【作者】 刘颖；

【导师】 方俊；

【作者基本信息】 中国科学技术大学 ， 安全科学与工程， 2021， 硕士

【摘要】 近些年来,空气污染问题已经严重影响到人类的生产生活,化石燃料燃烧产生的烟颗粒是主要的污染源,而清洁替代燃料能够有效降低燃料碳烟颗粒排放。含氧燃料是目前清洁燃料领域的研究热点,其减排能力主要由分子结构及性质决定。因此,研究含氧混合燃料分子性质的作用机制及其对燃料发烟趋势的影响作用,对评价燃料发烟趋势以及发展高效选择制备清洁燃料的研究手段具有重要意义。本文选用柴油和8种含氧化合物为实验对象,设计并开展烟点测量实验,获取了含氧化合物在不同掺混体积比下与柴油混合燃料的烟点。应用氧修正发烟指数(OESI)归一化指标量化燃料的发烟趋势。该指标值随含氧添加剂掺混体积比的增加呈现指数衰减趋势。依据衰减指数系数给出了混合燃料的发烟趋势顺序:乙醇/柴油<碳酸二甲酯/柴油<二甲氧基甲烷/柴油<丁酸甲酯/柴油<正丁醇/柴油<甲基叔丁基醚/柴油<癸酸甲酯/柴油<顺丁烯二酸二丁酯/柴油。基于影响燃料发烟趋势的分子性质因素(含氧量、含氧官能团、碳数和H/C比),依据含氧化合物分子结构及混合燃料动力学反应机制,提出了新的影响指标,分别是含氧量作用指标、碳数作用指标和H/C 比作用指标。通过分析8种混合燃料分子中O、C原子影响产烟的作用数,建立了作用指标的计算公式。利用相对权重分析,得到了 3个作用指标对被测混合燃料(顺丁烯二酸二丁酯/柴油除外)发烟趋势的影响优先级顺序为:碳数作用指标>含氧量作用指标>H/C 比作用指标。综合采用作用指标值及其对燃料发烟趋势的影响优先级顺序,能够有效评价大部分被测混合燃料的发烟趋势,特别对于同种类含氧添加剂的柴油混合燃料,采用这种评价方法能得到合理的解释。更多还原

【Abstract】 In recent years,air pollution has posed a big threat to the environment of our human beings.The soot particles produced by combustion of the fossil fuels are the main source of air pollution,while clean alternative fuels can address this serious problem.Oxygenated fuel has attracted attention in the research field of clean candidates,which emission reduction ability is mainly determined by its molecular structure and properties.Therefore,it is of great significance to investigate the affecting mechanism of molecular properties of the oxygenated blended fuels upon the sooting tendency.This study will provide a guide for the evaluation of the sooting tendency of blended fuels and development of the efficient selection and preparation of clean alternative fuels.In this paper,firstly,diesel fuel and eight kinds of oxygenated compounds were selected,and the smoke-point measurement device were designed and used to obtain the smoke-point values of oxygenated compounds blended with diesel fuel at different blending volume percentages.Normalized Oxygen Extended Sooting Index(OESI)was introduced to quantify the sooting tendency of fuel.The index values incorporating the smoke-point values were established to decrease with increasing blending volume percentage of the oxygenated additives in blends,following an exponential fitting relationship.Then the resulting exponents were used to quantify the sooting tendencies of the blended fuels,which were shown to increase in the order:ethanol/diesel<dimethyl carbonate/diesel<dimethoxy methane/diesel<methyl butanoate/diesel<n-butanol/diesel<methyl tertiary-butyl ether/diesel<methyl decanoate/diesel<dibutyl maleate/diesel.Furthermore,based on the molecular property factors of oxygen content,oxygenated functional group,carbon number,and H/C ratio which affect the sooting tendency of the blended fuels,three affecting indicators were proposed,taking into account the molecular structure of oxygenates and the combustion mechanism of blended fuels.So-called indicators were termed the affecting oxygen content,affecting carbon number and affecting H/C ratio.A calculation algorithm of three affecting indicators was established by the functional numbers of oxygen and carbon atoms of blended fuel molecules on the sooting tendency.Additionally,priority order of three affecting indicators on the sooting tendency of the tested blended fuels(except dibutyl maleate/diesel blend)should follow the results by Relative Weight Analysis,that decreased in the order of affecting carbon number>affecting oxygen content>affecting H/C ratio.Finally,comprehensive combination of three affecting indicator value and their priority order was shown to be able to evaluate the sooting tendency of most of the tested blended fuels effectively,especially that of diesel blended fuels with the same type of oxygenated additives could be reasonably interpreted by this evaluation method.更多还原