Fossil fuels, combustion

Selection of pollution control methods is generally based on the need to control ambient air quaUty in order to achieve compliance with standards for critetia pollutants, or, in the case of nonregulated contaminants, to protect human health and vegetation. There are three elements to a pollution problem a source, a receptor affected by the pollutants, and the transport of pollutants from source to receptor. Modification or elimination of any one of these elements can change the nature of a pollution problem. For instance, tall stacks which disperse effluent modify the transport of pollutants and can thus reduce nearby SO2 deposition from sulfur-containing fossil fuel combustion. Although better dispersion aloft can solve a local problem, if done from numerous sources it can unfortunately cause a regional one, such as the acid rain now evident in the northeastern United States and Canada (see Atmospheric models). References 3—15 discuss atmospheric dilution as a control measure. The better approach, however, is to control emissions at the source. 

Natural gas is attractive as a fuel ia many appHcatioas because of its relatively clean burning characteristics and low air pollution (qv) potential compared to other fossil fuels. Combustion of natural gas iavolves mixing with air or oxygen and igniting the mixture. The overall combustion process does not iavolve particulate combustion or the vaporization of Hquid droplets. With proper burner design and operation, the combustion of natural gas is essentially complete. No unbumed hydrocarbon or carbon monoxide is present ia the products of combustioa. 

Nuclear power plants of the future are to be designed and operated with the objective of better fiilfiUing the role as a bulk power producer that, because of reduced vulnerabiUty to severe accidents, should be more broadly accepted and implemented. Use of these plants could help stem the tide of environmental damage caused by air pollution from fossil-fuel combustion products (64). 

DESIGN CONSIDERATIONS IN FOSSIL FUEL COMBUSTION SYSTEMS... 

W. Bartok and A. F. Sarofkn, Fossil Fuel Combustion A. S ource Book, John Wiley Sons, Inc., New York, 1991. 

Unburnt hydrocarbon (UHC) and carbon monoxide (CO) are only produced in incomplete combustion typical of idle conditions. It appears probable that idling efficiency can be improved by detailed design to provide better atomization and higher local temperatures. CO2 production is a direct function of the fuel burnt (3.14 times the fuel burnt) it is not possible to control the production of CO2 in fossil fuel combustion, the best control is the increasing of the turbine efficiency, thus requiring less fuel to be burnt for the same power produced. 

Continuing dependence on fossil fuels raises several major ethical issues. Ethical questions concerning our responsibilities to future generations arc raised by the fact that fossil fuels are a nonrenewable energy source, so that eveiy barrel of oil or ton of coal burned today is forever lost to future generations. Further, the by-products of fossil fuel combustion pose hazards to both present and future generations. 

Many dozens of industrialized countries now employ nuclear reactors for power generation, and some countries produce more electrical power by nuclear reaction than by fossil fuel combustion (France is an example). The United States, however, has the largest installed capacity of nuclear-powered boiler plants (in the year 2000 there are more than 120 nuclear reactor power plants in the United States). Nuclear power is also widely used for marine duty in both commercial and naval vessels. 

Nitrogen Dioxide (NO2) Is a major pollutant originating from natural and man-made sources. It has been estimated that a total of about 150 million tons of NOx are emitted to the atmosphere each year, of which about 50% results from man-made sources (21). In urban areas, man-made emissions dominate, producing elevated ambient levels. Worldwide, fossil-fuel combustion accounts for about 75% of man-made NOx emissions, which Is divided equally between stationary sources, such as power plants, and mobile sources. These high temperature combustion processes emit the primary pollutant nitric oxide (NO), which Is subsequently transformed to the secondary pollutant NO2 through photochemical oxidation. 

However, with "only" 1000 Pg emitted into the system, i.e. less than 3% of the total amount of carbon in the four reservoirs, the atmospheric reservoir would still remain significantly affected (20%) at steady state. In this case the change in oceanic carbon would be only 2% and hardly noticeable. The steady-state distributions are independent of where the addition occurs. If the CO2 from fossil fuel combustion were collected and dumped into the ocean, the final distribution would still be the same. 

Fig. 11-20 Rate of transfer of carbon to the atmosphere due to fossil fuel combustion according to Rotty (1981).

Bolin, B. and Eriksson, E. (1959). Changes of the carbon dioxide content of the atmosphere and sea due to fossil fuel combustion. In "Atmosphere and Sea in Motion" (B. Bolin, ed.), pp. 130-142. The Rockefeller Institute Press. 

As seen in Table 12-2, global NO production is dominated by anthropogenic sources. In an urban environment, virtually all NO is from fossil fuel combustion. 

Emissions of NOj due to fossil fuel combustion emissions (Tg N/yr) Fertilizer production and usage (TgN/yr) ... 

Delwiche, C. C. and Likens, G. E. (1977). Biological response to fossil fuel combustion products. In "Global Chemical Cycles and Their Alterations by Man" (W. Stumm, ed.), pp. 73-88. Dahlem Kon-ferenzen, Berlin. 

Bertine, K. K. and Goldberg, E. D. (1971). Fossil fuel combustion and the major sedimentary cycle. Science 173,233-235. 

The Use of Electric Induction to Replace Fossil Fuel Combustion... 

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