外文翻译-生物质作为替代燃料用来发电

1、生物质作为替代燃料用来发电前言电能有许多不同的产生来源而且可用不同的方式来生产。然而，各国竞相寻找能源，并试图寻找的无限能源来生产电能。此外，生产电能而使用的矿物燃料，如石油，煤炭等，都会产生一些从能源成本到环境的污染等重大问题。在上世纪末，工程师们开始寻找新的能源，这些能源既具有与化石燃料相同的优点势外，同时也避免了其弊端。事实上，有一些能源因来自自然而著称，这就是所谓的可再生能源。之所以称它是可再生能源，是因为它不能耗尽并且可以重复使用。这种能源有不同种类和不同的形式，例如风能，太阳能，水能，水电能源，生物质能等。“在美国，自1973年以来便开始大量利用生物质，特别是木屑在热能及电力应用的

2、利用上”。本文将探讨利用生物质作为电力行业中使用的替代燃料。文章开头，将涉及生物质的背景和它的历史来源。其次，将对利用生物质能发电的电厂进行调查。再次随后，陈述一些利用生物质的优点和缺点。最后，一个结论将总结全文。生物质能简介生物质是世界上最古老的可再生能源之一。虽然我们一直在使用它，但很少有人知道它的学名。生物质学名为活着的物质，或具体地讲，它是在死亡的树木，树枝，木材，农作物，甚至动物能量存储能源的转换，从而让我们可以使用它。例如，“在今天的美国，物质燃料的使用范畴，包括木屑，花草残叶，农业残留物和城市碎木”。因此，生物质能源可在任何时间和地点找到。事实上，如果生物质不转换成其它形式的话它

3、将一无是处。因此，如果任何公司想利用生物质能作为石油或天然气的替代能源，就必须收集生物质（植物，木材等）并将它在某一地点燃烧，燃烧产生的热量可用于推动汽轮机发电。同样，电厂可以使用生物量在的燃烧中的气化过程。在这种情况下，将把生物量加热到极高温度而产生可燃气体，可用于推动涡轮旋转从而产生电能。据加州能源委员会的网页介绍，加州每年生产约60万吨的生物质，这意味着2000兆瓦的电能。事实上，这些能量足以满足市场需求和约2百万户人家使用。虽然生物质能源已被使用多年，一些国家一直以来仍把它作为燃料用作发电。与此相反，一些国家因为其对环境的负面影响而停止使用。有人说，生物质导致了环境的污染。但是，该能源

4、的益处鼓励一些企业使用它，例如，“BEG（生物质能源集团）推算，在苏格兰，生物质产业有望在提供2000人就业岗位和促进其他部门经济增长的同时供应多达450兆瓦的电力”。美国电子协会对生物质的估计表明，每年美国有生物质资源约5.9亿湿吨（相当于4.13亿干吨）可供利用。事实上，生物质发电可使用不同的方法，而各种方法都有各自的效率和生产力。 废弃物发电 用化石燃料发电是世界上最通用的方法。然而，利用生物质能发电，并遵守一些规定和限制会更有效率。眼下主要有四种类型的生物发电系统：直燃，混烧，煤气化，模块化系统。大多数发电厂使用生物质直燃系统，用化石燃料来发电。图1显示了如何使用生物质燃料在工厂中发电

5、。生物质的燃烧锅炉产生高压蒸汽，蒸汽被引入汽轮机，带动一系列气动涡轮叶片，使涡轮旋转，而涡轮连接到发电机，因此，流动的蒸汽致使涡轮旋转，发电机旋转和电力的生产。生物质能锅炉产生的电一般在50兆瓦范围左右，相比燃煤发电厂中的15兆瓦左右。因此，有人建议，在一些电厂，如在美国亚什兰的海湾发电站，在高负荷期使用煤而在低负荷期使用生物质发电，这将节俭煤的使用。然而，到目前为止，用直接燃烧的木材发电是最省事的方法。另外，除非它和像煤一样的其它能源组合使用，否则就可能没有竞争力。图1 用生物质在电厂发电生物质能的优点：使用生物质作为替代能源来发电具有一定的经济效益。再者，它也是一种有效的社区或工业区的资源

6、来源。相比而言，即使发达国家能够利用这一资源，以弥补其它像石油，天然气或煤资源的不足。其中最重要的优势是它的价格低廉;而且是一种现成的能源。此外，它是一种可持续、可长期使用的资源，它可以在任何时候任何地方很容易地发现使用。生物质发电厂更大的优势是能帮助许多国家减少失业。施安那 贝尔德，中型项目的苏格兰绿党的能源发言人说： “就新的发电站的建立和它创造的相当数量的就业机会而言，这是个好消息” 。如在苏格兰邓弗里斯郡的洛克比建立的生物质能源发电厂，将支持英国经济也将帮助政府降低失业率。生物质能的缺点：如同任何可再生能源一样，利用生物质发电存在一定的缺陷。生物质确实影响环境吗？这个问题已经被问了很多

7、次。事实上，因为它在燃烧时会产生碳气体，因此许多人担心的是它在全球气候变暖中的作用。然而，如果你了解生物质周期的话，可能知道从这个角度看是错误的。虽然生物质可在世界任何地方看到，有些地方如在中东的沙漠地区，如沙特阿拉伯，找到足够的可用作生物质的植被是一件很困难的事。因此，把植被运送到该地区，将是昂贵的和毫无用处的。图2 碳循环结论：总之，这篇文章已经表明，使用生物质的行业，特别是像发电厂这样的工业，将有助于人们找到工作，并有助于各国政府减少失业率。此外，每年许多国家花费数十亿美元购买石油或天然气用来发电，为此，如果用生物质作为替代能源来发电将是更加经济和有效。在电力市场，可以说：能源就是金钱。

8、就生物质能源而言，这一说法更为确切。此外，生物质可用于不同的地方，这意味着更多的灵活性。虽然使用生物质的电厂将产生功耗低于它使用化石燃料时而产生的电能，但在村庄和小城镇，使用生物质将比使用常用的化石燃料更为经济。 Biomass as an Alternative Fuel for Generating ElectricityWritten by : Eng. Fahad A. Rafairefaeefahotmail SeptemberIntroductionElectrical energy has many different sources and can be produced in

9、 different ways. However, countries are competing to produce energy and trying to have unlimited sources for producing it. Moreover, producing electrical energy using normal fossil fuels, such as, oil, coal and so on has some major problems, from the cost of fuel to the pollution. At the end of the

10、last century, engineers have started looking for new sources which have the same advantages as the fossil fuels while avoiding their disadvantages. In fact, there some sources were already known from the natural, one of them is called renewable energy. It called renewable because it will not run out

11、 and can be reproduced. This kind of energy has different types and can be found in different forms, for instance, wind energy, solar energy, hydroelectric energy, biomass energy and so on. In the United States, since 1973 there has been a dramatic increase in biomass use, especially in thermal and

12、electrical applications of wood residues. This essay will examine the using of biomass energy as an alternative fuel in the electricity industry. Initially, it will cover a brief background on biomass and include its sources and history. Secondly, the using of biomass for generating electricity in p

13、ower plants will be investigated. Then, some of the advantages and disadvantages of using biomass will addressed . A conclusion will complete the essay.Biomass in BriefBiomass is one of the oldest sources of energy in the world. Although we have been using it all the time, it may have been never hea

14、rd about its scientific name. Biomass known as living material or specifically, it is the conversion of the stored energy in the dead trees, tree branches, wood, crops and even animals into energy so that we can use it. For example, The major categories of biomass fuels used in the United States tod

15、ay include, wood processing residues, in-forest residues, agricultural residues and urban wood residues.As a result, biomass energy can be found easily in any place and any time. In fact, biomass will not be useful for producing electrical power energy unless converted into another form. Consequentl

16、y , if any company wants to use biomass as a source of energy instead of oil or gas, it will need to collect the biomass ( plants, wood and so on ) and burn it in special places, then the heat of this burning can be used in a steam turbine to generate electricity. In the same way, power plants can u

17、se biomass in a different process which called Gasification. In this case, biomass is going to be heated at very high temperature degrees to produce flammable gases which can be used to rotate the turbine and produce electricity. According to the California Energy Commission web site, California pro

18、duces about 60 million tons of biomass every year, which means around 2000 megawatt of electrical power. In fact, this power is enough to market and could supply about two million homes.Although biomass energy has been used many years ago, some countries still use it as a fuel in electrical power ge

19、neration until now. In contrast, some countries stopped using it because of its environmental impacts. It has been said that biomass has been contributing to the environmental pollution. However, the benefits of this energy encouraged some societies to use it, for instance, BEG (The Biomass Energy G

20、roup) has concluded that a biomass industry in Scotland has the potential to supply as much as 450 MW of electricity from the wood fuel resource while employing over 2000 people and stimulating other sectors of the Scottish economy. In addition ，EIA (The Energy Information Administration) estimation

21、 of biomass resources shows that there are 590 million wet tons (equivalent to 413 million dry tons) of biomass available in the United States on an annual basis.In fact, biomass can be used in power plants using different methods and each method has its own efficiency and productivity.Electrical Po

22、wer Generation from wasteGenerating electricity in power plants using fossil fuel is the most popular method in the world. However, using biomass to generate electricity can be efficient with some regulations and limitation. There are four main types of biomass power systems: direct-fired, co-fired,

23、 gasification, and modular systems. Most of the power plants which use biomass are direct-fired systems which use the same technique of fossil-fuel fired power plants. Figure 1 shows how to use biomass as fuel in power plants. The biomass is burned in a boiler to produce high-pressure steam. This st

24、eam is introduced into a steam turbine, where it flows over a series of aerodynamic turbine blades, causing the turbine to rotate. The turbine is connected to an electric generator, thus, as the steam flow causes the turbine to rotate, the electric generator turns and electricity is produced. Biomas

25、s power boilers are typically in the 50 MW range, compared to coal-fired plants in the 150MW range. Therefore, it was suggested that in some power plants, such as, the Bay Front Station in Ashland in the United States it would beneficial to operate the units ( turbines) using coal in the peak period

26、s and using biomass in the low load periods . However, direct combustion of wood to generate electrical power is the most advanced method at present. Also, it might be not competitive unless used in combination with other sources, such as coal and gas.Figure 1: Using Biomass to produce electricity i

27、n power plants.Advantages of using Biomass:Using biomass as an alternative energy to generate electrical power has some economical benefits. Moreover, it can be a useful source for energy in the small societies or small industrial areas. In contrast, even developed countries can use this source to c

28、ompensate for the lack of the other sources, such as, oil, gas or coal. One of the most important advantages of biomass is its cheap prices; also it is a readily available source of energy. In addition, it is a continuous and long term source, it can be found easily, any time and almost anywhere. On

29、e more advantage for biomass power plants is helping to reduce the unemployment in various countries, Shiona Baird, MSP, the Scottish Green Partys energy spokeswoman, said to The Scotsman: The new power station, and the considerable number of jobs that it will create, is good news. This contribution

30、 by establishing a biomass power plant at Lockerbie, Dumfriesshire in Scotland it will support the economy in the UK and will help the government in its fight against unemployment.Disadvantages of using BiomassLike any renewable source, biomass has some disadvantages for using it to generate electri

31、cal power. Does biomass affect the environment? This question has been asked many times. In fact, many people are concerned about the contribution of biomass in the global warming because the combustion of biomass will produce carbon into the air. However, this point of view could be wrong if you un

32、derstand the biomass cycle. Although biomass can be found anywhere in the world, some places like desert areas in the middle east such as Saudi Arabia, possibly will face difficulties to get enough plant and trees to be used as a biomass source. As a result, the transportation of the plant and tress

33、 to theses areas will be costly and using biomass in this case will be worthless.Figure 2: Carbon cycle.Conclusions:To sum up, this essay has shown that using biomass in industry and specifically in power plants to produce electrical power, would help many people to find jobs and could help the gove

34、rnments to diminish the unemployment rates. Moreover, every year, countries spend billions of dollars to sell oil or gas for generating electricity, for this reason, it will be more economical and useful if biomass has been used. In the electricity markets it can be said: energy is money. And by using biomass this saying can be verified. Moreover, biomass can be used in different methods which mean more flexibility. Although the power pla