Industrial process sources sulfur oxides

Controlling the Industrial Process Sources of Sulfur Oxides... 

A substantial portion of fhe gas and vapors emitted to the atmosphere in appreciable quantity from anthropogenic sources tends to be relatively simple in chemical structure carbon dioxide, carbon monoxide, sulfur dioxide, and nitric oxide from combustion processes hydrogen sulfide, ammonia, hydrogen chloride, and hydrogen fluoride from industrial processes. The solvents and gasoline fractions that evaporate are alkanes, alkenes, and aromatics with relatively simple structures. In addition, more complex... 

The paper pulping industry is reportedly not, in total, a very large emitter of sulfur oxides, although individual plants may present local problems. Kraft mills emit more malodorous reduced sulfur compounds, whereas sulfite mills are more important as emitters of sulfur dioxide. The pulping processes (particularly sulfite) are most interesting because the chemical recovery cycles use basic chemistry that could well be applied to recovery of sulfur dioxide and sulfur from the flue and process waste gases of other types of sources. 

Sulfur oxides, mainly SO2, are common contaminants in PEM fuel cell air streams. About 99% of the sulfur dioxide in the air comes from human sources [95,96], the main one being industrial activities that process sulfur-containing materials, e.g., electricity generation from coal, oil, or gas that contains sulfur. Some mineral ores also contain sulfur, and sulfur dioxide is released when they are processed. Sulfur dioxide is also present in motor vehicle emissions as a result of fuel combustion, and, thus, occurs in high concentrations in urban areas with heavy traffic. 

Sulfur oxides SOj in the air is almost entirely from human sources, including the main sources of electricity generation, fossil fuel combustion, and industrial processes sub-ppm levels SO can strongly adsorb on the Pt surface, blocking active sites for the ORR resulting in kinetic losses High potentials are required to remove the adsorbed sulliir species, and recovery can be slow or incomplete... 

Man-made sources The burning of coal and oil accounted for virtually all the sulfur oxides emitted from man-made sources in the eastern U.S., about 30.6 million tonnes (calculated as sulfate) in 1980. (Table 2). (Emissions are estimated from the sulfur content of each type of fuel and the amount of fuel consumed.) Electric utilities contributed 71% of the total SO2, with the majority of emissions coming from coal-fired power plants. The remainder came chiefly from industrial, commercial and residential combustion transportation smelters and industrial processes. An additional 2.1 million tonnes entered the U.S. from Canada, principally emissions from metal smelters,- and 1.2 million tonnes entered the region from the western U.S. ... 

Phenol is the major source of Bakelite and phenol resins, which are utihzed in many commodities worldwide phenol is also used as reagent for syntheses of dyes, medicines and so on. The industrial demand for phenol has increased every year and its production now exceeds 7.2 megaton year 94% of the worldwide production of phenol is processed in the cumene process. The cumene process involves the reaction of benzene with propene on acid catalysts like MCM-22, followed by auto-oxidation of the obtained cumene to form explosive cumene hydroperoxide and, finally, decomposition of the cumene hydroperoxide to phenol and acetone in sulfuric acid (Scheme 10.3) [73],... 

The principal cause of acid rain is the combustion of fossil fuels that produce sulfur and nitrogen emissions. The primary sources are electrical power plants, automobiles, and smelters. Power plants produce most of the sulfur emissions and automobiles most of the nitrogen emissions. Other sources of acid rain include nitrogen fertilizers, jet aircraft, and industrial emissions. Just as in our discussion of ozone, numerous reactions are involved in the formation of acid rain. The process can be understood by considering the transformation of sulfur and nitrogen oxides into their respective acidic forms sulfuric acid and nitric acid. Sulfur, present up to a few percent in fuels such as coal, is converted to sulfur dioxide when the fuel is burned. The sulfur dioxide reacts with water to produce sulfurous acid, H,SO ,, that is then oxidized to sulfuric... 

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