英语动力工程概论题目集锦.doc

Sustainability：It raises from the perception that human activity is using up natures resources at rates beyond the capacity of nature to restore them. Sustainability implies maintaining these resources for future generation。How to achieve sustainability?1. Continual improvements in technology permit extraction of lower-grade deposits and increased recycling of metals. 2. Extraction and processing spread metals around the globe, raising concern about threats to health from toxic elements, such as mercury and lead.3. There are incentives to recycle these metals, in order to save energy and minimize pollution, but none to stop using them.1、The issues of energy supply and resource substitution （资源替代）are profoundly （深刻地） influenced by the rate at which energy is used.2、Reducing energy consumption lowers environmental impacts, stretches out （延伸）the resource base, and buys time for the development of new, more benign （优良的） technologies.3、It is little doubt that new technology and conservation measures （节能措施） can substantially increase the efficiency with which we use energy. n To make sure we have plenty of energy in the future, its up to all of us to use energy wisely. n We must all conserve energy and use it efficiently. Its also up to those who will create the new energy technologies of the future.n All energy sources have an impact on the environment. Concerns about the greenhouse effect and global warming, air pollution, and energy security have led to increasing interest and more development in renewable energy sources such as solar, wind, geothermal, wave power and hydrogen. n But well need to continue to use fossil fuels and nuclear energy until new, cleaner technologies can replace them. One of you who are taking this class might be another Albert Einstein or Marie Curie and find a new source of energy. Until then, its up to all of us. 温室效应n 定义Thegreenhouse effectis a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases.n Extra carbon dioxide (CO2) has been added to the atmosphere by human activity, largely since the beginning of the Industrial Age, when we began burning fossil fuel(coal, oil and natural gas) to drive industry, transport and to generate electricity. This CO2 had been underground for 300 million years, so releasing it into the atmosphere is proving too much for the carbon cycle to manage. So more and more CO2 is remaining in the atmosphere and is causing global warming. Greenhouse gases such as carbon dioxide accumulate in the atmosphere and trap heat that normally would exit into outer space.1煤的优缺点： 优点Coal is one of the most abundant sources of energy, more so than oil and natural gas Coal is inexpensive when compared to other fossil fuels (or alternative energy sources) Coal is versatile enough to be used for recreational activities such as BBQs or simply for home fires Burning coal can produce useful by-products that can be used for other industries or products Electricity produced from coal is reliable Coal can be safely stored and can be drawn upon to create energy in time of emergency Coal based power is not dependent on weather which cannot be said for alternative forms of renewable energy such as wind or solar power Transporting coal does not require the upkeep of high-pressure pipelines and there is no requirement for extra security when transporting coal Using coal reduces the dependence on using oil, which is often found in nations where there is unstable political regimes 缺点：Burning coal emits harmful waste such as carbon dioxide, sulphur dioxide, nitrogen oxides, sulphuric acids, arsenic and ash. It also emits twice as much carbon dioxide when compared with natural gas to produce the same level of heat, which increased the levels of harmful greenhouse gases emitted into the earths atmosphere. The burning of coal by large-scale factories to power industry has led to acid rain in some regions Coal can be cleaned and/or turned into a liquid or gas but this technology has yet to be fully developed and adds to the expense of creating fuel via coal Coal mining can scar the landscape and the equipment used for mining is large and noisy which may affect local wildlife Transporting coal can be problematic because it requires an extensive transportation system and can also cause additional pollution in the form of emissions from transportation vehicles such as lorries, etc There are limited stocks of coal remaining - they will be entirely depleted this millennium if we continue to burn coal in the future at the same rate we are today. Coal is considered as a non-renewable energy source The mining industry can cause health difficulties for miners and fatalities due to the potentially dangerous nature of the work 2石油的优缺点： 优点：Petroleum is a liquid and therefore easily transported. Petroleum fuels are relatively clean, since the refinery produces hydrocarbon fractions, leaving most of the sulfur- and metal-containing compounds in the residue 缺点：Oil is a non-renewable energy source. Oil spills cause inevitably catastrophic effect on marine life, birds and coastlines. Burning oil generates carbon dioxide, a greenhouse gas Oil contains sulfur which when burnt forms sulfur dioxide and sulfur trioxide. Oil is neither as clean nor efficient in use as natural gas. Many of the countries where oil can be found are politically unstable - around 70% of the worlds oil reserves are believed to be located in the Middle East. Developed nations with an oil-dependency have a vested interest in such countries and may seek to influence the politics of such countries to their own advantage. While many of the products obtained from oil are hugely beneficial to mankind, many are also highly toxic. 3天然气的优缺点： 优点：Natural gas is a clean fuel, requiring very little processing. Natural gas is readily transported overland through pipelines. CO2 emission rate per unit of energy from natural gas is lower than other fossil fuels. Natural gas contributes less to smog formation than does gasoline. 缺点：Natural gas is much harder to carry around than liquid hydrocarbons. To pack enough of natural gas into a reasonable space for mobile power sources requires high pressures or low temperatures, or both. Compressors and/or refrigerators are required The storage tank must be thick-walled and/or insulated. Methane is a potent greenhouse gas. Consequently, leaks of methane are a serious environmental concern. Leaks can occur at the gas wells during transfers from power sources during idling of gas-powered vehicles 核裂变定义：Nuclear fission: nucleus splits into two daughter nuclei, with a very large release of energy.核聚变定义：Nuclear fusionis the process by which two or moreatomic nucleijoin together, or fuse, to form a single heavier nucleus. This is usually accompanied by the release of large quantities ofenergy. Fusion is the process that powers active stars, thehydrogen bomband some experimental devices examiningfusion powerforelectrical generation. Nuclear power plant generates electricity in a manner similar to a coal-burning power plant. heating a fluid (usually water) generates steam (directly or indirectly) drives turbine blades connected to a power generator Difference the method for heating the water: nuclear reactions vs. coal combustion 核能优缺点：Advantages of nuclear power inexpensive (after plant is constructed) few deaths per energy unit produced no CO2 gas emitted small amounts of solid waste generated Disadvantages Unresolved high level radioactive waste problem What do we do with it, where do we store it, how do we transport it safely? Requires a very large capital investment & advanced technology Poor technology, operation (human error), and plant design can lead to costly and deadly accidents (e.g., Chernobyl) complex design (40,000 valves vs. 4000 in coal plants) Breeder reactors (not in use in the US) produce plutonium from 238U (France, Japan) Pu = one of the most toxic substances known Dangerous to produce due to chances of falling into the wrong hands! Produces weapons-grade material But, does reduce need for additional fuel太阳能定义： Originates with the thermonuclear fusion reactions occurring in the sun. Represents the entire electromagnetic radiation (visible light, infrared, ultraviolet, x-rays, and radio waves).太阳能优缺点： Advantages All chemical and radioactive polluting byproducts of the thermonuclear reactions remain behind on the sun, while only pure radiant energy reaches the Earth. Energy reaching the earth is incredible. By one calculation, 30 days of sunshine striking the Earth have the energy equivalent of the total of all the planets fossil fuels, both used and unused! Disadvantages Sun does not shine consistently. Solar energy is a diffuse source. To harness it, we must concentrate it into an amount and form that we can use, such as heat and electricity. Solar thermal electricity the generation of electricity from sunlight. To collect the suns rays directly to heat water and run a steam generator. Solar thermal designs: parabolic troughs, power towers, and dish/engine systems. It is an advantage that daylight hours coincide with high electricity demand, for heating, air-conditioning, and many other purposes, so that solar generators are well-matched to the peak loads of electrical utilities.Photovoltaic Electricity Sun provides power only during the day is countered by the fact that 70% of energy demand is during daytime hours. At night, traditional methods can be used to generate the electricity. Reduces the effects of acid rain, carbon dioxide, and other impacts of burning coal and risks associated with nuclear energy. pollution free, indefinitely sustainable.生物质能优缺点：优点：1. Renewable, theoretically inexhaustible fuel source.2. Available throughout the world. 3. When direct combustion of plant mass is not used to generate energy (i.e. fermentation, pyrolysis, etc. are used instead), there is minimal environmental impact.缺点：1. Low heat value, large volume, causing collection difficulties;2. Could contribute a great deal to global warming and particulate pollution if directly burned; 3. Seasonal characteristics power generation from municipal solid waste (MSW) power generation from crop strawMethod for municipal solid waste treatment:electricity recycle; landfill; incineration.Biomass (Crop straw) power generation Co-fired: joint combustion of two different fuels, such as straw and coal. Straw direct combustion. Gasification and CHP (combined heat and power). The straw is gasified first and a combustible gas is obtained. The combustible gas is then burned to generate electricity. The heat contained in the exhaust gas can be recovered.水能水电站工作原理：The running water can be used to turn a turbine and generate electricity. Water trapped in a hydroelectric dam conserves large amount of gravitational potential energy. As the difference between the water level and the water outflow increase, so does the potential energy of the water. The water run through a channel called the penstock （水道） to drive the turbine. The rotational energy of the turbine is converted to electricity by the generator. The electricity generated is supplied to public electricity network, and is transferred to homes and businesses. 水能优缺点：优点1 Using this type of energy to generate electricity is not dependent upon the price of uranium, oil, or other types of fuel. This makes electricity costs lower and more stable, one of its most significant advantages. 2 The pollution created by hydroelectric energy generation is quite minimal. 3 it is more reliable than wind, solar and wave energy.缺点：Dams usually flood large river valleys, covering a lot of native habitat with water, displacing animals and sometimes people.风能对环境的影响： In the 1970s, oil shortages pushed the development of alternative energy sources. In the 1990s, the push came from a renewed concern for the environment in response to scientific studies indicating potential changes to the global climate if the use of fossil fuels continues to increase. Wind energy is an economical power resource. Wind is a clean fuel; wind farms produce no air or water pollution because no fuel is burned. The most serious environmental drawbacks to wind machines may be their negative effect on wild bird populations and the visual impact on the landscape. To some, the glistening （闪耀的）blades of windmills on the horizon are an eyesore（眼中钉）; to others, they are a beautiful alternative to conventional power plants. 海洋能： The ocean can produce two types of energy: thermal energy from the suns heat, and mechanical energy from the tides and waves. Tides are driven primarily by the gravitational pull of the moon, and waves are driven primarily by the winds. The oceans are vast and these energy forms are highly dispersed. Ocean Thermal Energy Conversion (OTEC) In tropical regions, the surface water can be 40 or more degrees warmer than the deep water. This temperature difference can be used to produce electricity. The OTEC system must have a temperature difference of at least 25 to operate. Hawaii has experimented with OTEC since the 1970s. There is no large-scale operation of OTEC today. There are many challenges. The OTEC systems are not very energy efficient. Pumping water is a giant engineering challenge. Electricity must also be transported to land. It will probably be 10 to 20 years before the technology is available to produce and transmit electricity economically from OTEC systems. 潮汐发电优缺点优点：It reduces the dependence upon fossil fuels; Tides are active 24 hours a day, 365 days a year; Tidal energy is clean; Tidal power is a renewable source of energy; It produces energy for free, once the initial costs are recovered. 缺点：It is not cost effective. It leads to the displacement of wild life habitats. It can only be used where there is suitable tidal flow. So it cannot be used inland. It only produces electricity during tidal surges. 波浪能优缺点优点：The energy is free - no fuel needed, no waste produced. Not expensive to operate and maintain. Can produce a great deal of energy. 缺点：Depends on the waves - sometimes youll get loads of energy, sometimes almost nothing. Needs a suitable site, where waves are consistently strong. Must be able to withstand very rough weather.地热电站种类：There are three basic types of geothermal power plants: Dry steam plants - use steam piped directly from a geothermal reservoir to turn the generator turbines. Flash steam plants - take high-pressure hot water from deep inside the earth and convert it to steam to drive the generator turbines. When the steam cools, it condenses to water and is injected back into the ground to be used over and over again. Most geothermal power plants are flash plants. Binary power plants - transfer the heat from geothermal hot water to another liquid. The heat causes the second liquid to turn to steam which is used to drive a generator turbine.The environmental impact of geothermal energy depends on how it is being used. l Direct use and heating applications have almost no negative impact on the environment.l Geothermal power plants do not burn fuel to generate electricity, so their emission levels are very low. l Geothermal heat pumps are the most energy-efficient, environmentally clean, and cost-effective systems for temperature control. 地热能来源：Geothermal energy is unconnected with the sun.Geothermal energy is derived from heat within the earth. Geothermal energy is a renewable energy source because the water is replenished by rainfall and the heat is continuously produced inside the earth. 煤与环境 There are significant environmental costs associated with the extraction, transport, and combustion (burning) of coal Although laws enacted in the 1970s resulted in improved pollution controls on new power plants, coal is still the dirtiest energy source in the US When it is burned, coal releases a number of problem pollutants: Mercury a known nervous system toxin Sulfur which leads to the formation of acid rain Nitrogen which also contributes to acid rain as well as smog Carbon dioxide the chief global warming gas Acid mine drainage is also a product of coal extraction Refers to the outflow of acidic water from abandoned coal mines Although coal is still the most widely used fossil fuel, it is at least acknowledged that there must be efforts to clean use of coal. A number of nations have passed Clean Air Laws and have actively taken steps to make mining companies liable （有责任的） to ensure that the landscape is not irreparably （不可恢复地）damaged by wide scale mining activities. There are also continuing technological efforts being introduced by industry to burn coal in a more efficient manner that will not emit as many pollutants into the atmosphere. Many of these types of carbon cleaning or carbon capture technologies are still in concept form, but there is at least an awareness that efforts need to be made in this area. 石油与环境 Although oil is considerably cleaner in use than coal, it is a far dirtier fuel than natural gas. Combustion of oil and oil derivatives is one