Critical Technologies The Role of Chemistry and Chemical Engineering (1992) / Chapter Skim
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Energy and Transportation
Energy and Transportation
Pages 20-30
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From page 21... ...
Broad research efforts by chemists and chemical engineers are aimed at optimizing these chemical reactions to allow more efficient combustion, reduce volatility, or remove atoms such as sulfur and nitrogen that contribute to air pollution when the fuel burns. Refined petroleum satisfies the present demand for clean transportation fuel at low cost.
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From page 22... ...
For example, catalysts with larger pore openings must be constructed to accommodate the larger molecules present in heavier crude oils. These zeolite-type catalysts are porous oxide materials that allow molecules to diffuse into their cavities, where the chemical reactions take place.
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From page 23... ...
We may someday be forced to follow the lead of New Zealand, where up to one third of the liquid fuel required can now be obtained from chemical plants that convert natural gas to gasoline with zeolite catalyst technology that was originally developed in the United States. Another technology for converting natural gas into liquid fuels first uses partial oxi dation to convert the natural gas into carbon monoxide and hydrogen, which are then cat alytically recombined to form larger hydro- This plane converts natural gas to methanol, which Is then Processed carbon molecules.
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From page 24... ...
or 71 percent of the worId's total fossil fuel resources; 25 percent of the worId's coal reserves are located in the United States. Depending on competitive technologies and on the cost of meeting environmental regulations, coal may be used increasingly for future electric power generation and for conversion to liquid fuels, replacing the less abundant petroleum resources, which total only 3,100 quads worldwide.
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From page 25... ...
Examples include camcorders as well as laptop and notebook computers, complete with bright displays and largecapacity hard disks; long-lived cardiac pacemakers that make frequent surgical replacement unnecessary; cordless power tools that enhance freedom of mobility in the workplace; intelligent, motorized cameras for high-performance photography; blood sugar analyzers no larger than a fountain pen
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From page 26... ...
and that offer several additional advantages: they can be recharged simply by filling the fuel tank, there is no need to store an oxidizing agent, and combustible fuels can be used without generating noxious nitrogen oxides. High-temperature, solid-state fuel cells can use hydrocarbon fuels for the net production of water and carbon dioxide plus a flow of electricity through an external circuit.
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From page 27... ...
If the United States continues with a commitment to water-cooled reactors using enriched fuels, it will eventually become necessary to build new uranium enrichment facilities. Whether these enrichment facilities are the current gaseous diffusion type or use more environmentally friendly alternatives depends on advances in research associated with isotope separation.
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From page 28... ...
For example, multibandgap solar cells employ several different semiconductors to use light over a broader range of the solar spectrum. Although they are currently very expensive, gallium arsenide solar cells have steadily increased in efficiency from 13 to 26 percent under terrestrial conditions, and efficiencies approaching 30 percent have been obtained in space solar simulators.
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From page 29... ...
Hydrogen gas is regarded as a nonpolluting fuel because it burns in oxygen to yield water as the only product; an ultimate quest of solar energy research is to devise a practical system to use sunlight to drive the reaction backwards and split water into this useful and lightweight fuel. For the present generation of photoelectrochemical ceils, efficiencies for conversion of solar to electrical energy fall in the range of 15 to 20 percent.
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From page 30... ...
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