Reserves of fossil fuels

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. 

The simple fact is that the world s reserves of fossil fuels will eventually run out, depending on the rate of use, and therefore, if the consumption of these forms of energy are reduced, the existing reserves will last longer. Research and experimentation could lead to those reserves currently available but uneconomic to recover and use being rendered economic, thus extending further the number of years before these non-renewable sources of energy do eventually run out. 

The projection of future emissions of fossil fuel CO2 is subject to a number of uncertainties. The growth rate has already shown great variations and the reserves of fossil fuels are not... 

Chemical processes should be designed as part of a sustainable industrial activity that retains the capacity of ecosystems to support both life and industrial activity into the future. Sustainable industrial activity must meet the needs of the present, without compromising the needs of future generations. For chemical process design, this means that processes should use raw materials as efficiently as is economic and practicable, both to prevent the production of waste that can be environmentally harmful and to preserve the reserves of raw materials as much as possible. Processes should use as little energy as is economic and practicable, both to prevent the build-up of carbon dioxide in the atmosphere from burning fossil fuels and to preserve the reserves of fossil fuels. Water must also be consumed in... 

Figure 2. Canadas potential recoverable reserves of fossil fuels (in barrels-of-oil equivalent). Total 1000 billion source Federal Government Publication An Energy Policy for Canada. ...

The relative share of oil is now culminating from a peak production around year 2000, whereas natural gas is still foreseen to have a substantial relative growth potential. However, owing to the limited reserves of fossil fuels the role of natural gas can only be seen as a bridge to the future. 

The end of the Stone Age did not come because man ran out of stones. But if man runs out of stones, then man must be ready to leave the Stone Age. Similarly, the reserves of fossil fuels such as natural gas, crude oil, tar sands, and coal are expected to last some time, but this has passed, the alternative options should be ready to go. It is probably best not to wait until there is a real shortage. 

The United States contains about one-third of the world s coal reserves, and coal represents over 90 percent of U.S. proven reserves of fossil fuels. Recoverable reserves of U.S. coal are estimated to be 250 billion tons. Bituminous coals (with a heating value of 10,GOO-15,000 BTU/lb) comprise nearly one-half of total U.S. coal reserves. Eastern U.S. coals are generally bituminous. Western and southwestern U.S. coals are mainly sub-bituminous... 

Photosynthesis is the largest-scale synthetic process on earth. About 1.06 x 1014 kg (106 billion tons) of carbon are fixed annually into organic compounds by photosynthetic organisms (a quantity often called the net primary productivity). This equals about 1% of the world s known reserves of fossil fuels (coal, gas, and oil), or 10 times the world s current annual... 

Oil shale represents an enormous reserve of fossil fuel for domestic and foreign needs (1,2). Shale oil production can be divided into direct and indirect heating processes (2). In direct heating, some of the products or some other fuel is combusted to raise the oil shale to the necessary temperature for conversion to gas and oil while an indirect process transfers heat from an outside source. Although high yields have been demonstrated in some indirect procedures (3), the application to in situ retorting has been limited. Direct processes developed for in situ recovery of shale oil have not demonstrated sufficient control of the underground combustion for reliable operation. 

The known reserves of fossil fuels are too small to warrant the difficulties of a major transition from today s fossil technologies to the new "clean" ones, and only the belief that a high proportion of the general resources known to exist can indeed in the future be converted to "reserves" and exploited in practical, economic and environmentally acceptable operations will make the fossil scenario interesting. 

Solar cells based on silicon or gallium arsenide provide a way to convert the radiant energy of the sun directly into electrical work by a technology that is virtually nonpolluting (Fig. 22.26). The high capital costs of solar cells make them uncompetitive with conventional fossil fuel sources of energy at this time, but as reserves of fossil fuels dwindle, solar energy will become an important option. 

Table 4.12 Estimated total reserves of fossil fuels (after World Energy Council 2002). Approximate conversion to tonnes of oil equivalent based on energy equivalence factors of 1.07 for natural gas liquids (condensate), 0.9 for heavy oils, 0.7 for hard coals, 0.47 for brown coals, 0.23 for peat and 0.861 per 103m3 for gas (1 tonne crude oil = c.7.3 barrels = c.l.lbm3)...

How long will remaining reserves of fossil fuels last For coal, the answer is measured in centuries, while for oil and natural gas the answer is measured in decades. How many decades is the subject of considerable debate, especially for oil. This debate is referred to as the "peak oil" argument. 

Fig. 7. The future atmospheric CO2 concentration projection if only known, proved reserves of fossil fuel are used (low projection) and the future atmospheric CO2 concentration projection if known, proved reserves of fossil fuel plus estimated future discoveries of fossil fuel are used (high projection). The historical record is shown through 2001 (Keeling and Whorf, 2002, available at http //cdiac.oml.gov) allowing 11 years of data to be compared to the projections.

Figure 2.1 shows the economically recoverable reserves of fossil fuel, i.e. oil. 

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