Fossil fuel combustion energy from

Also, by the very nature of chemical transformations, there are almost always unused chemicals remaining. These chemical leftovers include contaminants in the raw materials, incompletely converted raw materials, unavoidable coproducts, unselective reaction by-products, spent catalysts, and solvents. There have long been efforts to minimize the production of such waste products, and to recover and reuse those that cannot be eliminated. For those that cannot be reused, some different use has been sought, and as a last resort, efforts have been made to safely dispose of whatever remains. The same efforts apply to any leftovers from the production of the energy from the fuels produced or consumed by the processing industries. Of particular immediate and increasing concern are the potential detrimental effects of carbon dioxide emissions to the atmosphere from fossil fuel combustion, as discussed further in Chapters 9 and 10. 

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. 

On the global-scale, the destruction of ozone by halocarbons was addressed in the U.S. by banning chlorofluorocarbons in aerosol products. The release of carbon dioxide to the atmosphere from fossil fuel combustion wil1 continue well into or through the twenty-first century. Energy requirements of nations of the temperate zone will require combustion of gas, oil and coal and the atmospheric burden of carbon dioxide will continue to increase with uncertain consequences. 

Figure 1.11, prepared by the U.S. Energy Information Administration, describes the global carbon cycle. It provides data that was collected in 2001. Since that date, the yearly anthropogenic carbon emissions (measured in carbon equivalent terms) increased from 6.3 to about 9 billion metric tons (over 1 ton per capita in the world). In November 2007, the National Academy of Science reported actual emissions for 2006 as 8.4 billion tons. Carbon equivalent means that the emission of 3.7 tons of COz is counted as the emission of 1 ton of carbon, so the 8.4 billion tons per year of carbon that enters the atmosphere owing to fossil fuel combustion corresponds to 33 billion tons per year of C02 because of the molecular weight ratio of COz to carbon (44/12). 

The requirements for combustion control of incinerators used for disposal of toxic materials are far more severe than for combustors burning more conventional fuels. Whereas a combustion efficiency of 99% may be quite acceptable for a fossil-fuel-fired energy conversion system, the carryover of 1 % of the feed from an incinerator results in an unacceptable release to the environment. 

The urban heat island effect has implications for chemical emissions in several ways. Elevated temperatures increase the consumption of energy for air conditioning and other cooling systems, with attendant increases in fossil fuel combustion-related contaminants (Cardelino et al., 2001 Adams, 1999). Increased ambient air temperatures also increase volatilization of POPs such as PCBs, PCNs and PBDEs from urban sources (Priemer and Diamond, 2002 Helm and Bidleman, 2003). 

Economic and social research on the factors which will determine future emissions of carbon dioxide. This should include the probable rise of future rates of world energy use and the future misuse of energy sources — that is, the ratio of energy from fossil fuel combustion to that from other energy sources. Also needed are better estimates of possible future changes in the areas of forests. 

TABLE 1.9 Carbon Dioxide Generated from Fossil Fuel Combustion by World Region and the 10 Highest Energy-Consuming Countries"... 

The consumption of fossil fuels is not sustainable. With business as usual, the proven and economically recoverable fossil reserves will be exhausted in little more than 100 years. Substitution of fossil fuels is therefore required anyway on the long term. If CO2 emission from fossil fuel combustion is responsible for adverse climate changes like global wanning, substitution is desirable on the short term. The share of the renewable energy sources like wind, hydropower and biomass may be increased in a relatively short time. Each of these traditionally well known sources can contribute a... 

The chemical industry is a major energy user (7 percent of world energy use in 1998) (IEA, 2000), and yet it contributes only 4 percent of overall emissions of CO2 from fossil fuel combustion (IEA, 1999). However, when compared to other industries (e.g., pulp and paper contributes just 1 percent), the chemical industry in OECD17 countries is a major industrial emitter of CO2. Over the last 15 years,... 

The combustion of fossil fuels releases energy as well. This energy is in the form of heat, and carbon dioxide and water are formed as the bonds in the fossil fuel rearrange themselves during the combustion reaction. Coal, petroleum, and natural gas are known as fossil fuels and are formed from the decay of living matter. 

---