【作者】 丁一；

【导师】 张百良；

【作者基本信息】 河南农业大学 ， 农业生物环境与能源工程， 2007， 博士

【摘要】 能源是人类文明的先决条件。能源安全就是实现一个国家或地区国民经济持续发展和社会进步所必需的能源保障。由于能量含量高和液体性质,石油在化石燃料中相对来说占有更重要的地位。狭义的能源安全指的是石油安全。除供应安全以外,石油安全还存在价格风险。世界上已经发生过三次石油危机,石油危机对世界经济造成了不利影响,尤其是对那些进口石油依存度高的国家。本世纪以来没有发生过石油供应中断导致的石油危机,但是国际石油市场中原油价格却一路攀升。2006年最高曾经涨到每桶78美元。国际石油安全问题出现的根本原因在于石油资源和生产与石油消费在地域上存在严重的差异。2005年剩余探明石油储量中,中东地区占61.9%,其产量也占全世界总产量的31%。但是,2005年世界石油消费量排名前8位的国家是美国、中国、日本、俄罗斯、德国、印度、韩国、加拿大,除俄罗斯外,都是石油净进口国,这8个国家的石油消费量占全世界石油总消费量的54.4%。石油资源(生产)与消费市场在地理上的严重不均匀分布是客观存在的事实,只要石油仍然是液体燃料的主要来源,石油安全问题必然长期存在。我国自从1993年成为石油净进口国以来,石油进口量逐年提高。2006年我国原油进口量达1.45亿吨,花费超过664亿美元,同年我国成品油进口量为3638万吨,总计155.51亿美元。我国2006年的石油进口依存度已经超过40%。我国面临的石油安全形势越来越严峻。解决石油安全问题的途径有很多,具体措施包括建立战略石油储备、保障石油进口、稳定国内石油产量、推广节能技术和设备、发展生物质液体燃料替代石油消费。这些措施各有利弊,侧重点也不同。就目前的发展条件看,没有任何一项措施能够单独地彻底解决石油安全问题,必须互相配合,互相补充,才能够最大限度地降低石油安全的风险。在这些解决石油安全问题的措施中,大力发展生物质液体燃料是解决我国石油替代保障石油安全的必然途径。目前生物质液体燃料主要是指燃料乙醇和生物柴油。以淀粉等糖类原料生产燃料乙醇的技术已经是完全成熟的技术,而以纤维素秸秆为原料的生产技术尚有一些难点未能克服,比如:原料的预处理困难、戊糖发酵问题、纤维素酶的价格高昂等。生物柴油的生产技术已经基本上成熟,但是化学法存在工艺复杂、能耗高、色泽深、酯化产物难于回收、成本高、生产过程有废碱液排放等缺点;生物酶法存在反应时间长、生物酶价格较高、酶的使用寿命短等问题。发展生物质液体燃料的最关键问题在于生产原料的供应。由于粮食安全是比能源安全更加重要的国家安全问题,而且我国人均耕地面积远远低于世界平均水平,我国要发展生物质液体燃料必须选择非粮食作物的能源作物和能源植物作为生产原料,并尽可能地利用非耕地进行生产。在我国,燃料乙醇的理想生产原料是甜高粱秸秆、木薯、和甘薯;生物柴油的理想生产原料是油菜籽、麻疯树和黄连木等富油木本植物。这些原料都可以不占用正常生产粮食作物的耕地,而且单位面积的燃料乙醇或生物柴油的产率较高。我国目前燃料乙醇的年产量为102万吨,以玉米和小麦等粮食作物为主要生产原料,而生物柴油的产量很小,主要生产原料是废弃动植物油脂。即使我国2005年的主要农产品全部用来生产生物质液体燃料,其替代石油的数量也远远低于当年的石油消费量。如果要发展生物质液体燃料,就必须在非耕地上发展非粮食作物,这几乎是一个全新的产业。在任何一块土地上,生物质液体燃料的产量与可利用的土地面积和原料的燃料乙醇或生物柴油产率呈正相关关系,原料的燃料乙醇或生物柴油产率则与原料的单位面积产量、含糖(油)率、和转化率呈正相关关系。我国能够用来种植能源作物和能源植物的土地资源主要有甜高粱替代高粱和部分玉米的耕地、南方冬闲田、退耕还林的土地、油料林地、和后备土地。按照这些土地资源的数量和质量计算,我国生物质液体燃料的最大可能产量为2.3～2.5亿吨左右,能够替代石油约2.7万吨,依然低于2005年的石油消费量。因此,虽然发展生物质液体燃料是解决我国石油安全问题的理想途径,但是受土地资源量的限制,仅仅依靠生物质液体燃料的发展绝对不能完全解决我国的石油安全问题。从替代效果和我国汽油柴油消费量的比例来看,我国更应该大力发展生物柴油。但是,从原料的种类来看,燃料乙醇的生产原料基本上都是农作物,而生物柴油的生产原料则大多是油料木本植物,其开发成本、见效时间、不确定性、收获难度都要高于农作物,所以我国发展生物柴油的难度要高于燃料乙醇。在发展生物柴油时应该对这些困难做好准备,才能使生物质液体燃料能够在品种间实现协调发展,并在替代石油方面取得更好的效果。我国的生物质液体燃料刚刚起步,要使这一新兴产业迅速发展并能真正缓解石油安全问题,国家应该大力支持生物质液体燃料的发展,在立法层面,应该明确规定:改革、完善管理体制,建立协调高效的领导、管理体系;厉行法律赋予的职责,尽快建立经济补贴和激励机制;制定鼓励科研开发的政策,鼓励科研人员到农村、企业进行项目研发、试验示范;制定生物能源开发与粮食安全、环境安全目标一致的保障法规,既鼓励能源作物的种植,又不与粮争地;制订生物质液体燃料自由进入成品油销售体系的规定,使符合质量要求的生物质液体燃料能够自由进入燃料销售体系。另外,我国还应该尽快开展生物质液体燃料的原料资源普查并制定区域发展规划,以及重视生物质液体燃料项目的试验和示范。更多还原

【Abstract】 Energy resources are the precondition for human civilization.Energy security is the guarantee of energy supply that is needed by the economic development and social progress over a country or a region.Because of the high energy content and liquid property,oil takes a more important position in all fossil fuels.Besides supply security,oil security all considers price risks.There have been three oil crises in the world history.Oil crisis caused negative impacts to the world economy,especially for those countries with higher dependence on imported oil. There is no oil crises caused by supply intermission in the new century,but the price of crude oil in the world oil market is ascending continuously.In 2006,the price of crude once reached a peak of 78 US dollars per barrel.The fundamental reason of the existence of international oil security is the great difference of geographic distribution of oil resources and consumption.In the remaining proven oil reserves in 2005,61.9%is located in Middle East.The oil production in the region is 31%of the total oil production in the world.However,the top 8 countries in oil consumption are USA,China,Japan, Russia,Germany,India,Korea,and Canada,7 of 8 countries are net oil import countries,except Russia.Because the asymmetric distribution of oil resource and consumption is the existing fact, the problem of oil security will exist as long as oil is still the main source of liquid fuel.China became the net oil import country in 1993,and amount of imported oil are increasing year after year.In 2006,the total amount of imported crude oil is 145 Mt,with expenditure of more than 66.4 billion US dollars.In the same year,China imports 36.38 Mt of oil products, with expenditure of 15.55 billion US dollars.The dependence on imported oil is over 40%.Many approaches can be applied to mitigate the oil security problem,including establishment of strategic oil reserve,ensuring oil import,increasing domestic oil production,disseminating energy-saving technologies and equipment,and developing biomass-based liquid fuel.All of these approaches have their own advantages and disadvantages,and none of them can solve the problem of oil security independently.Development of biomass-based liquid fuels is the certain approach to substitute oil and to guarantee the oil security.At present,the biomass-based liquid fuels are mostly fuel ethanol and bio-diesel. Technology of fuel ethanol production from saccharine material such as starch is already mature. The technology of fuel ethanol production from cellulose(straw)still has some obstacles to overcome,e.g.difficulties in pre-treatment of raw material,problem of pentose fermentation,high cost of cellulose enzyme,etc.Technologies of bio-diesel production are basically mature. However,the chemical method has such disadvantages as complicated procedure,high energy consumption,dark color of product,high cost,and pollutant disposal.Biological enzyme method has such disadvantages as long reaction time,high cost of biological enzyme,and short life of enzyme.Material production is the key to development of biomass-based liquid fuels.Because the food security is more important than energy security,and plantation field per capita is much less than the world average,China will have to select non-food crop and trees to be the material for developing biomass-based liquid fuels.For China,the ideal materials for fuel ethanol production are sweet sorghum stem,cassava,and sweet potato;and for bio-diesel rape seed and woody plant such as Jatropha curcas.Production of these materials does not engross the plantation field for food crops,and fuel ethanol or bio-diesel production rate per unit area is relatively high.Currently,the annual production of fuel ethanol is 1.02 Mt,with material of food crops such as maize and wheat;the production of bio-diesel is small,with material of wasted animal or plant. grease.Even if all the major agricultural products in 2005 were used to produce liquid fuel,the substitution for oil would still much less than the oil consumption in the same year.On any piece of land,the production of biomass-based liquid fuel is positively relative to the available land area and fuel ethanol or bio-diesel production rate per unit area.The fuel ethanol or bio-diesel production rate per unit area is positively relative to the material yield and saccharine content or oil content of material.In China,the land resources that can be used to produce material for liquid fuels are:plantation field of sorghum and maize that can be substituted by sweet sorghum,winter idle field in South China,sloping landthat is needed to convert into forest, oil plant forestry land,and in-support plantation land.Based on the quantity and quality of these land resources,the maximum of possible production of biomass-based liquid fuel is 220 Mt, which can substitute crude oil of 270 Mt,less than the oil consumption in 2005.Therefore, development of biomass-based liquid fuel is one of the good approaches to solve the problem of oil security in China,but because of the restriction of land resource,bare dependence on biomass-base liquid fuel can not solve the problem.In terms of substitution effect and the ratio of gasoline and diesel consumption,China should vigorously develop bio-diesel rather than fuel ethanol.However,the materials for fuel ethanol production are agricultural crops,while the materials for fuel ethanol production are oil wood plants,of which the cost and harvest difficulties are higher than crops.These difficulties must be fully considered in the process of developing bio-diesel in order to realize the coordinated development between different products of biomass-based liquid fuel.At the initial phase of biomass-based liquid fuel development in China,the government must give great supports to the new industry.Laws and regulations should clearly prescribe:reform and perfect the administration system,establish efficient leading and management system;strictly enforce the responsibilities invested by the laws,establish the subsidy and other financial incentive mechanism as soon as possible;encourage the research and development of technology and engineering;constitute laws or regulations to ensure the biological energy development in line with the targets of food security and environment security,encourage the plantation of energy corps and plants on the condition of no confliction with food crop production;establish the laws or regulations to enable qualified biomass-based liquid fuels to freely enter the fuel distribution system.In addition,China should carry out a national survey on material for biomass-based liquid fuel as soon as possible,and formulate the regional development planning.China should also recognize the importance of experiment and demonstration of biomass-base liquid fuel project.更多还原