Atmospheric emission control

A UN-ECE Protocol of heavy metal atmospheric emissions control was signed in 1998. This document designated cadmium (Cd), mercury (Hg) and lead (Pb) as first priority toxic elements. In point of fact the Protocol, in contrast to others as far as the water, soil or sediment pollution with heavy metal is concerned, is the unique Screen of atmosphere protection. Legislation does not yet exist for other elements with respect to defining the atmospherie pollution by heavy metals. It is left to each country to respect and to protect the atmosphere from pollution through heavy metals. 

Waste disposal and mining activities are characteristic point sources for environmental pollutants in air, vater, and soil (Table 9.3). Waste incineration typically releases more volatile metals such as mercury, cadmium and lead into the atmosphere emission control, therefore, is not only crucial for smelting activities, but also the decisive prerequisite for all technologies involving higher temperature and vaste materials. Landfill leachates are enriched... 

The air pollution problems associated with combustion of coal are of major concern. These problems generally occur away from the coal mine. The problems of atmospheric emissions due to mining, cleaning, handling, and transportation of coal from the mine to the user are of lesser sigruficance as far as the overall air pollution problems are concerned. Whenever coal is handled, particulate emission becomes a problem. The emissions can be either coal dust or inorganic inclusions. Control of these emissions can be relatively expensive if the coal storage and transfer facilities are located near residential areas. 

Most petrochemical processes are essentially enclosed and normally vent only a small amount of fugitive emissions. However, the petrochemical processes that use air-oxidation-type reactions normally vent large, continuous amounts of gaseous emissions to the atmosphere (10). Six major petrochemical processes employ reactions using air oxidation. Table 30-5 lists the atmospheric emissions from these processes along with applicable control measures. 

Alfalfa dehydration is carried out in a direct-fired rotary dryer. The dried product is transported pneumatically to an air cooler and then to a collecting cyclone. The collected particles are ground or pelletized and then packaged for shipment. The major atmospheric emission from the process is particulate matter, which is controlled by baghouses. Odors may also be a problem, but they disperse rapidly and are no longer a problem at distances of over 1 km. 

Control of atmospheric emissions from petroleum refining can be accomplished by process change, installation of control equipment, and improved housekeeping and maintenance. In many cases, recovery of the pollutants will result in economic benefits. Table 30-26 lists some of the control measures that can be used at petroleum refineries. 

Details of any proposed release of prescribed substances and an assessment of the environmental consequences of emissions. (Eor local authorities air pollution controlled processes this applies only to atmospheric emissions.)... 

See also Acid Ram Air Quality, Indoor Atmosphere Automobile Performance Climatic Effects Emission Control, Vehicle Emission Control, Power Plant Environmental Economics Environmental Problems and Energy Use Gasoline and Additives Transportation, Evolution of Energy Use and Turbines, Gas. 

The process will adversely affect air quality by releasing nitrogen oxides, sulfur oxides, carbon monoxides and other particulates into the atmosphere. Better control of the conversion conditions and better control of emissions can make the process cleaner, yet technology cannot do anything to curb carbon emissions. Since much of the carbon in coal is converted to carbon dioxide in the synthesis process, and is not part of the synthetic fuel itself, the amount of carbon dioxide that will be released to the environment during combustion is 50 to 100 percent more than coal, and around three times more than natural gas. 

In very extreme cases, total containment can be provided to prevent any atmospheric emission or to provide a surge volume for controlled flaring, absorption, or other disposal methods. This approach, however, requires use of a very large pressure vessel to provide the required volume, and is usually only a last choice alternative. 

Matheson, D.H. Elder, F.C., Eds. Atmospheric Contribution to the Chemistry of Lake Waters, J. Great Lakes Res., Suppliment 2, pp 225. National Academy of Science, Air Quality and Stationary Source Emission Control, Comm, on Nat. Resources, National Academy of Sciences, National Research Council, U.S. Gov t Print. Office, Washington, DC, 1975. Whelpdale, D.M. (Chair) Long-Range Transport of Air Pollutants A Summary Report of the Ad Hoc Committee, Atmospheric Environment Service, Environment Canada, Downsview, Ontario, 1976. 

Processes for the control of atmospheric emissions are summarized in Table 17.9. Some of these involve the types of chemical engineering operations referred to in Chapter 7 the added complications are ... 

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