Nonrenewable fuels

The resultis given inFigure 13.7 for an assumed ratio of T0/T, = 0.5, that is, an ordinary power station. For a renewable fuel / is close to 0 and the optimal efficiency is 0.3 as opposed to the Carnot value of 0.5. For a costly nonrenewable fuel such as natural gas with/ = 0.5 (i.e., 50% of all costs are spent on fuel), the optimal efficiency is 0.35, so around 15% better, although possible environmental costs related to the emission of waste have been ignored (although we should not exclude environmental costs for renewable fuel beforehand). Figure 13.8 depicts how the situation improves when Tu the temperature of the heat source, increases. Nevertheless, the trend that nonrenewable fuels are more favorable appears to persist, however, under the same restriction as just mentioned. By the way, this optimum, which we call the economic optimum, is also known as the thermoeconomic optimum and the analysis with which it was obtained is known as thermoeconomic analysis. 

In a handbook such as Szargut et al. [31], these values are tabulated and the exergy values of XO and X are found, for example, to be 50 and 440kJ/mol, respectively. So this reaction requires an amount of exergy of at least some 390kJ/mol product. Usually, this is supplied by a nonrenewable fuel such as... 

The process of extracting hydrogen from fossil fuels and carbon compounds is termed reforming. Today, this is the principal and least expensive method of producing hydrogen. Unfortunately, reforming emits pollutants and consumes nonrenewable fuels. It is very difficult to eliminate or reduce the presence of carbon monoxide, carbon dioxide, and other derivatives. 

Nonrenewable Fuels - Fuels that cannot be easily made or "renewed," such as oil, natural gas, and coal. 

Figure 18.2 shows the current and projected electricity generation capacity by fuel type. Table 18.1 lists typical power plant parameters for facilities using different fuel types. Current power generation is dominated by thermal processes that use the action of heat generated by either renewable or nonrenewable fuels on a working fluid to drive a turbine. This includes fossil fuel combustion, nuclear fission, biomass combustion, geothermal extraction, or solar-thermal collection. 

FossU fuels are nonrenewable fuels once they are consumed, they cannot be replaced. 

Rayon is unique among the mass produced man-made fibers because it is the only one to use a natural polymer (cellulose) directly. Polyesters, nylons, polyolefins, and acryflcs all come indirectly from vegetation they come from the polymerization of monomers obtained from reserves of fossil fuels, which in turn were formed by the incomplete biodegradation of vegetation that grew millions of years ago. The extraction of these nonrenewable reserves and the resulting return to the atmosphere of the carbon dioxide from which they were made is one of the most important environmental issues of current times. CeUulosic fibers therefore have much to recommend them provided that the processes used to make them have minimal environmental impact. 

When this reaction was first discovered, a considerably higher (ca 1300°C) temperature was required than that used in the 1990s. Thus, until Haber discovered the appropriate catalyst, this process was not commercially attractive. As of this writing (ca 1995), the process suffers from the requirement for significant quantities of nonrenewable fossil fuels. Although ammonia itself is commonly used as a fertilizer in the United States, elsewhere the ammonia is often converted into soHd or Hquid fertilizers, such as urea (qv), ammonium nitrate or sulfate, and various solutions (see Ammonium COMPOUNDS). 

Nonrenewable energy sources include the fossil fuels (natural gas,... 

Continuing dependence on fossil fuels raises several major ethical issues. Ethical questions concerning our responsibilities to future generations arc raised by the fact that fossil fuels are a nonrenewable energy source, so that eveiy barrel of oil or ton of coal burned today is forever lost to future generations. Further, the by-products of fossil fuel combustion pose hazards to both present and future generations. 

Fossil fuels are a nonrenewable resource. Whatever fossil fuel we use in the present will be forever lost to posterity. Is this fair The harmful effects of global warming are unlikely to occur tor many years. Should we care Is it ethical to take risks... 

For nonrenewable energy sources such as fossil fuels, expectations about the future price and interest rates influence the current quantity supplied. Expectations of higher future prices should cause less production today and more production tomorrow. 

Fossil fuels are nonrenewable, and combustion products contaminate the atmosphere. Consequently, scientists are searching for new sources of energy. One possibility is molecular hydrogen, which releases energy when it reacts with oxygen 2 H2(g) + 02(g) 2H2 0(/) + Energy Hydrogen powers the rockets of the space shuttle,... 

Industrial civilization was built by the consumption of fossil fuels. Currently, well over 80% of world energy comes from the three main fossil fuels petroleum, natural gas, and coal. Because these are nonrenewable resources, there will come a time when these energy bank accounts are exhausted. Experts disagree on how soon the depletion of fossil fuels will occur, but eventually it will be necessary to find other energy sources. 

Focusing on a clean, economical alternative to nonrenewable energy, this volume provides the latest information on the hydrogen fuel economy. 

The transition from nonrenewable fossil fuel should consider the development of technologies that can use the available energy of the sun. It is reasonable to assume that solar energy will eventually serve as a primary energy source. As we attempt to use solar energy to replace the use of fossil and nuclear fuels, this relationship between solar energy and hydrogen returns and one may not effectively work without the other. 

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