【作者】 赵瑞芬；

【导师】 范国梁；

【作者基本信息】 天津大学 ， 材料学， 2007， 硕士

【摘要】 随着柴油汽车保有量的急剧增加,其对环境的污染和能源消耗备受人们的关注。推广使用醇类燃料是解决柴油燃料短缺、减少柴油机排气污染的有效措施之一,然而羰基非常规污染物排放增加的问题是制约醇类燃料在柴油机上广泛使用的重要因素之一。因此,为了最大限度地降低醇类燃料发动机排气对人体的危害,有必要深入开展羰基类排放物的检测技术、排放规律等的研究。本文利用机外掺烧方法制备混合燃料,分别采用高碳醇和有机硝酸酯作为助溶剂与着火促进剂以提高柴油和乙醇的互溶稳定性及着火性。通过对乙醇柴油混合燃料的物理化学性质的测试证明,本试验所制备的混合燃料,其主要理化特性满足车用柴油的国家使用标准,为乙醇/柴油混合燃料的推广使用提供依据。在对羰基化合物进行的检测试验中,从两方面进行研究:1.根据目标物的特性及尾气采集要求,设计非常规排放物采样装置,比较分析了影响采集效率的各因素。结果表明合适的采样体积、流速,即采样温度保持47℃-50℃,两柱串联时采样效率达97%;2.利用高效液相色谱法/二极管阵列检测器对尾气中羰基化合物的衍生物进行定性定量分析,通过对分离条件的优化,实现了在一根色谱分离柱上,14min内对尾气中13种羰基化合物的同时测量。对此方法进行重现性、准确性的测试证明用此方法对尾气中羰基化合物测量可靠、有效。在发动机未作任何改动或优化调整的前提下,在YC6J180-21柴油机台架上对乙醇/柴油混合燃料进行试验。考察了发动机燃用混合燃料的经济型及动力性,结果表明,随着乙醇掺烧比例的增加,发动机动力性逐渐的降低,燃油消耗率增加;总体说来可以达到原机的功率。能量消耗率在小负荷时较柴油恶化,在中高负荷与原柴油相当。同时研究了燃料组成、发动机转速、负荷对羰基化合物排放特性的影响。其中最显著的污染物为乙醛,占总检测羰基化合物排放浓度的41.4%-60.7%,其次是甲醛6%-28.4%。羰基排放物中C1-C3的醛酮占主要部分,排放情况较传统燃油排放高2-3倍;羰基化合物的总体排放水平随乙醇添加量增多而增加;在高、低转速时排放较高,中等转速排放显著减少;负荷的增加时,羰基化合物的排放水平先增加后减少。对于排放浓度相对低的高碳数羰基化合物排放规律的变化不是很明显。更多还原

【Abstract】 With the sharply increasing of vehicle population, great attention was paid on the atmospheric environmental pollution and energy consume from vehicle. To resolve the shortage of diesel fuel and decrease exhaust emission from diesel engines, alternative ethanol has been one of advanced and effective measures. But one of key factors limited the wide application of fuel ethanol on diesel engine was the increasing un-regulating emission of carbonyl compounds. Therefore, it needs to take deep research on the measurement technique, emission rules with carbonyl compounds.Mixing technique prior to injection was used in this paper, and the higher alcohols and nitric acid ester were used as an additive and a fire accelerant, which they can individually improve the dissolvability of the ethanol in the diesel and enhance the cetane number. The physical and chemistry characteristics of the ethanol-diesel blend were studied. The result showed ethanol diesel blended fuel prepared met the nation application standard of fuel, and provided the reference.The measurement technology of carbonyl compounds was taken from two aspects. 1) Based on the nature of analyte and requirement of emission sampling, different factors of sampling efficiency were compared on the device which was designed to sample carbonyl compounds. The results indicated that the efficiency was up to 97% when sampling volume and flow was set, sampling temperature was hold 47℃-50℃and two cartridges were in series. 2) Through optimizing the separating conditions on high performance liquid chromatography/diode array detector, 13 kinds of aldehyde and ketone emissions from the diesel engine fueled with diesel or alcohol-diesel blends can be qualitatively and quantitatively analyzed. After optimizing the detecting condition, 13 kinds of aldehydes and ketones can be simultaneously determined on one chromatography column in 14 min. Reproduction and veracity experiments also confirmed the reliability and efficiency of this method.Comparisons of engine performance between ethanol-diesel blends and standard diesel in unmodified YC6J180-21 engines showed reductions in power that are approximately the same as the reductions in energy content of the blends relative to diesel fuel. In total carbonyl emissions, acetaldehyde was the most abundant, and accounted for 41.4% to 60.7%,and formaldehyde 6%-28.4%. C1-C3 carbonyl compounds were the main emissions, and three times than convient fuel emission. The total carbonyl emission increased with the increasing proportion of ethanol in diesel, and was higer at low or high speed/load than that at medium speed/load.更多还原