基于激光诱导击穿光谱技术的原油元素定量分析研究

发布时间：2018-04-09 04:34

  本文选题：激光诱导击穿光谱　切入点：定量分析　出处：《长江大学》2015年硕士论文

【摘要】：激光诱导击穿光谱技术(laser induced breakdown spectroscopy, LIBS)是激光应用领域中的一种分析技术。LIBS使用脉冲激光蒸发少量的样本生成等离子体,处于激发态的物质(如原子、离子)发射出的光谱信息用于元素的定性与定量分析。原油及输油管道污垢中微量元素会腐蚀反应器和输油管道,造成严重的后果。本文以LIBS的技术原理及实际应用为基础,针对灰化后的原油样品及输油管道污垢中的元素开展了以下研究。根据原油和输油管道污垢中微量元素的危害及LIBS分析技术的特点来说明课题的来源及研究意义,简述LIBS技术的发展历程、优缺点及工作原理。从应用领域,检测能力及设备开发三个方面介绍LIBS技术在国内外应用方面的研究现状。对课题研究时使用的仪器——-RT100-HP LIBS及其功能进行简介。提出“散点图”分析和处理异常数据的方法,并对处理的效果进行分析说明。引入相关系数R作为检验回归分析结果是否有意义的判断依据,再通过实验数据分析讨论激光脉冲能量、照射光斑大小及探测延迟时间等仪器参数对光谱强度的影响。分析结果表明,在一定激光脉冲能量强度范围内,光谱强度与激光脉冲能量成正比；激光脉冲能量等其它条件不变时,随着激光照射光斑直径的增加,光谱强度逐渐减小；当延迟时间大于1微秒时,光谱强度随延迟时间的增加而逐渐降低。详细介绍LIBS的两个应用实例.在LIBS分析灰化后的原油一例中,以Na I588.995nm为主要分析对象。首先简单概述光谱背景的由来及处理方法。再利用降噪后的积分强度、峰值强度作定标曲线对Na进行定量分析；实验中选取Na I588.995nm、Mg Ⅰ 285.213nm、Al Ⅱ 308.215 nm、K Ⅰ 404.414nm、Ca Ⅰ 396.847nm、FeⅡ273.955nm作为分析线对原油样品灼烧后的6种元素进行分析,测得其含量分别为5.92%、0.32%、2.12%、0.19%、0.68%、16.86%,并得出了定标曲线的线性相关系数及检出限。结果表明,选用积分强度作定标曲线效果更好；激光诱导击穿光谱技术测量结果与X射线荧光光谱技术对Na的测量结果相对误差为6.28%；激光诱导击穿光谱技术可应用于对灰化后原油金属元素进行定量分析。在LIBS分析输油管道污垢一例中,以Mg为研究重点,首先将谱线Mg I285.213nm降噪前、后的积分强度、峰值强度作定标曲线的测量结果进行分析对比。再讲解重叠光谱的两种分解方法—高斯线型拟合分峰和洛伦兹线型拟合分峰。最后对比Mg Ⅱ 279.553nm、Mg Ⅱ 280.270nm和Mg Ⅰ 285.213nm三条谱线作定标曲线的分析效果。结果表明洛伦兹线型更适合对重叠光谱进行拟合分峰,采用相对强度大且降噪后的谱线的积分强度作定标曲线更适合对元素进行定量分析。在文章的最后对全文做了总结,并对后期的工作做了几点计划。
[Abstract]:Laser induced breakdown spectroscopy (Libs) is an analytical technique in the field of laser applications. Libs uses pulsed laser to vaporize a small amount of samples to form plasma, which is in an excited state, such as atoms.The emitted spectral information is used for qualitative and quantitative analysis of elements.Trace elements in crude oil and oil pipeline dirt will corrode reactors and pipelines, causing serious consequences.Based on the technical principle and practical application of LIBS, the following researches have been carried out on the ashes of crude oil samples and the elements in oil pipeline fouling.According to the harm of trace elements in the dirt of crude oil and oil pipeline and the characteristics of LIBS analysis technology, this paper explains the source of the subject and its research significance, and briefly describes the development course, advantages and disadvantages and working principle of LIBS technology.This paper introduces the application of LIBS technology in China and abroad from three aspects: application field, detection ability and equipment development.This paper introduces the instrument used in the research-RT100-HP LIBS and its functions.This paper puts forward the method of analyzing and dealing with abnormal data by "scatter plot", and analyzes and explains the effect of processing.The correlation coefficient R is introduced as the basis for judging whether the regression analysis results are meaningful or not. The influence of the parameters of laser pulse energy, spot size and detection delay time on the spectral intensity is discussed through the analysis of experimental data.The results show that the spectral intensity is proportional to the laser pulse energy in a certain range of laser pulse energy, and the spectral intensity decreases gradually with the increase of laser spot diameter when other conditions such as laser pulse energy are not changed.When the delay time is more than 1 microsecond, the spectral intensity decreases with the increase of delay time.Two application examples of LIBS are introduced in detail.In the case of LIBS analysis of crude oil after ashing, Na I588.995nm was used as the main analysis object.Firstly, the origin and processing method of spectral background are briefly summarized.The calculated integral intensity and peak intensity were used as calibration curves for quantitative analysis of Na, and mg 鈪，

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