外文翻译---天然气.docx

附录一：英文原文原文：Natural gasFrom Wikipedia, the free encyclopediaJump to: navigation, search For other uses, see Natural gas (disambiguation).Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, with up to 20 percent1 concentration of other hydrocarbons (usually ethane) as well as small amounts of impurities such as carbon dioxide. Natural gas is widely used and is an important energy source in many applications including heating buildings, generating electricity, providing heat and power to industry and vehicles and is also a feedstock in the manufacture of products such as fertilizers.Natural gas is found in deep underground natural rock formations or associated with other hydrocarbon reservoirs, in coal beds, and as methane clathrates. Most natural gas was created over time by two mechanisms: biogenic and thermogenic. Biogenic gas is created by methanogenic organisms in marshes, bogs, landfills, and shallow sediments. Deeper in the earth, at greater temperature and pressure, thermogenic gas is created from buried organic material.2Before natural gas can be used as a fuel, it must undergo processing to clean the gas and remove impurities including water in order to meet the specifications of marketable natural gas. The by-products of processing include ethane, propane, butanes, pentanes, and higher molecular weight hydrocarbons, hydrogen sulphide (which may be converted into pure sulfur), carbon dioxide, water vapor, and sometimes helium and nitrogen.In the 19th century, natural gas was usually obtained as a byproduct of producing oil, since the small, light gas carbon chains came out of solution as the extracted fluids underwent pressure reduction from the reservoir to the surface, similar to uncapping a bottle of soda pop where the carbon dioxide effervesces. Unwanted natural gas was a disposal problem in the active oil fields. If there was not a market for natural gas near the wellhead it was virtually valueless since it had to be piped to the end user. In the 19th century and early 20th century, such unwanted gas was usually burned off in the oil fields. Today, unwanted gas (or stranded gas without a market) associated with oil extraction often is returned to the reservoir with injection wells while awaiting a possible future market or to repressurize the formation, which can enhance extraction rates from other wells. In regions with a high natural gas demand (such as the US), pipelines are constructed when economically feasible to move the gas from the wellsite to the end consumer.Another possibility is to export the natural gas as a liquid. Gas-to-liquids (GTL) is a developing technology that converts stranded natural gas into synthetic gasoline, diesel, or jet fuel through the Fischer-Tropsch process developed during World War II by Germany. Such fuel can be transported to users through conventional pipelines and tankers. Proponents claim GTL burns cleaner than comparable petroleum fuels. Most major international oil companies are in an advanced stage of GTL production, with a world-scale (140,000 barrels (22,000 m3) a day) GTL plant in Qatar scheduled to be in production before 2010.dated infoNatural gas can be associated (found in oil fields) or non-associated (isolated in natural gas fields), and is also found in coal beds (as coalbed methane). It sometimes contains significant amounts of ethane, propane, butane, and pentaneheavier hydrocarbons removed for commercial use prior to the methane being sold as a consumer fuel or chemical plant feedstock. Non-hydrocarbons such as carbon dioxide, nitrogen, helium (rarely), and hydrogen sulfide must also be removed before the natural gas can be transported.3Natural gas is commercially extracted from oil fields and natural gas fields. Gas extracted from oil wells is called casinghead gas or associated gas. The natural gas industry is extracting gas from increasingly more challenging resource types: sour gas, tight gas, shale gas, and coalbed methane.The worlds largest proven gas reserves are located in Russia, with 4.7571013 m (1.681015 cubic feet). With the Gazprom company, Russia is frequently the worlds largest natural gas extractor. Major proven resources (in billion cubic meters) are world 175,400 (2006), Russia 47,570 (2006), Iran 26,370 (2006), Qatar 25,790 (2007), Saudi Arabia 6,568 (2006) and United Arab Emirates 5,823 (2006).It is estimated that there are about 900 trillion cubic meters of unconventional gas such as shale gas, of which 180 trillion may be recoverable.4 In turn, many studies from MIT, Black & Veatch and the DOE - see natural gas - will account for a larger portion of electricity generation and heat in the future.5The worlds largest gas field is Qatars offshore North Field, estimated to have 25 trillion cubic meters6 (9.01014cubic feet) of gas in placeenough to last more than 420 yearscitation needed at optimum extraction levels. The second largest natural gas field is the South Pars Gas Field in Iranian waters in the Persian Gulf. Located next to Qatars North Field, it has an estimated reserve of 8 to 14 trillion cubic meters7 (2.81014 to 5.01014 cubic feet) of gas.Because natural gas is not a pure product, as the reservoir pressure drops when non-associated gas is extracted from a field under supercritical (pressure/temperature) conditions, the higher molecular weight components may partially condense upon isothermic depressurizingan effect called retrograde condensation. The liquid thus formed may get trapped as the pores of the gas reservoir get deposited. One method to deal with this problem is to re-inject dried gas free of condensate to maintain the underground pressure and to allow re-evaporation and extraction of condensates. More frequently, the liquid condenses at the surface, and one of the tasks of the gas plant to collect this condensate. The resulting liquid is called natural gas liquid (NGL) and has commercial value.Town gasTown gas, a synthetically produced mixture of methane and other gases, mainly the highly toxic carbon monoxide, is used in a similar way to natural gas and can be produced by treating coal chemically. This is a historical technology, not usually economically competitive with other sources of fuel gas today. But there are still some specific cases where it is the best option and it may be so into the future.Most town gashouses located in the eastern US in the late 19th and early 20th centuries were simple by-product coke ovens which heated bituminous coal in air-tight chambers. The gas driven off from the coal was collected and distributed through networks of pipes to residences and other buildings where it was used for cooking and lighting. (Gas heating did not come into widespread use until the last half of the 20th century.) The coal tar (or asphalt) that collected in the bottoms of the gashouse ovens was often used for roofing and other water-proofing purposes, and when mixed with sand and gravel was used for paving streets.BiogasMain article: biogasWhen methane-rich gases are produced by the anaerobic decay of non-fossil organic matter (biomass), these are referred to as biogas (or natural biogas). Sources of biogas include swamps, marshes, and landfills (see landfill gas), as well as sewage sludge and manure8 by way of anaerobic digesters, in addition to enteric fermentation, particularly in cattle.Methanogenic archaea are responsible for all biological sources of methane, some in symbiotic relationships with other life forms, including termites, ruminants, and cultivated crops. Methane released directly into the atmosphere would be considered a pollutant. However, methane in the atmosphere is oxidized, producing carbon dioxide and water. Methane in the atmosphere has a half life of seven years, meaning that if a tonne of methane were emitted today, 500 kilograms would have broken down to carbon dioxide and water after seven years.Other sources of methane, the principal component of natural gas, include landfill gas, biogas, and methane hydrate. Biogas, and especially landfill gas, are already used in some areas, but their use could be greatly expanded. Landfill gas is a type of biogas, but biogas usually refers to gas produced from organic material that has not been mixed with other waste.Landfill gas is created from the decomposition of waste in landfills. If the gas is not removed, the pressure may get so high that it works its way to the surface, causing damage to the landfill structure, unpleasant odor, vegetation die-off, and an explosion hazard. The gas can be vented to the atmosphere, flared or burned to produce electricity or heat. Experimental systems were being proposed for use in parts of Hertfordshire, UK, and Lyon in France.Once water vapor is removed, about half of landfill gas is methane. Almost all of the rest is carbon dioxide, but there are also small amounts of nitrogen, oxygen, and hydrogen. There are usually trace amounts of hydrogen sulfide and siloxanes, but their concentration varies widely. Landfill gas cannot be distributed through utility natural gas pipelines unless it is cleaned up to less than 3% CO2, and a few parts per million H2S, because CO2 and H2S corrode the pipelines.9 It is usually more economical to combust the gas on site or within a short distance of the landfill using a dedicated pipeline. Water vapor is often removed, even if the gas is combusted on site. If low temperatures condense water out of the gas, siloxanes can be lowered as well because they tend to condense out with the water vapor. Other non-methane components may also be removed in order to meet emission standards, to prevent fouling of the equipment or for environmental considerations. Co-firing landfill gas with natural gas improves combustion, which lowers emissions.Gas generated in sewage treatment plants is commonly used to generate electricity. For example, the Hyperion sewage plant in Los Angeles burns 8 million cubic feet (230,000 m3) of gas per day to generate power10 New York City utilizes gas to run equipment in the sewage plants, to generate electricity, and in boilers.11 Using sewage gas to make electricity is not limited to large cities. The city of Bakersfield, California, uses cogeneration at its sewer plants.12 California has 242 sewage wastewater treatment plants, 74 of which have installed anaerobic digesters. The total biopower generation from the 74 plants is about 66 MW.13Biogas is usually produced using agricultural waste materials, such as otherwise unusable parts of plants and manure. Biogas can also be produced by separating organic materials from waste that otherwise goes to landfills. This method is more efficient than just capturing the landfill gas it produces. Using materials that would otherwise generate no income, or even cost money to get rid of, improves the profitability and energy balance of biogas production.Anaerobic lagoons produce biogas from manure, while biogas reactors can be used for manure or plant parts. Like landfill gas, biogas is mostly methane and carbon dioxide, with small amounts of nitrogen, oxygen and hydrogen. However, with the exception of pesticides, there are usually lower levels of contaminants.附录二：中文译文天然气来自维基百科，自由的百科全书作其他用途,见天然气(区别)。天然气是一种自然产生的烃类气体的混合物，主要由甲烷组成， 1其他碳氢化合物的浓度高达20（通常乙烷）以及少量的杂质，如二氧化碳。天然气用途广泛并且是一个重要能源应用在许多包括采暖建筑，机组发电，提供热和力量给产业和车并且也是一种制造产品的原料 例如肥料。 天然气在地下深处的天然岩层中被发现，或在煤层中，和其他油气藏，如甲烷水合物。生物活动所产生和热量这两个机制随着时间的推移形成了大多数天然气。生物气是由甲烷的生物体在沼泽，沼泽，垃圾填埋场，浅层沉积物中的活动产生的。在地球的更深处，在更高温度和压力的条件下，被埋藏的有机材质形成了地藏天热气在天然气可以使用作为燃料之前 ，它必须经过加工,清洗和清除杂质包括包括水处理,让天然气满足市场的需求。天然气被加工后的产品包括乙烷，丙烷，丁烷，戊烷，和较高分子量的烃类，硫化氢（可转换成纯硫），二氧化碳，水蒸气，偶尔会有氦气和氮气。天然气经常简单地不拘形式地被指气体，特别是当与其他能源比较时例如石油或煤炭。 天然气在 19 世纪，天然气通常被作为一种石油生产而产生的副产品，自小而轻的碳链溶解出来，作为提取液从内到外减小储藏器的压力，类似于打开一瓶苏打汽水所排放的二氧化碳那样。在在活动中的油田中，不需要的天然气是被作为一个问题来处理。如果在天然气井口附近没有市场的话，它是毫无价值的除非用管道输送到终端用户那里。在 19 世纪和 20 世纪初，这样不需要的气体在油田通常被烧掉了 今天，不需要的气体(或没有市场的搁浅的气体)常常与石油开采相关的经常被返回注射到油井中。在等待一个可能的未来市场的形成或者再增加压力使其相变，可以增强从其他油井提取率。在有较高天然气需求的地区（例如美国），当经济上可行的话会铺设管道把天然气从出口井输送到用户手上。另外一种可能性是出口液体天然气。气液转换是一种发展中的技术，可以通过开发二次世界大战期间的德国的费-托合成过程把不能送出的天然气合成汽油，柴油或者别的能源。这种燃料可以运到用户通过传统的管道和加油机，支持者声称 GTL 燃料比可比石油燃料干净。主要的大多数国际石油公司进入一个GTL生产的高级阶段，在卡塔尔的GTL厂2010年以前预定的产量具有世界级规模的（14万桶（22,000立方米）的一天）。天然气可以关联”（在石油领域）或“非”（孤立在天然气领域），而且还发现在煤层（煤层气）。天然气有时含有大量的乙烷，丙烷，丁烷，戊烷，甲烷作为燃料消费或化工原料商业使用之前需除去更重的碳氢化合物。在天然气运输之前，非烃如二氧化碳，氮，氦（很少），和硫化氢也必须被处理掉。商业上天然气是从油田和天然气田提取出来的。从石油井中提取的天然气被称为油井气或者半生气。天然气工业从越来越多的挑战资源类型：酸气，致密气，页岩气，煤层气等中提取天然气。世界上已经探明储气量最大的气田位于俄罗斯，储气量高达4.7571013米（1.681015立方英尺）。与俄罗斯天然气工业股份公司，俄罗斯经常是世界上最大的天然气提取者。世界上主要的已经探明的天然气资源是175400（2006），俄罗斯47570（2006）26370（2006），伊朗，卡塔尔，沙特阿拉伯，25790（2007）6568（2006）和阿拉伯联合酋长国5823（2006）。据估计，约有900000000000000立方米的“非常规”的天然气页岩气等，其中180000000000000立方米可以持续利用。反过来，来自麻省理工学院，博莱克威奇和能源部的许多研究者看到天然气将占据大部分的供热能源和发电能源在不远的将来。世界上最大的天然气田是卡塔尔海上北场，在那里估计有25000000000000立方米（91014cubic英尺）气体。在最佳提取的水平上足够用420年以上。第二最大的天然气田南帕尔斯气田在在波斯湾伊朗水域。位于旁边的卡塔尔北场，估计有储量为8至14000000000000立方米（2.81014至51014立方英尺）的气体由于天然气不是一个单纯的产品，当伴生气在超临界（压力/温度）条件下被提取出来时就如同储层压力下降一样，较高分子量的成分可能部分凝结后等温减压这个效果叫称为逆行缩合，这样形成的液体可能被作为气体储存器的毛孔被沉淀下来，处理这个问题的方法是重新注入干气凝析油，以保持地下压力并允许重新蒸发和冷凝萃取。更经常地，液体凝结在表面，并且其中一项天然气加工厂的任务就是收集这些凝析油，由此产生的液体被称