Power plants emissions minimization

Heat recovered from process off-gas as high-pressure steam can be used for drying the feed material or for electricity generation, reducing the demand for electricity from power plants and minimizing green house gas emissions. 

Sulfur pollutants. The principal means of minimizing SO2 release is by scrubbing power-plant emissions with limestone. Another method reduces SO2 with methane, coal, or H2S, and the mixture is converted catalytically to sulfur, which is sold as a byproduct ... 

Dust (especially from industrial activities) and salt spray will also exacerbate atmospheric corrosion (Section 16.4). In enclosed industrial premises, atmospheric corrosion could be minimized by preventing noxious emissions, filtering the air to remove particulate matter, and scrubbing the air with water to remove SO2 and other objectionable gases, although the humidity should itself be kept as low as possible (e.g., steam leaks should not be tolerated). On the global scale, however, the cost to the public of atmospheric corrosion could be substantially reduced by sharply limiting SO2 and, to a lesser extent, NO. emissions from power plants, smelters, automobiles, and other industrial functions. This is an aspect of the acid rain threat (Chapter 8) that is usually overlooked. 

Most bulk coal transportation is by rail, with trucks used for local transport. For reasons of economics, most of the world s coal consumption is in power plants located nearby coal mines, which minimizes the necessity for long-distance transportation. More than 60 percent of the coal used for power generation worldwide is consumed within 50 km of the mine site. In the United States, the average distance that coal is shipped by rail is farther, at about 800 miles. That distance has increased in recent years owing to the move toward greater use of coals with lower sulfur content (found mainly in the West) to meet sulfur oxide emissions standards in plants located mainly in the South and the East. As coal is currently shipped over great distances in the United States,... 

TJ eduction in SO2 emissions from coal-burning power plant stacks is essential to minimize atmospheric pollution from this source. Projections of energy demand show that by 1980 coal will account for about 25 million tons of total sulfur oxides output, mostly SO2, unless effective control methods are developed. 

Besides, new combustion conditions increasingly being specified in order to minimize NOx emissions in power plant stack gases result in increased carbon content in the fly ash produced under these new conditions. This further restricts the types and amounts of fly ash that can be utilized as a filler, and decreases commercial applications of coal combustion fly ash even more. Therefore, many methods have been developed to remove carbon particles from the fly ash and minimize the adverse effects of the carbon on characteristics of the filler materials. These methods include chemical combustion, gravitational, flotational, electrostatic, magnetic, and mechanical means, and combinations of these [12-19]. 

You have been asked to formulate the problem of determining the best location for a new power plant from the standpoint of minimizing the average yearly exposure of the population to its emissions of SO2. Assume that the long-term average concentration of SO2 downwind of the plant can be fairly accurately represented by the Gaussian plume equation. Let (X Y, Z ) be the location of the source in the (a, z ) coordinate system. Assume that... 

Sensor-enabled feedback control makes it possible for combustion processes to operate at peak efficiency, maximizing energy output and minimizing pollutant emissions. It is estimated that yearly savings of 409 million could be enabled through combustion optimization within coal-fired power plants alone [25]. For optimal combustion, the levels of oxygen need to be carefully controlled and thus oxygen sensors are used extensively in the power and transportation industries. 

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