Handbook of Alternative Fuel Technologies “Green Chemistry and Chemical Engineering” 2nd Edition.
Chapter 1 Global and U.S. Energy Overview
Chapter 2 Gasification of Coal
Chapter 3 Clean Liquid Fuels from Coal
Chapter 4 Coal Slurry Fuel
Chapter 5 Liquid Fuels from Natural Gas
Chapter 6 Resids
Chapter 7 Liquid Fuels from Oil Sand
Chapter 8 Shale Oil from Oil Shale
Chapter 9 Shale Gas and Shale Fuel
Chapter 10 Methanol Synthesis from Syngas
Chapter 11 Ethanol from Corn
Chapter 12 Ethanol from Lignocellulosics
Chapter 13 Biodiesel
Chapter 14 Algae Fuel
Chapter 15 Thermochemical Conversion of Biomass
Chapter 16 Energy Generation from Waste Sources
Chapter 17 Geothermal Energy
Chapter 18 Nuclear Energy
Chapter 19 Fuel Cell
Energy has always been the foremost important resource upon which humans have relied for survival and productive activities. Industrialization and technological advancement of modern society have also been possible through the effective use of energy. There is a strong correlation between the index for quality of life and energy consumption. Heightened economic strength of a country, technological prosperity of a society, higher production output of an industry, improved finances of a household, and increased activities of an individual are also realized by effective utilization of energy.
A number of important factors have historically dominated the trend, market, and type of energy utilization. These factors are (1) resource availability, (2) convenience of energy utilization, (3) efficiency of conversion, (4) technological feasibility, (5) portability and ease of transportation, (6) sustainability, (7) renewability, (8) cost and affordability, (9) regional strength, (10) safety and health effects, and (11) environmental acceptance and impact. The technological success and prosperity of petrochemical industries in the twentieth and early twenty-first centuries can largely be attributed to the vast utilization of fossil fuels, especially petroleum, as well as technological breakthroughs and innovations by process industries. Industry and consumers have seen and come to expect a wide array of new and improved polymeric materials and other chemical and petrochemical products. However, the fossil fuel resources upon which industry is heavily dependent are limited in available quantities and are expected to be close to depletion in the near future.
The unprecedented popularity and successful utilization of petroleum resources observed in the twentieth century may decline in the twenty-first century due to a lack of resource availability, thus making prospects for future sustainability seem grim. Public appetites for convenient and alternative fuel sources and superior high-performance materials are, however, growing. Therefore, additional and alternative sources for fuels and petrochemical feedstocks not only should be developed further but are also needed for immediate commercial exploitation.
Use of alternative fuels is no longer a matter for the future; it is a realistic issue of the present. Additional and alternative sources for intermediate and final products, whether fuels or petrochemicals, directly contribute to the conservation of petroleum resources of the world by providing additional raw material options for generating the same products for consumers. Examples may include biogas for methanol; grain ethanol; lignocellulosic alcohol; biodiesel from crop oil and algae; BTX (benzene, toluene, and xylenes) and valuable petrochemicals from coal; biogas or bioliquid from agricultural wastes and plant biomass; hydrogen as transportation fuel and for fuel cells; biohydrogen from a variety of biological sources; jet fuel from shale oil or crop oil; Fischer–Tropsch fuel from coal or biomass; bisphenols from agricultural sources; liquid transportation fuels from a natural gas source by catalysis; dimethyl ether (DME) for internal combustion engines; target olefins via conversion of synthesis gas; use of coal-derived acetylene for petroleum-derived ethylene as a building block chemical; liquid fuels from spent tires or mixed wastes; natural gas from shale gas, tight gas, and natural gas hydrates; polymer synthesis using wet gas from oil shale; solar liquid fuels; and so forth.
If usable energy or deliverable power is the final product to be desired, alternate sources for energy may strongly and directly affect the lifestyle of consumers, as well as their energy consumption patterns. A good example can be found in electric cars that are powered by powerful rechargeable batteries. These powerful batteries serve no use for conventional gasoline motors, while in turn, premium gasoline is not needed in these electric cars. Another good example is the solar house whose climate control inside the house is provided solely by solar energy. Other examples include liquefied petroleum gas (LPG) vehicles, DME buses, hybrid cars, E85 vehicles, hydrogen vehicles, fuel cell vehicles, solar-powered equipment and vehicles, wind energy–powered equipment, geothermal heating and cooling, and so forth. During the past several decades, there has been a considerable increase in research and development (R&D) in areas of environmentally acceptable alternative fuels. Synthetic fuels were of prime interest in the 1970s, due to a sudden shortage of petroleum supply kindled by an oil embargo in 1973, as well as public concerns of dwindling petroleum reserves. While synfuels seemed to be a most promising solution to the conservation of petroleum resources (or, at least, frugal use of the resources) and the development of additional sources for conventional liquid fuels, some of the focus has been shifted toward environmental acceptance of the fuel and the long-term sustainability of world prosperity in the last decade of the twentieth century.
Efforts have been made to reduce emissions of air pollutants associated with combustion processes whose sources include electric power generation and vehicular transportation. Air pollutants that have been targeted for minimization or elimination include SOx, NOx, COx, VOCs, particulate matter (PM), mercury, and selenium. These efforts have significantly contributed to the enhancement of air quality and associated technologies. Concerns of global warming, via greenhouse gases (GHGs), have further intensified the issue of environmental acceptance of fuel consumption.
Combustion of fossil fuels inevitably generates carbon dioxide due to an oxidation reaction of hydrocarbons and carbonaceous materials. Carbon dioxide is known as a major GHG, whose emission needs to be significantly reduced. Therefore, new developments in alternative fuels and energy have focused more on nonfossil sources or on mitigation and fixation of carbon dioxide in fossil fuel utilization. Renewable energy sources are certainly very promising due to their long-term sustainability and environmental friendliness. Of particular interest are solar (solar thermal and photovoltaic), wind, hydropower, tidal, and geothermal energies, in addition to biomass (wood, wood waste, plant/cropbased renewables, agricultural wastes, food wastes, and algae) and biofuels including bioethanol, biohydrogen, bio-oil, and biodiesel. It should be noted that hydropower is also regarded as a “conventional” energy source, as it has provided a significant amount of electrical energy for over a century. Government mandates, tax incentives, and stricter enforcement of environmental regulations are pushing environmentally friendly alternative fuels into the marketplace at an unprecedented rate. The number of alternative-fueled vehicles in use in the world is expected to increase sharply. These alternative-fueled vehicles are powered by LPG, liquefied natural gas (LNG), compressed natural gas (CNG), ethanol 85% (E85), methanol 85% (M85), electricity, neat methanol (M100), ethanol 95% (E95), DME, Fischer– Tropsch fuel, and hydrogen, among which hydrogen presently accounts for very little but is considered quite promising by many. It should be noted that this list of alternative fuels in vehicles represents only the successful results of the past developments and does not include recent advances and breakthroughs in the field. R&D efforts in alternative-fueled vehicles and utilization of renewable energy sources have intensified in the past few years. Alternative-fueled vehicles and emission-free cars are expected to gain more popularity due in part to enforcement of stricter emission standards, the unmistakable fate of depletion for conventional transportation fuels, and numerous tax incentives for such vehicles. This intensified interest is coupled with the record-high prices of gasoline and petroleum-based products experienced all over the world. Perhaps the key difference between the 1973 oil embargo era and the present is that this time around, efforts are likely to firmly latch on to the roster of ongoing priorities most exigent to mankind. Energy from wastes cannot be neglected as a valuable energy source. If effectively harnessed, energy from wastes, including municipal solid waste (MSW), agricultural refuse, plastic wastes and spent tires, and mixed wastes can be employed to alleviate the current burden for energy generation from fossil fuel sources. Moreover, energy generation from wastes bears extra significance in reducing the volume of wastes, thus saving landfill space and utilizing resources that would otherwise be of no value. Environmental aspects involving waste energy generation are to be fully addressed in commercial exploitation.