Solid wastes coal combustion

EXPOSURE ROUTES leaded gasoline combustion combustion of solid waste, coal, and oils emissions from iron and steel production lead smelters tobacco smoke food and soil lead-based paints flaking paint paint chips weathered paint powder drinking water pipes, solder, and fixtures lead smelting and refining industries steel and iron factories gasoline stations battery manufacturing plants... 

Figure 8.7 PCDD/F I-TEQ (pg/g) values of flue gas after the combustion of lignite coal, solid waste, and PVC in the samples without inhibitor and 19 different compounds used with a 10% inhibitor of the fuel. (From M. Pandelova et al.. Environ. Sci. Technol, 2005.)...

Cresols have been identified as components of automobile exhaust (Hampton et al. 1982 Johnson et al. 1989 Seizinger and Dimitriades 1972), and may volatilize from gasoline and diesel fuels used to power motor vehicles. Vehicular traffic in urban and suburban settings provides a constant source of cresols to the atmosphere. Hence, urban and suburban populations may be constantly exposed to atmospheric cresols. Cresols are also emitted to ambient air during the combustion of coal (Junk and Ford 1980), wood (Hawthorne et al. 1988, 1989), municipal solid waste (James et al. 1984 Junk and Ford 1980), and cigarettes (Arrendale et al. 1982 Novotny et al. 1982). Therefore, residents near coal- and petroleum-fueled electricity- generating facilities, municipal solid waste incinerators, and industries with conventional furnace operations or large-scale incinerators may be exposed to cresols in air. People in residential areas where homes are heated with coal, oil, or wood may also be exposed to cresols in air. 

Anaerobic digestion to methane, on-site combustion, mixing with coal to form solid fuel Direct combustion, can utilize carbon dioxide from industrial flue gas, can grow in municipal waste facilities... 

A minor part of mined fossil fuels is used as a raw material for the chemical industry (e.g., plastics, synthetic fabrics, carbon black, ammonia, and fertilizers). The major part supplies the energy needs for modem society. Fossil fuels supply about 86% of global primary energy consumption (39% oil, 24% coal, and 23% natural gas), providing energy for transportation, electricity generation, and industrial, commercial, and residential uses (El A 2001). Coal, and to a lesser extent oil, combustion leaves a significant amount of solid waste. The treatment of solid waste from fossil fuel combustion is treated in different chapters of this book. In this chapter we focus on air emissions of fossil fuel combustion, and their impact on human health and the environment. 

The description of the workings of the control technologies is beyond the scope of this article. However, it is worth noting that many of these technologies create substantial amounts of solid or liquid waste that needs to be disposed of properly. For example, in the USA the total amount of fly ash produced from coal combustion alone is about 57 Mt/y (Kalyoncu 2000). About one-third is utilized as secondary raw material (e.g., for aggregate and asphalt), but the rest is usually disposed of in landfills. The wet and dry scrubbers for S02 control produce a sludge or dry waste that finds little secondary use, and a large amount is disposed in landfills. 

EPA 1988. US Environmental Protection Agency Report to Congress Wastes from the Combustion of Coal by Electric Utility Power Plants. Office of Solid Waste and Emergency Response, Washington, DC. Report No. EPA/530-SW-88-002. 

Some industries that produce large amounts of combustible solid wastes have used such materials to augment solid fuels, such as coal, to generate utility steam and hot water. See article on Wastes as Energy Sources. 

There is a large class of industrially important heterogeneous reactions in which a gas or a liquid is brought into contact with a solid and reacts with the solid transforming it into a product. Among the most important are the reduction of iron oxide to metallic iron in a blast furnace the combustion of coal particles in a pulverised fuel boiler and the incineration of solid wastes. These examples also happen to be some of the most complex chemically. Further simple examples are the roasting of sulphide ores such as zinc blende ... 

Aluminum is the third most abundant element in the soil, constituting about 8% of the minerals (Rosseland et al. 1990). This element can be released naturally by the weathering of aluminum-containing rocks. Aluminum is also released to soil as a major constituent of many mining wastes and is also contained in solid wastes from coal combustion and aluminum reduction and other metal processing operations (Gablerand Stroll 1983 Krishnaswamy 1984). 

A positive result of TDF use in waste wood boilers is that facilities are able to bum sludge and waste wood more successfully, decreasing the likelihood of solid waste disposal problems. Results from a series of waste wood boiler performance tests using ASMS codes concluded that use of TDF supplementally in hog-fuel boilers enhances combustion of wood waste, and enables disposal of biological sludge in conjunction with wood waste without necessitating use of other fossil fuels such as coal.2 No applicable environmental limits were exceeded during these tests.2... 

Currently, CDDs are primarily released to the environment during combustion of fossil fuels (coal, oil, and natural gas) and wood, and during incineration processes (municipal and medical solid waste and hazardous waste incineration). While incineration may be the primary current source of release of CDDs into the environment, the levels of CDDs produced by incineration are extremely low. CDDs are associated with ash generated in combustion and incineration processes. 

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