本文關(guān)鍵詞：可調(diào)諧半導(dǎo)體激光光譜儀對(duì)高溫下CO的測(cè)量研究　出處：《上海大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

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【摘要】：人類工業(yè)的快速發(fā)展帶來了能源枯竭以及空氣污染等嚴(yán)重問題,其中由化石燃料燃燒產(chǎn)生的CO氣體不僅能夠與人體血紅蛋白結(jié)合造成機(jī)體缺氧而中毒,排放到大氣中也會(huì)對(duì)OH自由基產(chǎn)生消耗,極大降低了大氣的自凈化能力。對(duì)工業(yè)燃燒爐內(nèi)CO濃度和溫度的測(cè)量能夠?qū)崟r(shí)監(jiān)測(cè)燃料的燃燒效率,同時(shí)也能抑制尾氣中CO的濃度。與傳統(tǒng)的氣體測(cè)量方法相比,可調(diào)諧半導(dǎo)體激光光譜技術(shù)具有選擇性好、抗干擾能力強(qiáng)、靈敏度低、快速、實(shí)時(shí)在線檢測(cè)的優(yōu)勢(shì),能夠?qū)怏w組分濃度、溫度、壓強(qiáng)、氣體流速進(jìn)行測(cè)量,在工業(yè)領(lǐng)域得到了廣泛的應(yīng)用。結(jié)合波長(zhǎng)調(diào)制技術(shù)可以有效去除由于TDLAS光電器件產(chǎn)生的白噪聲,極大優(yōu)化了測(cè)量檢測(cè)線,拓寬了該技術(shù)在痕量氣體濃度檢測(cè)領(lǐng)域的應(yīng)用。本文以波長(zhǎng)調(diào)制可調(diào)諧半導(dǎo)體激光吸收光譜技術(shù)為理論指導(dǎo),自主搭建了一套用于高溫條件下CO測(cè)量的實(shí)驗(yàn)裝置,主要取得了以下成果:1)通過對(duì)高斯、洛倫茲、福吉特吸收線型函數(shù)進(jìn)行機(jī)理分析,得到了在常壓條件下,使用洛倫茲線型函數(shù)對(duì)實(shí)際吸收線型進(jìn)行模擬最為合理。2)使用傅里葉變化對(duì)洛倫茲線型函數(shù)的n階導(dǎo)數(shù)進(jìn)行理論推導(dǎo),給出了同時(shí)考慮波長(zhǎng)調(diào)制和功率調(diào)制下洛倫茲線型函數(shù)的二次諧波信號(hào)表達(dá)式,為后續(xù)的最小二乘法擬合待測(cè)信號(hào)提供了理論依據(jù)。3)結(jié)合HITRAN數(shù)據(jù)庫,對(duì)化石燃料產(chǎn)生的尾氣吸收峰位置進(jìn)行模擬,最終確定選取干擾小、強(qiáng)度大且適用于DFB激光器的R14線(1563.6nm)作為CO的待測(cè)吸收線。4)自主搭建一套同時(shí)包含激光調(diào)制系統(tǒng)、標(biāo)氣配制系統(tǒng)、高溫系統(tǒng)、信號(hào)探測(cè)解調(diào)系統(tǒng)以及信號(hào)采集儲(chǔ)存系統(tǒng)的實(shí)驗(yàn)裝置,該裝置基于波長(zhǎng)調(diào)制可調(diào)諧半導(dǎo)體激光光譜技術(shù),使用DFB激光器作為可調(diào)諧半導(dǎo)體激光器,以高頻正弦信號(hào)作為調(diào)制信號(hào),使用鎖相放大器對(duì)測(cè)量信號(hào)進(jìn)行解調(diào),得到最終的二次諧波作為定量的標(biāo)準(zhǔn)。5)實(shí)驗(yàn)采取標(biāo)定定量法,通過建立水汽背景庫扣除CO吸收峰附近的水汽干擾信號(hào),并以CO標(biāo)準(zhǔn)吸收庫作為標(biāo)定對(duì)待測(cè)組分中CO的濃度進(jìn)行標(biāo)定定量。6)最終的測(cè)量結(jié)果包括水汽、CO濃度和溫度值,其中CO測(cè)量的線性動(dòng)態(tài)范圍為0~10%,檢測(cè)限在100ppm量級(jí);溫度測(cè)量范圍為300~1000°C;水汽、CO濃度以及溫度的測(cè)量誤差分別在5%、5%、10%以內(nèi)。7)本套實(shí)驗(yàn)裝置基于波長(zhǎng)調(diào)制可調(diào)諧半導(dǎo)體激光光譜技術(shù),具有抗干擾、低檢測(cè)限、實(shí)時(shí)在線的特點(diǎn),且適用于高溫等惡劣工作條件下,在煤發(fā)電、鋼鐵冶煉等領(lǐng)域具有極大的應(yīng)用潛力。
[Abstract]:The rapid development of human industry has brought serious problems such as energy depletion and air pollution. The CO gas produced by fossil fuel combustion can not only combine with human hemoglobin but also lead to hypoxia and poisoning. Emissions into the atmosphere will also produce consumption of OH free radicals, greatly reducing the self-purification capacity of the atmosphere. The measurement of CO concentration and temperature in industrial combustion furnace can monitor the combustion efficiency of fuel in real time. Compared with the traditional gas measurement method, the tunable semiconductor laser spectrum technology has good selectivity, strong anti-jamming ability, low sensitivity and fast. The advantage of real-time on-line detection is to measure the concentration, temperature, pressure and velocity of gas components. Combined with wavelength modulation technology, white noise generated by TDLAS optoelectronic devices can be effectively removed, and the measurement line can be greatly optimized. The application of this technology in the field of trace gas concentration detection is broadened. The wavelength modulated tunable semiconductor laser absorption spectroscopy is used as the theoretical guide in this paper. A set of experimental equipment for CO measurement under high temperature was built independently. The following results were obtained: 1) the mechanism of the absorption line function of Gao Si, Lorenz and Fugit was analyzed by means of the absorption line function of Gao Si, Lorentz and Fugit. It is obtained that under normal pressure, it is most reasonable to use Lorentz linear function to simulate the actual absorption line. 2) Fourier variation is used to deduce the n-order derivative of Lorentz linear function. The second harmonic signal expression of Lorentz linear function considering both wavelength modulation and power modulation is given. It provides a theoretical basis for the following least square method to fit the signal to be tested. 3) combined with the HITRAN database, the location of the tail gas absorption peak produced by fossil fuel is simulated, and the selection is determined with small interference. R14 line (1563.6nm), which is high intensity and suitable for DFB laser, is used as the absorption line of CO. (4) A set of simultaneous laser modulation system, standard gas preparation system and high temperature system are built independently. Signal detection and demodulation system and signal acquisition and storage system experimental device, this device is based on wavelength modulation tunable semiconductor laser spectrum technology, using DFB laser as tunable semiconductor laser. The high frequency sinusoidal signal is used as the modulation signal and the phase-locked amplifier is used to demodulate the measured signal. The final second harmonic is obtained as the quantitative standard. 5) the calibration method is adopted in the experiment. The water vapor interference signal near the CO absorption peak is deducted by establishing the water vapor background pool. The CO standard absorption library is used as calibration method to calibrate the concentration of CO in the measured components. 6) the final measurement results include the concentration of CO in water vapor and the temperature value. The linear dynamic range of CO measurement is 0 ~ 10 ppm and the detection limit is 100 ppm. The temperature measurement range is 300 鈩，

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