Association with coal burning

Industrial-type smog is often associated with (coal burning/sunlight). 

A comparison of the characteristics associated with propellant burning, explosive detonation, and the performance of conventional fuels (see Coal Gas, NATURAL Petroleum) is shown ia Table 1. The most notable difference is the rate at which energy is evolved. The energy Hberated by explosives and propellants depends on the thermochemical properties of the reactants. As a rough rule of thumb, these materials yield about 1000 cm of gas and 4.2 kj (1000 cal) of heat per gram of material. 

Because sulfuric acid is a strong acid, it is a more potent weathering agent than carbonic acid. By serving as a source of H (aq), sulfuric acid is transformed into SO Caq). The oxidation of pyrite is responsible for 11% of the sulfete in river water, with pollution now contributing 54%. The latter is largely associated with the burning of sulfur-rich coal. 

One of the main problems associated with the burning of fossil fuels is that even though they are abundant in Earth s crust, they are also finite. Fossil fuels originate from ancient plant and animal life and are a nonrenewable energy source—once they are all burned, they cannot be replenished. At current rates of consumption, oil and natural gas supplies will be depleted in 50 to 100 years. While there is enough coal to last much longer, it is a dirtier fuel (it produces more pollution) and, because it is a solid, is less convenient (more difficult to transport and use) than petroleum and natural gas. 

Concern over the release of hazardous trace elements from the burning of coal has been highlighted by the 1990 Clean Air Act Amendments. Most toxic elements are associated with ash-forming minerals in coal (5). As shown in Table 1, levels of many of these toxic metals can be significantly reduced by physical coal cleaning (6). 

NO, emissions are less dependent on the type of coal burned, and two oxidation mechanisms are associated with the release of NO, into the atmosphere during the combustion process. Thermal NO results from the reaction of nitrogen in the comhustion air with excess oxygen at elevated temperatures, and fuel NO., is a product of the oxidation of nitrogen chemically hound in the coal. 

Sulphur attack on nickel-chromium alloys and nickel-chromium-iron alloys can arise from contamination by deposits resulting from the combustion of solid fuels, notably high-sulphur coals and peat. This type of corrosion, which has been observed on components of aircraft, marine and industrial gas turbines and air heaters, has been associated with the presence of metal-sulphate and particularly sodium sulphate arising directly from the fuel or perhaps by reaction between sodium chloride from the environment with sulphur in the fuel. Since such fuels are burned with an excess of air, corrosion occurs under conditions that are nominally oxidising although the deposits themselves may produce locally reducing conditions. 

Potential environmental hazards associated with solid residues arising from coal-burning power stations (Donahoe 2004 Glasser 2004 Groppo et al. 2004 Spears Lee 2004 Tishmack Burns 2004). 

T oxic elements are present in trace quantities in coal and other fossil fuels. Since enormous quantities of these fuels are consumed each year, appreciable quantities of the associated, potentially harmful toxic elements are produced. For example, if 600 million tons of coal are burned each year in the U.S. with average concentrations (ppm) of Hg-0.10, Pb-20, Cd-0.4, As-5, Se-5, Sb-4, V-25, Zn-200, Ni-100, Cr-20, and Be-2, the corresponding tonnages of the elements released are Hg-60, Pb-12,000, Cd-240, As-3000, Se-3000, Sb-2400, V-15,000, Zn-120,000, No-60,000, Cr-12,000, and Be-1200. (The concentrations are representative of values measured for coal burned at the Allen Steam Plant.)... 

The results from a test may also be used as an indication of the caking characteristics of the coal when it is burned as a fuel. The volume increase can be associated with the plastic properties of coal coals that do not exhibit plastic properties when heated do not show free swelling. It is believed that gas formed by thermal decomposition while the coal is in a plastic or semifluid condition is responsible for the swelling. The amount of swelling depends on the fluidity of the plastic coal, the thickness of bubble walls formed by the gas, and interfacial tension between the fluid and solid particles in the coal. When these factors cause more gas to be trapped, greater swelling of the coal occurs. 

Air emissions testing data from five facilities were evaluated for this report. The results are summarized here, by pollutant. The most extensive testing was performed by WP L, who tested criteria pollutants, heavy metals, dioxins and furans, and other organic compounds. Table 6-2 summarizes test data for all criteria pollutants at WP L.18 Ohio Edison tested particulate, S02, NOx, and lead emissions results from this whole tire test are provided in Table 6-3.12 Illinois Power tested PM, metals, and S02 their emissions data are summarized in Table 6-4.4 In 1979, United Power Association performed two TDF tests at their Minnesota facility, and conducted air emissions tests during the first test burn for particulate, NOx, SOz, sulfuric acid, and chloride.17 These emission results are summarized in Table 6-5.17 Northern States Power tested TDF in their wood-fired utility boiler in 1982, without much success.9 Their emissions data are summarized in Table 6-6.9 Comparisons of the data from these plants are provided in the pollutant specific discussions that follow the Northern States Power data are not included with graphical summaries of the other four facilities, because its boiler is wood fired, while the other four co-fire the TDF with coal. 

CDDs are released into the air in emissions from municipal solid waste and industrial incinerators. Exhaust from vehicles powered with leaded and unleaded gasoline and diesel fuel also release CDDs to the air. Other sources of CDDs in air include emissions from oil- or coal-fired power plants, burning of chlorinated compounds such as PCBs, and cigarette smoke. CDDs formed during combustion processes are associated with small particles in the air, such as ash. The larger particles will be deposited close to the emission source, while very small particles may be... 

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