for quality control of materials and fabrication (including welding and galvanizing), and the need for attention to structural details for force transfer. Examples are also drawn from design of generation buildings, coal handling and substation structures; construction of silos, cooling towers, and pond liners; and behavior of chimneys and stacks in both along-wide and across-wind directions.

Trace element leaching in bench-scale recirculating ash transport systems

Fly and bottom ash from coal-fired power generating stations are commonly disposed by transporting the ash in a water slurry to a lagoon. The recently developed "Environmental codes of practice for steam electric power generation" recommend the use of recycled lagoon decant water rather than fresh makeup water for these sluicing operations. To provide background information during the development of these environmental codes of practice, bench-scale studies were conducted to simulate the operation of recirculating bottom ash and combined fly/bottom ash lagoon systems, and data were collected on the concentrations of trace elements in the ash sluice waters. The ashes were obtained from seven Canadian coal-fuelled power generating stations. For most ash systems, the pH of the slurry water remained relatively constant after the first two recirculation cycles, and generally was lower in a bottom ash system than in the corresponding fly/bottom ash system. The major dissolved species in the slurry waters were sulphate, calcium, and sodium. Concentrations in bottom ash systems usually increased linearly with increasing cycles of concentration, whereas concentrations in fly/bottom ash systems generally increased during the first several cycles, then either remained constant or decreased. Scaling was observed only in studies involving fly/bottom ash from stations burning western Canadian coal or a mixture of western Canadian and U.S. bituminous coals. Key words: ash handling, fly ash, lagoons, leaching.

Morphologie und Mineralogie der Flugasche von einem Kohlekraftwerk

Morphology, chemical composition and mineralogy of fly ash from a coal-fueled power plant have been investigated. Optical and scanning electron microscopic examinations on both untreated particle samples and thin sections have enabled the investigation of internal and superficial microstructure. Chemical and diffractometric analyses performed on fly ash samples, fractionated by means of magnetic and gravimetric separators, associated the particle morphology to the elemental and mineralogical composition. A classification of single particles was achieved as follows: 1) glassy aluminosilicate with avariable composition; 2) spongy carbonaceous; 3) spherical metallic particles constituted of different iron oxide phases (magnetite, hematite, maghemite); 4) spherical rutile particles; 5) spherical lime particles; 6) mineral formless particles (i.e. quartz and mullite). The mineralogical composition of the coal utilized during instack samplings is also given. Lastly a correlation between the crystalline and amorphous particles constituing the fly ash and the mineral matter present in the burnt fuel has been proposed.

Reliability analysis of a fluidized-bed boiler for a coal-fueled power plant : Thomas G. Woo. IEEE Trans. Reliab.R-29 (5) 422 (December 1980)

Reliability analysis of a fluidized-bed boiler for a coal-fueled power plant : Thomas G. Woo. IEEE Trans. Reliab.R-29 (5) 422 (December 1980)

Legal Problems of Reactor Safety

Nuclear energy has already reached a stage at which it is not only competitive with but superior to other forms of energy in terms of all such factors as economy, reliability, safety, and environmental effects. During the next 25-30 years of nuclear power, there will be no alternative energy source capable of competing with it. The nearly 25 years of experience of operation of nuclear power plants (NPPs) has persuasively demonstrated their economic and ecological superiority over coal-fueled thermal power plants (TPPs). In a number of countries nuclear energy already accounts for a significant share of electric power output. In Switzerland, for example, it accounts for about 20 percent; in England, 15 percent; in West Germany, 12 percent; in the USA, about 10 percent; and in the Common Market countries as a whole, about 10 percent. Approximately the same figures apply to the German Democratic Republic, Bulgaria, Japan, India, and other countries.

Reliability Analysis of a Fluidized-Bed Boiler for a Coal-Fueled Power Plant

This is a reliability study of an experimental fluidized-bed boiler for a coal-fueled plant. The study determined the major contributors to plant outage in terms of equipment failure and plant management. The major problems associated with fluidized-bed development and operation are related to a plant startup and research environment rather than to equipment reliability. Consequently, operations of this experimental facility were continued on the optimistic note that future plant performance could be appreciably improved by modifying operating practices to minimize plant outage attributed to: 1. Prolonged equipment maintenance due to the lack of readily available spare parts. 2. Delayed startup due to performing non-critical preventive maintenance. 3. Minimal repair activity performed on the second and third work shifts or for an entire weekend. 4. Delayed startups after the completion of repairs until a subsequent shift or until the end of a weekend. A clearer understanding of existing system and equipment problems enabled engineering to improve plant availability by: 1. Minimizing coal fines plugging of feed needles by increasing needle diameters from 1.5 to 2.0 inches. 2. Relieving excessive strain on the fuel handling system by eliminating stop and start operation of the coal bucket elevators under full load. 3. Eliminating dependence on outside plant services and facilities sharing host-plant feedwater.

Nuclear Power and Geology of Uranium: ABSTRACT

Nuclear and coal-fueled power plants are the only economically viable large-scale sources of new electrical energy available to man in the next several decades. Even without the ERA-required best-available of stack-gas scrubbers for coal-fired power plants, the total cost to produce electricity from nuclear power plants is clearly less expensive than from coal-fired power plants at most locations in the United States. Current equivalency of electrical-generating costs between coal and nuclear would support a nuclear fuel cost of approximately $100/lb of U3O8 (the 1979 price is $43/lb of U3O8). The present domestic worldwide supply-demand relations indicate a continued strong need for successful uranium exploration and development programs through the next several decades. The economic realities would cause the price of uranium to rise to permit the development of low-grade uranium resources (100 to 500 ppm U3O8) competitively with coal should the discoveries of higher grade uranium resources be insufficient to fulfill the increased demand. Historically (1950s to 1978), the bulk of the world's uranium has been produced from: (1) lower Proterozoic uraninite placer deposits in quartz-pebble conglomerates of braided-river systems, (2) epigenetic uranium deposits in sandstones located at or near groundwater oxidation-reduction interfaces, commonly in close association with organic material in fluvial sandstones, and (3) hydrothermal vein uranium deposits. These three distinctly different geologic environments continue to be important exploration targets in the search for new uranium deposits. Exploration for economic uranium deposits has expanded to many geologic environments which have generally been overlooked in the past. Most notable among these are: (1) granitic uranium deposits (commonly anatectic), (2) alkalic igneous-hydrothermal uraniferous environments, (3) altered acidic or alkalic volcanic ash, ash flow, or volcaniclastic environments, (4) metamorphic-hosted uranium deposits, variously interpreted as a metamorphic-hydrothermal or unconformity-related environment, (5) calcrete uranium deposits in evaporative, desert groundwater environments, and (6) unconformity-related environments. Significant uranium deposits have been discovered in each of these geologic environments in the 1970s. The expanded search for economically viable uranium resources and the improved market and technology factors have caused exploration and development efforts to advance far in recent years. Low-grade uranium resources that have been long known and ignored, such as uraniferous, black, organic-rich shales and marine phosphorites are currently being developed for uranium production. In-situ solution-mining activities have permitted economic exploration of uranium deposits that heretofore have been uneconomic because of their small size, low grade, or depth. Exploration drilling and development activities are expanding to greater depths. End_of_Article - Last_Page 1599------------

Experiences with Identification of Power Plant Dynamics

Dynamic testing was performed on three nuclear power plants and one coal fueled power plant. Low level perturbations were used so as to cause insignificant disturbance to normal power generation and tests were designed to use standard plant hardware and instrumentation in order to minimize costs. The test results were used in identification work that included estimation of parameters in physical models and construction of empirical (black box) models.It was found that certain important performance-related parameters can be identified using physical models if appropriate identifiability conditions are satisfied. Empirical models were found to be simple to generate and low order models were found to be suprisingly capable of predicting plant behavior.

Asthma and air pollution from a coal-fueled power plant.

Asthma and air pollution from a coal-fueled power plant.

Nuclear Power - Social Needs and Benefits

The present severe shortage of electric power plants cannot be ignored. Some alternatives are discussed and the merits of building nuclear plants presented. The environmental effects of nuclear and fossil fuel plants are compared. It is argued that the small but finite risk of living near a nuclear plant is preferable to the certain pollution of a coal-fueled power station.