本文關(guān)鍵詞：基于激光誘導(dǎo)擊穿光譜煤質(zhì)分析儀的研制　出處：《山西大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 激光誘導(dǎo)擊穿光譜 數(shù)據(jù)預(yù)處理 激光功率穩(wěn)定 煤質(zhì)檢測 工業(yè)分析

【摘要】：激光誘導(dǎo)擊穿光譜(Laser-Induced Breakdown Spectroscopy, LIBS)是一種新興的激光燒蝕光譜分析技術(shù)。該技術(shù)基于原子光譜與離子光譜的波長與特定的元素一一對應(yīng),光譜強度與對應(yīng)元素的含量具有一定的量化關(guān)系的基本原理,利用高功率脈沖激光與物質(zhì)相互作用產(chǎn)生等離子體,采用光學(xué)系統(tǒng)對等離子體中的原子和離子發(fā)射光譜進行收集,根據(jù)對應(yīng)的光譜實現(xiàn)對物質(zhì)化學(xué)元素的定性與定量分析。該技術(shù)由于具有無需樣品預(yù)處理,可多元素同時分析,速度快,無輻射等優(yōu)勢,已經(jīng)逐漸被應(yīng)用到各行各業(yè)中。例如,在快速或在線煤質(zhì)檢測方面。目前國內(nèi)外一些單位已經(jīng)開展了LIBS應(yīng)用于燃煤電廠快速煤質(zhì)檢測方面的研究,并取得了一定的成果。但大多數(shù)還主要停留在實驗室階段,尚未真正實現(xiàn)工業(yè)化應(yīng)用和推廣。本文首先介紹了煤質(zhì)檢測的現(xiàn)狀,LIBS技術(shù)的先進性、基本原理、定量分析原理及技術(shù)特點；然后搭建了LIBS煤質(zhì)分析實驗裝置,系統(tǒng)的優(yōu)化了LIBS實驗裝置參數(shù),發(fā)展了脈沖激光功率穩(wěn)定系統(tǒng),使得脈沖激光功率長時間運行時始終位于預(yù)設(shè)的區(qū)間內(nèi),保證了長期測量的穩(wěn)定性；發(fā)展了合理的光譜預(yù)處理方法,并采用支持向量機和偏最小二乘法建立了煤質(zhì)預(yù)測模型；在以上研究的基礎(chǔ)上,開發(fā)了可快速檢測煤樣中灰分、揮發(fā)分、發(fā)熱量等工業(yè)指標的LIBS煤質(zhì)分析儀,并進行了工業(yè)現(xiàn)場測試,推動了該技術(shù)的實用化。論文就以上內(nèi)容分為以下四個部分：1.介紹了激光誘導(dǎo)擊穿光譜技術(shù)的應(yīng)用背景和現(xiàn)狀,詳細的了解了等離子體形成過程、等離子體元素譜線產(chǎn)生的過程和展寬機制、LIBS技術(shù)的特點。2.建立了LIBS煤質(zhì)分析實驗裝置,對裝置中的關(guān)鍵參數(shù)進行了系統(tǒng)的優(yōu)化,針對該技術(shù)在實用化當(dāng)中,激光器輸出的功率會由于長時間測量產(chǎn)生慢漂移的問題,我們建立了閉環(huán)負反饋式激光功率穩(wěn)定系統(tǒng),使得激光功率能夠穩(wěn)定在設(shè)定的區(qū)間,從而保證了長時間測量的穩(wěn)定性。3.構(gòu)建了實用有效的LIBS光譜數(shù)據(jù)預(yù)處理方法,包括采用洛倫茲與線型相結(jié)合的方式對光譜進行擬合并進行歸一化與篩選。采用支持向量機和偏最小二乘法建立煤炭灰分工業(yè)分析指標的定標模型,利用上述兩種模型對煤灰分值進行預(yù)測,預(yù)測的均方根誤差分別為4.4%和4.5%。4.研制了適用于化驗室分析的光電一體化的全自動激光煤質(zhì)分析儀,可在120s內(nèi)完成對煤樣的灰分、揮發(fā)分、發(fā)熱量等工業(yè)指標的測量。
[Abstract]:Laser induced breakdown spectroscopy (Laser-Induced Breakdown Spectroscopy, LIBS) is a new kind of laser ablation spectroscopy. The technique is based on atomic spectra and ion spectral wavelength and specific elements corresponding to the basic principle and content of spectral intensity corresponding to the elements with a certain quantitative relationship, using high power pulsed laser interaction with matter. The optical system to produce plasma, plasma atomic and ionic emission spectra were collected, according to the qualitative and quantitative analysis of chemical elements of the corresponding spectrum. This technique has no sample pretreatment, simultaneous multielement analysis, fast speed, no radiation and other advantages, has been gradually applied to all walks of life. For example, in the fast or online coal quality testing at home and abroad. Some units have carried out the application of LIBS in the coal-fired power plant soon Study on fast coal quality detection, and achieved certain results. But most are still in the laboratory stage, has not yet realize the application and promotion of industrialization. This paper introduces the present situation of coal quality testing, the basic principle of the advanced LIBS technology, quantitative analysis, principle and technical features; then experiments of LIBS coal quality analysis the optimization of the system parameters, LIBS experimental device, the development of pulse power system stability, the operation interval of pulse laser power long time always located in the default, to ensure a stable long-term development of measurement; spectrum pretreatment method is reasonable, and the establishment of the coal quality prediction model and partial least squares support vector machine; on the basis of the above research, the development of the rapid detection of the coal ash, volatile matter, LIBS coal analyzer calorific industrial index, and the The industrial field test, promote the practical technology. The above content is divided into the following four parts: 1. introduce the application background and the present situation of laser induced breakdown spectroscopy, detailed understanding of the plasma formation process, plasma spectral lines broadening mechanism of the process and the characteristics of LIBS technology,.2. established experiment LIBS device for coal quality analysis, optimization of the key parameters in the device, according to the technology in the practical, power output due to long time measurement of slow drift problem, we established a closed-loop negative feedback laser power stabilization system, the laser power can be stabilized in the set range, to ensure.3. long time stability measurement method to construct LIBS spectral data preprocessing is practical and effective, including the use of Lorenz and linear combination of spectra For fitting and normalization and screening. The calibration model was established index analysis of coal ash industrial support vector machine and partial least squares method to predict the ash score using the above two models, the root mean square error of prediction for photoelectric integration 4.4% and 4.5%.4. was developed for laboratory analysis respectively full automatic laser coal analyzer. Can complete the ash of coal samples in 120s volatile, measuring the calorific value and other industrial index.

【學(xué)位授予單位】：山西大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN249;O433

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本文編號：1402307