Atmospheric emissions operating conditions

Coal combustion is a major source of particulate emissions into the atmosphere, especially of particles 0.1 to 5 pm in diameter [9]. Certain toxic elements, e.g., As, Se, Sb, and Zn, are preferentially concentrated in the smaller sizes. The characteristics of coal combustion aerosols depend on a number of factors, such as the type, properties, and size of the parent coal and the furnace design and operating condition. 

Metallic mat gas combustion occurs in operating conditions (i.e., premixed combustion with large excess air), which do not allow particle formahon. Flowever local conditions, far from the ideal ones, and metal catalytic effects could promote the undesirable formation of particulate matter and its emission in the atmosphere. 

Reduced polluting emissions to the atmosphere occur during start-up, due to the rapid attainment of operating conditions and during shut down as a result of the relatively small amount of waste in the bed. 

Dryers are one of the major sources of atmospheric emissions in industrial operations as the majority of industrial dryers operate in an open-cycle systan. A drying installation may cause air pollution by the emission of dust, gases, and odors. Even plumes of clean water vapor are unacceptable in some areas. The nature of the emissions is determined by the material being dried and the operating conditions. As no such... 

In principle, all metallic elements can be determined by plasma emission spectrometry. A vacuum spectrometer is necessary for the determination of boron, phosphorus, nitrogen, sulfur, and carbon because the emission lines for these elements lie at wavelengths less than 180 nm, where components of the atmosphere absorb radiatjon. The usefulness for the alkali metals is limited by two difliculties (1) the compromise operating conditions that can be used to accommodate most other elements are unsuited for the alkalis, and (2) the most prominent lines of Li, K, Rb, and Cs are located at near-infrared wavelengths, which lead to detection problems with many plasma spectrometers that arc designed primarily for ultraviolet radiation. Because of problems of this sort, plasma emission spectroscopy is generally limited to the determination of about 60 elements. 

Volatile cyanides occur only occasionally in the atmosphere, due largely to emissions from plating plants, fumigation, and other special operations (Towill et al. 1978). Under normal conditions, cyanide has relatively low persistence in air, usually between 30 days and 1 year (Way 1981), although some atmospheric HCN may persist for up to 11 years (Marrs and Ballantyne 1987). Data are lacking on the distribution and transformation of cyanide in the atmosphere (Towill et al. 1978) and should be acquired. 

The Impact of North American Emissions on the Composition of the Atmosphere over the Western Atlantic Ocean. As part of WATOX-82 (August 1982) and WATOX-83 (January and February 1983), General Motors Research Laboratories operated air-monitoring sites on the Atlantic coast near Lewes, Delaware, and on the southwest coast of Bermuda, 1250 km to the southeast of the Delaware site. Their overall purpose was to study the transformations of the principal acid-precipitation precursors, NOx and SOx species, as they were transported under conditions not complicated by emissions from local sources. Three papers have resulted from this study (16. 17. 18). 

---