Fossil fuels, sulfur oxides from

The environmental, health, and cultural impacts of acid rain were well documented in the late 20th century. Acid rain results from combustion of the sulfur and nitrogen contents of fossil fuels. Sulfur and nitrogen oxides combine with atmospheric water to form acids. The prevalence of mobile (e.g., automotive and aircraft) sources globally hints at the requirement for control of Title IV compounds and precursors. 

Acid Rain - A term used to describe precipitation that has become acidic (low pH) due to the emission of sulfur oxides from fossil fuel burning power plants. 

Acid deposition occurs when sulfur dioxide and nitrogen oxide emissions are transformed in the atmosphere and return to the earth in rain, fog or snow. Approximately 20 million tons of SOj are emitted annually in the United States, mostly from the burning of fossil fuels by electric utilities. Acid rain damages lakes, harms forests and buildings, contributes to reduced visibility, and is suspected of damaging health. 

The increasing number of atomic reactors used for power generation has been questioned from several environmental points of view. A modern atomic plant, as shown in Fig. 28-3, appears to be relatively pollution free compared to the more familiar fossil fuel-fired plant, which emits carbon monoxide and carbon dioxide, oxides of nitrogen and sulfur, hydrocarbons, and fly ash. However, waste and spent-fuel disposal problems may offset the apparent advantages. These problems (along with steam generator leaks) caused the plant shown in Fig. 28-3 to close permanently in 199T. 

Power plant emissions result from the comhustion of fossil fuels such as coal, gas, and oil. These emissions include sulfur dioxide (SO,), nitrogen oxides (NO.,), particulate matter, and hazardous air pollutants, all of which are subject to environmental regulations. Another emission is carbon dioxide (CO,), suspected of being responsible for global warming. 

Acid rain is caused primarily by sulfur dioxide emissions from burning fossil fuels such as coal, oil, and natural gas. Sulfur is an impurity in these fuels for example, coal typically contains 2-3% by weight sulfur.1M Other sources of sulfur include the industrial smelting of metal sulfide ores to produce the elemental metal and, in some parts of the world, volcanic eruptions. When fossils fuels are burned, sulfur is oxidized to sulfur dioxide (SO2) and trace amounts of sulfur trioxide (SC>3)J21 The release of sulfur dioxide and sulfur trioxide emissions to the atmosphere is the major source of acid rain. These gases combine with oxygen and water vapor to form a fine mist of sulfuric acid that settles on land, on vegetation, and in the ocean. 

A biosorption method for the separation of sulfur compounds from fossil fuels, by using a sulfur-biosorption agent and followed by the oxidation of the biosorbed complex. The oxidation is carried out in an aqueous phase containing an effective amount of oxygen and, optionally a biocatalyst, in which case an incubating stage is incorporated for the reaction to take place. 

Emissions from catalytic reforming (Figure 4.14) include fugitive emissions of volatile constituents in the feed and emissions from process heaters and boilers. As with all process heaters in the refinery, combustion of fossil fuels produces emissions of sulfur oxides, nitrogen oxides, carbon monoxide, particulate matter, and volatile hydrocarbons. 

Acid deposition acid rain a form of pollution depletion in which pollutants, such as nitrogen oxides and sulfur oxides, are transferred from the atmosphere to soil or water often referred to as atmospheric self-cleaning. The pollutants usually arise from the use of fossil fuels. 

Acid rain. Lakes in some areas of the world are now registering very low pH s because of excess acidity in rain. This was first noticed in Scandinavia and is now prevalent in eastern Canada and the northeastern U.S. Normal rainfall is 5.6 (because of CO2 in the air forming H2CO3). However, excessive use of fossil fuels (especially coal) with high sulfur and nitrogen content cause sulfuric and nitric acids in the atmosphere from the sulfur dioxide and nitrogen oxide products of combustion. Some rain in the Adirondack Mountains of upper New York State has been measured with a pH of 3.0. This problem is not specific to the chemical industry but should be of concern to all of us. 

Particulate matter is the term used to describe solid particles and liquid droplets found in the atmosphere. Particulates are produced by a host of natural and anthropogenic sources. Mist and fog are both forms of natural particulates, as are windblown soil, dust, smoke from forest fires, and biological objects, such as bacteria, fungal spores, and pollen. The incomplete combustion of fossil fuels is one of the most important anthropogenic (human-made) sources of particulates. Such processes release unhurned carbon particles, oxides of sulfur and nitrogen, and a host of organic compounds into the air. 

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